A Pareto-Optimal Local Optimization Framework for Multiobjective Ergodic Search
Zhongqiang Ren, Akshaya Kesarimangalam Srinivasan, Bhaskar Vundurthy, Ian Abraham, Howie Choset
Abstract
Our work is motivated by humanitarian assistant and disaster relief (HADR) where often it is critical to find signs of life in the presence of conflicting criteria, objectives, and information. We believe ergodic search can provide a framework for exploiting available information as well as exploring for new information in applications, such as HADR. Existing ergodic search methods typically consider search using only a single information map. However, one can readily envision many scenarios where multiple information maps that encode different types of relevant information are used. Ergodic search methods currently do not possess the ability to simultaneously search multiple information maps, nor do they have a way to balance which information gets priority. This leads us to formulate a multiobjective ergodic search (MO-ES) problem, which aims to find the so-called Pareto-optimal solutions, for the purpose of providing human decision makers various solutions that trade off among conflicting criteria. To efficiently solve MO-ES, we develop a framework called sequential local ergodic search (SL-ES), which leverages the recent advances in ergodic search methods as well as the idea of local optimization to efficiently compute Pareto-optimal solutions. Our numerical results show that SL-ES computes solutions of better quality and runs faster than the baselines.