A Study on State Dependent Disturbance Compensation Method for Motor System with Output Time Delay

Abstract

This thesis suggests a state dependent disturbance compensation method for an output time delay existing motor system control. A name of the component which realizes the suggested compensation method is designated as a state dependent disturbance observer (SDDOB). Because the SDDOB uses conventional linear disturbance observer (DOB) scheme, it inherits the advantages of DOB including simple structure to add on the main controller, modeling error compensation property and powerful disturbance compensation ability. The SDDOB and a main PI controller constitute a robust controller in this thesis. The SDDOB can compensate current state dependent disturbance precisely although known output time delay which is frequently provoked in the practical implementation and internal time delay from Q-filter exist in an operating environment. Because the majority of state dependent disturbances of motor system is rotor angle dependent disturbances and to give illustrative explanation with theoretical analyses, this thesis demonstrates the method which only targets to reject the rotor angle dependent disturbances although the proposed method can handle other kinds of state dependent disturbances. To validate the effectiveness of proposed compensation method theoretically, several lemmas and theorems that are related to the state dependent disturbance compensation ability and stability of suggested sub-controller are contained in this thesis. In addition, results of fulfilled computer simulations and experiments are included in this thesis also to confirm the properties of SDDOB. The computer simulations use an identical system model to the experiments

a direct-drive motor within a 0.25 [rad] tilted 1-degree-of-freedom (1-DOF) planar robot. The results of computer simulations and experiments show that the suggested method promptly compensates the current state dependent disturbance even if known output time delays were included in the control environment.