Design Of Bionic Prototype Milli-micro 2D Force Measuring System Based On LabVIEW

In the field of mechanical bionics research,it is necessary to test the milli-micro Newton force generated by the smaller bionic prototypes such as locusts,beetles and moths.Because the surface morphology and structure of the bionic prototype are mostly micro-nano scale,it is easy to be destroyed.The existing micro-force testing system can’t meet the testing requirements of milli-micro Newton force generated by various bionic prototypes in terms of test range,test accuracy,and fixed platform of test samples.Therefore,this paper developed a milli-micro Newton two-dimensional force test system to meet the test requirements in terms of range,accuracy,and sample fixing mechanism.Based on the virtual instrument LabVIEW,a milli-micro Newton two-dimensional force test system was developed.The hardware part of the system mainly includes self-developed force sensor,the auxiliary mechanical mechanism to realize the test function and easy replacement of test samples,the output signal conditioning module SCXI-1520 of the force sensor and the data acquisition card USB-6351 which can complete A/D conversion.As the core component of force sensor,the parallel double-reed cantilever beam is calculated theoretically and simulated.Then three parallel double-reed cantilever beams were calibrated to obtain the transmission characteristic equations.Combined with the eddy current displacement sensor,the measuring range and resolution of the force sensor are finally obtained.The elastic coefficients are 220.62 mN/mm,160.74 mN/mm,50.37 mN/mm,the range is 0~800 mN,and the highest resolution is 50 μN.It is composed of the user management interface and the display interface of the two-dimensional force information acquisition system,which realizes the functions of user security management,parameter input and control,data acquisition image display and storage.Based on the completion of the milli-micro Newton two-dimensional force test device and the acquisition system software,the static characteristics of force measuring sensor are analyzed.The linearity(1.248%~2.303%),hysteresis(0.600%~0.857%)and repeatability(0.803%~1.457%)of the information acquisition system are within the standard range(≤5%).It indicates that the force sensor has excellent static characteristics and has no influence on the accuracy of test results.In order to test the function of the milli-micro Newton two-dimensional force information acquisition system,the bionic prototype friction force,normal force and puncture resistance were tested for 20 to 30 times,and the data were calculated and analyzed uniformly.The results showed that the friction force(the locust claw tip-Nepenthes slip zone)was 17.23±0.19 mN,the friction force(the locust claw tip-1200 mesh sandpaper surface)was 10.28±0.41 mN,and the piercing resistance(the jujube tree hook thorn-the animal liver epidermis)is 331.25±3.97 mN.The smaller variance indicates that the developed milli-micro Newton two-dimensional force information acquisition system has high stability and accuracy.The results confirmed that the system can obtain these force values with milli-micro magnitude accurately,and display these force values in interface window in real time and intuitively,as well as data group preservation.The testing requirements of the micro-micro Newton force generated by the bionic prototype in the process of mechanical bionics research are realized,which provides a theoretical basis for the future research of bionic prototype,exhibiting a certain practical application value.