4-SPS/SP并联机构的奇异位形分析
Singular Configuration Analysis of 4-SPS/SP Parallel Mechanism

对4-SPS/SP并联机构的运动学和静力学进行分析，得到该机构的降维运动学和静力学奇异位形曲线。对比这两组曲线发现它们相差了β=±90°两条直线。通过对机构运动Jacobian矩阵分析，发现该±90°是欧拉角的“奇点”，并非该并联机构的奇异位形，并运用实例加以验证。在排除该非奇异位形曲线后，根据两种方法得到的奇异位形是相同的，并对其物理意义进行了解释说明。运用静力Jacobian矩阵得到了该机构的姿态奇异位形曲面，找到了该机构的动平台只绕Z轴旋转时存在的一组特殊的奇异位形，并根据力螺旋相关性修改动平台参数避免该组奇异位形，改善该机构的运动性能。
The reducing-dimensional kinematics and the statics singular configuration curves of 4-SPS/SP parallel mechanism were obtained respectively through analyzing the mechanism kinematics and statics. Positive and negative 90 degree lines were found from the comparison of the two curves. The positive and negative 90 degrees were proved to be the Euler angles' singular points who caused the singularity of the Euler kinematic equation instead of the singular configuration of the parallel mechanism, which was verified by examples. The two singular configuration curves were found to be the same after non-singular ones being eliminated, which was explained with physical principle. Finally, the posture singular configuration surface of the mechanism is acquired with the statics Jacobian matrix from which a special singular configuration group is found when the moving platform of the mechanism is rotated merely around Z axis. The special group was escaped through modifying the parameters of moving platform with the improvement of mechanism movement performance according to the correlation of force screw