Adaptive control of pneumatic end-effector polishing force based on dual extended state observer

In the process of aero-engine blade polishing, parameter uncertainties and unmodeled disturbances in the pneumatic end-effector cause fluctuation of the polishing force, affecting the quality of blade processing. To solve the problems mentioned above, a polishing force adaptive controller based on dual extended state observer is proposed. A novel mathematical model of the pneumatic end-effector is established based on the flow characteristics near the zero position of the proportional valve, and a matched disturbance factor is introduced. The controller proposed in this paper contains parameter adaptive law and dual extended state observer. The former aims to compensate for the parameter uncertainties, and the latter aims to compensate for the matched and unmatched disturbances, respectively. The experimental analysis including aero-engine blade polishing constant contact stress control is applied. Simulation and experimental studies show that the controller proposed in this paper can effectively compensate for the influence of parameter uncertainties and unmodeled disturbances on the fluctuation of the polishing force. The fluctuation of the polishing force is 0.41 N, and the quality of the surface finish of aero-engine blades is improved.