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

A Stability Criterion for Hybrid-driven Underwater Bladed Legged Robot Based on Capture Point Theory

由8个推进器和6条刀锋腿混合驱动的水下机器人可在水底或水下结构物表面上行走.所提方法旨在研究这类机器人运动稳定性的评判准则,即稳定性判据.现有的稳定性判据多集中于同一机构(腿)驱动的陆地机器人,未涉及混合驱动的水下刀锋腿机器人.针对该问题,提出了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.首先,在建立混合驱动水下滚动倒立摆模型的基础上,利用机器人运动状态预测摆动腿和支撑腿切换瞬间机器人的动能;然后,根据推进器所能提供的推力范围,计算迫使机器人静止的捕获点变化范围,即获取捕获域;最后,根据捕获域与支撑域的空间关系,判断机器人是否稳定,并计算机器人的稳定裕度.水下实验结果表明,所提出的稳定性判据具有较好的充要性和普适性.

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.