A Compound Control Strategy based on Disturbance Feedforward Control for Automatic Precision Press-Fit System

Abstract

Automatic precision press-fit systems are widely used in intelligent manufacturing, where high positioning accuracy and stable dynamic performance are essential for assembly quality. However, nonlinear friction, structural flexibility, and press-fit force disturbances significantly degrade servo tracking performance during the pressing process. To address these issues, this study develops a coupled electromechanical dynamic model of the press-fit system and develops an electromechanical disturbance-aware compound control framework integrating disturbance feedforward compensation with an improved variable universe fuzzy PID controller. The servo motor, feed mechanism, and press-fit process are modeled to analyze the influence of nonlinear disturbances, and a feedforward controller is designed to compensate for measurable press-fit force disturbances. Meanwhile, the Sparrow Search Algorithm (SSA) is adopted to optimize the scaling factors of the variable universe fuzzy controller, improving the adaptability of the feedback controller. Simulation results show that the maximum tracking error is reduced from 0.630 mm under PID control to 0.338 mm under VUFPID with feedforward compensation. Experimental validation further demonstrates that the proposed strategy effectively suppresses stick-slip fluctuations and improves press-fit stability. The proposed method provides an effective solution for improving the accuracy and robustness of automatic precision press-fit systems.