Automatic Extension of a Symbolic Mobile Manipulation Skill Set

TL;DR

This paper presents a method for autonomous robots to automatically extend their symbolic skill set, enabling better adaptation to environmental changes and improving task success rates in simulation.

Contribution

It introduces strategies for generalizing skills, completing action sequences, and discovering preconditions to enhance symbolic planning adaptability.

Findings

29% higher success rate compared to baseline

68% faster runtime in simulation

Effective skill set extension in object rearrangement tasks

Abstract

Symbolic planning can provide an intuitive interface for non-expert users to operate autonomous robots by abstracting away much of the low-level programming. However, symbolic planners assume that the initially provided abstract domain and problem descriptions are closed and complete. This means that they are fundamentally unable to adapt to changes in the environment or task that are not captured by the initial description. We propose a method that allows an agent to automatically extend its skill set, and thus the abstract description, upon encountering such a situation. We introduce strategies for generalizing from previous experience, completing sequences of key actions and discovering preconditions to ensure the efficiency of our skill sequence exploration scheme. The resulting system is evaluated in simulation on object rearrangement tasks. Compared to a Monte Carlo Tree Search baseline, our strategies for efficient search have on average a 29% higher success rate at a 68% faster runtime.