Comparison between fuzzy logic based controllers for robot manipulator trajectory tracking

Most industrial processes nowadays are still controlled by proportional-integral-derivative (PID) controllers. Ziegler and Nichols proposed the well-known Ziegler-Nichols method to tune the coefficients of PID controller. Although this tuning method is simple, but it gives fixed values for the coefficients which makes PID controller has weak adaptabilities for the model parameters variation and changing in operating conditions. In order to achieve adaptive controller, fuzzy logic (FL) based controllers are tested in this paper which combines conventional PID controller and FL capabilities. The conventional PID controller in the robot manipulator is replaced by fuzzy based controllers so as to achieve trajectory tracking with minimum steady-state error and improving the dynamic behavior (overshoot). The simulation results showed that the controllers have strong self adaptability over the conventional PID controller.