Design and analysis of a hybrid two-wheel-hopping robot

In order to increase the adaptation of the robot to the environment, this paper proposes a new hybrid mechanism which combines the wheeled movement with the hopping. The wheeled movement will be selected to enhance the mobility performance and efficiency when the road is flat or the obstacle is less than the radius of the wheel. When there are big obstacles or ditches on the ground which are difficult for wheeled movement, hopping is a better choice. Based on the design of the mechanism, the robot's two movements can be approximately decoupled: 1) the wheeled movement which is completely free from the vertical direction of hopping; 2) the hopping movement where the robot controls the wheel horizontal velocity at the hopping instance to control the hopping angle and height. The paper firstly introduces the mechanical configuration of a two-wheel-hopping robot, then develops the hopping dynamics model and hopping process for the two-wheel-hopping robot. The effects of the spring rate and the whole mass to the hopping performance are analyzed. Finally the whole mechanism is given for the future development of the robot. The combination of the wheel drive with hopping can greatly improve the mobility of the mechanism.