Recursive Decentralized Control for Trajectory Tracking of Flexible Space Manipulators

Abstract

A recursive decentralized control scheme is presented for the trajectory tracking issue of flexible space manipulator. In the traditional decentralized control for manipulators, each link in the manipulator is viewed as an isolated second-order subsystem. Its interconnections with other links are viewed as disturbances. As a consequence, the obtained decentralized control has a simple structure but lacks high control performance. In this paper, the manipulator is considered as a set of connected secondorder subsystems. The interconnections between two adjacent links are revealed by the recursive kinematics and dynamics. In such a manner, the nominal value of the interaction forces is constructed and used for compensation to improve the tracking accuracy. Then, decentralized control is devised for each link to achieve trajectory tracking and vibration suppression of the flexible manipulator. The actuators are chosen as the joint motors and the distributed force or torque actuators on the flexible links. Under the assumption that the modal information of the flexible links is obtainable by the modal filter technique, an adaptive term in the controller is deduced for estimating the bound of the model uncertainties. Moreover, a steering logic is devised for the actuators to produce the required control. The obtained controller inherits the simple structure of the decentralized control and also achieves a higher tracking performance. The numerical examples of a free flying flexible manipulator are given to illustrate the effectiveness of the proposed control scheme. INDEX TERMS Decentralized control, flexible space manipulators, recursive dynamics, trajectory tracking.

Neural Network Control of Space Manipulator Based on Dynamic Model and Disturbance Observer

“…Additionally, the flexible arm produces large elastic deformation during large movement, and may even cause a large vibration [21]. This vibration can seriously affect the positioning accuracy of the arm [23], [47]. Therefore, in this paper, the dynamic model is compensated for using the powerful approximation ability of the neural network, thereby reducing the tremor of the end effector and improving positional accuracy.…”

“…Gao et al [22] combined the Lagrangian method with the assumed mode method to establish the dynamic equation. Su et al [23] studied the trajectory tracking problem of flexible arms. Feng et al [24] and Yang et al [25] studied the dynamics model of flexible multibody systems.…”

Virtual Decomposition Based Modeling for Multi-DOF Manipulator With Flexible Joint

“…Ailon et al [8] considered motor dynamics and parameter uncertainties to improve the previous dynamic model. A recursive decentralized control scheme was presented by Su et al [9] to address the trajectory tracking problems of flexible manipulators, and the interconnections between the adjacent flexible links were calculated by recursive kinematics and dynamics. This scheme could achieve both trajectory tracking and vibration suppression for the flexible manipulator.…”