Design of Sliding Mode Extended State Observer for Active disturbance rejection control of Air Intake System

The air intake control system is a key part of a type of propulsion system test bed. However, the existence of disturbances and random measurement noise in the control system, directly affect the reliability of the engine transition state test results. In this paper, a novel sliding mode extended state observer is designed to improve the anti-disturbance performance of the intake pressure control system. First, a sliding-mode convergence law is designed to improve the convergence speed and accuracy of the system state, and then a sliding mode surface is designed to reduce tracking error. Based on the designed sliding-mode convergence law and sliding mode surface, a nonlinear convergence function is designed to modify the structure of traditional extended state observer, improving tracking accuracy and speed. Simulation experiment results show that the proposed sliding mode extended state observer reduces the overshoot by $\mathbf{3 2. 7 \%}$ when tracking the intake pressure and 48.9% when tracking the intake temperature, indicating its effective anti-disturbance performance while ignoring the temperature feedback delay.