A new wheel-legged locomotive system was put forward.An attribute of this mechanism, from the mechanism view point,lay in the fusion in function and in structure, just using a set of mechanisms. Unlike previous locomotive system, the actuators in this system were fixed on the base. The change of the actuator positions reduced the payload of the system and simplified the wire routing. Afterwards, the working characteristics were analyzed in legged mode and wheeled mode. Furthermore, the kinematic model was deduced step by step, from the single legged/wheeled mode to the wheel-legged mode. Especially, the interaction between the two modes was pointed out.An example was given to testify the kinematic equations. Results from the theoretical computation and the virtual prototyping simulation indicate the equations accord with the actual working state of the system. Finally, a moving platform is assembled as a mechanical-only pose realizing test model. It is clear that the system proposed herein works well in legged/wheeled or wheel-legged mode.
