A motion control of a two-wheeled mobile robot

Abstract

We discuss the motion control of a two-wheeled mobile robot. In the design of a controller for the system, a kinematic model is usually used; the wheels do not skid at all and the mobile robot is regarded as a 3D 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.