Structural Design And Simulation Analysis Of A Kind Of Grinding Force Compensation Robot

The parallel mechanism has the advantage of simple mechanism and rapid response,which is widely used in packaging field.Because of the traditional grinding robot with complicated operation,narrow working space and large size,the parallel mechanism is limited in the service enterprise automatic grinding processing production when it is applied to the grinding processing production line.Besides,the stress of mechanism grinding makes the mechanism member elastic deformed,at the same time,phase coupling between mechanism movement and system itself intensifies elastic deformation of the mechanism member,which affect the movement characteristics of the robot system.To enlarge the application range of parallel grinding robot and improve the machining accuracy of grinding robot system,a 3-P4 R grinding force compensation parallel robot is studied,and the main research contents are as follows:Firstly,the researcher has been designed the force compensation and solved mechanism freedom of the force compensation according to screw theory,and reached inverse kinematics of mechanism with D-H method and analyzed of the effective working space of mechanism in accordance,and got the functional relationship between the input and output of mechanism the derivation of inverse equations,and analyzed the singularity of mechanism according to the Jacobian matrix.The virtual prototype of force compensation mechanism is established by Adams software,and to make the kinematics and dynamics simulation on it.Using MATLAB to compare the results of the positive and negative solutions of the kinematics with those of the virtual prototype,the result shows that theoretical curves of the slider displacement,velocity and acceleration are the same as simulation curves.It proves that the kinematics inverse solution and the virtual prototype are right.The dynamic variation of the input of the slider is obtained by simulating the dynamic simulation of the grinding force.Secondly,the finite element model of force compensation mechanism is established by workbench,and to make static stiffness analysis and modal analysis on it.After stiffness analysis we can reach that the overall deformation and stiffness of corresponding mechanism will change with the change of the position of the moving platform.When the moving platform is closer to the boundary position,the deformation will become large and the stiffness will become smaller,and the deformation position occurs mostly on the connecting rod;the deformation analysis shows that the vibration of the screw is relatively severe at the low order natural frequency drive.With the order increasing,a large vibration and deformation will occur on the rod connected with the moving platform.Finally,with the help of ANSYS we will convert the connecting rod into a flexible rod,and then make the rigid flexible coupling dynamics simulation on the mechanism.Because of the elastic deformation of the connecting rod and the coupling of the mechanism,the deformation of the connecting rod is exacerbated,which causes displacement and velocity curves of the moving platform fluctuate in grinding startup phase.The result shows that the rigid-flexible coupling simulation of the parallel mechanism with long connecting rods can accurately reflect the dynamic characteristics of the mechanism,and verifies that the machining accuracy of the new type of grinding force compensation robot meets the requirement.