Fuzzy control of a dc motor driven four-bar mechanism

Despite the basic assumption that the angular velocity of the crank is constant in much mechanism analysis, this may not be validated when the mechanism is connected to an electric motor. In this paper, a complete state-space mathematical model for a motor-mechanism system is first developed and numerically simulated to demonstrate the crank angular speed fluctuations for the case of a constant voltage supply. Then, a fuzzy logic controller is designed to regulate the crank angular speed of the mechanism and compared to an optimal PID controller. The inputs to the fuzzy controller are the error and change of error in the crank speed and the output is the applied voltage. The results obtained from the fuzzy controller are not only superior in the rise time, speed fluctuations, and percent overshoot but also much better in the controller output signal structure, which is much remarkable in terms of the hardware implementation.