Robust attitude control of a 3-DOF helicopter prototype subject to wind disturbance and communication delay

Abstract

In this paper, a robust control strategy is developed for unmanned helicopter prototype to simultaneously deal with random wind disturbances and remote communication delays. First, in the helicopter system modeling, the wind gust is not only treated as bounded external load disturbance, but propeller force-thrust coefficient variation that is caused by wind disturbance is also considered. Then, by equivalently treating the remote communication delays as random input delays, a robust attitude controller with energy-to-energy performance is developed for the helicopter system. Lyapunov-Krasovskii functions are utilized to analyze the stability of the proposed robust attitude controller. The gains of controller are calculated by solving linear matrix inequalities. Finally, by selecting Quanser’s three degrees of freedom(3-DOF) helicopter prototype as the test bench, three groups of comparative tests are carried out respectively, in which electric fan is utilized to generate external wind gusts while random delays are added to the feedback loop. Compared with conventional H-infinity controller, the effectiveness as well as superiority of proposed control approach is well verified.