High-Performance Control of Electromechanical Servo System Based on Motor/Hydraulic Actuator

Motor/hydraulic actuators play an important role in high-performance electromechanical servo control. However, existing modeling uncertainties can reduce the system control performance or even cause the whole closed-loop system to become unstable. It should be noted that these uncertainties can be subdivided into endogenous uncertainties associated with the system states and exogenous uncertainties with regard to external disturbances. More importantly, these uncertainties are not only smooth but also nonsmooth. Furthermore, measurement noises, input saturation, and other factors can also affect the resulting control performance of the system. Overall, the modeling uncertainties, which not only come from diverse sources but also have complex forms, always inevitably exist in all electromechanical servo plants, making closed-loop controller design difficult and hindering the development of these systems towards high control performance. Therefore, methods for rejecting these uncertainties to improve the system control performance are of great significance. Other control methods such as prescribed performance control, preset time control, state constraint control, input constraint control, event-triggered control, optimal control, and so on also play a significant role in satisfying the system control requirements.