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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


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


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: 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


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


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


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


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


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


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


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

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

Description: To effectively address pandemics in a systematic and informed manner in the future, it is of fundamental importance to develop mathematical models and algorithms to predict the evolution of the spread of the disease to support policy and decision making at the governmental level. There is a strong literature describing the application of Bayesian sequential and adaptive dynamic estimation to surveillance (tracking and prediction) of objects such as missiles and ships; and in this article, we transfer some of its key lessons to epidemiology. 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.

Keywords: Fault Detection, Fault Tolerance


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


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


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


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


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


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


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


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


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


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


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


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


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


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)


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


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


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


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


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


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


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


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


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


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


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


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


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.

Keywords: None


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


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


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)


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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.