Journal of Astronautics ›› 2013, Vol. 34 ›› Issue (12): 1599-1604.doi: 10.3873/j.issn.1000-1328.2013.12.009

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Augmented Adaptive Control and Joint Vibration Suppression for Flexible Joint Space Robot with Flexibility Compensation

CHEN Zhi yong,  CHEN Li   

  1. College of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China
  • Received:2013-01-14 Revised:2013-05-16 Online:2013-12-15 Published:2013-12-25

Abstract:

The problems of joint motion control and flexible vibration suppression of a flexible joint space based robot for manipulating an unknown payload are studied. Based on the system linear momentum conservation and the Lagrange method, the under actuated dynamics model of the space robot is established. For convenience of the design of its control system, the system is divided into both fast and slow subsystems by using the joint flexibility compensation technique and the singular perturbation theory. A torque differential feedback controller is proposed for the fast subsystem to suppress the joints’ flexible vibration, meanwhile an adaptive control scheme based on the augmentation approach is designed for the slow subsystem to realize the joint trajectory asymptotic tracking under the condition of unknown payload parameters. Because of introduction of the flexibility compensation technique, the presented control scheme can equivalently increase the joint stiffness, and it is suitable to control the space robot systems with low joint stiffness. Moreover, the effect of unknown parameters is real time compensated by its adaptive controller, and then the specified joint motion task is achieved precisely. The effectiveness of the scheme is verified by the corresponding simulation results.

Key words: Flexible joint space robot, Flexibility compensation, Singular perturbation, Augmentation approach, Adaptive control

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