Research on torque measurement based on surface acoustic wave resonators
In view of the current status and existing problems of the surface acoustic wave(SAW)torque measure-ment technology in theoretical analysis,algorithm design and experimental test,the torque measurement technology based on the SAW resonator(SAWR)is studied.According to the feature that the torque on the shaft is transmitted to the SAWR by the strain,the theory model of the strain loading in the Lagrange coordinates is established.The torque coeffi-cient of frequency is defined as an important indicator for cuts optimization,and four SAWRs are designed and produced according to the principle of frequency division multiple access(FDMA).On the basis of the echo characteristics of the SAWR,the measurement methods of the SAWR resonance frequency and their characteristics are summarized.The wire-less measurement system for static and dynamic torque are built respectively.The static system utilizes the method of fre-quency sweep for the signal strength measurement,which combines big step for rough sweep with small step for fine sweep for the purpose of enhancing real-time performance and improving the frequency measurement accuracy.The dy-namic system employs the carrier frequency measurement method,and solves the problems of insufficient spectrum reso-lution and low torque measurement accuracy by the cubic spline interpolation in the frequency domain.The results show that the maximum measurement error of the static system does not exceed 1 N·m when the wireless distance exceeds 20 cm and the torque range is from-80 to 80 N·m;The maximum measurement error of the dynamic system does not exceed 3 N·m when the wireless distance exceeds 20 cm,the torque range is between 0 and 80 N·m,and the rotational speed does not surpass 600 r/min.The results validate the effectiveness of the torque measurement system based on the SAWRs,which provided a new approach for high-precision torque measurement.
万方数据
维普
