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Resilience: Awareness: Robotics: Testbeds: Type: Year:


Strategies for the Design and Operation of Resilient Extraterrestrial Habitats

Author(s): S.J. Dyke, K. Marais, I. Bilionis, J. Werfel, R. Malla
Details: Proc. SPIE Smart Structures + Nondestructive Evaluation Conference, March 22-26, 2021

Description: This keynote paper provides an overview of the RETH Institute, our approach to establishing the principles of resilience for complex systems such as SmartHab (deep space habitat systems). We discuss the challenges and the approach being taken to address this scientific grand challenge. We also discuss the three testbeds being developed to conduct our research.

Keywords: Safety, Autonomy, Robotics (General), Cyber-Physical Testing

Increasing the Payload Capacity of Soft Underactuated Robot Arms via Selective Joint Stiffening

Author(s): Bruder D., Graule M., Teeple C., and Wood R.
Details: Science Robotics

Description: This paper presents a model-based design approach to effectively increase the payload capacity of soft robot arms. The proposed approach uses localized body stiffening to decrease the compliance at the end effector without sacrificing the robot’s range of motion. This approach is validated on both a simulated and a real soft robot arm.

Keywords: Robotics (General), Manipulation

Sim-Suction: Learning a Suction Grasp Policy for Cluttered Environments Using a Synthetic Benchmark

Author(s): Li J. and Cappelleri D.
Details: IEEE Transactions on Robotics

Description: This paper presents Sim-Suction, a robust objectaware suction grasp policy for mobile manipulation platforms with dynamic camera viewpoints, designed to pick up unknown objects from cluttered environments. Sim-Suction-Pointnet generates robust 6D suction grasp poses by learning point-wise affordances from the Sim-Suction-Dataset, leveraging the synergy of zero-shot text-to-segmentation. The Sim-Suction policies outperform state-of-the-art benchmarks tested by approximately 21% in cluttered mixed scenes.

Keywords: Robotics (General), Manipulation

An information field theory approach to Bayesian state and parameter estimation in dynamical systems

Author(s): Hao K., and Bilionis I.
Details: arXiv, 2023

Description: The objective of this paper is to develop a scalable Bayesian approach to state and parameter estimation suitable for continuous-time, deterministic dynamical systems. We construct a physics-informed prior probability measure on the function space of system responses so that functions that satisfy the physics are more likely. In summary, the developed methodology offers a powerful framework for Bayesian estimation in dynamical systems.

Keywords: Fault Detection, Decision Making, Autonomy

A Resilience-Oriented Extra-Terrestrial Habitat Design Process

Author(s): J. Ulmer
Details: Master's Thesis at Purdue University, 2023

Description: In this thesis, the question of how habitats can be designed to protect human life far from Earth is discussed. The development of a control-theoretic approach to habitat resilience, a database of potential hazards to a habitat, metrics for resilience quantification, and simulation platforms for design verification allows for the proposition of a resilience-oriented habitat design process. This process takes the shape of a typical systems vee, and proposes a way to build resilience into the requirements development and design verification of extra-terrestrial habitats.

Keywords: Safety, Assessment, Damage

Establishing Standards for Lunar ISRU Structural Materials

Author(s): S.J. Dyke, A. Sharma, E.M. Mount, A. Bobet, J.A. Ramirez
Details: AIAA Journal, 2024

Description: Lunar structures will be exposed to one of the most extreme environments that has ever been considered for human settlements. No standards or building codes exist for design and construction of infrastructure on the Moon. Here we discuss the technical challenges in establishing such standards. Using the timely example of a landing pad on the Moon, we identify the gaps in both knowledge and testing capabilities that exist today.

Keywords: Safety, Structure

Establishing Standards for Lunar In Situ Resource Utilization Structural Materials

Author(s): Eliza Mount
Details: RETH Institute, May 2024

Description: This video discusses the technical challenges in establishing standards for lunar structures such as landing pads.

Keywords: Safety, Structure

SmartHab Resilient Design Research of the Resilient Extraterrestrial Habitat institute

Author(s): Eliza Mount
Details: RETH Institute, June 2023

Description: In this video we share the approach we are taking in the RETH institute to establish the knowhow to design resilience extraterrestrial habitats.

Keywords: SmartHab, Damage

Seismic Assessment of a Long-Term Lunar Habitat

Author(s): Patiño C., Ruiz S., Gomez D., Cruz A., Dyke S.J., and Ramirez J.
Details: Acta Astronautica

Description: This paper proposes assessing the structural response of a lunar habitat made of sulfur concrete covered with a regolith layer. The results of temporal analyses reveal that shallow moonquakes with return periods greater than 475 years can lead to the loss of the global stability of the structure. Consequently, the findings imply that seismic loads have the potential to impose unacceptable demands on lunar structures constructed from in-situ materials like sulfur concrete.

Keywords: Assessment, Damage, Safety

Preliminary approach to assess the seismic hazard on a lunar site

Author(s): Ruiz S., Cruz A., Gomez D., Dyke S.J., and Ramirez J.
Details: Icarus 2022

Description: This paper proposes a preliminary seismic hazard assessment imposed by shallow moonquakes. The hazard assessment is performed using the Probabilistic Seismic Hazard Analysis (PSHA) methodology, considering previous studies and theories regarding the seismic environment of the Moon. The developed seismic hazard assessment provides a preliminary approach for realistic scenarios to conduct structural designs that ensure the seismic performance of fully operational long-term lunar structures.

Keywords: Safety, Damage, Structure

Thermomechanical Real-Time Hybrid Simulation: Conceptual Framework and Control Requirements

Author(s): Montoya H., Dyke S.J., Silva C.E., Maghareh A., Park J., and Ziviani D.
Details: AIAA Journal, Article in Advance

Description: Real-time hybrid simulation (RTHS) is an enabling technology that has transformed engineering experimentation and helped researchers expand modeling capabilities. This paper discusses the development of a new thermomechanical RTHS framework and a systematic approach to determining RTHS control requirements. Through an illustrative example considering the influence of temperature on a lunar habitat, this paper demonstrates how to establish controller requirements for RTHS and demonstrate that this approach can be used to conduct RTHS on structures with thermomechanical loading.

Keywords: Cyber-Physical Testing, Thermal

Visual Communication of Potential Anomalies with Boundary Lines in ISS Mission Control

Author(s): Parsons P. and Zhang Z.
Details: IEEE VIS Conference Viscomm Workshop

Description: This presentation explores how visualization techniques be used to alert ISS flight controllers to potentially worrisome data values when continuous monitoring is not possible. As crews get farther away from Earth, significant communication delays will be inevitable, and as real-time support becomes less practical, more responsibility will need to be placed on autonomous monitoring and anomaly response.

Keywords: Assessment, Autonomy, Fault Detection

A force-mediated controller for cooperative object manipulation with independent autonomous robots

Author(s): Carey N.E., and Werfel J.
Details: The 16th International Symposium on Distributed Autonomous Robotic Systems (DARS) 2022, Montbéliard, France

Description: This paper considers cooperative manipulation by multiple robots assisting a leader, when information about the manipulation task, environment, and team of helpers is unavailable, and without the use of explicit communication. We present a controller, prove its stability, and demonstrate its utility through experiments with (a) an in-lab force-sensitive robot assisting a human operator and (b) a multi-robot collective in simulation.

Keywords: Robotics (General), Manipulation

SoMoGym: A toolkit for developing and evaluating controllers and reinforcement learning algorithms for soft robots

Author(s): Graule M.A., McCarthy T.P., Teeple C.B., Werfel J., and Wood R.J.
Details: IEEE Robotics and Automation Letters

Description: This paper introdudes the Soft robotsoffer, which hosts a variety of benefits over traditional rigid robots, including inherent compliance that lets them passively adapt to variable environments and operate safely around humans and fragile objects. To accelerate research in control and Reinforcement learning (RL) for soft robotic systems, SoMoGym (Soft Motion Gym) was developed, a software toolkit that facilitates training and evaluating controllers for continuum robots. SoMoGym provides a set of benchmark tasks in which soft robots interact with various objects and environments. It allows evaluation of performance on these tasks for controllers of interest, and enables the use of RL to generate new controllers. SoMoGym enables the use of RL for continuum robots, a class of robots not covered by existing benchmarks, giving them the capability to autonomously solve tasks that were previously unattainable.

Keywords: Robotics (General), Manipulation

Influence of Ductility on the Performance of Lunar Habitat Structures under Recurrent Disturbances

Author(s): Majlesi A., Behjat A., Shahriar A., Koodiani H., Dyke S., Ramirez J., and Montoya A.
Details: AIAA Journal, 2024

Description: This research examines how ductility affects the durability of lunar surface structures against recurring disturbances like moonquakes, micrometeorite impacts, and thermal cycles over an extended period. The findings revealed that structures with sufficient ductility capacity have a lower probability of sustaining severe damage or collapsing within a shorter time frame.

Keywords: Safety, Structure

Collective Transport of Unconstrained Objects via Implicit Coordination and Adaptive Compliance

Author(s): Carey N. E., and Werfel J.
Details: IEEE International Conference on Robotics and Automation, 2021

Description: This paper presents a decentralized control algorithm for robots to aid in carrying an unknown load. Coordination occurs solely through sensing of the forces on or movement of the shared load. The algorithm requires no direct communication between agents, and minimal knowledge of the system or task. We demonstrate the approach in simulation using a commercially available compliant robotic platform. This system could be utilized to assist a human astranout in moving a large or cumbersome object.

Keywords: Autonomy, Robotics, Perception, Manipulation, Navigation

Controlling Palm-Object Interactions via Friction for Enhanced In-Hand Manipulation

Author(s): Teeple C.B., Aktas B., Yuen M.C., Kim G.R., Howe R.D., and Wood R.J.
Details: IEEE Robotics and Automation Letters

Description: This paper presents how controlling the palm-object interaction for robotic hands enables access to different sets of motion primitives leading to in-hand manipulation and improved dexterity. Two design factors, friction and preload, can be actively controlled to enable 5-degree-of-freedom object motion within the hand. Variable-friction and variable-preload palms affects grip stability and enables on-the-fly switching between in-plane and out-of-plane manipulation modes. Objects than can be translated and pivoted within the hand by sequentially performing synchronized palm and finger actions.

Keywords: Robotics (General), Manipulation

Modular End-Effector System for Autonomous Robotic Maintenance & Repair

Author(s): Li J., Teeple C.B., Wood R.J., and Cappelleri D.J.
Details: IEEE International Conference on Robotics and Automation (ICRA) 2022

Description: This paper describes the development of a modular end-effector system (MEES) for autonomous robotic maintenance and repair tasks. The design consists of the following major components: Robot Side Mating Socket Module (RSMS), End-Effector Side Mating Socket Module (EEMS), the Modular Camera System (MCS), and Tool Holder/Changer unit. Multiple prototypes for each component were manufactured, tested, and evaluated resulting in the final concept. The MEES is demonstrated working with three different end-effectors and two different robots.

Keywords: Robotics (General), Manipulation

The Chain-link Actuator: Exploiting the Bending Stiffness of McKibben Artificial Muscles to Achieve Larger Contraction Ratios

Author(s): Bruder D. and Wood R.J
Details: IEEE Robotics and Automation Letters

Description: McKibben artificial muscles have the ability to generate forces without restricting motion to occur exclusively along the direction of actuation. This makes them attractive for a variety of applications including soft, wearable, and biomimetic robots. However, McKibben muscles have a restricted range of motion in the systems they actuate. This work introduces a novel ‘chain-link actuator’ that exploits the bending stiffness of McKibben muscles to achieve a larger range of motion. A static model that captures the relationship between pressure, displacement, and force is presented and validated on several real chain-link actuator systems.

Keywords: Robotics (General)

Shape Servoing of Deformable Objects using Model Estimation and Barrier Lyapunov Function

Author(s): Guthikonda V., and Dani A.P.
Details: IEEE Transactions on Mechatronics, 2024

Description: An adaptive shape servoing control method is presented in this article to manipulate a deformable object into a desired shape in 3-D. Simulations using a physical simulator and experiments using a robot platform are performed to validate the performance of the proposed controller on two different deformable objects.

Keywords: Robotics (General), Perception, Manipulation

Transformable Linkage-Based Gripper for Multi-Mode Grasping and Manipulation

Author(s): Kwon J., Bombara D., Teeple C., Lee J., Hoberman C., Wood R., and Werfel J.
Details: IEEE Robotics and Automation Letters, 2023

Description: Gripper hardware design often involves a trade-off between distinct and sometimes opposing goals (e.g., high grasping force vs. gentleness). To address this trade-off within a single device, this paper presents a multi-mode gripper with fingers that are scissor linkages, that can actively transform between three distinct modes by varying the number and locations of mechanical singularities. Gripper performance and the kinematic model are verified experimentally.

Keywords: Robotics (General), Manipulation

Sim-Suction Code Repository

Author(s): Juncheng Li
Details: Open Source Toolkit

Description: This GitHub package contains the Sim-Suction-API: a simulation framework to generate synthetic data and train models for robotic suction grasping in cluttered environments. It is used in the publication "Sim-Suction: Learning a Suction Grasp Policy for Cluttered Environments Using a Synthetic Benchmark."

Keywords: Robotics (General), Perception, Manipulation, Vision

A p-Refinement Method Based on a Library of Transition Elements for 3D Finite Element Applications

Author(s): Shahriar A. and Mostafa A.J.
Details: Mathematics

Description: This article presents a method to refine a 3D finite element mesh by increasing the polynomial order near the impact location. This paper develops a complete set of transition elements that facilitate the transition from first- to fourth-order Lagrangian elements, which facilitates mesh refinement following the protocols. The shape functions are computed and verified, and the interelement compatibility conditions are checked for each element case. To conclude the paper, two examples are presented to illustrate the applicability of this method.

Keywords: Assessment, Dormant, Damage

A General Procedure to Formulate 3D Elements for Finite Element Applications

Author(s): Shahriar A., Majlesi A., and Montoya A.
Details: Computation, 2023

Description: This paper presents a general procedure to formulate and implement 3D elements of arbitrary order in meshes with multiple element types. This procedure includes obtaining shape functions and integration quadrature and establishing an approach for checking the generated element’s compatibility with adjacent elements\’ surfaces. The formulation obtained for a 20-node element was in perfect agreement with the formulation available in the literature. Researchers and educators can use this procedure to efficiently develop and illustrate three-dimensional elements.

Keywords: Assessment

Reliability Modeling and Analysis of DC Space Microgrids

Author(s): Chebbo L., and Bazzi A.
Details: IEEE International Conference on DC Microgrids (ICDCM), 2023

Description: This work presents a space microgrid architecture for long-term space exploration and human presence in space. The paper presents different failure modes of the power system components, classifies their importance, and assesses the reliability of the system in multiple phases of operation and with different power management and control systems. Simulation results to assess the microgrid's reliability for various disturbance scenarios in a space habitat model are shown.

Keywords: Power, Fault Tolerance

Roles of Human and Robotic Agents Toward Operating a Smart Space Habitat

Author(s): Liu X., Behjat A., Dyke S.J., Whitaker D., Ramirez J., and Bilionis I.
Details: 52nd International Conference on Environmental Systems, July 16-20, 2023

Description: In this paper, two independent parallel scenarios are formed to compare the mission success with a human agent (HA) and a robot agent (RA). The outcome generated by the research scientist is the metric utilized to compare the performance of the agents, besides the equivalent costs to engage HA and RA.

Keywords: Assessment, Dormat, Robotics (General), Perception

Modeling and Operation of Microgrids for Deep Space Habitats Under Environmental Disturbances

Author(s): Chebbo L., Gultekin M.A., Bazzi A., Tomastik R., Pattipati K., Vaccino L., Azimi M., Lund A.
Details: IEEE Power and Energy Conference at Illinois

Description: This paper discusses power generation, transmission, distribution, storage, and power consumption, as well as power flow control and energy management in extraterrestrial microgrids that will be critical for deep space habitation. It also highlights the modeling, operational constraints and environmental challenges associated with extraterrestrial microgrids. To assess the effects of external disturbances, simulation results for different disturbance scenarios are shown using a space habitat model.

Keywords: Robotics (General), Manipulation

Neural Network-Based Pose Estimation Approached for Mobile Manipulation

Author(s): Chowdhury A., Li J., and Cappelleri D.J.
Details: Journal of Mechanisms and Robotics

Description: This paper illustrates two approaches for the mobile manipulation of factory robots using deep neural networks. The networks are trained using synthetic datasets unique to the factory environment. Approach I uses depth and red-green-blue (RGB) images of objects for its convolutional neural network (CNN) and Approach II uses computer-aided design models of the objects with RGB images for a deep object pose estimation (DOPE) network and perspective-n-point (PnP) algorithm. Recommendations of which approach is suitable under what circumstances are provided. The most suitable approach is implemented on a real mobile factory robot in order to execute a series of manipulation tasks and validate the approach.

Keywords: Robotics (General), Manipulation, Perception, Vision

A Reinforcement Learning Hyper-Heuristic In Multi-Objective Optimization With Application to Structural Damage Identification

Author(s): Tang J., Cao P., Zhang Yang., and Zhou K.
Details: Structural and Multidisciplinary Optimization, Volume 66, Issue 6

Description: Multi-objective optimization allows satisfying multiple decision criteria concurrently and generally yields multiple solutions. It has the potential to be applied to structural damage identification applications which are oftentimes under-determined. This article looks at formulating a reinforcement learning hyper-heuristic scheme to work coherently with a single-point search algorithm, which is then applied to an active damage interrogation scheme for structural damage identification where solution diversity/completeness and accuracy are critically important.

Keywords: Structure, Assessment, Damage

Lunar SmartHab Mission Operations and Crew Day-In-The-Life

Author(s): K. Pritchard, L. Vaccino, X. Liu, D. Whitaker, S. Dyke
Details: 52nd International Conference on Environmental Systems, July 16-20, 2023

Description: Toward the goal of developing realistic models and conducting useful trade studies, researchers, including those in the Resilient ExtraTerrestrial Habitat Institute (RETHi), depend on a shared notional understanding of how a smart planetary habitat (SmartHab) might look and operate. Models must originate from a baseline reference architecture for all mission characteristics. This project qualifies some general assumptions made about the daily activities and objectives of a SmartHab’s crew. It provides crew schedules to represent agent actions and availability through a day-in-the-life (DITL) but refrains from defining a concrete mission architecture that might infringe on simulation flexibility. Researchers and designers can use these DITL schedules and the content of this paper as a contextual reference point to inform future projects.

Keywords: Safety, Dormant

Simulation-Based Assessment of Hazardous States in a Deep Space Habitat

Author(s): L. Vaccino, K. Pritchard, M. Azimi, S. Dyke, A. Lund
Details: 52nd International Conference on Environmental Systems, July 16-20, 2023

Description: The goal of this paper is to investigate the use of the MCVT for studying a resilient SmartHab. By altering the initial conditions, certain input parameters, and repair prioritizations across several simulations for different disruption scenarios we demonstrate some scenarios in which simulation is an effective tool to support design. In the end, the lessons learned and the conditions that contribute to placing the SmartHab in an unsafe or unrecoverable state are identified, alongside with the best-practice emergency responses. These results form a framework for future studies into resilient SmartHab design via similar methods.

Keywords: Assessment, Trade Study, Pressure, Thermal

Development of a Damageable ECLSS and Interior-Environment Virtual Testbed Model to Simulate Future Resilient Deep Space Habitats

Author(s): S. Rhee, Z. Noble, J. Park, A. Lial, L. Collazo, D. Ziviani
Details: 52nd International Conference on Environmental Systems, July 16-20, 2023

Description: This paper will primarily focus on two ECLSS sub-systems namely the Active Thermal Control System (ATCS) and Interior Pressure Control System (IPCS). The ATCS encompassing a heat rejection loop (radiator-based) and a heat pump system based on a vapor compression cycle is designed to meet heating/cooling loads within the habitat to maintain the desired indoor temperature setpoint. The IPCS controls the interior total pressure by using an air supply line connected to a storage tank and safety valves. Additionally, breathable air generator model is combined with ATCS to control air quality and concentration. The behavior of coupled ECLSS and IE model has been verified under both nominal condition and damage scenarios that result in damage propagation on the components of ATCS and IPCS. Results of various cases with different initial damaged component will be compared. The results of analyses are presented and discussed along with future development plans.

Keywords: Safety Control, Pressure, Temperature

Performance evaluation of a vapor-compression-cycle based heat pump system for a lunar habitat under the impact of dust deposits on the coupled radiators

Author(s): Pan C.J., Ziviani D., and Braun J.E.
Details: Acta Astronautica, 2022

Description: Lunar dust is one of the dangerous environmental hazards causing serious problems for exploration activities. In this paper, a dynamic model is developed and used to study the impact of lunar dust on the performance of a thermal management system for a lunar habitat that is comprised of a vapor-compression cycle heat pump and a radiator loop. A synergetic design of a thermal management system, a power generation system and robotic maintenance system is proposed to achieve maximal mass reduction for a whole lunar habitat system.

Keywords: Power, Thermal

A Unifying View of Estimation and Control Using Belief Propagation with Application to Path Planning

Author(s): Palmieri F.A.N., Pattipati K.R., Fioretti G., Verolla F., Gennaro G.D., and Buonanno A.
Details: IEEE Access

Description: This paper presents the use of probability propagation on factor graphs to show that various algorithms proposed in the literature can be seen as specific composition rules in a factor graph, providing a very general framework and original recursions that includes the Sum-product, the Max-product, Dynamic programming and mixed Reward/Entropy criteria-based algorithms. Additionally, a comprehensive table of composition rules and a comparison through simulations, first on a synthetic small grid with a single goal with obstacles, and then on a grid extrapolated from a real-world scene with multiple goals and a semantic map are provided.

Keywords: Autonomy

Design Principles for Improving Precision and Dexterity of Soft Robotic Hands

Author(s): Teeple, C.
Details: PhD Dissertation at Harvard University

Description: This thesis explores how the design of soft robotic hands influences a robot’s overall manipulation capabilities from simple grasping to in-hand manipulation. Developing pneumatically-actuated soft fingers capable of robust precision grasping and power grasping allows for an investigation into the role of gripper compliance in grasping and manipulation of thin, flexible materials. Distributing controlled degrees of freedom into various parts of the hand contributes to overall dexterity. Additionally, controlling the interaction between objects and the palm (via the palm’s frictional properties and location relative to fingers) enables greater grasp stability and expanded access to different motion primitives. A set of application-specific design principles is provided to inform the design of soft hands for the particular application.

Keywords: Robotics (General), Manipulation

Variational Filter for Predictive Modeling of Structural Systems

Author(s): Lund A., Bilionis I., and Dyke S.J.
Details: 40th International Modal Analysis Conference, Orlando FL

Description: In this study we build on the theory of automatic differentiation variational inference to introduce a novel approach to variational filtering for the identification of complex structural systems. We evaluate our method using experimental observations from a nonlinear energy sink device subject to base excitation. Comparison between identification performed using our approach and the unscented Kalman filter reveals the utility of the variational filtering technique in terms of both flexibility in the stochastic model and robustness of the method to poor specification of prior uncertainty.

Keywords: Structure

Multi-Dimensional Compliance of Soft Grippers Enables Gentle Interaction with Thin, Flexible Objects

Author(s): Teeple C.B., Werfel J., and Wood R.J.
Details: IEEE International Conference on Robotics and Automation (ICRA) 2022

Description: In this paper, we discuss the role of gripper compliance in successful grasping and manipulation of thin, flexible materials. We show, both conceptually and empirically, that each axis of compliance in a planar gripper provides unique benefits in this domain. We explore these three benefits through empirical tests comparing a rigid gripper to a soft gripper, evaluating the level of vertical uncertainty each can handle for prehensile and non-prehensile manipulation, as well as the forces and displacements incurred during snags. The results show how a soft gripper's three-axis compliance provides a passive ability to prevent damage to delicate materials.

Keywords: Robotics (General), Manipulation

Resilient Extra-Terrestrial Habitat Design Using a Control Effectiveness Metric

Author(s): Cilento, M.
Details: Master's Thesis at Purdue University, 2022

Description: Extra-terrestrial habitats will be embedded in challenging environments and involve complex and tightly coupled combinations of hardware, software, and humans. Such systems will be exposed to many risks and anticipating all failures and environmental impacts will not be possible. In addition, complexity and coupling in these systems means space habitats are likely to experience system accidents, which arise not only from the failure of individual components but also from the interactions among components. Therefore, we propose a control-theoretic approach to resilient space habitat design, which is grounded in system safety engineering and goes beyond event and component-centric failure models underlying conventional risk-based design, and we take steps to validate this approach in part using a control effectiveness metric to assess safety controls in the MCVT.

Keywords: Safety Controls, Safety, Assessment

A Robot Factors Approach to Designing Modular Hardware

Author(s): Melenbrink N., Teeple C., and Werfel J.
Details: 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Kyoto, Japan

Description: In this paper, a deep learning-based multiple model estimation framework is presented for the state estimation of hybrid dynamical systems from high dimensional observations such as camera images. A low dimensional vector which represents the measurement of the latent dynamical system and its corresponding variance are learned using a deep encoder neural network. An Interacting Multiple Model (IMM) filter is used to generate the latent state estimates and covariances using multiple dynamical models, which can be learned using backpropagation through time. The state estimates of the dynamical system and the corresponding covariance matrix are generated from the latent state estimates and covariance using a deep decoder neural network. The whole network is trained in an end-to-end manner using a loss function which minimizes the negative log-likelihood of the neural network parameters. Simulation results are presented using a 2D bouncing ball example and estimation error statistics are computed which demonstrates the accuracy and consistency of the estimation.

Keywords: Robot (General), Manipulation

Contact-implicit Trajectory and Grasp Planning for Soft Continuum Manipulators

Author(s): Graule M.A., Teeple C., and Wood R.J.
Details: 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Kyoto, Japan

Description: As robots begin to move from structured industrial environments to the real world, they must be equipped to not only safely interact with the environment, but also reason about how to leverage contact to perform tasks. In this work, we develop a modeling and motion planning framework for continuum robots that accounts for contact anywhere along the robot. Overall, our model and planning approach further enhance soft and continuum robots where they already excel: utilizing contact with the world to achieve their goals with a gentle touch.

Keywords: Robotics (General), Manipulation

A Proprioceptive Method for Soft Robots Using Inertial Measurement Units

Author(s): Martin Y.J., Bruder D., and Wood R.J.
Details: 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Kyoto, Japan

Description: Proprioception, or the perception of the configuration of one's body, is challenging to achieve with soft robots due to their infinite degrees of freedom and incompatibility with most off-the-shelf sensors. This work explores the use of inertial measurement units (IMUs), sensors that output orientation with respect to the direction of gravity, to achieve soft robot proprioception, and will demonstrate the potential of IMUs to serve as inexpensive off-the-shelf sensors for soft robot proprioception.

Keywords: Robotics (General), Perception

Memetic Optimizer for Structural Damage Identification Using Electromechanical Admittance

Author(s): Zhang Y., Zhou K., and Tang J.
Details: ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference (IEDTC), St. Louis, MO

Description: Electromechanical impedance-based (EMI) techniques using piezoelectric transducers are promising for structural damage identification. The EMI data measurement points are usually limited, thus often times resulting in an under-determined problem. To tackle these challenges, in this research, a series of local search strategies are tailored to enhance the global searching ability and incorporated into particle swarm-based optimization. Case studies are carried out for verification, and the results show that the proposed memetic algorithm achieves good performance in damage identification.

Keywords: Structure, Damage, Sensor/Fusion

A Computational Framework for the Evaluation of Resilience in Deep Space Habitat Systems

Author(s): Behjat A., Ibrahimov. R., Lenjani A. et al
Details: ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference (IEDTC), St. Louis, MO

Description: Resilience is a vital consideration for designing and operating a deep space habitatsystem. The numerous hazards that may affect a deep space habitat and its crew during its lifecycle need to be considered early in the design. Trade-off studies are the typical method used to assess the cost and value of different design choices. Here we develop a modular dynamic computational framework (CDCM) intended for rapid simulation and evaluation of the resilience of different system configurations. We illustrate the use of the framework for supporting early-stage design decisions of a habitat system, including a case study on designing the power generation system considering cost and energy efficiency. This framework is the basis of the trade-off studies performed by RETHi.

Keywords: Trade Study, Assessment, Control

Smart and Resilient Extraterrestrial Habitats

Author(s): Dyke S.J.
Details: 8th World Conference on Structural Control and Monitoring, June 6, 2022

Description: Designing to withstand the demands that such extreme environments will place on long-term deep space habitats represents one of the greatest challenges in this undertaking, and is the main the know-how to establish deep space habitat systems that are smart and resilient. We define SmartHabs as habitats that have the ability to sense, anticipate, respond to, and learn from disruptions. Resilience requires that we first develop an understanding of the system architecture and features that are needed to support resilience in a space habitat system. However, system architecture alone is not sufficient, so we are working on techniques to extract the necessary amount of actionable information for repair and recovery through monitoring and embedded intelligence. The mission of the Resilient ExtraTerrestrial Habitats Institute (RETHi) is to provide situational awareness and autonomy to enable the design of habitats that are able to adapt, absorb and rapidly recover from expected and unexpected disruptions. Both fully virtual and coupled physical-virtual simulation capabilities are being established to enable us to explore a wide range of potential deep space SmartHab configurations and operating modes.


Learning Discrete-Time Uncertain Nonlinear Systems With Probabilistic Safety and Stability Constraints

Author(s): Salehi I., Taplin T., and Dani A.P.
Details: IEEE Open Journal of Control Systems, Volume 1, October 2022 Pages 354-365

Description: This paper presents a discrete-time dynamical system model learning method from demonstration while providing probabilistic guarantees on the safety and stability of the learned model. Simulations validate that the system model learned using the proposed method can reproduce the demonstrations inside a prescribed safe set while converging to the desired goal location starting from various different initial conditions inside the safe set. Furthermore, it is shown that the learned model can adapt to changes in goal location during reproductions without violating the stability and safety constraints.

Keywords: Control, Power

Comparison of Neural Network-Based Posed Estimation Approaches For Mobile Manipulation

Author(s): Chowdhury A., Li J., and Cappelleri D.J.
Details: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conferences (IDETC/CIE 2021)

Description: In this paper, we present two distinct neural network-based pose estimation approaches for mobile manipulation in factory environments. Synthetic datasets, unique to the factory setting, are created for neural network training in each approach. Each approach is evaluated and compared across pipeline complexity, dataset preparation resources, robustness, platform and run-time resources, and pose accuracy for manipulation planning. Finally, recommendations for when to use each method are provided.

Keywords: Robotics (General), Manipulation, Vision

RETHi Modular End-Effector System

Author(s): Jungchen Li
Details: MCVT Model, Demonstration

Description: This video demonstrates the key features of the RETHi Modular End-Effector System (MEES) for autonomous habitat maintenance and repair. It showcases the autonomous tool changing process, the modular camera system, and integrated manipulator path planning with the MEES.

Keywords: Autonomy, Robotics (General), Perception, Manipulation, Vision

The Role of Digit Arrangement in Soft Robotic In-Hand Manipulation

Author(s): Teeple C.B., St. Louis R.C., Graule M.A., and Wood R.J.
Details: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2021

Description: This work shows that the arrangement of digits in a soft robotic hand has a strong effect on in-hand manipulation capabilities. Introducing task-based performance metrics which quantify the range of motion, repeatability, and accuracy of in-hand manipulation tasks, we investigate hand designs with finger arrangements ranging from axisymmetric-circular to anthropomorphic. Using an open-source soft robot simulator, the effect of object size and aspect ratio on the in-hand manipulation performance is studied for a variety of finger arrangements, and findings are validated using a physical hardware platform.

Keywords: Robotics (General), Manipulation

SoMo: Fast and Accurate Simulations of Continuum Robots

Author(s): Graule M. A., Teeple C. B., McCarthy T., St. Louis R. C., Kim G., and Wood R. J.
Details: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2021

Description: Engineers and scientists often rely on their intuition and experience when designing soft robotic systems. The development of performant controllers and motion plans for these systems commonly requires time-consuming iterations on hardware. We present the SoMo (Soft Motion) toolkit, a software framework that makes it easy to instantiate and control typical continuum manipulators in an accurate physics simulator.

Keywords: Robotics (General), Manipulation

RETHi Presentation at the SPARC Symposium

Author(s): Shirley Dyke
Details: MCVT Model, SPARC Symposium, November 6th, 2020

Description: This presentation is about the Resilient Extra-Terrestrial Habitats institute and how we aim to establish tools for resilience and autonomy in our quest to enable a sustained human presence on the moon. The institute is funded by NASA, headquartered at Purdue University, and partners include the University of Connecticut, Harvard University and the University of Texas-San Antonio.

Keywords: Safety, Autonomy, Cyber-Physical Testing

A Reflective Framework for Performance Management (REFORM) of Real-time Hybrid Simulation

Author(s): Maghareh A., Fu Y., Montoya H., Condori J., Wang Z., Dyke S.J., and Montoya A.
Details: Frontiers in Built Environment, 2020

Description: This article proposes a framework named Reflective Framework for Performance Management (REFORM) of real-time hybrid simulation. REFORM will support the execution of more complex RTHS experiments than can be conducted today, and will allow them to be configured rapidly, performed safely, and analyzed thoroughly. This study provides a description of the building blocks associated with the first phase of this development (REFORM-I). REFORM-I is verified and demonstrated through application to an expanded version of the benchmark control problem for real-time hybrid simulation.

Keywords: Structure, Cyber-Physical Testing

A Control-Theoretic Approach to the Resilient Design of Extra-Terrestrial Habitats

Author(s): Kitching R.
Details: Master's Thesis at Purdue University, 2020

Description: Space habitats will involve a complex and tightly coupled combination of hardware, software, and humans, while operating in challenging environments that pose many risks, both known and unknown. It will not be possible to design habitats that are immune to failure, nor will it be possible to foresee all possible failures. Rather than aiming for designs where “failure is not an option”, habitats must be resilient to disruptions. In this thesis, a control-theoretic approach to resilient design is proposed for space habitats based on the concept of safety controls from system safety engineering.

Keywords: Safety, Safety Controls, Assessment

Size and Structural Stability Assessment of Lunar Lava Tubes

Author(s): A. Modiriasari, A. K. Theinat, A. Bobet, H.J. Melosh, S.J. Dyke, J. Ramirez, A. Maghareh, D. Gomez
Details: 49th Lunar and Planetary Science Conference 2018, The Woodlands, Texas, March 2018

Description: This paper adresses whether a lunar lava tube may realistically attain widths of 1-2 km without collapsing. In this work, we focus on the task of estimating the crosssection area of empty lunar lava tubes on the Moon through analytical and geometrical analyses, given estimated volumes of lava flows and lunar topography. In addition, numerical simulations are presented to analyze the structural stability of lava tubes.

Keywords: Safety

Modeling holes and voids in three dimensions using a single element within the Extended Finite Element framework

Author(s): Shahriar A., Majlesi A., and Montoya A.
Details: International Journal for Numerical Methods in Engineering, 2023

Description: This paper introduces a highly efficient computational approach using the extended finite element method to model three-dimensional mechanics of holes and voids. The method\’s results were compared against analytical solutions and conventional finite element method results for problems involving single and multiple holes. The comparison demonstrated that the method provides accurate stress concentration estimates while adhering to computational constraints.

Keywords: Assessment, Unknown Faults, Known Faults

Agent-based models for real-time fault-recovery in cyber-physical testbeds for Smart Habitats

Author(s): Krishnan M. and Bilionis I.
Details: ASCEND 2023

Description: This paper describes an agent-based model for real-time fault recovery in a cyber-physical testbed for Smart Habitats. The agent model achieves fault recovery in the sub-systems modeled in the testbed by decomposing high-level repair objectives to a set of sub-tasks which form the "basis" for the agent action-space, and is demonstrated to recover a fault modeled in the Environmental Control and Life Support Subsystem (ECLSS) and the Power Subsystem of the MCVT testbed.

Keywords: Autonomy, Fault Detection, Cyber-Physical Testing

A Simulation-Based Study of Operational Vulnerabilities and Contingency Planning for Smart Extraterrestrial Habitats

Author(s): K. Pritchard
Details: Master's Thesis at Purdue University, 2023

Description: In this thesis, developing an understanding of using simulations to study extra-terrestrial habitats is discussed along with how to make contingency plans for extra-terrestrial habitats under complex, changing conditions. To represent the challenges posed, common qualities of mission architectures are identified that are likely to be present in near-future habitats. These qualities are used to formulate sample crew schedules that contribute to developing realistic models for meaningful research. This thesis discusses the development of such models and demonstrates the suitability of simulation to enable the design and study of resilient space habitats.

Keywords: Safety, Safety Controls, Assessment

A Finite Element Approach for Simplified 2D Nonlinear Dynamic Contact/Impact Analysis

Author(s): Seok S., Shahriar A., Montoya A., and Malla R. B.
Details: Archive of Applied Mechanics, Volume 93, Issue 9

Description: In this paper, a simplified numerical approach for finite element dynamic analysis of an inelastic solid structure subjected to solid object impact is presented. The results obtained using the proposed approach are in a good agreement with those simulated using a commercial finite element code, ABAQUS dynamic/implicit, in terms of displacements and stress distribution fields. The proposed approach in this paper is shown to be computationally superior to general finite element method-based contact/impact analysis without significantly sacrificing the accuracy.

Keywords: Assessment, Fault Detection

The Effect of Temporal Correlations on State Estimation through Variational Bayesian Inference

Author(s): Mirfarah M., Lund A., and Dyke S.J.
Details: International Modal Analysis Conference

Description: This article focuses on the flexibility of the variational family and investigates the effect of considering dependency between the latent variables on the quality of posteriors, with respect to applications in structural health monitoring. To evaluate the effect of the temporal off-diagonal covariance matrix on the performance of the inference, a numerical simulation of a linear single-degree-of-freedom system is utilized. The findings show that for this linear system, the estimates of the parameters would not be meaningfully enhanced by adding the temporal dependency to the mean-field structure of the variational family.

Keywords: Assessment, Autonomy, Fault Detection

Scalable Impact Detection and Localization Using Deep Learning and Information Fusion

Author(s): Fu Y., Wang Z., Maghareh A., Dyke S. J., Jahanshahi M.R., and Shahriar A.
Details: 13th International Workshop on Structural Health Monitoring 2022, Stanford University, CA

Description: In this study, an effective impact localization strategy is proposed to identify impact locations from impact events using limited number of vibration measurements. Convolutional neural networks are trained for each sensor node and are fused using Bayesian theory to improve the accuracy of impact localization. Special considerations are paid to address both measurement and modeling errors. The proposed strategy is illustrated using a 1D structure, and numerically validated for a 2D dome-shaped structure. The results demonstrate that the proposed method detects and localizes impact events accurately and robustly.

Keywords: Sensor/Fusion, Damage, Fault Detection, Structure

Real-time rapid leakage estimation for deep space habitats using exponentially-weighted adaptively-refined search

Author(s): Rautela M., Mirfarah N., Silva C.E., Dyke S.J., Maghareh A., and Gopalakrishnan S.
Details: Acta Astronautica, Volume 203, February 2023, Pages 385-391

Description: The recent accelerated growth in space-related research and development activities makes the near-term need for long-term extraterrestrial habitats evident. Such habitats must operate under continuous disruptive conditions arising from extreme environments like meteoroid impacts, extreme temperature fluctuations, galactic cosmic rays, destructive dust, and seismic events. It is demonstrated that the proposed methodology can achieve real-time estimation and tracking of constant and variable leaks with accuracy.

Keywords: Structure, Assessment, Known Faults

Adaptive Performance: A Generative Theory for HCI Design in Extraterrestrial Habitats

Author(s): Parsons P.C., Zhang Z., and Murray J.
Details: SpaceCHI 2.0 Workshop at ACM SIGCHI 2022, New Orleans, LA

Description: This paper looks at how future habitats in deep space will experience long delays in communication with Earth. These delays will result in unprecedented situations where the crew cannot rely on synchronous support from Mission Control, and as a result the crew will need to act more autonomously and with limited resources when quick decision making is required. This paper proposes that theories of adaptive performance can play a generative role in designing interactive cognititve tools for extraterrestrial habitats.

Keywords: Autonomy, Human Interface

ICON Seminar: Autonomous Mobile Robotics at the Multi-Scale Robotics & Automation Lab

Author(s): Cappelleri D.J.
Details: ICON Seminar in Robotics

Description: This workshop is on the Multi-Scale Robotics & Automation Lab (MSRAL) at Purdue University. MSRAL performs cutting-edge research on robotic and automation systems at various length scales: macro-scale (cm to m), meso-scale (~100's of um to a few mm's), and micro-scale (10's of um to 100's of um).

Keywords: Robotics (General)

HabSim User Manual v6.3

Author(s): Luca Vaccino, Megan Rush
Details: User Manual, May 2024

Description: This document provides a detailed description of the HabSim model, formerly known as the Modular Coupled Virtual Tested (MCVT). This user guide includes information on available disruption scenarios, hazardous states, and safety controls using the lunar habitat simulation platform. Example simulations of micrometeorite impact and fire are included.

Keywords: Safety Controls

MCVT: Role, Implementation, and Real-Time Execution

Author(s): Herta Montoya, Yuguang Fu
Details: MCVT Model, Annual Review, 2021

Description: This presentation will describe the system architecture and key aspects of MCVT integration as a system of systems. It covers the design structure matrix to capture the physical and cyber interdependencies, implementation table to facilitate Simulink implementation, multi-rate simulation to minimize computation cost, and digital infrastructure to support real-time execution. The overall performance of MCVT has been demonstrated in an accelerated example scenario. The integrated system can enable our research on complex systems, and more features will be added in the future using the same simulation environment.

Keywords: Assessment, Trade Study, Cyber-Physical Testing

MCVT: Thermal Management Scenario Storyboard

Author(s): Aaron Barket
Details: MCVT Model, Annual Review, 2021

Description: The thermal management scenarios were created to develop a formulaic progression of repairing a habitat system in the case of hazards causing damage. This video summarizes the least and most extreme thermal management scenarios involving micrometeorite impacts and exhibits the resilience and autonomy of the habitat system.

Keywords: Damage, Autonomy, Fault Detection, Thermal

MCVT: External Environment Model

Author(s): Sachin Tripathi, Murali Krishnan
Details: MCVT Model, Annual Review, 2021

Description: This presentation will describe the design of two models: Solar Irradiation and the Dust Deposition Model used in the MCVT model. In the Solar Radiation Model, the structural dome habitat is divided into the number of the differential elements. The solar flux intensity at the differential elements were determined based upon the solar angle of incidence (angle between the solar rays and the normal vector to the surface) at that point. This model also contains the self-shadowing effect. In the dust deposition model, there are three events explicitly modeled: exhaust event, nominal dust, and the meteorite impact dust deposition model.

Keywords: Power, Thermal

MCVT: Simple Impact Model & Simple Mechanical Regolith Model

Author(s): Seungwook Seok
Details: MCVT Model, Annual Review, 2021

Description: This presentation will discuss the impact model and regolith material model, which were developed to simulate micro-meteorite impact events into the regolith-made protective layer for the habitat structure system. Since simulating nonlinear mechanical and nonlinear responses due to impact loading requires significant computational resources, the impact model and regolith protective layer model were created separately from the real-time executable MCVT model. These two models combined with structural mechanical model ran beforehand to pre-compute a set of the force-time histories at the boundary between the protective layer and the structural mechanical dome structure, which take into account the effects of the energy attenuation by the presence of the protective layer under micro-meteorite impact events considered. The force-time histories generated for different micro-meteorite masses and velocities will be used as the force boundary condition for the MCVT structural mechanical model.

Keywords: Damage, Structure

MCVT: Structural Mechanical Model

Author(s): Adnan Shahriar
Details: MCVT Model, Annual Review, 2021

Description: This presentation will describe the Structure Mechanical Model of habitat in the MCVT, which simulates the structure's response under operational loads and external disturbances. The process and methods used to develop a physics-based model with damageable-repairable capabilities that can be executed in real-time will be discussed briefly. An illustration of the implementation of the SMM within the MCVT will be shown to allow viewers to have a high-level intuitive understanding of this model.

Keywords: Safety, Damage, Fault Detection, Structure, Cyber-Physical Testing

MCVT: Structural Thermal Model (STM)

Author(s): Sachin Tripathi
Details: MCVT Model, Annual Review, 2021

Description: This presentation will describe the design of the structural thermal model used in the MCVT model. In this physics-based model, the solar flux intensity from the Solar Radiation Model and interior habitat temperature from the Habitat Interior Environment Model are taken as the external and internal boundary conditions respectively. The three-dimensional thermodynamics energy balance equation has been used in this study. The explicit finite difference scheme has been implemented to solve the problem. The model has been integrated in the MCVT model. The damageability and the reparability features have been incorporated in the model as well.

Keywords: Damage, Thermal

MCVT: Interior Air Environment Model

Author(s): Jeffrey Steiner
Details: MCVT Model, Annual Review, 2021

Description: The Internal Environment Model presentation will explain the modeling of pressure and temperature within the defined habitat space of the MCVT. The pressure distribution utilizes a zonal model approach that treats the air column as a series of fixed-volume finite elements whose mass changes based on changes in the system. The temperature distribution is determined using a similar approach, with changes in total energy being distributed throughout the system. These features allow for the simulation of the effects of varying degrees of damage severity, from pressure leaks to non-functional Life Support and Repair systems.

Keywords: Safety, Safety Controls, Assessment, Dormant, Damage, Pressure, Thermal

MCVT: Solar PV Array Power Subsystem Model

Author(s): Kairui Hao
Details: MCVT Model, Annual Review, 2021

Description: This presentation will explain the modeling of solar PV array system from 1) solar PV plant model, 2) solar PV array controller and maximum power point tracking, and 3) damageability and reparability features. It focuses on simulating dust accumulation due to micrometeorite strike considered in the thermal management scenario.

Keywords: Damage, Fault Detection, Known Faults, Power

MCVT: Nuclear Power System Model

Author(s): Ryan Tomastik
Details: MCVT Model, Annual Review, 2021

Description: This presentation will explain the process behind modeling the nuclear power generation system, particularly the reduced-order models that were developed. Additionally the damageability and reparability features will be discussed, specifically dust accumulation, as well as how the power distribution and storage system works to automatically redistribute power.

Keywords: Damage, Autonomy, Known Faults, Power

MCVT: ECLSS Active Thermal Control System

Author(s): Jaewon Park
Details: MCVT Model, Annual Review, 2021

Description: ECLSS is responsible for maintaining the well-being of the crew members in an extraterrestrial habitat environment. When only the thermal aspects are in consideration, ECLSS strives to provide appropriate heating and cooling to the interior habitat system to maintain desirable temperature suitable for the human activity. A simple PID controller is implemented to adjust the amount of heating and cooling loads, and two types of damages to the system were considered in the form of defects in radiator panels.

Keywords: Damage, Thermal, Control, Cyber-Physical Testing

MCVT: Communication Network Subsystem

Author(s): Jiachen Wang
Details: MCVT Model, Annual Review, 2021

Description: This presentation will describe the design of the internal communication network subsystem. The time-sensitive networking (TSN) based communication network supports time-critical communication among different subsystems. The network controller can support dynamic and redundant routing paths to handle transient and permanent network failures.

Keywords: Decision Making, Known Faults, Communication Network

MCVT: Intervention Agent Model

Author(s): Murali Krishnan
Details: MCVT Model, Annual Review, 2021

Description: This presentation describes the intervention agent model used in MCVT. It explains how the agent model breaks down a high-level repair/maintenance/sensing activity to a sequence of actions, which the agent performs sequentially. Further, the description of a simple plant model of the agent is presented, focusing on the thermal management scenario for which the MCVT has been developed.

Keywords: Safety Controls, Damage, Autonomy, Fault Detection, Decision Making

MCVT: Human Model

Author(s): Drake Hart
Details: MCVT Model, Annual Review, 2021

Description: This presentation describes the role of human crew members as a moving heat source within the habitat. The human model uses a daily schedule received from the crew and returns an amount of heat in real time corresponding to the activity being performed in each moment. The interior habitat uses this information to stabilize its temperature and maintain a nominal state.

Keywords: Thermal

MCVT Simulation Tutorial (Download and Execution)

Author(s): Herta Montoya
Details: MCVT Model, Simulation Tutorial, 2021

Description: This video explains the structure and demonstrates the execution of the Modular Coupled Virtual Testbed (MCVT) integrated simulation environment, for the specific models developed by the RETH institute team of modelers. This system of systems is meant to be one realization of a habitat system, that is being used to do the research of the team. The video does the following:

  1. Explains the structure of the MCVT code (as of March 2021)
  2. Demonstrates its execution, starting with downloading it from GitHub through to executing a sample simulation and plotting the results.

Keywords: Safety, Safety Controls, Assessment, Damage

Development of a Computational Framework for the Design of Resilient Space Structures

Author(s): Adnan Shahriar, Sterling Reynolds, Mehdi Najarian, Arturo Montoya
Details: 17th Biennial International Conference on Engineering, Science, Construction, and Operations in Challenging Environments

Description: The cyber-physical testing hybrid approach requires the development of a structural model that accounts for various hazards (e.g., micrometeorite and debris impact) and interacts with physical tests and other sub-system models (e.g., thermal) of the space habitat. A two-dimensional finite element analysis code was developed in MATLAB to facilitate the evaluation of potential designs under operating and unexpected loads and prepare the computational framework for eventually performing cyber-physical testing. In this study, the code is implemented to predict the response of a dome-style structure made of regolith concrete to impact loading and identify the force magnitude that will cause the tensile strength to be exceeded in domes with different thicknesses.

Keywords: Structure, Cyber-Physical Testing

Bayesian Identification of Nonlinear Structural Systems: Innovations to Address Practical Uncertainty

Author(s): Lund A.
Details: PhD Dissertation at Purdue University, 2021

Description: Within the structural engineering community, there is a lack of consensus on efficient methods for Bayesian inference approaches and their implementation to full-scale structural systems, which has led to a diverse set of Bayesian approaches, from which no clear method can be selected for full-scale implementation. The objective of this work is to assess and enhance those techniques currently used for structural identification and make strides toward developing unified strategies for robustly implementing them on full-scale structures. Addressing ther core concerns underlying full-scale structural identification will enable the practical application of Bayesian inference techniques and thereby enhance the ability of communities to detect and respond to the condition of infrastructure.

Keywords: Fault Detection, Structure, Cyber-Physical Testing

Role of Cyber-Physical Testing in Developing Resilient Extraterrestrial Habitats

Author(s): Maghareh A., Lenjani A., Krishnan M., Dyke S. J., and Bilionis I.
Details: 17th Biennial International Conference on Engineering, Science, Construction, and Operations in Challenging Environments

Description: Extraterrestrial habitat systems must operate as intended under continuous disruptive conditions. Designing for the demands that challenging environments will place on habitat systems (e.g., wild temperature fluctuations, galactic cosmic rays, destructive dust, meteoroid impacts, vibrations, and solar particle events) represents one of the greatest challenges in this endeavor. As the habitat system evolves—growing in physical size, complexity, population, and connectivity—and diversifies in operations, it must continue to be safe and resilient. This study highlights the importance of system resilience and cyber-physical testing to address the grand challenge of developing habitat systems.

Keywords: Safety, Safety Controls, Autonomy, Control, Cyber-Physical Testing

MAST: A Quickest Detection Procedure for COVID-19 Epidemiological Data to Trigger Strategic Decisions

Author(s): Braca P., Gaglione D., Marano S., Millefiori L.M., Willett P.K., and Pattipati K.R.
Details: 29th European Signal Processing Conference (EUSIPCO), 2021

Description: Signal processing tools play an important role in interpreting COVID-19 pandemic data, and hence contribute to timely and rational decisions. The authors propose a sequential test (MAST) designed to detect the passage from a controlled to a critical regime of the COVID-19 pandemic; and similarly from critical to controlled. This paper provides a performance assessment and analysis of MAST alerts from official COVID-19 infection data-the number of daily new positives and hospitalized individuals in several Italian regions.

Keywords: Decision Making

Computational Inference of Vibratory System with Incomplete Modal Information Using Parallel, Interactive and Adaptive Markov Chains

Author(s): Zhou K., and Tang J.
Details: Journal of Sound and Vibration

Description: Inverse analysis of vibratory system is an important subject in fault identification, model updating, and robust design and control. The aim of this research is to leverage upon computational intelligence through statistical inference to facilitate an enhanced, probabilistic framework using incomplete modal response measurement. This new framework is built upon efficient inverse identification through optimization, whereas Bayesian inference is employed to account for the effect of uncertainties.

Keywords: Fault Detection, Structure

MCVT: Designing for Resilience

Author(s): Herta Montoya
Details: MCVT Model, Developing Infrastructure for Tomorrow: An Introduction to Civil Engineering (Purdue's Summer College for High School Students), 2020

Description: This video explains the concept of resilience of engineered systems to students, focusing toward the 6-12th grade level. Examples are provided that introduce how resilience might be realized in terrestrial communities subjected to disruptions, and also in SmartHabs, habitats on the Moon or Mars that have built-in intelligence to sense, react, and bounce back.

Keywords: Safety, Assessment

On the Identification of Noise Covariances and Adaptive Kalman Filtering: A New Look at a 50 Year-old Problem

Author(s): Zhang L., Sidoti D., Bienkowski A., Pattipati K. R., Bar-Shalom Y., and Kleinman D. L.
Details: IEEE Journal, 2020

Description: The Kalman filter requires knowledge of the noise statistics; however, the noise covariances are generally unknown. Although this problem has a long history, reliable algorithms for their estimation are scant, and necessary and sufficient conditions for identifiability of the covariances are in dispute. this paper addresses both of these issues.

Keywords: Fault Detection, Fault Tolerance

Human-in-the-loop Robotic Control for Human-Robot Collaboration

Author(s): Dani A.P., Salehi I., Rotithor G., Trombetta D., and Ravichandar H.
Details: IEEE Control Systems Magazine, 2020

Description: The prospect of a collaborative work environment between humans and robotic automation in a manufacturing setting provides the motivation for finding innovative solutions to human-in-the-loop control for safe, efficient, and trustworthy human-robot collaboration (HRC) in cyberphysical human systems (CPHSs). Traditional methods to ensure the safety of humans around factory robots involve the use of cages. Recent work looked beyond cage-based safety to provide robot control and sensing-driven solutions for human safety around robots.

Keywords: Autonomy, Human Interface, Safety, Robotics (General)

Safe Tracking Control of an Uncertain Euler-Lagrange System with Full-State Constraints using Barrier Functions

Author(s): Salehi I., Rohtithor G., Trombetta D., and Dani A.P.
Details: 59th IEEE Conference on Decision and Control (CDC), 2020

Description: This paper presents a novel, safe tracking control design method that learns the parameters of an uncertain Euler-Lagrange (EL) system online using adaptive learning laws. The controller design is validated in simulations using a two-link planar manipulator. The results show the proposed method's ability to track the reference trajectory while remaining inside each of the predefined state bounds.

Keywords: Robotics (General), Vision, Perception, Navigation

Image Moment-Based Extended Object Tracking for Complex Motions

Author(s): Yao G., Saltus R., and Dani A.P.
Details: IEEE Sensors Journal, 2020

Description: A novel image moment-based model for shape estimation and tracking of an extended target moving with a complex trajectory is presented in this paper. The proposed extended object tracking algorithm is based on multiple noisy measurement points sampled from the target at each time step. The comparison results of the proposed algorithm with a benchmark algorithm from literature based on the IoU and RMSE metrics are presented.

Keywords: Robotics (General), Vision, Perception, Navigation

Shape estimation for elongated deformable object using B-spline chained multiple random matrices model

Author(s): Yao G., Saltus R., and Dani A.P.
Details: International Journal of Intelligent Robotics and Applications, 2020

Description: In this paper, a B-spline chained multiple random matrix models (RMMs) representation is proposed to model geometric characteristics of an elongated deformable object. The execution time is computed and the accuracy of the shape estimation results is evaluated based on the comparisons between the estimated width values and its ground-truth, and the intersection over union (IoU) metric.

Keywords: Robotics (General), Vision, Perception, Navigation

Lava Tubes as Resilient Extraterrestrial Habitats: An Option For A Permanent Human Settlement Beyond Earth

Author(s): A.K. Theinat, A. Modiriasari, J. Choi, A. Maghareh
Details: July/August 2019 Geostrata

Description: Recent data from spacecraft and orbiters suggest the presence of large, open sublunarean structures in the form of "lava tubes." The data indicate that the width of these lava tubes below the Moon’s surface could be as large as 1-2 km. Such underground lava tubes could be suitable candidates for temporary or permanent human shelters. To further gain insight into the influence of geometry and rock quality comprising the lava tubes, the authors explored lava tubes at the Lava Beds National Monuments (LBNM) in Tulelake, CA. The results from the surveillance of the lava tubes at LBNM helped to further our understanding of the geometry of the lava and rock mass characteristics. Our future work aims at extending the analyses to consider the potential for damage and failure of the tubes due to direct meteorite impact or seismicity induced by a remote impact.

Keywords: Safety

Geometry and Structural Stability of Lunar Lava Tubes

Author(s): A.K. Theinat, A. Modiriasari, A. Bobet, H.J. Melosh, S.J. Dyke, J. Ramirez, A. Maghareh, D. Gomez
Details: AIAA conference - 2018, Orlando, Florida, Sept 2018

Description: Underground habitats, given that they are not exposed to extreme hazards such as radiation, meteorite impacts, and temperature fluctuations, can potentially serve as secure shelters for human exploration. Using the mechanics and the morphology of lava flows, this paper develops an analytical solution to estimate the size of the lunar lava tubes. Additionally, a series of numerical simulations were conducted to investigate the stability of the lava tubes. The study shows that the tensile strenght of the rock mass is a crucial parameter for stability assessment.

Keywords: Safety

Shape Servoing of Deformable Objects using Adaptive Deformation Model Estimation

Author(s): Guthikonda V., Rotithor G., and Dani A.P.
Details: IFAC World Congress

Description: In this paper, an adaptive shape servoing method to deform a soft object into a desired 3D shape is proposed. A physics-based simulation is used to validate the proposed method and controller by performing manipulation tasks with different desired configurations. The performance is compared with a standard gradient update law to demonstrate the accuracy and robustness of the approach.

Keywords: Robotics (General), Perception, Manipulation

Experimental and Numerical Analysis of Environmental Control Systems for Reslient Extra-Terrestrial habitats

Author(s): H.A. Sakiewicz
Details: Master's Thesis at Purdue University, 2023

Description: In this thesis, the Environmental Control and Life Support System (ECLSS) for the Cyber-Physical Testbed (CPT) is discussed. To answer difficult research questions regarding ECLSS and thermal management of a deep-space habitat, a heat pump was modeled and validated with the physical part of the CPT. Once validated, the heat pump model is able to accurately predict the steady state behavior given the indoor and outdoor conditions of the testbed. When coupled with the interior environment (IE) model, it gives insight into the system’s requirements and response. Experimental testing was conducted with the heat pump in order to validate the model. Since the groundwork was laid through model development and experimentation, future work consists of designing a more versatile heat pump to test a variety of disturbance scenarios.

Keywords: Cyber-Physical Testing, Thermal

Modeling and Experimental Validation of a Resilient Extraterrestrial Habitat Interior Environment

Author(s): L.C. Carballude
Details: Master's Thesis at Purdue University, 2023

Description: In this Thesis, the Habitat Interior Environment Model (HIEM) for the MCVT is described, as well as the Cyber-Physical Testbed (CPT). One of the core aspects of both MCVT and CPT is the habitat interior environment which includes the coupled temperature and pressure effects due to interior and exterior loads as well as the necessary conditions to ensure the crew survival. The HIEM model can directly interact with other subsystems such as the ECLSS and structural protective layer (SPL) and features various disturbances including pressure leaks due to meteorite impacts or airlock failures. The HIEM was modified to describe the physical sizing of the bladder as well as to capture the heat transfer characteristics between the bladder, the aluminum structure, and thermal transfer panels.

Keywords: Cyber-Physical Testing, Thermal

Learning Methods for Image-based State Estimation and Control

Author(s): Rotithor G.
Details: PhD Dissertation at University of Connecticut, 2023

Description: This dissertation presents learning-based estimation and control algorithms using image data. The estimation algorithms aid the robot in understanding its environment, and one can use this understanding to design controllers that make the robot perform desired tasks. These depth estimates can be used to design image-based visual servo controllers, which generate robot end-effector velocities or accelerations such that the feature points move to desired locations in the image. The method is tested on the deformable cloth generated using a physics simulator called Blender.

Keywords: Robotics (General), Perception, Manipulation

Chance-Constrained System Identification of Nonlinear Discrete Systems with Safety and Stability Guarantees

Author(s): Salehi I., Taplin T., and Dani A.P.
Details: American Controls Conference 2022, Atlanta, GA

Description: This paper presents a discrete-time nonlinear system identification method while satisfying the stability and safety properties of the system with high probability. An Extreme Learning Machine (ELM) is used with a Gaussian assumption on the function reconstruction error. A quadratically constrained quadratic program (QCQP) is developed with probabilistic safety and stability constraints that are only required to be satisfied at sampled points inside the invariant region. The proposed method is validated using two simulation examples: a two degrees-of-freedom (DoF) robot manipulator with constraints on joint angles whose trajectories are guaranteed to remain inside a safe set and on motion trajectories data of a hand-drawn shape.

Keywords: Robotics (General), Manipulation

Learning-based State-dependent Coefficient Form Task Space Tracking Control of Soft Robot

Author(s): Bhattacharya R., Rotithor G., and Dani A.P.
Details: American Controls Conference 2022, Atlanta, GA

Description: In this paper, a data-driven modeling and control framework is developed for task space control of a soft robot gripper which consists of four individual soft fingers. Each of the four fingers is modeled as a manipulator with high degrees of freedom. The corresponding task space dynamics of the manipulator are derived using a rigid-link approximation of the continuum manipulator. A neural network approach is used to learn the derived dynamics in State Dependent Coefficient (SDC) form. Using the learned SDC matrices, an asymptotically stable optimal closed-loop tracking controller which is based on solving the State Dependent Riccati Equation (SDRE) is derived. The model learning and trajectory tracking controller is implemented on an open source Soft Motion (SoMo) platform simulating the soft gripper motion and corresponding tracking results are presented.

Keywords: Robotics (General), Manipulation

Deep Interacting Multiple Model Filtering

Author(s): Rotithor G. and Dani A.P.
Details: American Controls Conference 2022, Atlanta, GA

Description: In this paper, a deep learning-based multiple model estimation framework is presented for the state estimation of hybrid dynamical systems from high dimensional observations such as camera images. A low dimensional vector which represents the measurement of the latent dynamical system and its corresponding variance are learned using a deep encoder neural network. An Interacting Multiple Model (IMM) filter is used to generate the latent state estimates and covariances using multiple dynamical models, which can be learned using backpropagation through time. The state estimates of the dynamical system and the corresponding covariance matrix are generated from the latent state estimates and covariance using a deep decoder neural network. The whole network is trained in an end-to-end manner using a loss function which minimizes the negative log-likelihood of the neural network parameters. Simulation results are presented using a 2D bouncing ball example and estimation error statistics are computed which demonstrates the accuracy and consistency of the estimation.

Keywords: Robotics (General), Vision

Interior Environment Modeling for Resilient Extra-Terrestrial Habitats

Author(s): Lial A.
Details: Master's Thesis at Purdue University, 2022

Description: In this Thesis, the Habitat Interior Environment Model (HIEM) for the MCVT is described and validated. The HEIM monitors the interior environment of the lunar structure using physics-based calculations and inputs from its surroundings. There are three main disturbances that directly affect the interior environment—fire within the dome, meteorite impacts, and airlock failure. These scenarios either increase or decrease the temperature and pressure. This data is then forwarded to other subsystems for further evaluation. HIEM can be remodeled to fit the pressure box in the cyber physical testbed. By doing so, it is then possible to validate the pressure leakage calculations used in HIEM using experimental data. HIEM is specifically designed to the lunar habitat currently in development; however, the model can be refitted to a variety of applications such as terrestrial, aerospace, space, and marine.

Keywords: Thermal, Pressure, Cyber-Physical Testing

Resilient Space Habitat Design Using Safety Controls

Author(s): Kitching R., Mattingly H., Williams D., and Marais K.
Details: 17th Biennial International Conference on Engineering, Science, Construction, and Operations in Challenging Environments

Description: Space habitats will involve a complex and tightly coupled combination of hardware, software, and humans, while operating in challenging environments that pose many risks, both known and unknown. It will not be possible to design habitats that are immune to failure, nor will it be possible to foresee all possible failures. Rather than aiming for designs where “failure is not an option,” habitats must be resilient to disruptions. This paper proposes an approach to resilient design for space habitats based on the concept of safety controls from system safety engineering.

Keywords: Safety, Safety Controls, Assessment

Experimental Data on Open Circuit Voltage Characterization for Li-ion Batteries

Author(s): Ahmed M., Balasingam B., and Pattipati K.R.
Details: Data In Brief Journal, 2021

Description: This article presents datasets collected from nine different Li-ion batteries. These datasets contain voltage, current and time measurements during a full charge-discharge cycle of a battery at very low current. Such low current rate data is suitable for open circuit voltage characterization. The collection of this data was done through the use of an Arbin battery cycler and a thermal chamber was used to control the test temperature. Data were collected over a wide range of temperatures from −25 to 50 degrees Celcius.

Keywords: Sensor/Fusion

Classification and Regression Models of Audio and Vibration Signals for Machine State Monitoring in Precision Machining Systems

Author(s): Han S., Mannan N., Stein D.C., Pattipati K.R., and Bollas G.M.
Details: Journal of Manufacturing Systems, 2021

Description: This paper presents a data-driven method for monitoring machine status in manufacturing processes. Audio and vibration data from precision machining are first processed through Fast Fourier Transform and Principal Component Analysis to extract transformed and informative features. It is shown that the audio and vibration signals are sufficiently rich in information about the machine that 100% state classification accuracy could be accomplished. Data fusion was also explored, showing overall superior accuracy of data-driven regression models.

Keywords: Sensor/Fusion, Fault Detection

Adaptive Bayesian Learning and Forecasting of Epidemic Evolution—Data Analysis of the COVID-19 Outbreak

Author(s): Pattipati K.R., Gaglione D., Braca P., Millefiori L.M., Soldi G., Marano S., and Willet P.K.
Details: IEEE Access, 2020

Description: In this paper, we show that we can reliably estimate and forecast the evolution of the infections from daily — and possibly uncertain — publicly available information provided by authorities, e.g., daily numbers of infected and recovered individuals. The proposed method is able to estimate infection and recovery parameters, and to track and predict the epidemiological curve with good accuracy when applied to real data from Lombardia region in Italy, and from the USA.

Keywords: Decision Making

Resilience-oriented Design of Extraterrestrial Habitat Systems

Author(s): A. Maghareh, A. Lenjani, S.J. Dyke, K. Marais, D. Whitaker, A. Bobet, J. Ramirez, H.J. Melosh, A. Modiriasari, A.K. Theinat
Details: Proceedings of the 2019 AIAA Propulsion and Energy Forum, Indianapolis, August 19-22, 2019

Description: This paper builds upon the concept of resilience for complex, interconnected systems design, and develops a generic formula in terms of passive capacity (preventive capability) and active capacity (interventive and mitigative capabilities) in these complex systems. For design and analysis of resilient complex systems, we have developed a control-oriented dynamic computational (CDC) platform. In this study, the CDC platform is used to evaluate the performance of difference resilience allocations within an interconnected environmental control and life support system.

Keywords: Safety, Trade Study

Resilient Extraterrestrial Habitat Engineering

Author(s): S.J. Dyke, A. Bobet, J. Ramirez, H.J. Melosh, D. Gomez, A. Maghareh, A. Modiriasari, A.K. Theinat
Details: 49th Lunar and Planetary Science Conference 2018, The Woodlands, Texas, March 2018

Description: This abstract provides a brief overview of our vision for and accomplishments to date (2018) towards the challenges of engineering permanent extraterrestrial habitats. The results of these studies are being integrated into a system resilience framework for permanent extraterrestrial habitats.This framework provides a systematic approach to designing of space structures considering their operational dependencies and disruptive/degrading conditions.

Keywords: Safety

Resilience for Permanent Extraterrestrial Habitats

Author(s): A. Maghareh, D. Gomez, S.J. Dyke, A. Bobet, J. Ramirez, H.J. Melosh, A. Modiriasari, A.K. Theinat
Details: 49th Lunar and Planetary Science Conference 2018, The Woodlands, Texas, March 2018

Description: This abstract provides an overview of a resilience framework to design a safe and resilient Earth-independent permanent extraterrestrial habitat (EIPEH). Here, some desired properties of EIPEH systems are considered, such as reconfigurability, robustness, scalability and rapidity. Moreover, this framework adopts the essential elements of two civil engineering design approaches, performance-based design (PBD) and consequence-based design (CBD).

Keywords: Safety, Assessment

Time-Sensitive Networking (TSN) Code Repository

Author(s): Chuanyu Xue
Details: Open Source Toolkit for Python

Description: This GitHub package contains a scheduling toolkit and benchmark for Time-Sensitive Networking in Python. It is used in the publication "Real-Time Scheduling for 802.1Qbv Time-Sensitive Networking (TSN): A Systematic Review and Experimental Study."

Keywords: Decision Making, Communication Network, Cyber-Physical Testing

Development of a Cyber-Physical Testbed for Resilient Extra-terrestrial Habitats

Author(s): Park, J.
Details: Master's Thesis at Purdue University, 2022

Description: Presented in this paper, a dedicated thermal transfer system has been designed and constructed to provide realistic thermal boundary conditions to a physical habitat according to the real-time simulation results from the cyber substructure of the habitat. The extreme temperatures to be found at the interface between the external protective layer of the habitat (cyber) and the interior structural elements (physical) are emulated by means of a cryogenic chiller and an array of cooled panels that cover a dome-style structure. Moreover, the overall architecture of the cyber-physical testbed, the partitioning of the virtual and physical environments, and interface schemes were also established. The experimental results obtained from the thermal transfer system prototype setup were analyzed and interpreted to generate meaningful recommendations for future development and application of the full-sized testbed.

Keywords: Cyber-Physical Testing, Thermal, Control

Hybrid Data-driven and Model-informed Online Tool Wear Detection in Milling Machines

Author(s): Yang Q., Awasthi U., Bollas G.M., and Pattipati K.R.
Details: Journal of Manufacturing Systems, Volume 63 pp. 329-343

Description: Precision machining tool wear is responsible for low product throughput and quality. Monitoring the tool wear online is vital to prevent degradation in machining quality. However, direct real-time tool wear measurement is not practical. This paper presents residual-based anomaly detection models, combining a hybrid model comprised of a physics-based model and a data-driven model (a decision tree or a neural network) to predict signals of interest (e.g., power or forces) under nominal conditions, followed by Page’s cumulative sum test for detecting tool wear on-line using the computer numerical control machine measurements.

Keywords: Fault Detection

Diurnal Temperature Variation on an Intact and Damaged Lunar Habitat Structure

Author(s): Tripathi S., Steiner J., and Malla R.B.
Details: ASCE Earth and Space 2022: Space Exploration, Utilization, Engineering, and Construction in Extreme Environments, Denver, Colorado

Description: This paper presents the surface temperature and temperature through the thickness profile of a monolithic concrete dome habitat structure in the intact and damaged condition on the Moon. Due to long duration days and nights in the lunar environment, a habitat built on the Moon is subjected to extreme temperature fluctuations. The three-dimensional thermodynamics heat balance equation was solved using the explicit finite difference method. For the damaged condition, the difference between daytime high and nighttime low temperature at the interior wall surface of the lunar structure can be as large as 57 K.

Keywords: Structure, Pressure, Thermal

Air Pressure and Temperature Distribution within a Dome Habitat Structure on the Lunar surface

Author(s): Steiner J., Tripathi S., and Malla R.B.
Details: ASCE Earth and Space 2022: Space Exploration, Utilization, Engineering, and Construction in Extreme Environments, Denver, Colorado

Description: In order to seriously consider human habitation of the lunar surface, an in-depth analysis of the performance of a habitat under the extreme environmental pressures encountered on the lunar surface will be needed for any future designs. It is for this reason that a model of the air temperature and pressure changes within the habitat expected in various scenarios will need to be developed. In this study, a zone-based approach was considered to predict the pressure, temperature, and air mass flow at different points within the habitat space. The model serves as a foundation for development of a detailed lunar habitat model which accurately models expected internal conditions without intervention.

Keywords: Structure, Pressure, Thermal

A Study of Layered Structural Configurations as Thermal and Impact Shielding of Lunar Habitats

Author(s): Steiner J. and Malla R. B.
Details: 17th Biennial International Conference on Engineering, Science, Construction, and Operations in Challenging Environments

Description: The focus of this study is the analysis of a proposed multilayer material configuration as lunar habitat shielding so as to assess its ability to resist temperature extremes and impact. In order to resist this environmental hazard, the analysis compares various configurations of potential shielding layers using both in-situ resource utilization (ISRU) and Earth-based materials. The results of this study should be useful in determining the potential for implementation of efficient shielding layers for the initial lunar base.

Keywords: Thermal, Structure

An Autonomous Vault-Building Robot System for Creating Spanning Structures

Author(s): Melebrink N., Wang A., and Werfel J.
Details: IEEE International Conference on Robotics and Automation, 2021

Description: Research in autonomous robots for construction has largely focused on ground-based robots whose reach constrains the size of what they can build, or on climbing or aerial robots that build solid or unroofed structures. Autonomous construction of larger, multistory buildings, or bridges spanning unsupported distances, would require robots that build sturdy structures supporting their own weight. In this paper, we present VaultBot, a system of autonomous robots that build a load-bearing spanning vault using identical modular blocks. Such a system could be used to help enable construction of protective shelters in challenging environments, such as disaster relief scenarios, arctic settings, or extraterrestrial habitats.

Keywords: Autonomy, Robotics, Manipulation

Quickest Detection of COVID-19 Pandemic Onset

Author(s): Pattipati K. R., Braca P., Gaglione D., Marano S., Millefiori L. M., and Willett P.
Details: IEEE Journal, 2021

Description: This article develops an easily-implementable version of Page's CUSUM quickest-detection test, designed to work in certain composite hypothesis scenarios with time-varying data statistics. The decision statistic can be cast in a recursive form and is particularly suited for on-line analysis. By back-testing our approach on publicly-available COVID-19 data we find reliable early warning of infection flare-ups, in fact sufficiently early that the tool may be of use to decision-makers on the timing of restrictive measures that may in the future need to be taken.

Keywords: Decision Making

A critical look at Coulomb counting method for state of charge estimation in rechargeable batteries

Author(s): Balasingam B., Movassagh K., Raihan A., and Pattipati K.R.
Details: Energies Journal, 2021

Description: This paper considers the problem of state-of-charge estimation for rechargeable batteries. We formally construct and quantify the state-of-charge estimate error during Coulomb counting due to four types of error sources. It is demonstrated that the state-of-charge error produced can be either time-cumulative or state-of-charge-proportional. The study presents methods for reducing time-cumulative and state-of-charge-proportional mistakes through simulation analysis.

Keywords: Sensor/Fusion

An Enhanced Approach to Adaptive Kalman Filtering towards Real-time Estimation via Mini-batch Estimates

Author(s): Kim H.S., Zhang L., Bienkwoski A., and Pattipati K.R.
Details: IEEE Access, 2021

Description: This paper presents stochastic gradient descent algorithms for noise covariance estimation in adaptive Kalman filters that are an order of magnitude faster than the batch method for similar or better root mean square error. More significantly, these algorithms are applicable to non-stationary systems where the noise covariances can occasionally jump up or down by an unknown magnitude. The comparative evaluation of the proposed methods on a number of test cases demonstrates their computational efficiency and accuracy.

Keywords: Sensor/Fusion

Quickest Detection and Forecast of Pandemic Outbreaks: Analysis of COVID-19 Waves

Author(s): Pattipati K. R., Soldi G., Forti N. et al
Details: IEEE Communications Magazine, Vol. 59, Issue 9

Description: This article proposes an integrated detection-estimation-forecasting framework that, using publicly available data, is designed to: learn relevant features of the pandemic (e.g., the infection rate); detect as quickly as possible the onset (or the termination) of an exponential growth of the contagion; and reliably forecast the pandemic evolution. The proposed solution is validated by analyzing the COVID-19 second and third waves in the United States.

Keywords: Decision Making

Battery Thermal Model Identification and Surface Temperature Prediction

Author(s): Kumar P., Balasingam B., Pattipati K.R., and Rankin G.
Details: IECON – 47th Annual Conference of the IEEE Industrial Electronics Society, 2021

Description: Performance of a Li-ion battery is affected by temperature; low temperature causes reduced power output and high temperature affects state of health and compromises safety. To overcome these challenges and for reliable performance of batteries, thermal management is needed in electric vehicles. This paper presents a thermal-electrical equivalent circuit model to predict the surface temperature of a battery.


Dual Quaternion Visual Servo Control

Author(s): Saltus R., Salehi I., Rotithor G., and Dani A.P.
Details: 59th IEEE Conference on Decision and Control (CDC), 2020

Description: This paper focuses on a dual quaternion-based estimation and control approach for position-based visual servoing (PBVS). The method is distinguished from other PBVS methods in the sense that a compact representation of dual quaternion is used to represent the pose, and a joint stability of estimator and controller for PBVS in dual quaternion space is presented. The proposed dual quaternion PBVS method is validated using a simulation.

Keywords: Robotics (General), Vision, Perception, Navigation

Cities of the Future - Panel Discussion, part of ASCE Dream Big

Author(s): Steiner J.
Details: DREAM – BUILD – CREATE, organized by ASCE - SSI, 2020

Description: PhD Student Jeffrey Stiener participates as a panelist on the American Society of Civil Engineers' "Cities of the Future - Dream Team" event, where he discusses the difficulties associated with building off-planet structures and cities.

Keywords: Structure

The RETH Institute began at Purdue University in 2017, funded by the Purdue University Provost Office (through the New Horizons program) and the Dubai Future Foundation. For more information on the original RETH program at Purdue, visit the original RETH page.