A nonlinear robot joint friction compensation method including stick and sliding characteristics
ISSN: 0143-991x
Article publication date: 6 June 2023
Issue publication date: 9 August 2023
Abstract
Purpose
Due to dynamic model is the basis of realizing various robot control functions, and it determines the robot control performance to a large extent, this paper aims to improve the accuracy of dynamic model for n-Degree of Freedom (DOF) serial robot.
Design/methodology/approach
This paper exploits a combination of the link dynamical system and the friction model to create robot dynamic behaviors. A practical approach to identify the nonlinear joint friction parameters including the slip properties in sliding phase and the stick characteristics in presliding phase is presented. Afterward, an adaptive variable-step moving average method is proposed to effectively reduce the noise impact on the collected data. Furthermore, a radial basis function neural network-based friction estimator for varying loads is trained to compensate the nonlinear effects of load on friction during robot joint moving.
Findings
Experiment validations are carried out on all the joints of a 6-DOF industrial robot. The experimental results of joint torque estimation demonstrate that the proposed strategy significantly improves the accuracy of the robot dynamic model, and the prediction effect of the proposed method is better than that of existing methods.
Originality/value
The proposed method extends the robot dynamic model with friction compensation, which includes the nonlinear effects of joint stick motion, joint sliding motion and load attached to the end-effector.
Keywords
Acknowledgements
The authors are grateful to the editor, the associate editor and the anonymous referees for very helpful suggestions and comments. This work was partly supported by the funding of Guangdong Basic and Applied Basic Research Foundation under Grant No. 2021A1515110359, the National Key Research and Development Program under Grant No. 2018YFB1305702, the Natural Science Basic Research Program of Shaanxi under Grant No. 2023-JC-QN-0677, Shaanxi Key Research and Development Program under Grant No. 2021ZDLGY09-02 and the Fundamental Research Funds for the Central Universities under Grant No. G2023KY05102.
Citation
Feng, Y., Zhang, K., Li, H. and Wang, J. (2023), "A nonlinear robot joint friction compensation method including stick and sliding characteristics", Industrial Robot, Vol. 50 No. 5, pp. 814-829. https://doi.org/10.1108/IR-12-2022-0322
Publisher
:Emerald Publishing Limited
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