基于捕获点理论的混合驱动水下刀锋腿机器人稳定性判据

The underwater bladed legged robot hybrid-driven by 8 thrusters and 6 blade legs can walk on seafloor and the surface of underwater structure. This paper aims at investigating the evaluation criteria of the motion stability of this kind of robot, where the evaluation criteria is called as stability criterion. The existing stability criterions mainly focus on the robot that is driven by single mechanisms (legs), and not consider the hybrid-driven underwater bladed legged robot. Using capture point theory, we propose a stability criterion for hybrid-driven underwater bladed legged robot. Firstly, a hybrid-driven rolling inverted pendulum model that can reflect the dynamic characteristics of the robot is proposed, and the kinetic energy of the robot that the swinging legs are just touching the ground is predicted. Then, according to the maximum and minimum thrusts of the thrusters, we calculate the variation range of the expected capture point that can enforce the kinetic energy of the robot becoming zero, and the variation range is called as capture domain. Finally, the spatial relationship between the capture domain and the support domain can be employed to judge whether the robot is stable, and calculate the stability margin of the robot. Underwater experimental results show that the proposed stability criterion has better sufficiency and universality.