Locomotion Control of Quadrupedal Robot With Passive Wheels Based on CoI Dynamics on SE(3)

Roller-skating for a quadrupedal robot with passive wheels has higher efficiency than traditional walking. A new quadruped robot with passive wheels is designed to realize roller-skating and walking by switching configurations. An ingenious struct that combines the passive wheel and foot is designed and the double parallel four-bar linkage is utilized to realize exchanging configurations for the quadrupedal robot. Then, a roller-skating and walking fused dynamics controller based on the center of inertia on SE(3) is developed. The proposed controller can be used to achieve both roller-skating and walking for the quadrupedal robot. A new method of internal force distribution is built to eliminate the local motion generated by passive wheels of different legs. For achieving the desired motion of dynamic roller skating, a new floating coordinate system is built to compensate for the skating motion of the robot body to solve the problem that the walking controller can not be employed in roller skating directly. Roller-skating gaits of the quadrupedal robot are designed to verify the feasibility of the proposed controller. The experiments show the proposed controller can achieve roller-skating, walking, and exchanging configurations.