Abstract: Aiming at the problem of attitude control for lateral channel of underactuated hypersonic vehicle, a control method based on the auto coupling PD(proportional differential) control theory is proposed. Firstly, the lateral attitude model of the underactuated vehicle is transformed into a second order dynamic model composed of two channels of velocity inclination angle and sideslip angle, and a virtual command of sideslip angle is introduced into the velocity inclination angle channel, and then two total perturbations are defined respectively for the internal dynamics and external perturbations of the two channels. The nonlinear underactuated perturbed system is equivalent to the linear perturbed system with virtual full actuated system. Then, the minimum speed factor and its adaptive speed factor are used to design the auto coupling PD controller of the outer ring velocity inclination angle, so as to obtain the virtual instruction of sideslip angle. According to the virtual instruction, the auto coupling PD controller of the inner ring sideslip angle is designed to obtain the control of aileron deflection angle. Finally, the robust stability and anti disturbance robustness of the auto coupling PD control system are analyzed. The simulation results show that the auto coupling PD controller designed in this paper not only has good anti disturbance robustness, but also has good dynamic quality and steady state performance, which has great application value in the control field of underactuated hypersonic vehicle.

Key words: underactuated vehicle, lateral attitude model, auto coupling PD control, adaptive speed factor, robustness against disturbance