Publication

**The code and datasets of our research work can be found in our GitHub page
**The videos for illustrating our research work can be found in our YouTube channel

Textbook

1. S. Zhao, "Mathematical Foundations of Reinforcement Learning", Springer Nature Press and Tsinghua University Press, to be published in 2024 (The online version has received 2K+ stars on GitHub)

Recent Articles

1. Z Ning, Y Zhang, X Lin, and S Zhao*, "A Real-to-Sim-to-Real Approach for Vision-Based Autonomous MAV-Catching-MAV", Unmanned Systems, accepted

2. H. Guo, Y. Zheng, Y. Zhang, Z. Gao, and S. Zhao*, "Global-local MAV detection under challenging conditions based on appearance and motion", IEEE Transactions on Intelligent Transportation Systems, accepted, Mar 2024 (PDF)

3. H. Cao, J. Shen, C. Liu, B. Zhu, and S. Zhao*, "Motion planning for aerial pick-and-place based on geometric feasibility constraints", IEEE Transactions on Automation Science and Engineering, accepted, Mar 2024

4. Y. Zhang, J. Deng, P. Liu, W. Li, and S. Zhao*, "Domain adaptive detection of MAVs: A benchmark and noise suppression network", IEEE Transactions on Automation Science and Engineering, accepted, Feb 2024

5. K. Li, L. Li, R. Gross, and S. Zhao*, "A collective perception model for neighbor selection in groups based on visual attention mechanisms", New Journal of Physics, 26 012001, 2024

6. C. Zheng, Y. Mi, H. Guo, H. Chen, Z. Lin, S. Zhao*, "Optimal spatial-temporal triangulation for bearing-only cooperative motion estimation", arXiv:2310.15846, Oct 2023 (PDF)

7. H. Chen, W. Ji, L. Xu, and S. Zhao*, "Multi-agent consensus seeking via large language models", arXiv:2310.20151, Oct 2023 (Project website) (PDF)

Journal Articles

1. Z. Ning, Y. Zhang, J. Li, and Z. Chen, and S. Zhao*, "A bearing-angle approach for unknown target motion analysis based on visual measurements", The International Journal of Robotics Research, accepted, Jan 2024 (arXiv:2401.17117) (Matlab code)

2. J. Li, L. Li, and S. Zhao*, "Predator-prey survival pressure is sufficient to evolve swarming behaviors", New Journal of Physics, vol. 25, 2023

3. Z. Ning, Y. Zhang, and S. Zhao*, "Comparison of different pseudo-linear estimators for vision-based target motion estimation", Control Theory and Technology, vol. 21, pp. 448–457, 2023 (invited for a special issue)

4. G. Sun, R. Zhou, Z. Ma, Y. Li, R. Gross, Z. Chen, and S. Zhao*, "Mean-shift exploration in shape assembly of robot swarms", Nature Communications, vol. 14, no. 3476, 2023. (Video, Source code)

5. H. Cao, Y. Li, C. Liu, and S. Zhao*, "ESO-based robust and high-precision tracking control for aerial manipulation", IEEE Transactions on Automation Science and Engineering, accepted, Mar 2023. (Video)

6. J. Li, Z. Ning, S. He, C.-H. Lee, and S. Zhao*, "Three-dimensional bearing-only target following via observability-enhanced helical guidance", IEEE Transactions on Robotics, vol. 39, no. 2, pp. 1509-1526, 2023. (Video)

7. Y. Zheng, C. Zheng, X. Zhang, F. Chen, Z. Chen, and S. Zhao*, "Detection, localization, and tracking of multiple MAVs with panoramic stereo camera networks", IEEE Transactions on Automation Science and Engineering, vol. 20, no. 2, pp. 1226-1243, 2023. (Video)

8. X. Zhang, Y. Zhang, P. Liu, and S. Zhao, "Robust localization of occluded targets in aerial manipulation via range-only mapping", IEEE Robotics and Automation Letters, vol. 7, no. 2, pp. 2921-2928, 2022. (Video) (Presentation in ICRA 2022)

9. Z. Wang, R. Gross, and S. Zhao, "Aerobatic Tic-Toc control of planar quadcopters via reinforcement learning", IEEE Robotics and Automation Letters, accepted, vol. 7, no. 2, pp. 2140-2147, 2022. (Video) (Presentation in ICRA 2022)

10. Z. Wang, R. Gross, and S. Zhao, "Control of centrally-powered variable pitch propeller quadcopters subject to propeller faults", Aerospace Science and Technology, vol. 120, 107245, 2022.

11. Z. Li, H. Tnunay, S. Zhao, W. Meng, S. Q. Xie, and Z. Ding, "Bearing-only formation control with pre-specified convergence time", IEEE Transactions on Cybernetics, vol. 52, no. 1, pp. 620-629, 2022.

12. Y. Zheng, Z. Chen, D. Lv, Z. Li, Z. Lan, and S. Zhao, "Air-to-air visual detection of micro-UAVs: an experimental evaluation of deep learning", IEEE Robotics and Automation Letters, vol. 6, no. 2, pp. 1020-1027, 2021.  (Video)

13.  Y. Xu, S. Zhao, D. Luo, Y. You, "Affine formation maneuver control of high-order multi-agent systems over directed networks", Automatica, vol. 118, pp. 1-8, 2020. 

14. K. Li, J. Wang, C.-H. Lee, R. Zhou, and S. Zhao, "Distributed cooperative guidance for multi-vehicle simultaneous arrival without numerical singularities", AIAA Journal of Guidance, Control, and Dynamics, vol. 43, no. 7, pp 1365-1372, 2020. 

15. F. Pasqualetti, S. Zhao, C. Favaretto, and S. Zampieri, "Fragility limits performance in complex networks", Scientific Reports 10, 1774 (2020)

16. Z. Wang, R. Gross, and S. Zhao, "Controllability analysis and controller design for VPP quadcopters with one propeller failure", Advanced Control for Applications, p. e29, 2020 (invited special issue)

17. X. Li, X. Luo, and S. Zhao, "Globally convergent distributed network localization using locally measured bearings", IEEE Transactions on Control of Network Systems, vol. 7, no. 1, pp. 245-253, 2020.

18. S. Zhao, Z. Li, and Z. Ding, "Bearing-only formation tracking control of multi-agent systems", IEEE Transactions on Automatic Control, vol. 64, no. 11, pp. 4541-4554, 2019.

19. J. A. Douthwaite, S. Zhao, and L. S. Mihaylova, "Velocity obstacle approaches for multi-Agent collision avoidance," Unmanned Systems, vol. 7, no. 1, pp. 55–64, 2019.

20. S. Zhao and F. Pasqualetti, "Networks with diagonal controllability Gramian: analysis, graphical conditions, and design algorithms", Automatica, vol. 102, pp. 10-18, April 2019.

21. W. Song, J. Wang, S. Zhao, and J. Shan, "Event-triggered cooperative unscented Kalman filtering and its application in multi-UAV systems", Automatica, vol. 105, pp. 264-273, July 2019.

22. M.-H. Trinh, S. Zhao, Z. Sun, D. Zelazo, B.D.O. Anderson, and H.-S. Ahn, "Bearing-based formation control of a group of agents with leader-first follower structure," IEEE Transactions on Automatic Control, vol. 64, no. 2, pp. 598-613, 2019.

23. S. Zhao and D. Zelazo, "Bearing rigidity theory and its applications for control and estimation of network systems: life beyond distance rigidity", IEEE Control Systems Magazine, vol. 39, no. 2, pp. 66-83, 2019. [presentation slides]

24. S. Zhao, "Affine formation maneuver control of multi-agent systems", IEEE Transactions on Automatic Control, vol. 63, no. 12, pp. 4140-4155, 2018. [simulation animation: video 1, video 2] [presentation slides] [Matlab code]

25. S. Zhao, D. V. Dimarogonas, Z. Sun, and D. Bauso, "A general approach to coordination control of mobile agents with motion constraints," IEEE Transactions on Automatic Control, vol. 63, no. 5, pp. 1509-1516, 2018. [simulation animation]

26. S. Zhao and D. Zelazo, "Translational and scaling formation maneuver control via a bearing-based approach," IEEE Transactions on Control of Network Systems, vol. 4, no. 3, pp. 429-438, 2017 [Simulation animation: video1, video2]

27. S. Zhao and D. Zelazo, "Localizability and distributed protocols for bearing-based network localization in arbitrary dimensions," Automatica, vol. 69, pp. 334-341, 2016.

28. S. Zhao and D. Zelazo, "Bearing rigidity and almost global bearing-only formation stabilization," IEEE Transactions on Automatic Control, vol. 61, no. 5, pp. 1255-1268, 2016. [Simulation animation: youtube]

29. S. Zhao, F. Lin, K. Peng, X. Dong, B. M. Chen, and T. H. Lee, "Vision-aided estimation of attitude, velocity, and inertial measurement bias for UAV stabilization," Journal of Intelligent & Robotic Systems, vol. 81, no. 3, pp. 531-549, 2016. [Flight experimental video: youtube]

30. F. Wang, P. Liu, S. Zhao, B. M. Chen, S. K. Phang, S. Lai, T. Pang, B. Wang, C. Cai, and T. H. Lee, "Development of an unmanned helicopter for vertical replenishment," Unmanned Systems, vol. 3, no. 1, pp. 63-87, 2015. [Real flight video: youtube]

31. S. Zhao, Z. Hu, M. Yin, K. Z. Y. Ang, P. Liu, F. Wang, X. Dong, F. Lin, B. M. Chen, and T. H. Lee, "A robust real-time vision system for autonomous cargo transfer by an unmanned helicopter," IEEE Transactions on Industrial Electronics, vol. 62, no. 2, pp. 1210-1219, 2015. [Real flight video: youtube]

32. S. Zhao, F. Lin, K. Peng, B. M. Chen, and T. H. Lee, "Finite-time stabilization of cyclic formations using bearing-only measurements," International Journal of Control, vol. 87, no. 4, pp. 715-727, 2014.

33. S. Zhao, B. M. Chen, and T. H. Lee, "Optimal deployment of mobile sensors for target tracking in 2D and 3D spaces," IEEE/CAA Journal of Automatica Sinica, vol. 1, no. 1, pp. 24-30, 2014. (Invited for the inaugural issue)

34. S. Zhao, F. Lin, K. Peng, B. M. Chen, and T. H. Lee, "Distributed control of angle-constrained cyclic formations using bearing-only measurements," Systems & Control Letters, vol. 63, no. 1, pp. 12-24, 2014.

35. S. Zhao, B. M. Chen, and T. H. Lee, "Optimal sensor placement for target localization and tracking in 2D and 3D," International Journal of Control, vol. 86, no. 10, pp. 1687-1704, 2013. [presentation slides]

36. S. Zhao, R. Zhou, C.Wei, and Q. Ding, "Design of time-constrained guidance laws via virtual leader approach," Chinese Journal of Aeronautics, vol. 23, no. 1, pp. 103–108, 2010.

37. S. Zhao and R. Zhou, "Design and feasibility analysis of a closed-form guidance law with both impact angle and time constraints," Journal of Astronautics, vol. 30, no. 3, pp. 1064–1072, 2009.

38. S. Zhao and R. Zhou, "Cooperative guidance for multimissile salvo attack," Chinese Journal of Aeronautics, vol. 21, no. 6, pp. 533–539, 2008

39. S. Zhao and R. Zhou, "Multi-missile cooperative guidance using coordination variables," Acta Aeronautica Et Astronautica Sinica, vol. 30, no. 6, pp. 1605–1611, 2008. (in Chinese) (Award: F5000 Frontrunner--Top Articles from Outstanding S&T Journals of China)

*corresponding author

Conference Articles

1. Z. Sun, S. Zhao, D. Zelazo, "Characterizing bearing equivalence in directed graphs", in the Proceedings of the 22nd IFAC World Congress, (Yokohama, Japan), accepted, July 2023.

2. H. Cao and S. Zhao, "Predictive damped inverse kinematics for redundant and underactuated robotic systems", in the Proceedings of the 2020 IEEE 16th International Conference on Control & Automation (ICCA), Online, pp. 348-353, October 2020

3. Y. Xu, S. Zhao, D. Luo, and Y. You, "Affine formation maneuver control of linear multi-agent systems with undirected interaction graphs," in the Proceedings of the 2018 IEEE Conference on Decision and Control, (Miami Beach, FL, USA), pp. 502-507, December 2018. 

4. J. A. Douthwaite, S. Zhao, and L. S. Mihaylova, "A comparative study of velocity obstacle approaches for multi-agent systems", in the Proceedings of the 12th UKACC International Conference on Control, (Sheffield, UK), pp. 289-294, September 2018.

5. Y. Xu, S. Zhao, D. Luo, and Y. You, "Affine formation maneuver control of multi-agent systems with directed interaction graphs," in Proceedings of the 37th Chinese Control Conference, (Wuhan, China), pp. 4563-4568, July 2018.

6. S. Zhao, Z. Li, and Z. Ding, "A revisit to gradient-descent bearing-only formation control," in Proceedings of the 14th IEEE International Conference on Control and Automation, (Anchorage, Alaska, USA), pp. 710-715, June 2018.

7. S. Zhao and F. Pasqualett, "Controllability degree of directed line networks: Nodal energy and asymptotic bounds," in Proceedings of the 2018 European Control Conference, (Limassol, Cyprus), pp. 1857-1862, June 2018.

8. F. Pasqualetti, C. Favaretto, S. Zhao, and S. Zampieri, "Fragility and controllability tradeoff in complex networks," in Proceedings of the 2018 American Control Conference, (Milwaukee, USA), pp. 216-221, June 2018.

9. A. Samiei, B. Hu, S. Zhao, and L. Sun, "A Decision-Making Framework for Robust Multi-Agent Systems in Risky Communication Scenarios," in Proceedings of the AIAA Science and Technology Forum, (Kissimmee, Florida, USA), January 2018.

10. S. Zhao, Z. Sun, D. Zelazo, M. H. Trinh, and H.-S. Ahn, "Laman graphs are generically bearing rigid in arbitrary dimensions," in Proceedings of the 56th IEEE Conference on Decision and Control, (Melbourne, Australia), pp. 3356-3361, December 2017. [presentation slides]

11. S. Zhao and R. Zheng, "Flexible bearing-only rendezvous control of mobile robots," in Proceedings of the 36th Chinese Control Conference, (Dalian, China), pp. 8051-8056, July 2017.

12. S. Zhao and Z. Sun, "Defend the practicality of single-integrator models in multi-robot coordination control," in Proceedings of the 13th IEEE International Conference on Control and Automation, (Ohrid, Macedonia), pp. 666-671, July 2017.

13. S. Zhao and F. Pasqualetti, "Discrete-time networks with diagonal controllability Gramian," in Proceedings of the 20th IFAC World Congress, (Toulouse, France), pp. 8627-8632, July 2017.

14. L. Sun, B. Hu, and S. Zhao, "An event-triggering-based approach for three-dimensional local-level frame formation control of leader-follower UAVs," in Proceedings of the 2017 International Conference on Unmanned Aircraft Systems, (Miami, USA), pp. 472-479, June 2017.

15. S. Zhao and D. Zelazo, "Bearing-based formation stabilization with directed interaction topologies," in Proceedings of the 54th IEEE Conference on Decision and Control, (Osaka, Japan), pp. 6115-6120, December 2015.

16. S. Zhao and D. Zelazo, "Bearing-based formation maneuvering," in Proceedings of the 2015 IEEE Multi-Conference on Systems and Control, (Sydney, Australia), pp. 658–663, September 2015.

17. S. Zhao and D. Zelazo, "Bearing-based distributed control and estimation in networks of agents," in Proceedings of the 14th European Control Conference, (Linz, Austria), pp. 2207–2212, July 2015.

18. O. Rozenheck, S. Zhao, and D. Zelazo, "A proportional-integral controller for distance-based formation tracking," in Proceedings of the 14th European Control Conference, (Linz, Austria), pp. 1687–1692, July 2015.

19. S. Zhao and D. Zelazo, "Bearing-constrained formation control using bearing measurements," in Proceedings of the 55th Israel Annual Conference on Aerospace Sciences, (Haifa, Israel), February 2015.

20. O. Rozenheck, S. Zhao, and D. Zelazo, "Formation velocity tracking with proportional control," in Proceedings of the 55th Israel Annual Conference on Aerospace Sciences, (Haifa, Israel), February 2015.

21. F. Wang, P. Liu, S. Zhao, B. M. Chen, S. K. Phang, S. Lai, and T. H. Lee, "Guidance, navigation and control of an unmanned helicopter for automatic cargo transportation," in Proceedings of the 2014 Chinese Control Conference, (Nanjing, China), pp. 1013-1020, July 2014. (Best Paper Award/Guan Zhao-Zhi Award)

22. S. Zhao, Z. Hu, M. Yin, K. Ang, P. Liu, F. Wang, X. Dong, F. Lin, B. M. Chen, and T. H. Lee, "A robust vision system for a UAV transporting cargoes between moving platforms," in Proceedings of the 2014 Chinese Control Conference, (Nanjing, China), pp. 544-549, July 2014.

23. F. Lin, K. Peng, X. Dong, S. Zhao, and B. M. Chen, "Vision-based formation for UAVs," in Proceedings of the 11th IEEE International Conference on Control & Automation, (Taichung, Taiwan), pp. 1375-1380, June 2014.

24. K. Peng, S. Zhao, F. Lin, and B. M. Chen, "Vision-based target tracking/following and estimation of target motion," in Proceedings of the 2013 AIAA Guidance, Navigation and Control Conference, (Boston, USA), August 2013.

25. S. Zhao, X. Dong, J. Cui, Z. Y. Ang, F. Lin, K. Peng, B. M. Chen, and T. H. Lee, "Design and implementation of homography-based vision-aided inertial navigation of UAVs," in Proceedings of the 2013 Chinese Control Conference, (Xi'an, China), pp. 5101-5106, July 2013.

26. S. Zhao, F. Lin, K. Peng, B. M. Chen, and T. H. Lee, "Distributed control of angle-constrained circular formations using bearing-only measurements," in Proceedings of the 2013 Asian Control Conference, (Istanbul, Turkey), pp. 1-6, June 2013.

27. S. Zhao, F. Lin, K. Peng, B. M. Chen, and T. H. Lee, "Finite-time stabilization of circular formations using bearing-only measurements," in Proceedings of the 2013 IEEE International Conference on Control & Automation, (Hangzhou, China), pp. 840-845, June 2013.

28. K. Peng, S. Zhao, F. Lin, and B. M. Chen, "Vision based stabilization for aircraft in unknown environment without GPS signal," in Proceedings of the 2012 AIAA Guidance, Navigation and Control Conference, (Minneapolis, USA), August 2012.

29. S. Zhao, F. Lin, K. Peng, B. M. Chen, and T. H. Lee, "Homography-based vision-aided inertial navigation of UAVs in unknown environments," in Proceedings of the 2012 AIAA Guidance, Navigation and Control Conference, (Minneapolis, USA), August 2012.

30. S. Zhao, B. M. Chen, and T. H. Lee, "Optimal placement of bearing-only sensors for target localization," in Proceedings of the 2012 American Control Conference, (Montreal, Canada), pp. 5108-5113, June 2012. (Best Presentation in Session Award)