| The micro-nano operation measurement system is a kind of device for micro-nano scale operation and measurement.It has the ability of nano-scale displacement,force application and measurement.It is widely used to measure biological and physical information such as light,machine and electricity with high precision.With the development of nanotechnology,more fields will be able to realize nanoscale research.The existing systems have serious shortcomings in high-speed measurement and operation.One of the main reasons is the the design of nano-positioner with low natural frequency,so it is difficult to achieve high-speed motion.In order to solve this scientific and technical problem,this paper proposed a new design and control method of nanopositioner.A new T-shaped flexible hinge is created.The size of flexible hinge structure is greatly reduced by T-shape hinge with center rotating of both ends fixed beam.Optimizing the hinge stiffness of the mechanism within reasonable range,which greatly improves the compactness of the nano-positioner.According to the force form of different hinges when it works,the stiffness of the hinge is effectively increased by appropriately increasing the short plate spring hinge thickness.As a result,it increases the natural frequency of the nano-positioner.Appropriately increasing the width of the elastic hinge and shortening the length effectively improve the axial stability of the mechanism,and it guarantee the movement stability of the positioner.Center platform and the hinges are the only moving parts of the platform.There is no extra mass to reduce the natural frequency of the moving platform,which ensures the positioner meet the requirement of high-speed motion in mechanical structure.What is more,the flexible hinges applys wide hinge width that is relatively easy to machine,reducing the sensitivity of the platform to machining errors.The number of holes is reduced with few holes need to be processed when the nano-positioner is designed.The above factors reduce the processing difficulty of the high-speed nano-positioner and guarantee the processing precision and the performance of the final prototype.The stiffness matrix model of the high-speed positioner is built up with flexibility matrix theory.The model helped to decide hinge parameters.The finite element static simulation is used to obtain the stiffness of the platform,verify the correctness of the theory,analyze the causes of the error and optimize the parameters.The dynamic characteristics of the platform are obtained by mode simulation of the positioner.The natural frequencies of the three motion directions are calculated,and the design parameters are optimized.The complete design theory and test methods of high-speed nano-positioner are provided.The positioning accuracy,dynamic response speed and signal tracking capability of the platform are fully tested.Applying FPAA hardware control strategy to realize PI closed-loop motion control,achieved high-precision and high-speed position control,and realized AFM high-speed scanning work.Simulation and experiement show that the nano-positioner has excellent static and dynamic performance.The nano-positioner has the characteristics of low coupling and high positioning accuracy.When it is applied to a high-speed AFM,the scanning experimental images show the nanopositioner scan at high speed with FPAA closedloop control strategy and image stably and accuratly. |
