Research on the Application of Improve Sliding Mode Control Algorithm of Permanent Magnet Synchronous Linear Motor in Wire Bonding Machine

Abstract

Due to advantages such as strong thrust, fast response, high efficiency, and easy control, the permanent magnet linear synchronous motors (PMLSM) are widely used in the core servo shaft of wire bonding machine. Its speed planning, positioning accuracy and anti-interference ability directly determine the quality of bonding. Therefore, proper speed planning and excellent control algorithm are very necessary. The classic PID control algorithms is often used in the XY platform point motion control,which can achieve better control effect under fixed working conditions. However, in the face of internal and external disturbance factors such as system parameter perturbation, friction characteristics of guide rail and sudden load change, the traditional PID controller has poor robustness and can not automatically adapt to the change, resulting in the decline of system performance , which directly reduces the quality of welding. Sliding mode control (SMC) is a typical robust control strategy. Because the sliding mode can be designed and is independent of object parameters and disturbances, it has the advantages of simple design and strong robustness. In this paper, the Y-axis’ PMLSM of the XY motion platform is selected as the research object, and the mechanism is analyzed to establish its mathematical model under the d-q axis. Then, in order to solve the sudden change of acceleration and acceleration caused by T-shaped and third-order S-shaped speed curve planning, a fourth-order S-shaped speed curve planning algorithm is designed to make the acceleration and deceleration stable, flexible and fast, and reduce the negative effect on the wire bonding machine caused by impact and vibration. Finally, To reduce chattering and improve convergence speed and anti-interference ability, an improved adaptive non-singular terminal sliding mode control(IANTSMC) algorithm is proposed. Simulation results show that the proposed algorithm has faster convergence speed than PID, traditional linear sliding mode and higher positioning accuracy than traditional terminal sliding mode. Combined with feedforward control, the adjustment time of the proposed algorithm only 40.1ms (converges to ±1, µm), and the steady-state accuracy after interference is 0.45 µm, which proves the anti-disturbance ability of the proposed algorithm.