Experimental Curriculum for Learning Control Theory Using a Mobile Robot

Abstract

Many experimental devices employing DC motors have been used to study control engineering. The model of them can be approximated as a linear system and we can control the angle or the angular velocity of a DC motor sufficiently by using classical control theory, like PID control. However, just rotating a motor does not seem to attract the attention of students in mechanical engineering classes. Thus, an experimental curriculum employing a mobile robot is proposed to learn control theory. The kinematic model of the mobile robot includes non-linearity. In this paper, two representations are used to analyze and design a controller for the nonlinear mobile robot: a linear approximated model and a linear model obtained by a strict linearization method. The responses when a PID controller is applied are analyzed based on the linear approximated model, and the limits for controlling the mobile robot using a PID controller are shown. When the nonlinear controller designed based on a strict linearization method is used, the control gains can be adjusted based on linear control theory, that is, the pole assignment method. Students can recognize the relationship between the poles and responses of the controlled system as the traveling path of a mobile robot. The proposed experiments were actually performed in some classes and attracted the attention of the students.