| The spraying robot has the advantages of superior spraying quality,high efficiency,large flexibility,high paint utilization rate and the like,and has wide application in the field of automobile manufacturing.Existing spraying robots are mostly series structures.The series structures have many moving parts and joints,complex attitude control,slow response speed and large working space.It may not be the best choice for body painting applications with complex surfaces.On the contrary,the parallel structure has the characteristics of fast response speed,flexible attitude control,large rigidity and simple structure,which can be well adapted to the working requirements of complex curved surface painting of the vehicle body,but it has weak points of small working space.The paper designs a new series-parallel spraying robot with the advantages of serial and parallel structure.It not only meets the needs of a wide range of working spaces,but also ensures fast and flexible control within a small range of nozzles.Provide a new design for the painting robot.The specific work of this paper is as follows.(1)Designed a series of new 5 degree of freedom series-parallel spraying robot using SolidWorks.The overall structure of the robot consists of two parts in series and in parallel.The series part is mainly responsible for the large-scale movement of the nozzle,significantly expand the painting work space;the parallel part is mainly responsible for the small displacement and attitude change of the nozzle,it consists of a moving platform,a fixed platform and upper and lower links.The fixed platform and the lower link are connected in the form of a Hooke hinge(Ujoint),the upper and lower links are connected in the form of a translation pair(P joint),the upper link and the moving platform are connected by a spherical pair(S joint),form a 4-UPS structure.(2)Parameterized modeling of parallel sections in MATLAB,used to determine the critical dimensions of the organization,workspace,and flexibility analysis.Compared the impact of different size combinations on workspace size and condition number metrics by parameterizing the dimensions of the two platforms,the results show that the working space and condition index of the parallel mechanism are optimal when the ratio of the moving platform to the fixed platform is 1:2.(3)Kinematics simulation experiments were performed in ADAMS.Firstly,the inverse kinematics simulation of the spray robot was performed.Solved the displacement control curve of each driving motor by giving the nozzle displacement and attitude motion trajectory;then the forward kinematics simulation was performed based on the motor curve obtained by the inverse dynamics.The same nozzle displacement and attitude motion trajectory as the inverse dynamics were obtained.The analysis process is equivalent to the teaching simulation study of the designed painting robot to verify whether the robot meets the design requirements.(4)Rigid-flexible coupled multi-body dynamics simulation on MSC platform.The ball screws of the parallel mechanism with less rigidity and higher manufacturing cost was treated as a flexible body,established a rigid-flexible coupling model,the dynamic stress and deformation of the ball screw during motion were obtained through dynamic simulation The results show that the ball screws are strong enough to meet strength and stiffness requirements.Compared the nozzle displacement and pose of the multi-rigid model and the rigid-flexible coupling model,the difference between the two results is minimal.It shows that the robot can be designed and simulated according to the multi-rigid model. |
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