Planning for Multi-stage Forceful Manipulation

Abstract

Multi-step forceful manipulation tasks, such as opening a push-and-twist childproof bottle, require a robot to make various planning choices that are substantially impacted by the requirement to exert force during the task. The robot must reason over discrete and continuous choices relating to the sequence of actions, such as whether to pick up an object, and the parameters of each of those actions, such how to grasp the object. To enable planning and executing forceful manipulation, we augment an existing task and motion planner with constraints that explicitly consider torque and frictional limits, captured through the proposed forceful kinematic chain constraint. In three domains, opening a childproof bottle, twisting a nut and cutting a vegetable, we demonstrate how the system selects from among a combinatorial set of strategies. We also show how cost-sensitive planning can be used to find strategies and parameters that are robust to uncertainty in the physical parameters.

A Method for Designing Autonomous Robots that Know Their Limits

“…Junge et al [15] addressed the problem of slight variations in the time duration of each of the subtasks by optimizing learnt parameters that relate with the subtask duration. Wang et al [16] and Holladay et al [17] both address the challenge of uncertain position of the object being manipulated. They propose methods for generating robot motions based on the confidence of the estimated object pose.…”

“…They propose methods for generating robot motions based on the confidence of the estimated object pose. Additionally, Holladay et al [17] took into account force constraints. All the previous works focus on adaptations within a subtask, given a pre-specified sequence of subtasks.…”

Robust planning for multi-stage forceful manipulation

“…This paper is an extension of Holladay et al (2021) and the additional contributions beyond that work are as follows: a new domain (cutting a vegetable), additional demonstrations relating to robust planning and more detailed descriptions of the planning framework and domain specifications.…”