三转一移解耦并联机构型综合

Type Synthesis of Three-rotational and One-translational Decoupling Parallel Mechanisms

通过分析解耦并联机构的输入输出特点,基于支链独立驱动原则和螺旋理论提出了三转一移(3R1T)解耦并联机构构型综合方法。首先,基于解耦并联机构的雅可比矩阵为非零对角阵的要求,利用螺旋理论构造出满足期望要求的正逆雅可比矩阵,以确定支链驱动副作用于动平台上的使动螺旋,再得到该使动螺旋对应支链上的表示驱动副的驱动螺旋和除驱动螺旋之外的其他运动螺旋系,根据支链连接度的不同,可完成支链结构螺旋系的配置;最后根据解耦并联机构分支组合原则,依次选取四条支链连接动平台和定平台,得到3R1T解耦并联机构。综合的解耦并联机构的输出运动是由支链上独立的输入驱动提供的,属于解耦并联机构,此类机构结构紧凑,控制简单,具有一定的应用前景。

Based on the screw theory and driven-chain principle,a method of structural synthesis of decoupling three-rotational and one-translational（3R1T） parallel mechanisms was proposed according to the analysis of input and output characteristics of decoupling parallel mechanism. Firstly,because of the demands that the Jacobian matrices of decoupling parallel mechanisms had to be non-zero diagonal matrices,the direct and the inverse Jacobian matrices were constructed by screw theory. Then,the effective screws,the actuated screws and the mobile un-actuated screws of each limb were established based on reciprocal screw theory and all possible topology structures fulfilling the requirements were performed in the light of different connectivities of the limbs. Finally,the decoupling 3R1 T parallel mechanism was obtained by the connection of 4 limbs with the moving platform and fixed platform in terms of the parallel mechanism kinematic principles. The outputs of the synthesized parallel mechanism were provided by the independent input-driven of each chain. This decoupling parallel mechanism is compact,which can be controlled with ease and has a certain prospect.