Abstract: Considering the uncertain factors in flight simulator servo system, such as friction torque and modeling error, a sliding backstepping mode control strategy based on the nonlinear extended state observer (NESO) and differentiator was put forward. The uncertain factors were defined as compound disturbances, and the NESO was used for observations in combination with real-time compensations that reduced impact on the system brought by disturbances. Differentiator was used to estimate the system state variables, hence preventing the noise amplifications caused by the difference method; law design came under the control of a sliding backstepping mode controller designed in accordance with the estimated state, ensuring the stability and robustness of the system. The chattering caused by sliding mode control was effectively reduced based on the improvement of approaching law and disturbance compensation. The simulation result indicates that this control strategy can realize high-precision control over flight simulator servo system due to its ability to improve the control performance and anti-interference performance of the system.

Key words: flight simulator, nonlinear extended state observer (NESO), interference compensation, differentiator, sliding backstepping mode control