Smith-ADRC Based Z Axis Impact Force Control for High Speed Wire Bonding Machine

The z axis control system of high speed wire bonding machine has the characteristics of high dynamic, nonlinearity and strong coupling, which will cause the problems of large position and force overshoot through the conventional PID control methods. In this paper, we propose an Active Disturbance Rejection Control combined with Smith predictor (Smith-ADRC) method to improve the dynamic performance of the bonding head. Firstly, a mathematical control model and a second order ADRC model is designed and constructed for the z axis impact force control system. Secondly, considering the delay problem of the control signal, a Smith predictor is added to the control method to compensate the effects of time delay. Thirdly, simulation analysis is performed to compare the performance of the control methods, such as the conventional PID, the Smith-PID, the ADRC and the proposed Smith-ADRC method. The results indicated that the proposed Smith-ADRC method achieved a better performance in term of position overshoot and settling time, and showed the feasibility and the effectiveness in the high dynamic system. Based on the theoretic analysis and simulation results, the proposed control method could be applied for the wire bonding machine to control the bonding head impact force under high dynamic motion.