๐ค AI Summary
This work addresses the challenge of efficiently integrating task objectives with safety specifications in high-dimensional, complex environmentsโa setting where conventional approaches often struggle due to reliance on extensive manual tuning and limited scalability. The authors propose a novel Bellman value graph decomposition framework that decomposes temporal logic tasks into canonical subproblems, including Reach-Avoid, Avoid, and a newly introduced Reach-Avoid-Loop formulation, each governed by tailored Bellman equations. An end-to-end learning architecture is developed, leveraging a dual-layer neural network and the VDPPO algorithm to automatically balance safety (liveness) and performance without handcrafted heuristics. Empirical evaluations on high-dimensional nonlinear systems and heterogeneous multi-agent hardware platforms demonstrate substantial improvements over existing baselines, achieving synergistic optimization of safety constraints and task objectives.
๐ Abstract
Real-world tasks involve nuanced combinations of goal and safety specifications. In high dimensions, the challenge is exacerbated: formal automata become cumbersome, and the combination of sparse rewards tends to require laborious tuning. In this work, we consider the innate structure of the Bellman Value as a means to naturally organize the problem for improved automatic performance. Namely, we prove the Bellman Value for a complex task defined in temporal logic can be decomposed into a graph of Bellman Values, connected by a set of well-known Bellman equations (BEs): the Reach-Avoid BE, the Avoid BE, and a novel type, the Reach-Avoid-Loop BE. To solve the Value and optimal policy, we propose VDPPO, which embeds the decomposed Value graph into a two-layer neural net, bootstrapping the implicit dependencies. We conduct a variety of simulated and hardware experiments to test our method on complex, high-dimensional tasks involving heterogeneous teams and nonlinear dynamics. Ultimately, we find this approach greatly improves performance over existing baselines, balancing safety and liveness automatically.