Robust synchronous control of dual linear actuators with load variation, nonlinear friction and disturbances

This paper deals with the problem concerning the design method of synchronous motion controllers in form of output feedback for dual linear actuators with load differences, dynamic nonlinear friction and force ripples. The authors focus on not only nonlinear friction and disturbance but also the dual motors synchronous objective. The energy upper bound for conquering disturbances is estimated and used as compensation. After that, in order to improve the robustness of the dual-motor motion plant in the presence of external disturbances, an interference rejection approach is presented. Furthermore, due to load variation which degrades synchronous tracking performance for dual motors, the controller design method based on the convex optimization scheme is proposed. The illustrative examples show that the controller can significantly improve the tracking performance under nonlinear frictions. In the meanwhile, the disturbances with known model and random one can be restrained well.