PID Control Design and Kinematic Modelling of 3-DoF Robot Manipulator

This research proposes the PID-based controller for a 3 Degree-of-Freedom (DoF) manipulator. The manipulator has three servo motors which can measure the angular position and the angular velocity. The forward kinematics defines the desired angular velocity of each servo motor that will be used as a feed-forward value of the PID controller. The inverse kinematic provides the desired angle of each motor to reach the desired position. Correspondingly, the desired angular velocity and the desired angle are used as the input of the PID controller to control the angular velocity. Here, the PID controller is tuned using the Ziegler-Nichols Tuning 1st method. To show the effectiveness of the proposed method, we conduct three cases experiment: (1). 2D rectangular shape with four constant reference points, (2). 2D circular shape with time-varying reference points, (3). 3D rectangular shapes with time-varying reference points. It is shown that the proposed method gives less than 1% of angle error and less than 5% of velocity error.