Policy Synthesis for Finite Populations of MDP Agents under Aggregate Reach-Avoid Chance Constraints
Organizations: Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA · School of Electrical Engineering and Computer Science, Washington State University, Pullman, WA 99164, USA
Abstract
Consider a finite population of agents with decoupled Markov transition dynamics and empirical-density feedback, subject to the following constraints: with probability at least , at least a fraction of agents must reach a target region at some time , while, at each time up to , the unsafe population fraction must remain below with probability at least . However, standard mean-field methods enforce these constraints only in expectation, which fails to account for stochastic fluctuations at finite fleet size . To address this control problem, we propagate the second-order moment (variance) of the empirical density alongside the mean-field trajectory via a discrete-time Lyapunov recursion, and apply the Cantelli inequality to convert chance constraints into tractable deterministic conditions on the moments of the empirical density. We then incorporate these moment-based surrogate constraints into a gradient-based sequential convex approximation procedure for density-feedback policy synthesis. We further introduce additional moment-error bounds to construct a rigorous finite- certificate. The method is evaluated on a gridworld environment and a power-system EV-charging aggregation problem and compared with a standard deterministic population-level LP baseline.
Figures & tables
| MF-LP (baseline) | SCA (proposed) | |||||||
|---|---|---|---|---|---|---|---|---|
| emp. met? | / | |||||||
| 10 | 9.39 | 0.91 ✓ | 0.38 ✓ | 9.38 | 1.00 ✓ | 0.40 ✓ | ||
| 20 | 9.38 | 0.95 ✓ | 0.39 ✓ | 8.97 | 1.00 ✓ | 0.12 ✓ | ||
| 50 | 9.37 | 1.00 ✓ | 0.44 × | 9.23 | 1.00 ✓ | 0.08 ✓ | ||
| 100 | 9.38 | 1.00 ✓ | 0.47 × | 9.28 | 1.00 ✓ | 0.12 ✓ | ||
| MF-LP (baseline) | SCA (proposed) | |||||||
|---|---|---|---|---|---|---|---|---|
| emp. met? | / | |||||||
| 20 | 19.11 | 1.00 ✓ | 0.45 × | 17.62 | 1.00 ✓ | 0.27 ✓ | ||
| 50 | 19.09 | 1.00 ✓ | 0.49 × | 17.56 | 1.00 ✓ | 0.06 ✓ | ||
| 100 | 19.09 | 1.00 ✓ | 0.52 × | 17.99 | 1.00 ✓ | 0.08 ✓ | ||
| 200 | 19.09 | 1.00 ✓ | 0.51 × | 18.31 | 1.00 ✓ | 0.07 ✓ | ||