基于单位四元数的Stewart机构姿态工作空间研究

Orientation Workspace Analysis of Stewart Platform Based on Unit Quaternion

  • 摘要: 以单位四元数描述刚体的姿态,避免了欧拉角描述刚体姿态的奇异性问题,推导出Stewart机构处于给定位置时的姿态奇异表达式.提出了该机构处于给定位置时的非奇异姿态工作空间概念及其算法,并以非奇异姿态工作空间边界曲面的最小内切球作为实际姿态工作空间,以该球半径大小作为衡量机构处于给定位置时的实际姿态能力的性能指标.给定该机构的具体结构参数,描述了该机构处于某给定位置时的非奇异姿态工作空间,并进一步描述了在机构"初始姿态"的位置工作空间内实际姿态能力随位置不同而变化的情况.

     

    Abstract: Unit quaternion is used to represent the orientation of rigid body,orientation-singularity expression of the Stewart platform at a given position is deduced,and the singularities caused by Euler angles are avoided.The concept and algorithm for nonsingular orientation-workspace of the platform at a certain position are proposed.The minimum inscribed sphere of the boundary surface of nonsingular orientation-workspace is represented as the practical orientation-workspace,and the sphere radius is used as the performance index of the platform's practical orientation-capability at the given position.Specific structural parameters of the platform are given,and the nonsingular orientation-workspace of the platform at a certain position is described.Furthermore,the practical orientation-capability changing with the variation of positions in the position-workspace of "initial orientation" is described.

     

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