Unbiased linear active disturbance rejection control on angle of attack tracking

The angular rate is the derivative of pitch angle other than the derivative of angle of attack, there determinately exists a steady-state error in the closed-loop system output in the case that the control variable is the angle of attack. In this study, A linear compensation term is introduced into the extended state observer, and an unbiased linear active disturbance rejection control approach is proposed. The approach is employed to a hypersonic near space vehicle autopilot. The numeral simulations show that the proposed approach preserves the performance on frequency domain as good as that of the conventional active disturbance rejection control approach, furthermore, the steady-error of the closed system is removed simultaneously, and the angle of attack command is tracked with better accuracy than that of some previous active disturbance rejection control approaches.