Application of Nonstationary Sliding Mode Control for Positioning Problem of Conveyance System

This paper presents an unified design method of nonstationary sliding mode control system for the positioning problem of a conveyance system. In the positioning control of conveyance system high-speed and high-accuracy are required, the system possesses the dynamical characteristics of a flexible structure. In this case not only positioning but also vibration due to movement has to be controlled. The purpose of this study is reduction of vibration and high-speed positioning for the flexible structure by nonstationary sliding mode control method. The conveyance system has three constraints for control such as the maximum output of actuator, the number of observable states and the sampling time of the sensor. Solving these problems, we propose the nonstationary sliding mode control system which is constituted by using time-varying switching hyperplane, nonstationary VSS observer and integral sliding mode controller. The effectiveness of the designed controller is verified through a numerical calculation to compare with sliding mode controller and nonstationary optimal controller. Moreover we demonstrate the performance of nonstationary sliding mode controller with an experimental conveyance system.