Modelling of a rotating platform and its position control using various control algorithms

Ill ABSTRACT This study describes the application of various techniques to control the position of a rotating platform which simulates motion of an airplane or a ship on the plane perpendicular to their movement axis. The first step of the implementation is constructing an electromechanical model for experiments which consists of mechanical Simulator, a platform and a pulley and belt mechanism and a DC motor. Control system consists of data acquisition cards for data input and output and PC itself as a controller. There is a motor driver circuit consists a pulse width modulator to speed control and a half bridge circuit to drive motor. The second part of the study is to settle a mathematical model for the system. This model helps to determine system characteristics and coefficients of the controllers. To obtain a mathematical model results of two experiments are used. The first experiment is determining belt velocity change against change in computer output and the other is calculating platform transfer function by the mediation of impulse response. Third step is control applications, first a PCD controller based on simulation is implemented and tuned then fuzzy controller algorithms; fuzzy PD, fuzzy P and fuzzy P+D is implemented and results are given. According to results of experiments, fuzzy controllers have improved system performance then conventional PID controller especially from the point of time and noise sensitivity. Fuzzy P controller maybe a good alternative for controlling such systems.