Chopra, Nikhil
Professor
Mechanical Engineering
Electrical and Computer Engineering
The Institute for Systems Research
Maryland Robotics Center
Maryland Applied Graduate Engineering
Electrical and Computer Engineering
The Institute for Systems Research
Maryland Robotics Center
Maryland Applied Graduate Engineering
2149 Glenn L. Martin Hall
Dr. Nikhil Chopra is a Professor in the Department of Mechanical Engineering at the University of Maryland, College Park, with an affiliate appointment in the Department of Electrical and Computer Engineering. Before joining the University of Maryland, he was a Postdoctoral Research Associate in the Coordinated Science Laboratory at the University of Illinois at Urbana-Champaign from 2006-2007. He received a Bachelor of Technology (Honors) degree in Mechanical Engineering from the Indian Institute of Technology, Kharagpur, India, in 2001, an M.S. degree in General Engineering in 2003, and a Ph.D. degree in Systems and Entrepreneurial Engineering in 2006 from the University of Illinois at Urbana-Champaign. His research is broadly in systems, control, and robotics. Current research interests include the estimation and control of robotic systems, soft robotics, bilateral teleoperation, and machine learning. He is the co-author of the book Passivity-Based Control and Estimation Networked Robotics. He was previously the Co-Chair of the IEEE Technical Committee on Telerobotics. He was previously an Associate Editor of Automatica, IEEE Transactions on Control of Network Systems, and IEEE Transactions on Automatic Control.
Nonlinear control, Estimation and Control of Robotic Systems, Soft Robotics, Bilateral Teleoperation, and Machine Learning.
Books Authored
- T. Hatanaka, N. Chopra, M. Fujita, and M.W. Spong, Passivity-based Control and Estimation in Networked Robotics, Springer International Publishing, Online ISBN 978-3-319-15171, 2015.
Book Chapters
- T. Hatanaka, N. Chopra, J. Yamauchi and M. Fujita, “A Passivity-Based Approach to Human-Swarm Collaboration and Passivity Analysis of Human Operators,” In Trends in Control and Decision-Making for Human–Robot Collaboration Systems, Y. Wang, F. Zhang (Eds.), Springer, pp. 325-355, 2017.
- Y-C. Liu and N. Chopra, “Control of Robotic Manipulators with Input-Output Delays: An Experimental Verification,” In Experimental Robotics, Springer Berlin Heidelberg, pp. 823-837, 2014.
- P. Tallapragada and N. Chopra, “Lyapunov based Sampling for Adaptive Tracking Control in Robot Manipulators: An Experimental Comparison,” In Experimental Robotics, pp. 683-698. Springer, Heidelberg, 2013.
- Y-C. Liu and N. Chopra, “On Adaptive and Robust Controlled Synchronization of Networked Robotic Systems on Strongly Connected Graphs,” In Flight Formation Control, J. Guerrero and R. Lozano (Eds.), Wiley, March 2012.
- N. Chopra and M.W. Spong, “Output Synchronization of Nonlinear Systems with Relative Degree One,” In Recent Advances in Learning and Control, V.D. Blondel, S.P. Boyd, H. Kimura (Eds.), Lecture Notes in Control and Information Sciences, Springer-Verlag, pp. 51-64, 2008.
- N. Chopra and M.W. Spong, “Passivity-Based Control of Multi-Agent Systems,” in Advances in Robot Control, From Everyday Physics to Human-Like Movements, Sadao Kawamura and Mikhail Svinin, Eds., Springer-Verlag, pp. 107-134, Berlin, 2006.
- N. Chopra, M.W. Spong, R. Ortega, and N.E. Barabanov, “Position and Force Tracking in Bilateral Teleoperation,” Lecture Notes in Control and Information Sciences, Vol. 308, Springer Verlag, Berlin, pp. 269-280, 2004.
Articles in Refereed Journals
- T. Hatanaka, T. Mochizuki, T. Sumino, J. M. Maestre and N. Chopra, "Human Modeling and Passivity Analysis for Semi-Autonomous Multi-Robot Navigation in Three Dimensions," in IEEE Open Journal of Control Systems, Vol. 3, pp. 45-57, 2024.
- K. Chakrabarti, and N. Chopra, “A Control Theoretic Framework for Adaptive Gradient Optimizers,” Automatica, 2024, Volume 160, February 2024, 111466.
- J. N. Twigg, F. Dagefu, N. Chopra and B. M. Sadler, “Robotic Parasitic Arrays for Increased RSS in Non-Line-of-Sight,” IEEE Robotics and Automation Letters, Vol. 7, no. 4, pp. 9167-9174, Oct. 2022.
- N. Chopra, M. Fujita, R. Ortega and M. W. Spong, “Passivity-Based Control of Robots: Theory and Examples from the Literature,” IEEE Control Systems Magazine, Vol. 42, No. 2, pp. 63-73, 2022.
- K. Chakrabarti, N. Gupta and N. Chopra, “On Preconditioning of Decentralized Gradient-Descent When Solving a System of Linear Equations,” IEEE Transactions on Control of Network Systems, Vol. 9, No. 2, pp. 811-822, 2022.
- K. Chakrabarti, N. Gupta, and N. Chopra, “Iterative Pre-Conditioning for Expediting the Gradient-Descent Method: The Case of Distributed Linear Least-Squares Problem,” Automatica, Vol. 137, 110095, 2022.
- K. Chakrabarti, N. Gupta, and N. Chopra, “Robustness of Iteratively Pre-Conditioned Gradient-Descent Method: The Case of Distributed Linear Regression Problem,” IEEE Control Systems Letters, 5(6), pp. 2180-2185, 2020.
- N. Gupta, S. Gade, N. Chopra, and N.H. Vaidya, “Preserving statistical privacy in distributed optimization,” IEEE Control Systems Letters, 5(3), pp. 779-784, 2020.
- T. Liu, S. Azarm, N. Chopra, “Decentralized Multisubsystem Co-Design Optimization Using Direct Collocation and Decomposition-Based Methods. Journal of Mechanical Design, 142(9), 2020.
- J. N. Twigg, N. Chopra and B. M. Sadler, “Communication Maintenance of Robotic Parasitic Antenna Arrays,” IEEE Robotics and Automation Letters, vol. 5, no. 4, pp. 6475-6482, Oct. 2020.
- T. Liu, S. Azarm, N. Chopra, “Integrating Optimal Vehicle Routing and Control With Load-Dependent Vehicle Dynamics Using a Confidence Bounds for Trees-Based Approach." Journal of Dynamic Systems, Measurement, and Control 142.4, 2020.
- Y. Dong and N. Chopra, “Passivity-Based Bilateral Tele-Driving System with Parametric Uncertainty and Communication Delays,” IEEE Control Systems Letters, Vol. 3, No. 2, pp. 350-355, 2019.
- Y. Dong, N. Gupta, and N. Chopra, “False Data Injection Attacks in Bilateral Teleoperation Systems,” IEEE Transactions on Control Systems Technology, Vol. 28, No. 3, pp. 1168-1176, 2020.
- T. Hatanaka, N. Chopra, T. Ishizaki, and N. Li, “Passivity Based Distributed Optimization with Communication Delays using PI Consensus Algorithm,” IEEE Transactions on Automatic Control, Vol. 63, No. 12, 2018.
- M.W.S. Atman, T. Hatanaka, Z. Qu, N. Chopra, J. Yamauchi, and M. Fujita, “Human-enabled Motion Synchronization for Semi-Autonomous Robotic Swarm with a Passivity-short Human Operator," International Journal of Intelligent Robotics and Applications, Vol. 2, No. 2, pp. 235- 251, 2018.
- P.V. Chanekar, N. Chopra, and S. Azarm, “Co-design of Linear Systems using Generalized Benders Decomposition,” Automatica, Vol. 89, pp. 180-193, 2018.
- T. Liu, S. Azarm, N. Chopra, “On Decentralized Optimization for a Class of Multisubsystem Codesign Problems,” ASME Journal of Mechanical Design, Vol. 139, No. 12, pp. 121404-11, 2017.
- T. Hatanaka, N. Chopra, J. Yamauchi, M. Doi, Y. Kawai, M. Fujita, “A Passivity-Based System Design of Semi-Autonomous Cooperative Robotic Swarm,” ASME. Mechanical Engineering, Vol. 139, No. 06, pp. S14-S18, 2017.
- Y. Dong, N. Gupta, and N. Chopra, “Content modification attacks on consensus seeking multi-agent system with double-integrator dynamics,” Chaos: An Interdisciplinary Journal of Nonlinear Science 26.11 (2016): 116305.
- L. Sabattini, C. Secchi, N. Chopra, “Decentralized Estimation and Control for Preserving the Strong Connectivity of Directed Graph,” IEEE Transactions on Cybernetics, Vol. 45, No. 10, pp. 2273-2286, Oct. 2015.
- L. Sabattini, C. Secchi, N. Chopra, “Decentralized Connectivity Maintenance for Networked Lagrangian Systems with Collision Avoidance,” Asian Journal of Control, Vol. 17, No. 1, pp. 111-123, Jan. 2015.
- P. Tallapragada and N. Chopra, “Decentralized Event-Triggering for Control of Nonlinear Systems,” IEEE Transactions on Automatic Control, Vol. 59, No. 12, pp. 3312-3324, 2014.
- Y-C. Liu and N. Chopra, “Gravity Compensation Driven Position Regulation for Robotic Systems under Input-Output Delays,” IEEE Transactions on Control Systems Technology, Vol. 22, No.3, pp. 995-1005, 2014.
- Y-C. Liu and N. Chopra, “On Stability and Regulation Performance for Flexible-Joint Robots with Input/Output Communication Delays,” Vol. 50, No. 6, Automatica, pp. 1698-1705, 2014.
- L. Sabattini*, N. Chopra, and C. Secchi, “Decentralized Connectivity Maintenance for Cooperative Control of Mobile Robotic Systems,” International Journal of Robotics Research, Vol. 32, No.12, pp. 1411-1423, 2013.
- L. Sabattini*, C. Secchi, N. Chopra, and A. Gasparri, “Distributed Control of Robotic Systems with Global Connectivity Maintenance,” IEEE Transactions on Robotics, Vol. 29, No. 5, pp. 1326-1332, 2013.
- Y-C. Liu and N. Chopra, “Synchronization of Networked Mechanical Systems with Communication Delays and Human Input,” ASME Journal of Dynamic Systems, Measurement, and Control, Vol. 135, No. 4, 2013.
- P. Tallapragada and N. Chopra, “On Event-Triggered Tracking for Nonlinear Systems,” IEEE Transactions on Automatic Control, Vol. 58, No. 9, pp. 2343-2348, 2013
- Y-C. Liu and N. Chopra, “Control of Semi-Autonomous Teleoperation System with Time Delays,” Automatica, Vol. 49, No. 6, pp. 1553-1565, 2013.
- N. Chopra, “Output Synchronization on Strongly Connected Graphs,” IEEE Transactions on Automatic Control, Vol. 57, No. 11, pp. 2896-2901, 2012.
- Y-C. Liu and N. Chopra, “Control of Robotic Manipulators under Input-Output Communication Delays: Theory and Experiments,” IEEE Transactions on Robotics, Vol. 28, No. 3, pp. 742-751, 2012.
- Y-C. Liu and N. Chopra, “Controlled Synchronization of Robotic Manipulators in the Task Space,” IEEE Transactions on Robotics, Vol. 28, No. 1, pp. 268-275, 2012.
- N. Chopra and M.W. Spong, “On Exponential Synchronization of Kuramoto Oscillators,” IEEE Transactions on Automatic Control, Vol. 53, No. 4, 2009.
- N. Chopra, M.W. Spong, and R. Lozano, “Synchronization of Bilateral Teleoperators with Time Delay,” Automatica, Vol. 44, No. 8, pp. 2142-2148, 2008.
- N. Chopra, P. Berestesky and M.W. Spong, “Bilateral Teleoperation Over Unreliable Communication Networks,” IEEE Transactions on Control Systems Technology, Vol.16, No. 2, pp. 304-313, 2008.
- N. Chopra, M.W. Spong, R. Ortega, and N.E. Barabanov, “On Tracking Performance in Bilateral Teleoperation,” IEEE Transactions on Robotics, Vol. 22, pp. 861-866, 2006.