Control method of magnetic levitation ball system based on ACPI

Aiming at the technical limitations of traditional control algorithms in solving the highly nonlinear characteristics, parameter perturbations and external disturbances in the magnetic levitation ball system, a magnetic levitation ball system control method was proposed based on Auto-coupling PID (ACPID) control theory. Firstly, according to the electromagnetic force, the first-order Taylor expansion was carried out near the equilibrium point. The dynamic model of the electromagnetic coil was combined to form a magnetic levitation ball position dynamic system with voltage as the control input. Based on the dynamic model of the magnetic levitation ball, the uncertain high-order term, the unknown current dynamics of the electromagnetic coil and the external unknown bounded disturbance were defined as the total disturbance, so that a nonlinear uncertain magnetic levitation ball system can be mapped to a second-order linear disturbance system. Secondly, based on the error function constructed by ACPID control dimension matching, the second-order linear disturbance system can be mapped to the first-order linear system, and then a closed-loop controlled error system under the antiphase excitation of the total disturbance was constructed. Based on this, a magnetic levitation ball position channel controller based on velocity factor was designed. A magnetic levitation ball position control system was established. The robust stability analysis was carried out, and the effectiveness of the ACPI method was proved theoretically. Finally, compared with the existing advanced control methods abroad, the square wave tracking experiment, sinusoidal tracking experiment, anti-disturbance experiment and robustness experiment were carried out respectively. Compared with the NTSMC+GPIO method, in the square wave tracking experiment, the response speed of the ACPI control system is increased by 50%. The ITAE value is reduced by 82%, the RMSE value is reduced by 22.4%, and the control performance under other simulation experiments is also significantly improved. The ACPI control strategy can achieve faster response speed, higher control accuracy, stronger antidisturbance ability, and better robustness when the overshoot is small. The controller has a simple structure and a small amount of calculation, which has a certain application prospect in the field of magnetic levitation ball control system. © 2024, Central South University Press. All rights reserved.