Mechanism Configuration Design And Research Of A Kind Of Machine Tool For Machining Arc-Shaped Workpiece

Machine tool manufacturing industry is one of the ten important fields of “China made 2025”.As a tool of machinery manufacturing,the performance of the machine tool is directly related to the quality of the workpieces and products.Since the arc-shaped workpieces are widely used in transportation,aerospace,military,medical equipment and other fields,a kind of machine tool configuration based on 3-PRPUR/RUP parallel mechanism is proposed to machine arc-shaped workpieces.The machine tool can meet the needs of machining arc-shaped workpieces with varying radius.The configuration of this machine tool is taken as the research object,and its kinematic and dynamic properties are studied.Firstly,the configuration of the machine tool for machining arc-shaped workpieceis constructed.The degree of freedom of the configuration is analyzed to verify that the mechanism can meet the motion requirements.The appropriate kinematic pair is selected as the driver according to the driver selection principle.The correctness of the driver selection is verified.Secondly,the position and orientation of the moving coordinate system in the static coordinate system are described using D-H parameter method and rigid body transformation method,respectively.The relationship between the independent parameters and the non-independent parameters of the terminal output point is obtained according to the equivalence of two kinds of position and orientation description.Through the analytic geometry method and the condition of fixed side length of the moving platform,the position inverse solution of the mechanism is obtained.The forward position constraint equation of the mechanism is established using closed solution method.The correctness of positional positive and inverse solutions is verified by mean of numerical points.The velocity of the mechanism is analyzed.The Jacobian matrix of the mechanism is obtained.Then,the motion of the main components on each limb is analyzed by the plane motion principle of rigid body.The force condition of the main components of the mechanism is analyzed in the working condition.The dynamic mathematical model of the mechanism is established using principle of virtual work.The correctness of the analysis is verified by example and simulation.Finally,the factors that influence the workspace of the mechanism are analyzed.The cloud map of the workspace of the mechanism is obtained using Matlab.Compared with the workspace diagram simulated using SolidWorks,the correctness of the workspace solution is proved.A virtual prototype of the designed configuration is built using Adams and SolidWorks.The mechanical properties including the forward and inverse position solutions,velocity,acceleration,and dynamics is simulated on a virtual prototype according to certain trajectory.The simulation curve is smooth and there is no mutation,which shows that the kinematic and dynamic performances of the mechanism are good.