采摘机器人承载平台构型设计与工作空间分析

The Configuration Designing and Workspace Anlysis of Bearing Platform About Harvesting Robot

通过构型演变,设计一种五自由度采摘机器人承载平台机构,去掉Stewart六自由度并联机构的一条驱动支链,得到五驱动支链并联机构。机构采用SPS支链为驱动支链,驱动支链对运动平台无约束。由于仅有5条驱动支链,需增加1条约束从动支链限制运动平台1个空间自由度。为此,采用螺旋理论分析约束从动支链,得到满足不同自由度的从动支链约束螺旋和对应结构,综合出具有不同运动特征的五自由度并联机构。针对此类五自由度并联机构构型,提出了机构构型的符号表示方法,建立了机构的输入与输出关系方程,利用速度Jacobian矩阵研究机构的奇异性,选取无奇异的机构构型为承载平台,并计算了承载平台的工作空间。

The bearing platform of harvesting robot which possesses 5-DOFs is designed by configuration evolution. One driving-limb of Stewart 6-DOFs parallel mechanism （ PM ） is removed and five driving-limbs PM are obtained. SPS- limb is known as driving-limb that is unrestraint and five driving-limbs are input, so one driven-limb that restricts one DOF of movement platform is added. The screw theory is used to analyze constraint screw and structure of driven-limb, 5-DOFs PMs possessing different motion feature are synthesized. Based on 5-DOFs PMs configuration, code representa- tion method of PMs is put forward and the relationship equations of input and output are built. Last, singularities of PMs are studied by Jacobian matrix. By eaculation, the nonsingularity parallel mechanism is used for bearing platform.