四足机器人足端复合轨迹的优化与性能分析

Optimization and performance analysis of foot compound trajectory of quadruped robot

关节空间轨迹规划是机器人运动控制的重要内容之一。为了将笛卡尔空间轨迹规划和关节空间轨迹规划相结合,文章提出了一种新型仿生足端轨迹,并使用等间距点、第二类切比雪夫点和等时点三种不同的方式对该足端轨迹离散采样并确定插补点位置,将插补点映射到关节空间,进行了机器人的关节控制。首先,采用五次多项式进行关节空间轨迹规划,并构造Hermite多项式曲线进行插补点的角速度和角加速度估计,获得关节空间轨迹曲线。通过对虚拟样机进行仿真分析和单腿实体样机实验,分析实际曲线和设计的足端轨迹的拟合程度,得出基于等时点进行插值的轨迹曲线与设计的复合足端轨迹曲线拟合程度更高;采用Hermite多项式估计方法进行角速度和角加速度估计的曲线不仅拟合程度更高,而且轨迹更加平滑,角加速度突变减少,具有更好的运动学性能。

Joint space trajectory planning is one of the important contents of robot motion control.In order to combine Cartesian space trajectory planning with joint space trajectory planning,this paper proposes a new type of bionic foot trajectory,and uses three different methods:equidistant points,second type Chebyshev points and isochronous points.The foot trajectory is discretely sampled and the position of the interpolation point is determined,and the interpolation point is mapped to the joint space to control the joint of the robot.Firstly,the fifth-degree polynomial is used to plan the joint space trajectory,and the Hermite polynomial curve is constructed to estimate the angular velocity and angular acceleration of the interpolation point,and the joint space trajectory curve is obtained.The virtual prototype is simulated and the single-leg physical prototype experiment is analyzed,and the fit between the actual curve and the designed foot trajectory is analyzed,and the trajectory curve based on the isochronous point interpolation and the planned composite foot trajectory curve are obtained.The degree of fitting is higher;the curve of angular velocity and angular acceleration estimation using the Hermite polynomial estimation method not only has a higher degree of fitting,but also has a smoother trajectory,reduced angular acceleration mutations,and better kinematics performance.