Development Of A Two-Dimensional Ultra-Precision Positioning Platform With Nanometer Resolution

Nowadays, with the rapid development of nanotechnology, the positioningaccuracy has a transfer from micron scale to the nanometer class in ultra-precisionmeasurement and processing equipment area. This paper proposes a newultra-precision positioning technique based on phase tracking and locking and theprinciple of laser heterodyne interference, which extremely simplifies the structure ofthe ultra-precision positioning system by taking the phase difference instead ofmonitoring displacement data from interferometer as the control signal ofmicro-displacement actuator, reduced the error term and improved the frequencyresponse. The two-dimensional ultra-precision positioning platform, as displacementexecution unit in this new positioning system, its precision and stability directlyaffect the positioning precision and efficiency. The thesis designs a two-dimensionalultra-precision positioning platform, and designs a power supply with high accuracy,high frequency response and low ripple, which was used to supply power forpositioning platform. The main content of the thesis is as follows:Firstly, according to the technical requirements of the ultra-precision positioningsystem, and flexible hinge have some advantages of no mechanical friction, zeroclearance, high sensitivity and simple processing etc. The thesis designs atwo-dimensional ultra-precision positioning platform based on flexible hinge andpiezoelectric actuator. Through analyzing the flexible hinge model and rigidity,maximum stress and natural frequencies of complex parallel four-connecting rods,we design the platform and build the entity model to simulate and analyze the staticand dynamic characteristics by ANSYS.Secondly, according to the properties of the selected piezoelectric actuator andthe positioning system requirements, we design a power supply which have outputvoltages ranging from-300VDC to300VDC. In order to eliminate the self-excitedoscillation of circuit and improve power frequency response, we added RC delaycompensation in error amplifier circuit. Finally, this paper detailed analysis the two-dimensional positioning platform’serror sources, and do some experiences and data analysis in dynamic responsecharacteristics, positioning accuracy and stability about the platform. The maintechnical parameters are identical with expectation.Experimental results show that: with52um travel, the two-dimensionalpositioning platform’s resolution is8nm, positioning accuracy is better than25nm.