Suboptimal Integral Sliding Mode Control of a Quadrotor under Input Saturation

In this paper, the set-point tracking problem for a linear quadrotor dynamics model is considered, and a suboptimal integral sliding mode controller is proposed under input saturation. Firstly, it is illustrated that the constrained control can be applied in suboptimal sliding mode control, and the range of values for the suboptimal control is given. Secondly, the online feedback of the input saturation is achieved by taking advantage of the state dependent Riccati equation (SDRE) method. The designed controller not only eliminates the tracking error both in position and attitude, but also approximately minimizes the cost function of the quadrotor system. Finally, simulation results compare the controller proposed in this paper with PID controller. It is verified that the suboptimal integral sliding mode controller has a better performance and can reject the external disturbances efficiently under input saturation.