Planning for Multi-stage Forceful Manipulation

TL;DR

This paper presents an augmented planning system for multi-stage forceful manipulation tasks, integrating controllers and constraints to handle discrete strategies and continuous parameters considering force, torque, and friction limits.

Contribution

It introduces a novel approach that combines task and motion planning with force control and constraint reasoning for complex manipulation tasks.

Findings

Successfully applied to opening bottles and twisting nuts

System considers numerous strategies and robustness to parameter variations

Demonstrates improved planning for forceful manipulation tasks

Abstract

Multi-stage forceful manipulation tasks, such as twisting a nut on a bolt, require reasoning over interlocking constraints over discrete as well as continuous choices. The robot must choose a sequence of discrete actions, or strategy, such as whether to pick up an object, and the continuous parameters of each of those actions, such as how to grasp the object. In forceful manipulation tasks, the force requirements substantially impact the choices of both strategy and parameters. To enable planning and executing forceful manipulation, we augment an existing task and motion planner with controllers that exert wrenches and constraints that explicitly consider torque and frictional limits. In two domains, opening a childproof bottle and twisting a nut, we demonstrate how the system considers a combinatorial number of strategies and how choosing actions that are robust to parameter variations impacts the choice of strategy.