面向多向3D打印的混联机构及其运动分析

为解决多向3D打印装备瓶颈问题，提出一种完全解耦五自由度混联机构作为3D打印的执行机构，该机构由并联模块3-CPaRR和串联模块RRo组成，其中并联模块由3条相同CPaRR支链构成，可实现空间的三维移动，串联模块RRo用于调整打印头姿态，改善3D打印过程中的台阶现象、干涉问题。基于约束螺旋理论，分析了3CPaRR&RRo机构自由度，并通过ADAMS建模对其进行了验证。然后运用D-H法求得混联机构的运动学方程，对机构的位姿正解表达式求导，得到了机构的雅可比矩阵和末端速度方程，分析了机构在工作空间内的奇异性问题，通过对模型运动仿真，绘制出了机构末端输出速度曲线，验证了上述分析的正确性。

Hybrid Kinematics Mechanisms and Its Kinematic Analysis Oriented to Multi 3D Printing

In order to solve the bottleneck problems of multi 3D printing equipment, a fully-decoupled five degree of freedom (5-DOF) HKM was presented as the actuator of 3D printing. HKM consisted of 3-CPaRR parallel module and RRo serial module, and the parallel module consisted of three identical CPaRR limb chains, it might realize three-dimensional translations, the serial module RRo was used to adjust the print head posture, improve 3D printing process step phenomenon and interference problems. Screw theory was applied to analyze the kinematic characteristics of mechanisms and to calculate the degrees of freedom of 3CPaRR&RRo which were verified via the ADAMS software. The kinematic matrix of the hybrid mechanisms was carried out by using the D-H convention. The expression of the forward kinematics was deduced to obtain the Jacobian matrix and velocity equations, and the analysis of singularity was carried out. Moreover, simulation model was built with ADAMS, the velocities of the end-effectors of mechanisms were drawn. Thus, the validity of the theoretical analyses was proved.