The Kinematics Design Of A 5-Axis Pronated CNC Machine Tools Based On A Novel 5-DOF Parallel Mechanism

The thesis focuses on the configuration of a 5 axis pronated virtual CNC machine tool which is based on a novel 5-DOF parallel mechanism and investigates the related issues systematically.Since it is difficult to comprehend the motion of the 5-DOF parallel mechanism, a double parallelogram mechanism is presented to illuminate the motion of the 5-DOF parallel mechanism. By analysing the condition number of Jacobian matrix, it can be well known that the 5-DOF parallel mechanism has two characteristics: identical performance and symmetrical performance, which can be well explained for its particular architecture and is convenient to the analysis of the mechanism.Based on the new definition of workspace, a method for the design of the 5-DOF parallel mechanism is presented. The method described in the thesis has been implemented in the determination of some geometry parameters of the 5-DOF parallel mechanism. Moreover, this thesis also presents a method which makes use of identical performance of the characteristics of the 5-DOF parallel mechanism and the new definition of workspace for the efficient determination of the workspace of the parallel machine tool. Some graphical representations of the workspace which are available for engineering application can also be obtained in two dimension and three dimension.Considering the characteristics in the aspect of singularity pose, an efficient method which leads to reduce extremely the quantity of calculation has been implemented in the singularity analysis of the 5-DOF parallel mechanism.Since physical limitations can exist on the passive joints, some installation settings are presented to overcome the disadvantageous influence of the passive joints. In the same time some novel joint structures which have many advantages compared with the traditional joint structures are presented. At last, owing to the possibility of the link interference, a kind of interference model of the links has been implemented in the links of the 5-DOF parallelmechanism.