Adaptive Stiffness and Damping Impedance Control for Environmental Interactive Systems With Unknown Uncertainty and Disturbance

Gangqi Dong,Panfeng Huang,Zhiqiang Ma

doi:10.1109/access.2019.2955961

Gangqi Dong, Panfeng Huang + Show 1 more

Open Access

https://doi.org/10.1109/access.2019.2955961

Copy DOI

Abstract

This paper presents an impedance controller with adaptive stiffness and damping terms for environmental interactive system with unknown modeling error and external disturbance. The objective is to compensate the uncertainty and disturbance and form a desired close-loop impedance architecture. A disturbance observer for nonlinear system is employed to estimate the lumped uncertainty and disturbance. The stiffness and damping are adjusted by the state-variable-related negative power type parameters. Consequently, the control input is designed with the consideration of the estimation of lumped uncertainty and disturbance as well as the regulated stiffness and damping. The stability is proved and the criterion of parameter selection is pointed out. Although the state-variable-related stiffness and damping parameters will intuitively be singular, the system works without any singularity due to the independence of these parameters in stability analysis. To verify the proposed approach, a one degree of freedom mass system is adopted and numerical simulation is performed accordingly. The simulation results demonstrate the effectiveness and the superiority of the proposed control scheme for environmental interactive system with unknown modeling error and external disturbance.

Highlights

Robotic systems are widely adopted in industry, agriculture, and many other fields, to perform tasks or missions where exists dynamic interaction with the environments in most cases [1]–[4]
The impedance control is based on the concept that the controller should be used to regulate the dynamic behavior between the motion of the environmental interactive system and the force exerted on the environment so as to achieve an objective impedance architecture, rather than considering the motion control and force control problems separately [6]
Aiming at addressing these issues in general, this paper proposes a framework of impedance control with adaptive stiffness and damping

Summary

INTRODUCTION

Robotic systems are widely adopted in industry, agriculture, and many other fields, to perform tasks or missions where exists dynamic interaction with the environments in most cases [1]–[4]. G. Dong et al.: Adaptive Stiffness and Damping Impedance Control for Environmental Interactive Systems admittance control was proposed in [8] to address the stability issues of the switch system with dynamic interaction in changing environment. According to the above discussion, the stability, system uncertainties, and external disturbances are regarded as the main problems in robotic systems while interacting with the environment Aiming at addressing these issues in general, this paper proposes a framework of impedance control with adaptive stiffness and damping. The objective of this paper is to develop controllers for environmental interactive systems with the consideration of system uncertainty, disturbance and environmental interaction generated external force, so as to achieve fast changing surface tracking ability as well as a desired impedance architecture.

BACKGROUND

NUMERICAL SIMULATION

CONCLUSION