Robust attitude control of a 3-DOF helicopter considering actuator saturation

This paper presents a comparative research of robust attitude control for helicopter system. Considering the actuator saturation problem in the controller design process, two control approaches are mainly investigated. A mixed H-infinity performance and linear quadratic regula-tor (LQR) based robust controller is proposed as the first approach, in which the control input is indirectly constrained in the cost function. While a constrained H-infinity performance based robust attitude controller is developed as the other approach, in which the actuator saturation problem is directly considered in the dynamical model as well as following controller gain calculation. Based on Lyapunov stability theory, sufficient conditions in terms of linear matrix inequalities (LMI) are given. By using Quanser's 3-DOF laboratory helicopter platform, comparative simulation and experimental tests are conducted. Payload variation and wind disturbance are all considered in the experimental test. And the results demonstrate the effectiveness as well as different performance of proposed robust attitude controllers. (c) 2020 Elsevier Ltd. All rights reserved.