Development of a transformable wheel-track mobile robot and obstacle-crossing mode selection

According to the terrain features of irregular environment, a novel mobile mechanism of the transformable wheel-track robot is proposed. The robot can adapt to the irregular environment by transforming the track configuration. The robot mechanism consists of a control box, two symmetric transformable wheel-track units and a sub-arm equipped with a single-direction wheel. The wheel-track unit is composed of two walking gear rings, a double four-bar linkage mechanism and a retractable track. Driven by a servo motor, each wheel-track unit can change its locomotion mode according to the environment. In the paper, the system structure and key mechanical points-positioning method of double four-bar linkage mechanism and retractable track are presented. Meanwhile, the step-climbing ability is analyzed separately in wheel mode and track mode. The result shows that, the structure of the robot is reasonable, which can quickly switch between two modes. If the step height is no more than 80mm, the robot can cross in wheel mode, and in track mode to climb higher steps.