Research on Passive Energy-Regulated Bionic Shell for Lateral Fall Recovery Behavior of Large Quadruped Robots

The lateral fall of a quadruped robot is difficult to avoid. However, there are few studies on the fall recovery of quadruped robots, especially that with large size and weight. One of the important reasons originates from the driving capability of robot joints. This paper analyzes the fall recovery behavior of several animals in nature, and designs a bionic shell structure. Then the working mechanism and critical conditions of the shell have been studied in detail. The shell that with the ability of regulating the energy changes of the robot when rolling, can make the quadruped robot withstand large impacts and avoid tipping. Based on the compliant movement generated by the arc-shaped contour of the bionic shell, the demand for the explosive joint driving force can be greatly reduced. These inherent advantages of the mechanism of the shell make it suitable for the lateral fall recovery of a large quadruped robot. The effectiveness of the mechanism is verified by simulation. Moreover, the performance of the bionic shell is discussed, for different factors including impacts, terrains and structures.