四足机器人静-动步态平滑切换算法

Smooth walk-to-trot gait transition algorithm for quadruped robot

为提高四足机器人对不同地形的适应能力,给出间歇静步态向对角小跑步态切换(walk-to-trot)的不同情况以及最优(在保证稳定切换的前提下,实现速度的平滑变换和不同步态情况下的最短时间切换)切换方法。为保证步态切换过程中的平滑性,给出关于时间的速度公式,使机体重心保持恒定加速度;为保证切换阶段的稳定性,利用改进的泛稳定裕度判别法(wide stability margin method,MWSM),通过调整足端与质心相对位置,消除步态变换过程中由惯性力导致零力矩点后移对稳定性的影响。基于Webots仿真软件,建立四足机器人仿真模型,验证方法的可行性和有效性。该方法可应用于间歇静步态中的6个状态点并将其平滑、稳定的切换为对角小跑步态。

In order to improve the adaptability of quadruped robot for various terrains,different cases that could occur when robot changed its gaits from walk to trot were analyzed and the optimal transition algorithms which could let gait transition more smooth and waste least time when robot kept stability were proposed. In order to ensure the smoothness of transition sequence,the speed formula of time was given to keep the center of gravity constant acceleration. An algorithm named modified wide stability margin method（ MWSM） was proposed to offset the stand back influenced by inertial force and caused by the acceleration through adjust the relative position of the trunk and four feet. The model of quadruped robot was constructed based on the robot simulator Webots,and simulation results showed the validity and effectiveness of the algorithm. The approach could be applied in six points of one static walk circle and switched to trot smoothly and steadily.