Stability and robustness analysis of the position control systems with disturbance observer

The aim of this paper is to provide a new analysis and design tool for the acceleration based position control systems. Disturbance observer (DOB), which is the key point of the acceleration based motion control systems, guarantees the robustness of a system by nominalizing real plant and suppressing external disturbances. Although the DOB has been widely used, specifically in motion control area, in the last two decades, it has no a systematic design tool, and its design methodology highly depends on the designer´s own experiences. The Bode-Integral theorem and root-locus are implemented into the DOB based position control system so as for clarifying its stability and robustness. New design criteria are provided to improve the robustness and stability of the acceleration based position control systems. Furthermore, the acceleration based position control systems are compared with the conventional one, and its superiorities are shown.