Model-based self-tuning PID controller for the temperature control of laser soldering systems

The purpose of this study is to propose a model that can describe the laser soldering process and to design temperature control algorithms based on the model to improve the soldering quality. Through the careful research on laser soldering, based on the heat-transferring analysis on the brazing material, a mathematical model of heat-transfer is established. The change laws and ranges of the model parameters are identified based on experimental data. Subsequently, a model-based self-tuning Proportional-Integrative-Derivative (PID) (MBSTPID) control method for the temperature control of laser soldering systems is proposed. The effectiveness of the proposed model and control method are verified through experiments and simulations. The proposed MBSTPID method is compared with the conventional PID control algorithm and exhibited a superior performance; the temperature errors controlled by the MBSTPID method are only approximately 33% of those controlled by the conventional PID control algorithm. Therefore, the proposed MBSTPID control method can guarantee accuracy in temperature control and thereby assist in providing ideal conditions for technical studies on laser soldering. In this method, the poles of the closed-loop control system are always ensured near the configured poles, guaranteeing the stability and reliability of the soldering process.