Symbolic Optimal Control
It provides a theoretical framework for computing symbolic controllers with guaranteed performance for a broad class of optimal control problems, including minimum time and pursuit-evasion games, without assuming continuity of the value function.
The paper presents a method for solving a class of leavable, undiscounted optimal control problems for nonlinear systems using symbolic controllers derived from discretized abstractions, proving convergence to the optimal value function as discretization refines.
We present novel results on the solution of a class of leavable, undiscounted optimal control problems in the minimax sense for nonlinear, continuous-state, discrete-time plants. The problem class includes entry-(exit-)time problems as well as minimum time, pursuit-evasion and reach-avoid games as special cases. We utilize auxiliary optimal control problems (`abstractions') to compute both upper bounds of the value function, i.e., of the achievable closed-loop performance, and symbolic feedback controllers realizing those bounds. The abstractions are obtained from discretizing the problem data, and we prove that the computed bounds and the performance of the symbolic controllers converge to the value function as the discretization parameters approach zero. In particular, if the optimal control problem is solvable on some compact subset of the state space, and if the discretization parameters are sufficiently small, then we obtain a symbolic feedback controller solving the problem on that subset. These results do not assume the continuity of the value function or any problem data, and they fully apply in the presence of hard state and control constraints.