A linear active disturbance rejection control approach for near space vehicle autopilot

The conventional PID controller parameters are difficult to be decided on the dynamics of the near space vehicle within a large flight envelope. In this study, a linear active disturbance rejection control approach is proposed. The model perturbation is estimated by the extended state observer, and then the error of closed-loop system is compensated by the conventional PD control. Furthermore, a reduced-order observer is introduced to reduce the phase lag and lessen the feedback gains. The approach is employed to a hypersonic near space vehicle autopilot. The numeral simulations show that the proposed approach has a good performance on frequency domain and time domain, the angle of attack command is tracked very well, and the controller parameters are easy to be determined.