Structured H∞ controller design for unmanned helicopters using H∞ extended static output feedback control

Considering the high order of the unmanned helicopter´s model and the immeasurability of the flapping states and the state of one order approximate model of yaw rate gyro dynamics, it is conservative to use the standard static output feedback control. The present paper designs a structured H∞ controller based on H∞ extended static output feedback (HESOF) control. This method divides the systems to inner-loop and outer-loop control structure and using a precompensator and a postcompensator to shape the singular values of the nominal plant to attenuate the high frequency disturbance of measuerement, then design a HESOF control using the output and its derivatives as feedback states. Therefore, it can improves the structured H∞ controller´s performance. As an example, a design for hover of an unmanned helicopter is presented. The simulation results show that using this method can obtain excellent decoupling and robust performance.