Study On Dynamic Simulation Of Micro Polishing Robot Based On ADAMS

1.IntroductionWith the development of the automobile industry,the electrical appliances, the aerospace and one batch of new high technology, more and more high requirement are made for quality and the efficiency in machining die and mould with free-form surfaces.But,regardless of which one kind of shape processing method,All must be gring,polishing after shape process to obtain conforms to the request work piece surface quality.At present,processes of precision machining such gring and polishing still mainly depend on skilled worker's manual operation, which has some weak as low efficiency,quality unstable and difficult to adapt for the die and mould manufacturing with low cost,short production cycle and high quality.In order to overcome this question,The various countries begin to develop automated polishing processing technology take the computer technology as main assistance,and come forth some polishing special machine tool to develop automated equipment for free-form surface process and the key technologies.The modeling and the simulation are the important process in the robot design.Its goal is when the design can forecast the robot's performance and carries on optimizes.When institute overall project,is extremely essential to establishes three-dimensional model and carries on the simulation on its various aspects performance besides the kinematic analysis design.The robot dynamic simulation also may apply the movement simulation before the actual processing to processes, discovered possibly appears question in the processing process.The paper is in summarizes domestic and foreign related polishing technical and the robot technology, make use of VPT study on specialized polishing robot,make ADAMS software to carry on the simulation analyze for the designed thepolishing robot.This paper depends on The National Natural Science Foundation:the study of seft-positioning micro-polishing robot processing large scale free-form surface.Create 3D model by UG,and carry on simulation by ADAMS on polishing process,and simulation analysis about displacement,velocity,acceleration,angle-velocity,force,moment of important part of robot.2.Polishing robot configuration analysisThe robot of research in this paper using three-wheeled chassis parabolic,Motor-driven institutions differential(fig 1),Three wheel rounds into isosceles triangle distribution,the wheel at the back is driven round, The two left and right front wheel is an active round which respectively link drive integration.Two integration include MAXON motor,planetary reducer GP32C(16691)and digital encoder MR,the two active round are not turned,but they are independent of each other connect to different control module.Robot movement is the main line movement,turning around,marking zero turning radius,etc. Omnidirectional wheel Right drive wheel Lewfth dereilve Right drive integrationLeft drive integrationRobot's end effector is part of the core,it will directly affect the performance of the robot processing results,it is mainly supported by the plate cylinder,linear bearings,polishing head,swing motor,rotary motor,rotary motor sets,bearings component parts.End effector have three degrees of freedom:polishing rotation,polishing upgrade,polishing head's swing.the previous two freedom is necessaryon polishing process,the latter will adapt surface to ensure the accuracy of processing.The overall structure of robot figure 2,Mainly robot composed of two parts:One is the body structure,and the other is polishing system,just end effector. Polishing robot systembody structure Polishing systemSteer appliance Aadpspolirapnticoen apSpwliainngc e Enadp pelfifaencctoers Drive wheel Omniwdihreecetli onal emleacgtrniceat lSwing joint Pnseyusmtemati c Pohliesahdin g slideway3.Polishing Robot virtual prototyping model establishmentBased on the analysis of the structure of polishing robot,create model by high Modeling Software UG4.0,conversion to the dynamics simulation software ADAMS2005 by Parasolid format,In ADAMS model for the establishment of virtual prototyping including unnecessary components deletion,definition rigid body,the increase restrains,defines related parameter,increase actuation and so on,and applies ADAMS bringing model examination tool to exam the restraint and the degree of freedom,completes the virtual prototyping model.4.Polishing Robot Motion SimulationBased on the establishment virtual prototyping model of polishing robot,then carry on the interactive simulation and simulation of circular surface movement,the latter through adding contacts force on robot wheel,the robot can move forward to achieve,In the end effector of the robot control,Step function used to simulate telescopic movement on polishing process,Function as follows:step(time,0.0,0.011,0.5,0.011)+step(time,0.5,0.0,24.0,0.0)+step(time,24.0,0.0,26,-0.011)We can obtain some curve about polishing head′s displacement and speed,Because the robot lays aside the position is X,Y plane,and the polishing head is not completely parallel with the Z direction,exists polishing head curve about the displacement and speed.For starting after the robot movement 5 seconds to carry on polishing head expansion and contraction movement.Its curve in Y,Z direction increase after 5 second.Like Fig 3.Polishing head's speed also start from 5 second and Y,Z direction only then starts to appear maintains stable value.This had reflected fully polishing head the robot before the processing,polishing head drop in the process its displacement and speed change situation.The robot obtained some performance curve related on circular arc surface simulation.Fig 4 is the polishing head displacement curve.It is increases graduallyalong with the time change,and increases the speed also to speed up,reflected polishing head the processing position variation to realizes the robot path plan to have certain reference value.After polishing head's speed passed through two caper type rise to maintain at stable value.Fig 5 is the polishing head's speed curve.The explanation the speed has certain undulation in front of the robot work when process the polishing head's speed basically to be possible to maintain constant.It is extremely advantageous for polishing precision.This paper also analyzed polishing head angular speed,driving gear contact force Omni-directional wheel contact force,the moment of force and driven.Polishing head's angle speed maintain basically at constant value invariable,Fig 6.The driving gear receives the contact force also maintains at stable value,Fig 7.The omni-directional wheel receiveed the contact force and the contact moment of force quite complex and very small with not consider.Motion4,the polishing head's drive,X direction is about undulates in 8(a) likely sine curve,demonstrated strength change tendency in other two directions.The Y controlling force from 0 changes the maximum value,then changes 0 gradually,some in the change process to undulate,but the total tendency has not changed.The Z direction was polishing head expansion and contraction direction,when polishing head and the circular arc surface just contacted the strength is the zero then increased gradually,increases to a fixture,looked from the chart approximately 6.5N,this process only then the very short time,meets down maintains basically about this value.5.Conclusion1.This paper establish 3D solid modeling for polishing robot and parametric design.UG NX4.0 is used for robot assembly,The model can be established to provide a foundation for the next generation robot parabolic research and reference.2.Carry on polishing robot visual simulation by the ADAMS,to examine several joints of the robot,such as wheels,polishing head,swing institutions for the interactive simulation,In which polishing head the displacement and the speed has reflected robot some performance.In the robot rate process,polishing head X direction not to move,only then Y and Z direction exists moves and in simulation preliminary 5 second is a stable value before the polishing head drop.5 second begin to increase.The Y direction to is increasing.The Z direction negative increases.The polishing head's speed is the similar situation,X direction only has the rotary motion,Y and Z two directions also has an undulation in 5 second,then starts to have the speed.3.Simulation the polishing the operation of the robot and take the circular arc camber for example to dynamic simulation for polishing robot.The polishing head's displacement is increases gradually,moreover increases the speed also tospeed up.The speed has two caper type increase.The polishing head's angular speed is maintain basically in the fixed value is invariable.The driving gear contact force passes through the instantaneous change to achieve the stable value.