Mixed H/sub 2//H/sub /spl infin// control of direct-drive electromechanical actuator

This paper introduces the structure and principle of a missile electromechanical actuator (EMA) based on a limited angle torque motor (LATM). According to the problem that direct-drive system is sensitive to the load disturbance and parameter perturbation, a mixed H/sub 2//H/sub /spl infin// controller of the actuator is designed in which H/sub 2/ functions to ensure the dynamic performance of the system while H/sub /spl infin// performs to ensure the stability of the whole system on the condition that the object has indeterminacy in modules and parameters, unmodeled dynamics and the existence of bounded disturbance. Simulation and analytical results show that the designed system has robust stability to the change of the parameter and perturbation; also it has the robustness of tracing without steady state error.