1. School of Automation, Northwestern Polytechnical University, Xi'an 710072, China
2. School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China
Corresponding author (email@example.com
Precision control of flexible-link manipulator for space operation is challenging due to the dynamics coupling and system uncertainty. In this paper, to deal with system uncertainty and time-varying disturbance, two performance enhanced controller designs, named Composite Learning Control and Disturbance Observer Based Control are presented respectively. To overcome the nonminimum phase, using output redefinition, the dynamics is transformed to two subsystems: internal system and input-output system. For the internal dynamics, the PD (proportion differentiation) control is used with pole assignment. For the input-output subsystem, considering the unknown dynamics, the composite learning control is designed using neural modeling error while in case of disturbance, the disturbance observer based design is proposed. The stability analysis of the closed-loop system is presented via Lyapunov approach. Simulation of 2-degrees of freedom (DOF) flexible-link manipulator is conducted and the results show that the proposed methods can enhance the tracking performance.
This work was supported by Beijing Natural Science Basic Research Plan (Grant No. 4142028) National Natural Science Foundation of China (Grant Nos. 61304098, 61622308), Aeronautical Science Foundation of China (Grant No. 2015ZA53003), Natural Science Basic Research Plan in Shaanxi Province (Grant Nos. 2014JQ8326, 2015JM6272, 2016KJXX-86), Fundamental Research Funds for the Central Universities (Grant Nos. 3102015AX001, 3102015BJ(II)CG017), and Fundamental Research Funds of Shenzhen Science and Technology Project (Grant No. JCYJ20160229172341417). The authors acknowledge Dr Xu Bin's students Zhang Qi, Yang Daipeng, Xia Yingzhou for their help of the simulation result.
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