Motion control of a two-wheeled mobile robot

In this paper, we discuss a motion control of a twowheeled mobile robot. In the design of a controller for the system, a kinematic model is usually used; The wheels don’t skid at all and the mobile robot is regarded as a 3-dimensional 2-input nonholonomic system without drift. Many controllers based on the kinematic model have been proposed. However, in a real world, the wheels may skid on the ground or float away from the ground according to the rolling motion of the body. Therefore, we derive a dynamic model of a two-wheeled mobile robot which implies the translational motion with 3 degrees of freedom and the rotational motion with 3 degrees of freedom of the body and the rotational motion with one degree of freedom of each wheel, and then reduce the dynamic model to the kinematic model under certain assumptions. We design a controller based on the kinematic model by extending the Lyapunov control and analyze whether the designed controller works well in a real world by numerical simulations based on the dynamic model.