A Novel Robust Control System Design and Its Application to Servo Motor Drive

This paper proposes a new control system by integrating integral state feedback control and sliding mode control to eliminate the influences from the reference input change, external load, and parameter variations. For most control systems, integral action is used to overcome the reference input change and external load. However, its control performance cannot be guaranteed. State feedback control is used to dominate the pole location of the closed-loop control system. However, the system parameters determine their pole locations and may change due to uncertainties. Thus, the characteristics of the closed-loop control system are changed. Sliding mode control is used to compensate for the effect of the parameter variations and make the system invariant. The resulting system combines linear state feedback and sliding mode control to guarantee the desired performance. This shows that the proposed system can be easily applied and designed. A servo control system is used to demonstrate the performance, and simulations and experiments are carried out to evaluate the newly defined structure. They show that the strategies and control design can reach robust performance even with uncertainties or external load, and the chattering of the sliding mode control can be minimized.