Selected Publications

Under Review & Preprints

1. \(\mathcal L_1\)Quad: \(\mathcal L_1\) adaptive augmentation of geometric control for agile quadrotors with performance guarantees
   Z. Wu, S. Cheng, P. Zhao, A. Gahlawat, K. Ackerman, A. Lakshmanan, C. Yang, J. Yu, and N. Hovakimyan
   Submitted, 2023
   [Video] [ArXiv]

2. Robust adaptive control of linear parameter-varying systems with unmatched uncertainties
   P. Zhao, S. Snyder, N. Hovakimyan, and C. Cao
   Submitted, 2021
   [ArXiv]

3. Guaranteed nonlinear tracking in the presence of DNN-learned dynamics with contraction metrics and disturbance estimation
   P. Zhao, Z. Guo, Y. Cheng, A. Gahlawat, H. Kang, and N. Hovakimyan
   arXiv preprint arXiv: 2112.08222, 2022

Journal Papers

1. Convex synthesis of control barrier functions under input constraints
   P. Zhao, R. Ghabcheloo, Y. Cheng, H. Abdi, and N. Hovakimyan
   IEEE Control System Letters, vol.7, pp.3102-3107, 2023
   [Code]

2. Integrated adaptive control and reference governors for constrained systems with state-dependent uncertainties
   P. Zhao, I. Kolmanovsky, and N. Hovakimyan
   IEEE Transactions on Automatic Control, conditionally accepted, 2023
   [ArXiv]

3. \(\mathcal L_1\) adaptive control with switched reference models: Application to Learn-to-Fly
   S. Snyder, P. Zhao and N. Hovakimyan
   Journal of Guidance, Control, and Dynamics, 45(12): 2229-2242, 2022
   [Video]

4. Tube-certified trajectory tracking for nonlinear systems with robust control contraction metrics
   P. Zhao, A. Lakshmanan, K. Ackerman, A. Gahlawat, M. Pavone, and N. Hovakimyan
   IEEE Robotics and Automation Letters, 7(2): 5528-5535, 2022
   [ArXiv]  [Video]  [Code]

5. Improving the robustness of reinforcement learning policies with \(\mathcal L_1\) adaptive control
   Y. Cheng* , P. Zhao*, F. Wang, D. J. Block, and N. Hovakimyan
   IEEE Robotics and Automation Letters, 7(3): 6574-6581, 2022
   [ArXiv]  [Video]

6. Robust nonlinear tracking control with exponential convergence using contraction metrics and disturbance estimation
   P. Zhao, Z. Guo, and N. Hovakimyan
   Sensors, 22(13): 4743, 2022
   

7. Adaptive control for linear parameter-varying systems with application to a VTOL aircraft
   S. Snyder, P. Zhao and N. Hovakimyan
   Aerospace Science and Technology, 112: 106621, 2021

8. Novel stealthy attack and defense strategies for networked control systems
   Y. Mao, H. Jafarnejadsani, P. Zhao, E. Akyol and N. Hovakimyan
   IEEE Transactions on Automatic Control, 65(9): 3847-3862, 2020

9. Experimental validation of a robust \(H_\infty\) control method on miniaturized optical image stabilizer prototypes
   A. Alizadegan, P. Zhao, R. Nagamune and M. Chiao
   Journal of Dynamic Systems, Measurement, and Control, 142(12): 124501, 2020

10. Switching linear parameter-varying control with improved local performance and optimized switching surfaces
    P. Zhao and R. Nagamune
    International Journal of Robust and Nonlinear Control, 28: 3403-3421, 2018

11. Multiple parameter-dependent robust control of miniaturized optical image stabilizers
    P. Zhao, R. Nagamune and M. Chiao
    Control Engineering Practice, 76: 1-11, 2018

12. Robust \(H_\infty\) control of miniaturized optical image stabilizers against product variabilities
    A. Alizadegan, P. Zhao, R. Nagamune and M. Chiao
    Control Engineering Practice, 80: 70-82, 2018
    

13. Switching LPV controller design under uncertain scheduling parameters
    P. Zhao and R. Nagamune
    Automatica, 2017, 76: 243-250

14. Adaptive fuzzy torque control of passive torque servo systems based on small gain theorem and input-to-state stability
    X. Wang, S. Wang, P. Zhao
    Chinese Journal of Aeronautics, 25(6): 906-916, 2012

Book chapter

• Design, fabrication, and robust control of miniaturized optical image stabilizers
  K. Yuan, A. Alizadegan, P. Zhao, R. Nagamune, J. Chu, S. Park and M. Chiao
  Advanced Mechatronics and MEMS Devices-II, Dan Zhang and Bin Wei (eds.), Springer International Publishing Switzerland, Chapter 28, pp. 189-207, 2017.

Conference Papers

1. Optimizing Crop management with reinforcement learning and imitation learning
   R. Tao, P. Zhao, J. Wu, N. F. Martin, M. T. Harrison, C. Ferreira, Z. Kalantari, and N. Hovakimyan
   Proceedings of the Thirty-Second International Joint Conference on Artificial Intelligence (IJCAI-23), 2023
   

2. Safe and efficient reinforcement learning using disturbance observer-based control barrier functions
   Y. Cheng, P. Zhao, and N. Hovakimyan
   5th Conference on Learning for Dynamics and Control, PMLR, 211:104-115, 2023

3. Safety embedded stochastic optimal control of networked multi-agent systems
   L. Song, P. Zhao, N. Wan and N. Hovakimyan
   2023 American Control Conference, 2023
   

4. Optimizing nitrogen management with deep reinforcement learning and crop simulations
   J. Wu*, R. Tao*, P. Zhao*, N. Martin and N. Hovakimyan
   Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pp. 1712-1720, 2022
   [ArXiv]

5. \(\mathcal L_1\) adaptive augmentation for geometric tracking control of quadrotors
   Z. Wu, C. Sheng, K. A. Ackerman, A. Gahlawat, A. Lakshmanan, P. Zhao, and N. Hovakimyan
   IEEE Conference on Robotics and Automation, 2022.
   [ArXiv]  [Video]

6. Adaptive robust quadratic programs using control Lyapunov and barrier functions
   P. Zhao, Y. Mao, C. Tao, N. Hovakimyan and X. Wang
   Proceedings of the 59th IEEE Conference on Decision and Control, pp. 3353-3358, 2020
   [ArXiv]

7. \(\mathcal L_1\)-GP: \(\mathcal L_1\) adaptive control with Bayesian learning
   A. Gahlawat, P. Zhao, A. Patterson, N. Hovakimyan and E. A. Theodorou
   2nd Conference on Learning for Dynamics and Control, PMLR, 120:1-12, 2020

8. \(\mathcal L_1\) adaptive control for switching reference systems: Application to flight control
   S. Snyder, P. Zhao and N. Hovakimyan
   IFAC-PapersOnLine, 52(16), pp.718-723, 2019.

9. Detectability of intermittent zero-dynamics attack in networked control systems
   Y. Mao, H. Jafarnejadsani, P. Zhao, E. Akyol and N. Hovakimyan
   Proceedings of the 58th IEEE Conference on Decision and Control, pp. 5605-5610, 2019.

10. Switching LPV control of a floating offshore wind turbine on a semi-submersible platform
    P. Zhao and R. Nagamune
    Proceedings of IEEE 28th International Symposium on Industrial Electronics, pp. 664-669, 2019

11. Discrete-time state-feedback switching LPV Control with seperate Lyapunov functions for stability and local performance
    P. Zhao and R. Nagamune
    Proceedings of American Control Conference, pp. 2023-2028, 2018

12. Optimal switching surface design for switching LPV control and its application to air-fuel ratio control of an automotive engine
    P. Zhao and R. Nagamune
    Proceedings of IEEE Conference on Control Technology and Applications (CCTA), pp. 898-903, 2017

13. Optimal switching surface design for state-feedback switching LPV control
    P. Zhao and R. Nagamune
    Proceedings of American Control Conference, pp. 817-822, 2015

14. Robust control of large-scale prototypes for miniaturized optical image stabilizers with product variations
    P. Zhao, A. Alizadegan, R. Nagamune and M. Chiao
    Proceedings of SICE Annual Conference, pp. 925-930, 2015

15. Modeling and robust control of miniaturized magnetically-actuated optical image stabilizers
    A. Alizadegan, P. Zhao, R. Nagamune and M. Chiao
    Proceedings of IEEE International Conference on Advanced Intelligent Mechatronics, pp. 846-851, 2016

Workshop Papers & Extended Abstracts

1. Optimizing crop management with reinforcement learning and imitation learning
   R. Tao, P. Zhao, J. Wu, N. F. Martin, M. T. Harrison, C. Ferreira, Z. Kalantari, and N. Hovakimyan
   22nd International Conference on Autonomous Agents and Multiagent Systems (AAMAS), 2023

2. Robustifying reinforcement learning policies with \(\mathcal L_1\) adaptive control
   Y. Cheng*, P. Zhao*, M. Gandhi, B. Li, E. Theodorou and N. Hovakimyan
   ICRA Workshop on Safe Robot Control with Learned Motion and Environment Models, 2021

3. Socially aware motion planning for a flying robot with model predictive path integral control
   H.-J. Yoon, P. Zhao, C. Tao, C. Widdowson, R. Wang, N. Hovakimyan and E. Theodorou
   ICRA Workshop on Algorithms and Architectures for Learning-in-the-Loop Systems in Autonomous Flight workshop, 2019

4. Guaranteed nonlinear control with DNN-learned dynamics using robust contraction metrics and disturbance estimation
   P. Zhao, Z. Guo, Y. Cheng and N. Hovakimyan
   AAAI Workshop on Trustworthy Autonomous Systems Engineering, 2022