基于螺旋理论的3T1R完全解耦并联机构型综合

利用螺旋理论和独立驱动原则对3T1R类完全解耦并联机构进行型综合。首先根据期望3T1R完全解耦并联机构的运动特征(沿X、Y、Z轴方向的移动和绕Z轴方向的转动)和完全解耦并联机构的正逆雅可比矩阵必为对角阵的要求，利用螺旋理论来构造满足所期望形式的正逆雅可比矩阵；然后根据正逆雅可比矩阵所要满足的条件，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，可以配置支链的所有可能构型；最后根据并联机构运动原理依次取出四条支链连接动平台和定平台得到3T1R完全解耦并联机构。综合的并联机构的输出运动是由支链上独立的输入驱动提供的，且机构的正逆雅可比矩阵在运动过程中始终保持为对角阵，所以属于完全解耦并联机构，此类机构控制简单，具有一定的应用前景。

Type Synthesis of Fully-decoupled 3T1R Parallel Mechanism Based on Screw Theory

Based on the screw theory and the driven-chain principle, a method of structural synthesis for fully-decoupled three-translational and one-rotational (3T1R) parallel mechanisms was proposed. Firstly, according to the desired characteristics of the parallel mechanism (moving along X, Y, Z axis and rotating about Z axis, respectively) and requirements,the direct  and the inverse Jacobian matrices had to be diagonal, the desired forms for the direct and the inverse Jacobian matrices were constructed. Secondly, according to the features of the direct and the inverse Jacobian matrices, the effective screws, the actuated screws and the mobile un-actuated screws of each leg were established based on the reciprocal screw theory and the structural synthesis of each kinematic chain for fully-decoupled 3T1R parallel robotic manipulators was performed in the light of different connectivity of the limbs. Finally, the parallel mechanism was obtained by the connection of 4 chains with the moving platform and the fixed base in terms of the parallel mechanism kinematic principles. The output of the synthesized parallel mechanism was provided by the independent input-driven of each chain and the direct Jacobian matrices maintained diagonal  during the moving process. The parallel mechanism is fully-decoupled,which can be controlled with ease and has a certain application prospect.