1. Approximate Optimal Control for Safety-Critical Systems with Control Barrier Functions
- Author
-
Max H. Cohen and Calin Belta
- Subjects
Equilibrium point ,0209 industrial biotechnology ,Mathematical optimization ,Optimization problem ,Computer science ,Time horizon ,02 engineering and technology ,Invariant (physics) ,Optimal control ,020901 industrial engineering & automation ,Control system ,Bellman equation ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Quadratic programming ,Relaxation (approximation) - Abstract
Control Barrier Functions (CBFs) have become a popular tool for enforcing set invariance in safety-critical control systems. While guaranteeing safety, most CBF approaches are myopic in the sense that they solve an optimization problem at each time step rather than over a long time horizon. This approach may allow a system to get too close to the unsafe set where the optimization problem can become infeasible. Some of these issues can be mitigated by introducing relaxation variables into the optimization problem; however, this compromises convergence to the desired equilibrium point. To address these challenges, we develop an approximate optimal approach to the safety-critical control problem in which the cost of violating safety constraints is directly embedded within the value function. We show that our method is capable of guaranteeing both safety and convergence to a desired equilibrium. Finally, we compare the performance of our method with that of the traditional quadratic programming approach through numerical examples.
- Published
- 2020
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