A Multimode Two-Wheel-Legged Land-Air Locomotion Robot and Its Cooperative Control

In recent years, land-air locomotion robot has emerged in an endless stream. However, the increasingly complex working conditions pose higher challenges to the stability, flexibility, and other characteristics of robots. In this article, the two-wheel-legged self-balancing robot (TSR) is adopted as the crawling mechanism for the first time, and a new two-wheel-legged land-air locomotion robot (TLR for short) is designed. It has three independent modes of flight, two-wheel and four-wheel designed for various working environments. In flight mode, TLR has the fastest speed. In two-wheel mode, TSR as the crawling mechanism has the advantage of flexibly moving at high speed and being adaptive to complex terrains. The four-wheel mode provides TLR with maximum stability and load capacity. To achieve flexible mode switching and high energy utilization efficiency, we studied the cooperative control of rotor power and leg power. Two cooperative algorithms are proposed: stable cooperative algorithm with better impact resistance and stability and walking cooperative algorithm with better mobility. Both algorithms improve the stability, load capacity, and uphill ability of two-wheel mode, even breaking the constraint of the inverted pendulum, which demonstrates that TLR can balance at the specific pitch angle for completing more complex tasks.