Research On The Blanking Robot Of Automobile Panel Stamping Line Based On Parallel Mechanism

Feeding and unloading robot is an important part of automobile panel stamping line.Its performance is directly related to the production efficiency of the whole stamping line.How to design a more excellent robot for feeding and unloading material has become an important subject for the scholars at home and abroad.At present,most of the automobile panel stamping lines use serial robot mechanisms to realize feeding and unloading.Because of the problems of low stiffness,large inertia,low accuracy and slow speed,the serial robot mechanism seriously restricts the machining efficiency and production quality of the automatic production line.The parallel robot mechanism has the advantages of high accuracy,high speed,high rigidity and low cost compared with the serial robot mechanism.It has the potential to be applied to the feeding and unloading process.This paper attempts to apply parallel mechanism to the design of the feeding and unloading robot for the panel stamping line,and design a new feeding and unloading robot based on parallel mechanism.This thesis focuses on the following aspects:Firstly,it studies the production process of automobile panel stamping line,getting related parameters of automobile panel,press layout,track of up and down material,analysing at least 2 degrees of freedom for the top and bottom blanking process.Combined with the spiral theory,the configuration design and selection design of the parallel mechanism are carried out,and the parallel mechanism which meets the requirements is obtained.Combined with the actual process of the upper and lower blanking process of the press room,a mobile mechanism is added to the end of the parallel platform.Then a new type of up and down robot with both the advantages of parallel mechanism and large working space is obtained.Secondly,for the parallel mechanism part of the upper and lower cutting robot,the closed loop vector method is used to establish the forward and inverse solution models of the mechanism,so as to get the analytical solution of the forward position and the inverse position of the mechanism.Combining the inverse solution equation of the position and the constraint conditions of the workspace,the working space of the end of the parallel mechanism is obtained by using the search algorithm in Matlab.Combined with stamping process and blanking trajectory,the effective space of workspace is determined,and effective working space evaluation method is established.Thirdly,by using the evaluation method of effective workspace,it gets the evaluation index of effective workspace,and analyzes the relationship between the evaluation index of effective workspace and the parameters of parallel mechanism.By the inverse position solution of the parallel mechanism of feeding and unloading robot,it gets the velocity Jacobian matrix of the parallel mechanism,establishing the dexterity evaluation index of Jacobian matrix based on,and then analyzes the relationship between the dexterity index and the parameters of the parallel mechanism.By the inverse position solution of parallel mechanism of up and down robot and principle of virtual work,it obtains the force Jacobian matrix of parallel mechanism,establishing evaluation index of bearing capacity and evaluation index of bearing stability based on Jacobian matrix,analysing the ralationship between the evaluation index of bearing capacity and the parameters of the parallel mechanism,and the relationship between the bearing stability and the parameters of the parallel mechanism.Because the influence trend of the parameters of the parallel mechanism does not agree with each other,the parameters of the same mechanism can not be optimal at the same time.For the optimization of comprehensive parameters for multi-parameter and multi-performance index,In this thesis,a Monte Carlo method based on the performance map is proposed,and a mechanism parameter probability model based on the performance index is established.The Matlab software is used to compile the program,and the sampling of the parameters of the mechanism are sampled within the parameter intervals,and the distribution of the sampling values of the various parameters of the mechanism is calculated,and a set of mechanism parameters which are more reasonable is determined.Fourthly,the trajectory planning and ADAMS simulation are carried out for the vehicle overburden robot.According to the result of parameter optimization,3D solid modeling is carried out in the Solidworks software,and the 3D solid model is imported into commercial ADAMS simulation software by data transformation technology.The modified trapezoidal trajectory is applied to systematically plan the displacement,velocity and acceleration of the feeding and unloading trajectory,and the spline interpolation curve of each driving rod corresponding to each key point is obtained by using the inverse position equation and spline interpolation.The spline curve which changes the length of the drive rod is used as the driving function,so that the robot is moving according to the modified trapezium trajectory.During the whole process of feeding and unloading,the robot runs well,and there is no interference,shedding and impact.It shows that it satisfies the basic feeding and unloading operation,and thus verifies the rationality of its structural design.The data export function of ADAMS software is used to compare the simulated trajectory data with the target programming trajectory data,and the tracking error table is given.The result shows that the trajectory error has the magnitude of 10^-12mm,which validates the correctness of the inverse solution equation.In addition,the displacement,velocity and acceleration curves of each bar are obtained through data post-processing.It can be seen of from the change curve that the variation is stable and has no mutation.This shows that its kinematic characteristics can be accepted,and thus the feasibility of the planning trajectory is verified,which provides a basis for the design of a physical prototype robot.