Robustness of disturbance observer on a six-DOF dynamic system

This thesis addresses the challenges of the modern control algorithm faced with the requirements of high resolution in high speed operations. A multiple axis disturbance observer theory was developed on a six axis mathematical model to simulate the control algorithm generated from the fundamental theory of the disturbance observer.; The theory of the disturbance observer with the Computed Torque Control is applied to a multi-electron beam stage requiring nanometer accuracy, a mathematical model of the stage was derived using Euler's method, then the simulations using Matlab was done to verify the performance of the disturbance observer. This research has validated the performance of the disturbance observer in multi axis dynamic system where high speed output with nanometer accuracy is required.