A Hybrid Position/Force Controller for Joint Robots

TL;DR

This paper introduces a hybrid position/force control method for joint robots that decouples motion and force regulation, validated through simulations and case studies like surface polishing and object grasping.

Contribution

It proposes a novel hybrid control approach that separates motion and force control using a smooth mapping, enhancing robot operation capabilities.

Findings

Effective decoupling of position and force control demonstrated

Successful application in surface polishing and object grasping

Validated through physics engine simulations

Abstract

In this paper, we present a hybrid position/force controller for operating joint robots. The hybrid controller has two goals -- motion tracking and force regulating. As long as these two goals are not mutually exclusive, they can be decoupled in some way. In this work, we make use of the smooth and invertible mapping from joint space to task space to decouple the two control goals and design controllers separately. The traditional motion controller in task space is used for motion control, while the force controller is designed through manipulating the desired trajectory to regulate the force indirectly. Two case studies -- contour tracking/polishing surfaces and grabbing boxes with two robotic arms -- are presented to show the efficacy of the hybrid controller, and simulations with physics engines are carried out to validate the efficacy of the proposed method.