Research And Application On PID Auto-tuning Control Method For Variable Load System

The variable load control is a difficult problem in practice. Among the control strategy, PID control is still the most widely used algorithms because its physical concept is clear and it is robust. However, as to variable load control system, PID parameter tuning is also cumbersome. Therefore, the PID parameter auto-tuning method based on PSO is presented to solve the PID auto-tuning problem.Particle Swarm Optimization (PSO) is an adaptive iterative optimization algorithm. It is widely used to solve the optimization problems. Based on the traditional PID control, the paper proposes PSO-PID control algorithm to achieve the purpose of variable load control system auto-tuning PID parameters. The core of this algorithm is that the PSO is introduced to the PID parameter optimization. Then it turns the variable load control system PID parameter auto-tuning into a mathematical optimization problem.First, a typical electric-hydraulic servo control system mathematical model is built to the simulation study about variable load control system. The simulation results show that PSO-PID control algorithm with respect to the classical PID control algorithm has stronger adaptability based on MATLAB. It can adjust the PID parameters dynamically to match the load changing system and find the optimization parameter accurately.Finally, we take multifunctional triaxial instrument as the experimental subjects. It makes two sets of shearing experience to prove the proposed PSO-PID algorithms. The result shows that the PID parameters adjusted to match the changing of load dynamically in the process of shearing. Meanwhile, the axial displacement and the internal surrounding pressure have better control effect. The partial stress curves meet the test requirements. Ultimately, it achieves satisfactory control performance.