Acceleration Feedback Enhanced H∞ Disturbance Attenuation Control for a Class of Nonlinear Underactuated Vehicle Systems

In this paper, a generalized acceleration feedback control (AFC) design method, named AFC enhanced H∞ controller, is proposed for both fullactuated and underactuated nonlinear autonomous vehicle systems. The AFC is designed as a robust enhancement to the normal control based on known dynamics. First, in order to reject the uncertainties and external disturbances, a linear prefilter is used in the new AFC design method to replace the high gain in the normal AFC. Then, backstepping algorithm is applied to the AFC design of underactuated systems. The analysis of both the disturbance attenuation in frequency domain and input-output finite gain L2 stability shows the new controller design method is applicable. In the end, simulations are conducted with respect to the tracking control of unmanned model helicopter. The results are compared with those obtained by the tracking control without AFC to verify the feasibility of the new method.