基于四元数和B样条的机械手平滑姿态规划器

Smooth orientation planner for manipulators based on quaternion and B-spline

为实现机械手作业姿态的平滑调整,提出一种平滑姿态规划器.采用四元数代替传统的齐次变换矩阵描述机械手姿态,推导了两者之间的转换关系.通过四元数球面立体插值,生成过关键姿态且平滑的姿态轨迹.按机械手终端定位精度将其离散化,逆运动学解算后得到关键关节位置,并以五次B样条曲线插值方法生成启停平稳且脉动连续的关节轨迹.试验结果表明,提出的规划器使机械手姿态调整平滑且关节运动平稳,有效解决了平滑姿态规划问题,提高了机械手轨迹跟踪精度.

A smooth orientation planner for manipulators was proposed to accomplish smooth orientation adjustment. Quaternion was adopted to represent orientation instead of the traditional homogeneous matrix, and conversion of them was deduced. The smooth orientation trajectory was generated by interpolating key orientations with the spherical spline quaternion interpolation method, and key joint positions were solved with the inverse kinematics algorithm according to discrete orientations sampled with specific positioning accuracy of the end-effect, and then smooth joint trajectories with stable start-stop motion and continuous jerk were obtained through interpolating key joint positions with B-spline of five degrees. Experimental results showed that, the proposed orientation planner supplied manipulators with smooth adjustment of orientation and stable movement of joints, as well as enhancement of trajectory tracking accuracy, which made it an effective solution for the smooth orientation planning problem of manipulators.