Topology Optimization Design Of Space-compliant Precision Positioning Platform For Nanoimprint Lithography Equipment

The precision positioning stage is one of the main factors affecting the stamping accuracy of the nano imprinting lithography equipment.The traditional mechanism topology optimization method cannot know the positioning stage input and output mapping matrix in advance,in view of this problem,this paper present a novel mechanism design method to design the positioning stage based on the optimal parallel prototype mechanism.The method take minimize the difference between the actual mapping matrix and the expected mapping matrix of the mechanism as objective function,and take the mapping matrix between the undesired degree of freedom(DOF)of mechanism and the driving input displacement and mechanism compliance as the constraints.The following researches are mainly carried out:(1)Parallel mechanism design.Take the DOF needed in the working process of the precision positioning stage as the parallel mechanism DOF form,to obtained the parallel mechanism screw expression.According to the theorem of reciprocal product of screw,obtained the kinematic screw system composed of the kinematic pairs of each branch chain of parallel mechanism.the form of the driving kinematic pair is specified,and then the composition of the branch chain of the parallel mechanism is obtained,finally,the parallel on-line configuration synthesis is completed.Taking the parallel mechanism parameters as the optimization object,obtained the parallel mechanism parameters with the largest moving space are by using genetic algorithm,and the scale synthesis of the parallel mechanism is completed.(2)Precision positioning stage design.In view of the traditional topology optimization method cannot know the mapping matrix between the output displacement and the input driving displacement of the positioning stage in advance,this paper present a novel mechanism design method to design the positioning stage based on the optimal parallel prototype mechanism,which takes the minimum error between the actual mapping matrix and the expected mapping matrix of the positioning stage as the optimization design goal,constrains the undesired freedom of motion of the positioning platform,and designs a positioning platform that meets the design requirements.Finally,the positioning accuracy of the stage in x,y and z direction is 0.033 ? m,0.037 ? m and 0.023 ? m respectively.(3)Analysis.The positioning stage obtained by topology optimization method is tested and simulated,and compared with the theoretical results,and drawn a conclusion.This paper takes the positioning stage as an example to show the effectiveness of this method,which provides the design basis for the follow-up design of spatial compliant mechanism,enriches the design method of compliant mechanism,and widens its application scope in the field of spatial mechanism design.