Design of Flexible Joint Controller Based on Desired Dynamics

doi:10.3901/JME.2023.03.038

Abstract

Abstract: Cooperative robots are flexible and safe, and have been widely used in automation and small and medium-sized enterprises. In order to ensure the safety of interaction with people, cooperative robots usually use the design scheme of hollow motor and hollow reducer to reduce the joint moment of inertia, so as to obtain good external force perception and control capability. This design leads to the flexibility of the joint of cooperative robots. A flexible joint controller based on expected dynamics is designed for a cooperative robot with flexible joints, which improves the trajectory tracking accuracy and vibration suppression ability of the flexible joint robot. On the flexible joint with harmonic reducer and torque sensor, the transformation from classical motor side control to link side control is realized based on link side position feedback and joint torque feedback. Further, the storage function is used to establish the Lyapunov function, and the passivity and asymptotic stability of the controller are proved. Finally, the performance of the flexible joint controller is verified through Simulink simulation and joint trajectory tracking experiment on a single joint experimental platform. The results show that compared with the full state feedback control, it has the advantages of small joint torque fluctuation, faster vibration suppression and smaller trajectory tracking error.

Key words: robots, flexible joint, desired dynamics, torque feedback, vibration suppression

CLC Number:

TP242

WANG Xinqing, WANG Xin, SHI Nianling, CHEN Zhaopeng. Design of Flexible Joint Controller Based on Desired Dynamics[J]. Journal of Mechanical Engineering, 2023, 59(3): 38-45.

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