Control PI difuso de un sistema de levitación magnética mediante un sistema embebido

Abstract

In the present work, the design and implementation of a control scheme is presented. The aim of the control scheme is to perform regulation and trajectory tracking tasks in the position of a magnetic levitation system, which acts by electromagnetic repulsion. Such levitation system consists of a beam operated by an active magnetic bearing in pendular configuration. Although the Proportional Integral Derivative (PID) controller shows arithmetic simplicity, ease of use, high robustness and error equal to zero in stable state (Pal & Mudi, 2008), the magnetic levitation system mathematical model is highly non-linear and is subject to uncertainty or variation of its parameters. Therefore, the PID control does not guarantee the fulfillment of trajectory tracking tasks (Precup & Hellendoorn, 2011). In summary, a diffuse PI is used due to the system non-linear dynamics and the hysteresis present in the electromagnet. The controller design was made with the following methodology: the mathematical model and the non-linear characteristics of the system are analyzed; the universes of error discourse (derived from error and control action) are experimentally measured. The experimental data was used for the fuzzification, defuzzification, statement of the rules and controller gains. The implemented rules were designed for a PD-Fuzzy in which a numerical integration of the control action was applied, obtaining a Fuzzy PI. Finally, the implementation was made on the STM32F407G-DISC card, which was programmed with MATLAB-Simulink software tools. The experimental results show that the proposed controller works even below the horizontal, where the behavior can show singularities or physical problems such as magnetization. In compliance with the stated objectives for a range of -5 to 10 radians, these results are maintained even in the presence of disturbances, demonstrating the feasibility of the controller.