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State estimation of a robot joint by a novel nonlinear tracking differentiator

Xiao Tu (School of Mechanical Science & Engineering, Huazhong University of Science and Technology, Wuhan, China)
Yunfei Zhou (School of Mechanical Science & Engineering, Huazhong University of Science and Technology, Wuhan, China)
Pu Zhao (School of Mechanical Science & Engineering, Huazhong University of Science and Technology, Wuhan, China)
Xin Cheng (Hubei Maglev Engineering Technology Research Center, Wuhan University of Technology, Wuhan, China and Institute of Advanced Material Manufacturing Equipment and Technology, Wuhan University of Technology, Wuhan, China)

Industrial Robot

ISSN: 0143-991x

Article publication date: 13 December 2017

Issue publication date: 2 January 2018

252

Abstract

Purpose

This paper aims to present a method for improving the state estimation of a robot in the presence of noise measurement, which can improve the performance of the robot controller.

Design/methodology/approach

In this work, a novel nonlinear tracking differentiator (NTD) was formulated to solve the problems of phase lag, low stability and amplitude attenuation faced by traditional tracking differentiators, which can be used for the state estimation of a robot. Based on the user-defined function stu() with linear and nonlinear characteristics, the authors establish a new acceleration function of NTD and confirm its global asymptotic stability by using the Lyapunov method and the system equivalence method. Phase plane analysis shows that the origin is its stable nodal point or focus point and uncovers the basic constraint conditions for parameter regulation. In addition, the convergence property and robustness performance against noises are studied by describing function method.

Findings

Comparative simulations, robot state estimation experiments and joint trajectory tracking experiments have indicated that NTD proposed integrates tracking rapidness, accuracy and transitional stability and has high approximation and filtering effects on generalized derivatives of the signal, which contribute to an excellent performance of robot controller in stability and response speed in practice.

Originality/value

The main contribution of this paper lies in the design of a novel NTD, which successfully improves the state estimation of a robot joint in noisy surroundings, the tracking performance of robot controller and the stability of the system.

Keywords

Acknowledgements

Research supported by National Natural Science Foundation of China (Project number: 51375194 and 51575411) and State Key Lab of Digital Manufacturing Equipment & Technology, School of Mechanical Science and Engineering, Huazhong University of Science & Technology.

Citation

Tu, X., Zhou, Y., Zhao, P. and Cheng, X. (2018), "State estimation of a robot joint by a novel nonlinear tracking differentiator", Industrial Robot, Vol. 45 No. 1, pp. 11-22. https://doi.org/10.1108/IR-08-2017-0149

Publisher

:

Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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