Robust control is becoming a necessity in almost all control fields. One method to achieve robust control in advanced control system is the two degree-of-freedom (2-DOF) control, in which two control loops will be assigned the performance and robustness goals separately. A Disturbance Observer (DOB), which is used in the designing of robust control systems, is a simpler and efficient tool. The applications of DOB lies mainly in motion control systems, e.g., robotic systems, automation in industries, and locomotives. This paper analyzes the robustness and stability of a robust position control system based on DOB. The Proportional Integral Derivative (PID) controller tuning for the aforementioned applications is an investigative job, because of their nonlinearities and anonymous perturbations, like friction, motor inertia which varies with time and effects of the connected load. A sensible tuning method for the robust PID controller incorporating the aid of DOB is proposed in this paper which can be used for the aforementioned applications and analysis of the design constraints of DOB parameters.
S. Anoop and Nandagopal, J. L., “Analysis of disturbance observer based position control system”, in 2016 International Conference on Control, Instrumentation, Communication and Computational Technologies (ICCICCT), Kumaracoil, India, 2016.