液压驱动型四足机器人对角小跑步态本体水平位置控制方法

摘要

In order to control the horizontal body position of a trotting hydraulic quadruped robot, an approximated dynamical model was built based on the motion decomposition along the support line, which simplifies the body and the stance legs to a seven-link mechanism and a linear inverted pendulum.A calculation method for landing positions of swing feet was proposed based on the analytic solution of the linear inverted pendulum model.It was realized to control the horizontal position of the body.For the velocity limitations of the hydraulic cylinders pushing and pulling, an optimization problem for the joint angular velocities was formatted as a QP problem, and a QP solver was designed to decrease the demands for the joint angular velocities.In comparison to the conventional pseudo-inverse optimization algorithm, the proposed algorithm could avoid the singular state of the leg more effectively.The simulation and experiment results show that the desired horizontal body position trajectories can be tracked accurately by using the proposed algorithms, even the joint angular velocities being limited.%为了对对角小跑中四足机器人本体的水平位置进行控制,建立基于沿支撑线方向运动分解的机器人近似动力学模型,将本体和对角支撑腿简化为一个七连杆结构和一个线性倒立摆,并且基于线性倒立摆解析模型提出摆动腿落足点位置计算方法,进而实现对本体水平位置的控制.针对液压作动器伸缩速度受限的问题,利用单腿冗余关节将关节角速度优化问题转化为标准二次型规划问题,通过设计二次型规划问题解法,降低对摆动腿关节角速度的需求,并且避免了传统伪逆方法可能产生的腿部奇异位型.仿真和实验结果表明:该方法能够实现在关节角速度受限的情况下,有效跟踪本体水平位置的期望轨迹.