Adaptive control of redundant robot manipulators with null-space compliance

Abstract

Purpose

The purpose of this paper is to propose an adaptive control for a redundant robot manipulator interacting physically with the environment, especially with the existence of humans, on its body.

Design/methodology/approach

The redundant properties of the robot manipulator are used and a reference velocity variable is introduced to unify the operation-space tracking control and the null-space impedance control under one common framework. Neural networks are constructed to deal with unstructured and unmodeled dynamic nonlinearities. Lyapunov function is used during the course of control design and simulation studies are carried out to further illustrate the effectiveness of the proposed strategies.

Findings

Satisfying tracking performance in the operation-space and compliance behavior in the null-space of the redundant robot manipulator are ensured simultaneously.

Originality/value

The design procedure of redundant robot manipulators control can be greatly simplified, and the framework of multi-priority control can be transformed into a joint-space velocity tracking problem via the introducing of a reference velocity variable.

Citation

Xu, Q. and Ge, S.S. (2018), "Adaptive control of redundant robot manipulators with null-space compliance", Assembly Automation, Vol. 38 No. 5, pp. 615-624. https://doi.org/10.1108/AA-02-2018-030