Design Of Tiny Magnet Matching Strategy And Automatic Matching Device Structure

The high-hardness permanent tiny-magnet with sizes ranging from micrometers to millimeters are critical for many precision instruments.The common application method is that the magnets group is composed of two or more tiny magnets and fixed in the instrument.The magnets form a uniform magnetic field at the air gap between them,and the magnetic properties of the magnets may result in insufficient instrument performance.In actual production,it is necessary to filtrate and match the magnetized magnets,to get the magnets group with the air-gap magnetic flux density to meet the requirements of use.At present,most of the matching work is still done manually.In order to improve the efficiency of magnet matching,ensure measurement repeatability,and reduce the rate of magnet scrap,it is urgent to study an intelligent and automated solution to meet production needs.In order to achieve the matching task of the tiny-magnets from a certain type of suspended wire pendulum accelerometer,the magnets characteristics and technical requirements are analyzed.Combined with simulation research and intelligent matching algorithms,an tiny-magnet matching strategy is proposed.According to the characteristics of tiny-magnet components,mechanical structures such as magnet multi-face-limit clamps are designed and an automated tiny-magnet selection device has been developed on those bases.The first is the research on the tiny-magnet matching strategy.Through the magnetostatics theory and finite element simulation,the distribution laws of magnetic flux density of magnets and air-gap magnetic field are ascertained.According to the simulation conclusion and the K-M algorithm,the tiny-magnets matching algorithm is designed,and numerical experiments are carried out to prove its stability and efficiency.The tiny-magnet matching strategy is designed with the matching algorithm as the core: The information of the magnet is collected first and then input into the algorithm.The magnet matching result is output by the algorithm,and the assembly of the magnet and the measurement of the air-gap magnetic flux density are performed based on the result.Then,the structure design of the automatic matching device for micro-magnets is carried out.Based on the matching strategy and simulation research proposed in this paper,the mechanical structures of the device such as magnet multi-face-limit clamps are designed.The main parts of the device are: magnet fixture module,magnet measurement module,magnet matching module,microscopic vision module and 3D displacement platform.And the reliability analysis of the magnet clamp structure is carried out.The electrical system with industrial computer as the main control core is designed.In addition,a tiny-magnet positioning strategy is also proposed: The spatial positions of magnets are obtained via the microscopic imaging module.According to those photos,the coarse positioning of magnets is realized.Using force servo and magnetic servo,the fine positioning is completed by controlling the feedback value of contact force and magnetic flux density.Finally,based on the tiny-magnet matching strategy,a series of tests and experiments were carried out on the matching device.The repeated positioning accuracy test of the 3D displacement platform,the pixel size calibration of the industrial camera,and the output linearity test of the micro-force sensor are carried out to prove that the key components meet the requirements of use.After that,the matching device is used to carry out tiny-magnet measurement and matching experiments.The results show: the automatic tiny-magnet matching device can complete the matching task,the standard deviations of the measured magnetic flux density of the magnets are less than 0.4 m T,and the average value of the air-gap magnetic flux density of the matched magnets is about 525 m T,which meets the matching requirements.