Development of Hybrid Parallel Mechanism for High Precision Work and Method for Compensating its Work Error

本研究开发了一种五自由度机床专用机构。由于该机构由空间3自由度并联机构和2自由度平面导台组成，因此具有较大的工作空间和较高的刚度。空间3-DOF并联机构由3-RPS链组成，并具有板状杆件以抑制转动副的弯曲变形，且两端均固定有转动副。因此，所提出的机构将实现更高的刚性和高速运动。其次，建立了利用任意方向力对多自由度机构的输出误差进行评定的方法。这里估计的输出误差是由驱动部件的弹性变形引起的。通过求解柔度矩阵中引入的矩阵的特征值问题，可以得到机构的评价值，揭示了输出误差与机构受力之间的关系。TH…对于多自由度机构，如并联机构，在设计中采用更多的方法将有利于提高其刚度。此外，该方法还可以考虑结构和驱动部件中的弹性变形。为此，本研究采用该方法对上述空间三自由度并联机构进行了分析，考虑了板状杆件的形状，以改善因平移和转动变形而产生的输出误差。在此基础上，设计了一台五自由度机床，并进行了实际装配。利用该机床进行了多自由度加工，验证了该机床的可行性。其次，考虑了并联机构输出和输入之间的非线性关系所引起的工作误差，提出了利用雅可比矩阵表示的微分运动学来评价并联机构工作误差的方法。该方法可以求出多自由度机构各构型任意方向上的输出/输入位移比的最大值。通过装配机对加工误差进行了实际测量，并与评定结果相吻合。在此基础上，提出了机床控制最佳步长的确定方法，并验证了其有效性。此外，研究还考虑了一种利用响应面法对所开发机构的各种误差进行补偿的方法。提出了估计结构误差引起的误差分布并给出输入位移补偿值的方法。通过对该机构的数值模拟，验证了该方法的有效性。较少

This research has developed a 5-dof special mechanism for machine tool. As the mechanism is composed of a spatial 3-dof parallel mechanism and a 2-dof planar guide table, it is expected to have a large workspace and high rigidity. The spatial 3-dof parallel mechanism comprises 3-RPS chains and furthermore has board-like links for suppressing bending deformation induced in prismatic pairs and the prismatic pairs are fixed on them at each end. Thus the proposed mechanism will realize higher rigidity and high speed motion. Next, the research has established a method for evaluating output errors of multiple degree-of-freedom mechanisms by forces applied to the output link in arbitrary direction. The output errors evaluated here result from elastic deformations of the driving parts. The evaluation values can be obtained by solving the eigenvalue problem of the matrix introduced from the compliance matrix which reveals the relations between the output error and force applied to mechanism. Th … More e method will facilitate to improve the rigidity of a multiple degree-of-freedom mechanism such as a parallel mechanism in its design. Furthermore, the proposed method can consider elastic deformation induced in the structures as well as the driving parts. Thus, the research analyzed the above mentioned spatial 3-dof parallel mechanism by the proposed method with considering the shape of the board-like links for improving the output errors caused by the translational and rotational deformation in the prismatic pairs. Based on the above results, we designed a 5-dof machine tool and assembled it actually. By the tool machine the research performed multiple degrees of freedom working and confirmed its availability. Next, the research considered the work error caused from the non-linearity relation between the output and input of parallel mechanism, and proposed the method for evaluating it by utilizing differential kinematics that is expressed by the Jacobian matrix. The method can evaluate the maximum value of the ratio of the output to input displacement to the arbitrary direction at each configuration of multiple degrees of freedom mechanism. We actually measured the work error by the assembled machine and confirmed it conforms to the evaluated results. From those results, the research has proposed the method for determining the optimum step size to control machine tool and confirmed its availability. Furthermore, the research considered a method for compensating the various error of the developed mechanism by the response surface methodology. We proposed the method for estimating the distribution of the error induced from the structural error and giving the compensation value for the input displacement. The availability of the proposed method has been confirmed by the numerical simulation of the present mechanism. Less