Learning a Formally Verified Control Barrier Function in Stochastic Environment (2403.19332v1)
Abstract: Safety is a fundamental requirement of control systems. Control Barrier Functions (CBFs) are proposed to ensure the safety of the control system by constructing safety filters or synthesizing control inputs. However, the safety guarantee and performance of safe controllers rely on the construction of valid CBFs. Inspired by universal approximatability, CBFs are represented by neural networks, known as neural CBFs (NCBFs). This paper presents an algorithm for synthesizing formally verified continuous-time neural Control Barrier Functions in stochastic environments in a single step. The proposed training process ensures efficacy across the entire state space with only a finite number of data points by constructing a sample-based learning framework for Stochastic Neural CBFs (SNCBFs). Our methodology eliminates the need for post hoc verification by enforcing Lipschitz bounds on the neural network, its Jacobian, and Hessian terms. We demonstrate the effectiveness of our approach through case studies on the inverted pendulum system and obstacle avoidance in autonomous driving, showcasing larger safe regions compared to baseline methods.
- A. D. Ames, J. W. Grizzle, and P. Tabuada, “Control barrier function based quadratic programs with application to adaptive cruise control,” in 53rd IEEE Conference on Decision and Control. IEEE, 2014, pp. 6271–6278.
- A. D. Ames, X. Xu, J. W. Grizzle, and P. Tabuada, “Control barrier function based quadratic programs for safety critical systems,” IEEE Transactions on Automatic Control, vol. 62, no. 8, pp. 3861–3876, 2017.
- A. D. Ames, S. Coogan, M. Egerstedt, G. Notomista, K. Sreenath, and P. Tabuada, “Control barrier functions: Theory and applications,” in 18th European control conference (ECC). IEEE, 2019, pp. 3420–3431.
- P. Jagtap, S. Soudjani, and M. Zamani, “Formal synthesis of stochastic systems via control barrier certificates,” IEEE Transactions on Automatic Control, vol. 66, no. 7, pp. 3097–3110, 2020.
- A. Clark, “Verification and synthesis of control barrier functions,” in 2021 60th IEEE Conference on Decision and Control (CDC). IEEE, 2021, pp. 6105–6112.
- G. Wu and K. Sreenath, “Safety-critical control of a planar quadrotor,” in 2016 American Control Conference (ACC), 2016, pp. 2252–2258.
- M. Tayal and S. Kolathaya, “Control barrier functions in dynamic uavs for kinematic obstacle avoidance: a collision cone approach,” arXiv preprint arXiv:2303.15871, 2023.
- Q. Nguyen and K. Sreenath, “Safety-critical control for dynamical bipedal walking with precise footstep placement,” IFAC-PapersOnLine, vol. 48, no. 27, pp. 147–154, 2015.
- A. Papachristodoulou and S. Prajna, “A tutorial on sum of squares techniques for systems analysis,” in Proceedings of the 2005, American Control Conference, 2005., 2005, pp. 2686–2700 vol. 4.
- U. Topcu, A. Packard, and P. Seiler, “Local stability analysis using simulations and sum-of-squares programming,” Automatica, vol. 44, no. 10, pp. 2669–2675, 2008.
- A. Robey, H. Hu, L. Lindemann, H. Zhang, D. V. Dimarogonas, S. Tu, and N. Matni, “Learning control barrier functions from expert demonstrations,” in 2020 59th IEEE Conference on Decision and Control (CDC), 2020, pp. 3717–3724.
- H. Zhao, X. Zeng, T. Chen, and Z. Liu, “Synthesizing barrier certificates using neural networks,” in Proceedings of the 23rd international conference on hybrid systems: Computation and control, 2020, pp. 1–11.
- A. Abate, D. Ahmed, A. Edwards, M. Giacobbe, and A. Peruffo, “Fossil: A software tool for the formal synthesis of Lyapunov functions and barrier certificates using neural networks,” in Proceedings of the 24th International Conference on Hybrid Systems: Computation and Control, 2021, pp. 1–11.
- A. Abate, D. Ahmed, M. Giacobbe, and A. Peruffo, “Formal synthesis of lyapunov neural networks,” IEEE Control Systems Letters, vol. 5, no. 3, pp. 773–778, 2020.
- A. Peruffo, D. Ahmed, and A. Abate, “Automated and formal synthesis of neural barrier certificates for dynamical models,” in Tools and Algorithms for the Construction and Analysis of Systems. Springer International Publishing, 2021, pp. 370–388.
- Q. Zhao, X. Chen, Z. Zhao, Y. Zhang, E. Tang, and X. Li, “Verifying neural network controlled systems using neural networks,” in 25th ACM International Conference on Hybrid Systems: Computation and Control, 2022, pp. 1–11.
- H. Zhang, J. Wu, Y. Vorobeychik, and A. Clark, “Exact verification of relu neural control barrier functions,” in Advances in Neural Information Processing Systems, A. Oh, T. Neumann, A. Globerson, K. Saenko, M. Hardt, and S. Levine, Eds., vol. 36. Curran Associates, Inc., 2023, pp. 5685–5705.
- C. Dawson, Z. Qin, S. Gao, and C. Fan, “Safe nonlinear control using robust neural Lyapunov-barrier functions,” in Conference on Robot Learning. PMLR, 2022, pp. 1724–1735.
- C. Dawson, S. Gao, and C. Fan, “Safe control with learned certificates: A survey of neural Lyapunov, barrier, and contraction methods for robotics and control,” IEEE Transactions on Robotics, 2023.
- S. Liu, C. Liu, and J. Dolan, “Safe control under input limits with neural control barrier functions,” in Conference on Robot Learning. PMLR, 2023, pp. 1970–1980.
- B. Dai, P. Krishnamurthy, and F. Khorrami, “Learning a better control barrier function,” in 2022 IEEE 61st Conference on Decision and Control (CDC), 2022, pp. 945–950.
- H. Zhang, L. Niu, A. Clark, and R. Poovendran, “Fault tolerant neural control barrier functions for robotic systems under sensor faults and attacks,” arXiv preprint arXiv:2402.18677, 2024.
- O. So, Z. Serlin, M. Mann, J. Gonzales, K. Rutledge, N. Roy, and C. Fan, “How to train your neural control barrier function: Learning safety filters for complex input-constrained systems,” arXiv preprint arXiv:2310.15478, 2023.
- M. Anand and M. Zamani, “Formally verified neural network control barrier certificates for unknown systems,” IFAC-PapersOnLine, vol. 56, no. 2, pp. 2431–2436, 2023.
- M. Lutter, C. Ritter, and J. Peters, “Deep lagrangian networks: Using physics as model prior for deep learning,” in International Conference on Learning Representations, 2019.
- P. Pauli, A. Koch, J. Berberich, P. Kohler, and F. Allgöwer, “Training robust neural networks using lipschitz bounds,” IEEE Control Systems Letters, vol. 6, pp. 121–126, 2021.
- A. J. Barry, A. Majumdar, and R. Tedrake, “Safety verification of reactive controllers for UAV flight in cluttered environments using barrier certificates,” in 2012 IEEE International Conference on Robotics and Automation. IEEE, 2012, pp. 484–490.
- L. E. Dubins, “On curves of minimal length with a constraint on average curvature, and with prescribed initial and terminal positions and tangents,” American Journal of Mathematics, vol. 79, no. 3, pp. 497–516, 1957.