Differential-Driven Wheeled Mobile Robot Mechanism With High Step-Climbing Ability

Abstract

Differential-driven wheeled mobile robots, such as logistics robots and mobile manipulators, are used for various tasks on flat ground. These differential-driven wheeled mobile robots are highly environmentally constrained when driven on flat ground. This study proposes a differential-driven wheeled mobile mechanism of the robot with high step-climbing ability and the capability to navigate narrow paths. This work shows that the novel wheel and differential-driven module improve the ability to climb stairs through the transfer of center of mass (C.O.M). A sub-wheel connected to the passive joint of the wheel is used to convert the drive into a vertical force to improve the mobile robot's ability to climb high stairs. By pitching the body of the wheel-powered robot through the advanced reaction force, the ability to climb stairs in reverse using the reaction force of the wall is improved. Furthermore, the proposed mechanism enables precise control of the robot's path, allowing it to effectively navigate narrow spaces. The prototype robot was tested for climbing stairs and high steps, as well as climbing a deformable slope while climbing obstacles. Even if the center of mass is located in the driving direction, this result uses a novel wheel to overcome the step in the front wheel and improve the overcoming performance of the rear wheel owing to the center-of-mass position in the driving direction. We expect that this method will be applicable to various differential-driven wheeled mobile robot mechanisms, especially for environments with confined spaces.