| With the development of nanotechnology towards plurality and high level,the demand for nanometer measurement technology has been increased.As an important micro-nano detection technology,the atomic force microscopy(AFM)is also becoming more rapid and more accurate.Based on tuning fork probe,a fast,high precision AFM system is developed,it is proposed that the system could be applied in 3D surface measurement and nanometer vibration measurement.The main contents are as follows:1)Three working modes of the AFM and the working principle of the new type tuning fork probe are introduced;To analyz the structural characteristics of the tuning fork,the mechanical and electrical models of the tuning fork probe are established.Then,the principle of measuring nanometer vibration by the AFM is expounded.2)An AFM measurement system is developed,which consists of imaging module,probe module,DSP feedback module,scanning module and PC control module.An integrated mechanical of probe is designed.it has simple structure.Based on TI’s DSP chip TMS320C6748,a feedback control module is manufactured.The PC control module for quick data acquisition and scan is compiled.3)In order to verify the functions of each module,the modules of the system are tested,including the test of the input-output relationship for the probe module,the test of the relationship between the probe amplitude and driving voltage,the test of the input-output response for the DSP feedback module and the scanning speed test for the scanning module.4)The scanning tests and nanometer vibration measurement are implemented on this system.A standard grid is used to be scaned in FM mode and AM mode.It is proved that the repeatability error of the system is about 1 nm with the linear velocity 10 um/s.In closed-loop mode,vibrations with frequencies less than 20 Hz or greater than 213 k Hz and amplitude in micron level can be measured.In open-loop mode.vibrations with less than 380 nm can be measured. |
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