Design of LQ-PID Controller for Direct Drive DC Motor

Abstract

Abstract. Direct Drive DC Motor can supplement the shortfalls of gear train, which induces nonlinear characteristics (backlash, friction, dead zone etc.), because it is directly connected to the load. However, it is a high sensitivity, a weakness, becasue it has an uncertainty due to the inertia of the load. Therefore, this study designed a LQ-PID Controller with having new state feedback and output feedback as new state equations by adding a new integral element to output variables by using the LQR method to guarantee the stability robustness and performance robustness. Moreover, the robostness and stability were guaranteed by selecting Q and R and using the ultimate behavior and a method to resolve the uncertainty problem, which induce the change of the direct drive DC motor's load inertia.