The Kinematics Design And Workspace Analysis Of A Novel 5-DOF PMT

The thesis investigates the issues related to parallel machine tool in China and overseas countries and focuses on the design and analysis of a series of aspects such as structure, kinematics, machine parameters etc. of a 5 axis virtual CNC machine tool which is based on a novel 5-DOF(5-UPS/PRPU) spatial parallel mechanism.Based on the kinematics of parallel mechanism the structural novelty of parallel mechanism is discussed and the structural type and parameters of the PMT model are determined by means of qualitative analysis. Meanwhile reverse kinematics analysis is presented separatedly based on the center of movable platform and cutterpoint, which makes it more applied to real PMT and makes it possible to determine the workspace due to cutterpoint. Five independent parameters represent five degrees of freedom.Geometry constraints are the main factor influencing the workspace of PMT. The thesis considers constraints of limb length, ball joint angle and interference, which mainly analyzes the interference between the limbs and between electrical principal axis and the limbs. Moreover, a method of analyzing the interference between electrical principal axis and the limbs is introduced. The definition of agility cutter sloping angle is presented.Based on which workspace's reduced dimension description is given. Some graphical representations of the workspace which are available for engineering application can also be obtained in two dimension and three dimension.The thesis also investigates the effect of some main parameters on workspace. The thesis's conclusion provides powerful foundation in determining the PMT's main parameters.