Stability control of four-wheel differentially driven mobile robot with variable center of mass

초록

The four-wheeled mobile platforms without steering mechanism have been widely used in many applications because of simplicity of system and weight reduction. However, the absence of steering mechanism makes the platform to nonholonomic system and requires skid-steering functionality which controls the steering motions by speed difference of each wheel of the platform. Therefore, many studies have been focused on linearizing the nonlinear mobile platform model, or applying nonlinear control algorithms in skid-steering and control. Nevertheless, previous studies assume that the Center of Mass (CM) of the platforms is fixed, which cannot be applicable for the developed duct cleaning robot with relatively heavy arms that change the CM of the platform. Therefore, in this paper a new control method is proposed to assure system controllability of the platform with moving CM such as a duct cleaning mobile robot. The mobile platform with cleaning brushes and arms have been modelled and the static and dynamic characteristics have been analyzed. In addition, controller has been designed and its control stability during cleaning operation has been verified with trajectory tracking simulation.