基于在线ZMP校正的下肢外骨骼上楼梯步态规划

Gait Planning of Lower Extremity Exoskeleton Climbing Stair based on Online ZMP Correction

为提高下肢外骨骼机器人上楼梯的稳定性,合理的步态规划与误差校正是至关重要的两个方面,为此,提出一种上楼梯过程中零力矩点(ZMP)的在线校正方法。首先,建立下肢上楼梯的运动模型,并进行运动学分析,利用5次B样条曲线进行下肢关节轨迹规划。其次,针对由穿戴过程中人不稳定扰动作用造成的实际与规划ZMP轨迹之间的较大误差,采用在线ZMP校正进行调节。最后,通过仿真和实际实验证明,这种在线校正能够明显减小机器人的ZMP误差,提高机器人ZMP的稳定裕度,保证下肢机器人系统的整体稳定性。

In order to improve the stability of the lower extremity exoskeleton robot climbing the stair,the reasonable gait planning and error correction are two important aspects. To this end,an online correction method of zero moment point(ZMP) during the stair step is proposed. Firstly,the movement model of the lower limbs climbing the stairs is established,the kinematics analysis is performed,and the lower limb joint trajectory planning is performed by using the 5 times B-spline curves. Secondly,the online ZMP correction is used to adjust for large errors between the actual and planned ZMP trajectories caused by unstable disturbances in the wear process. Finally,through simulation and actual experiments,this online correction can significantly reduce the ZMP error of the robot,improve the stability margin of the robot ZMP,and ensure the overall stability of the lower limb robotsystem.