A resistance torque compensation algorithm based on Luenberger observer for minimally invasive surgical robot
ISSN: 0143-991X
Article publication date: 5 January 2024
Issue publication date: 26 January 2024
Abstract
Purpose
The patient-side manipulator (PSM) achieves high torque capability by combining harmonic servo system with high reduction ratio and low torque motor. However, high reduction ratio can increase inertia and decrease compliance of the manipulator. To enhance the backdrivability of the minimally invasive surgical robot, this paper aims to propose a resistance torque compensation algorithm.
Design/methodology/approach
A resistance torque compensation algorithm based on dynamics and Luenberger observer is proposed. The dynamics are established, considering joint flexibility and an improved Stribeck friction model. The dynamic parameters are experimentally identified by using the least squares method. With the advantages of clear structure, simple implementation and fast solution speed, the Luenberger observer is selected to estimate the unmeasured dynamic information of PSM and realize the resistance torque compensation.
Findings
For low-speed surgical robots, the centrifugal force term in the dynamic model can be simplified to reduce computational complexity. Joint flexibility and an improved Stribeck friction model can be considered to improve the accuracy of the dynamic model. Experiment results show that parameter identification and estimated results of the Luenberger observer are accurate. The backdrivability of the PSM is enhanced in ease and smoothness.
Originality/value
This algorithm provides potential application prospects for surgical robots to maintain high torque while remaining compliant. Meanwhile, the enhanced backdrivability of the manipulator helps to improve the safety of the preoperative manual adjustment.
Keywords
Acknowledgements
Special thanks to the following two funds for their support: the National Natural Science Foundation of China (Grant No. 51975409) and the Program for Innovative Research Team in University of Tianjin (No. TD13-5037).
Erratum: It has come to the attention of the publisher that the article Sang, H., Huang, F., Lu, W., Han, R. and Liu, F. (2024), “A resistance torque compensation algorithm based on Luenberger observer for minimally invasive surgical robot”, Industrial Robot, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/IR-08-2023-0188, contained an error in the author’s affiliation, which was introduced during the production process. School of Mechanical Engineering, Tiangong University, Tianjin, UK has been changed to School of Mechanical Engineering, Tiangong University, Tianjin, China. The publisher sincerely apologises for this error and for any confusion caused.
Citation
Sang, H., Huang, F., Lu, W., Han, R. and Liu, F. (2024), "A resistance torque compensation algorithm based on Luenberger observer for minimally invasive surgical robot", Industrial Robot, Vol. 51 No. 1, pp. 7-19. https://doi.org/10.1108/IR-08-2023-0188
Publisher
:Emerald Publishing Limited
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