Design And Experimental Study Of Three-dimensional Micro/nano Machining System

Micro/nano scale structures have been widely used in micro mechanical systems,sensing devices,communication and medical instruments,etc.Aiming at the requirements of the fabrication technology,a three-dimensional micro/nano machining system has been developed in this dissertation,which includes a probe feeding system used to actuate the probe in the z direction and a micro/nano positioning stage used to drive the sample in xy plane.The static and dynamic properties of the entire mechanical system,the probe feeding subsystem and the micro/nano positioning subsystem have been investigated.For the hysteresis of the piezoelectric,a modified inverse Prandtl-Ishlinskii model based control methodology has been proposed.In order to investigate the influences of scratching parameters on the scratching result,the SPH method is utilized to simulate the micro/nano scratching.Based on the developed machining system,the theoretical analyses have been validated,and the fabrications of 2D/3D micro/nano structures have been realized.? A mechanical design methodology for the three-dimensional micro/nano machining system has been proposed,and then developed.The probe feeding system and the micro/nano positioning stage of the three-dimensional micro/nano machining system have been analyzed.For the probe feeding system,the electromagnetic force has been modeled theoretically.The compliance matrix of flexible beam is used to analyze the stiffness of the probe suspension mechanism.The effects of the mechanism thickness on stiffness and natural frequencies have been discussed.The measurement and calibration methods for the system have also been proposed in the end.For the micro/nano positioning stage,the double circular hinge linkage is used to realize the motion decoupling.The stiffness and dynamic model have been constructed based on simplified spring-mass system.The geometrical sizes of the flexure hinge have been optimized.Finally,the theoretical analyses have been validated by simulation and experiments.? The integral control strategy for the three-dimensional micro/nano machining system is firstly proposed.The hysteresis modeling and compensation strategy of the piezoelectric in the micro/nano positioning stage have been studied.A modified inverse P-I model has been proposed by reconstruct the model structure and introduce variable.Compared to the traditional inverse model,the proposed model can improve the model precision and lower the increase of the response time.Based on the modified P-I model,the feedforward controller,the feedforward/feedback controller and the decoupled feedforward/feedback controller have been designed,and both monodirectional and bidirectional trajectories have been tracked.The experimental results show the motion precision of the micro/nano positioning stage is improved.? In the investigation of micro/nano scratching simulation,according to the scratching depth,the probe tip has been modeled as a spherical capped conical tip or a spherical capped regular three-side pyramidal tip,and the horizontal projected areas of the probe-sample interfaces have been theoretically analyzed.The discrete sample model has been constructed.The SPH method is used to investigate the impact of scratching parameters and face angle on the scratching process.The simulation results can provide the reference for the following scratching experiments.? Based on the developed probe feeding system and micro/nano positioning stage,the three-dimensional micro/nano machining system has been constructed,and the scratching experiments have also been conducted.Through the micro/nano groove scratching,the influences of scratching direction,normal force,cycles,speed,feed and sample material on the scratching property have been investigated.Based on the scratching results,the proper parameters are selected for the fabrication of three-dimensional microstructures.