A motorized wheelchair has rear wheels driven by DC motors, and its speed and direction can be maneuvered by adjusting the motor speed. Because its front wheels are in the form of casters, the direction is easily changed by circumstances. This paper presents a study of modeling of motorized wheelchairs. In this paper, we propose on improved model of its body and front wheel dynamics for the smooth and stable control. We examined suitability of this model by digital simulations.