A Small Morphing Leg-Wheel Hybrid Quadruped Robot*

Having both leg and wheel movement modes, legwheel hybrid robots are widely used to explore the unknown environment. However, traditional leg-wheel hybrid robots cannot perform manipulation tasks due to the lack of additional arms. In this paper, we developed a small morphing leg-wheel hybrid quadruped robot which has several motion modes and operating capabilities. It is composed of morphing movement/manipulation platform, sensor and an embedded control system. Based on the analysis of the function and performance requirement, the structure and mechanisms are firstly designed. The design assures that the robot has several movement modes to adapt to different road environments. The mobility is largely improved. Moreover, two of the four limbs can be used as arms and can achieve a dualarm cooperative manipulation while the other limbs still support the body. In order to realize the corresponding motion planning and control, the kinematics equations are derived, and a criterion is defined to evaluate the stability ability. Then the trot gait of the legged mode are optimized by considering the working environments and stability. By integrating the ultrasonic sensor and WI-FI camera, the robot can detect the obstacles and monitor the environment. Finally, the developed morphing leg-wheel hybrid robot was experimented. The experiment results verify the mobility and manipulation performances.