Design And Manufacture Of The Micro-force Measurement System And Its Experimental Research

With the rapid development of the modern society, micro-Newton force valuehas been more and more widely used in medicine, Micro-Nano Manufacturing andMEMS mechanical analysis. However, the current existing force transmission systemfor the small force of10N or less has not been established. Because there is nospecific structural design and manufacturing process for micro-force measurementdevice, research on a micro-force measurement system which can measure10-5N orless is meaningful.This paper summarized the significance of the micro-force measurement,analyzed the present situation of the development of micro-force measurement,defined the design and manufacture of a micro-force measurement system forconcrete steps.In this paper, based on electromagnetic theory, the calculation method of thecapacitance value and the capacitance gradient of the coaxial cylindrical variable areatype capacitor sensor has been analyzed. Using finite element analysis softwareMaxwell to analysis the various factors of the force reproducing apparatus such as theelectrode material, the thickness of the electrode cap, the radius of the internalelectrode boss, fillet radius of internal and external electrode, the thickness of theexternal electrode’s insulating layer and in order to prevent short-circuiting, analysisthe electrostatic force and the electrostatic field after the electrode capacitor paperadded to the inner surface of the external electrode, which providing a theoreticalbasis for the further study of the micro-force measurement device.In this paper, a micro-force measurement device based on the lever principle andprinciple of reproduction has been designed. For the force value enlarge consideration,the balance amplification ratio is designed to be K (K>1). The gem knife cap is usedin the balance, including knife and knife edge. A knife edge and a thimble support arelocated at the ends respectively. Using the linear bearing and insulation stick to guarantee the concentricity of the electrodes. Fix the digital micrometer to the deviceto measure the displacement of the internal electrode. On the key components of themeasurement device, describe the specific processing methods and precautions. UsingANSYS finite element software to analysis the balance beam and compared with thetheoretical value based on the material mechanics theory, verify the deformation andstress of the structure in the permitted range. According to the theory of gem blade,the knife was checked. Based on the existing research results, the rolling resistance ofthe balance is calculated. The results indicate that1mg minimum standard weight canrotate the balance.In this paper, an embedded systems is designed, including drawing a schematic,circuit board processing, program development and debugging, achieve the purpose ofcapacitance measurement and real-time display. The system including thecapacitance-to-digital converter AD7747, AT89S52,1602A, ADP3303, a LEDlight-emitting diode,2*5ISP-DIP interface, etc. Using Keil for programming andProgisp for burning. Finally, debug the program so as to meet the experimentalrequirements.After installation and commissioning, a series of experiments were carried out,including system zero check experiment, nominal capacitance experiments, systemdrift experiment and capacitance gradient measurement experiment. Verify thecalculation method of the capacitance gradient, proving that the system has reachedcertain purposes of the experiments.