基于声表面波(SAW)技术,应用单端口SAW谐振器,设计了车辆驱动轴动态扭矩测量装置,实现车辆驱动轴扭矩无线无源实时测量。采用三点等间距对称方式布置信号收发天线,消除信号的绕射现象;以PWM信号控制FET时序通断,设计信号查询时序电路;通过差频测量方式,消除温度等因素的影响,提高了测量精度。模拟试验结果表明,测量装置所测得结果与理论模型一致,测量灵敏度约为1.15 kHz/(N·m),为车辆驱动轴动态扭矩的测量提供了一种可行的方案。
This paper presents a real-time measurement method of vehicle transmission shaft dynamic torque,which was based on two single-port SAW resonators.Using three-point equidistantly and symmetrically arranged signal transceiver antenna,the diffraction of signal was eliminated.The control circuit of signal transmitting and receiving sequence was achieved with PWM signal,therefore,the hardware circuit was simplified.Modeling of SAW torque sensor measurement with frequency difference was introduced into this measurement system,,and the influence of temperature or other factors was reduced and the measuring accuracy was improved.Theoretical and experimental results were compared and the results showed good agreement and supported the validity of the SAW torque sensor model.Obtained measurement sensitivity was 1.15 kHz /(N·m),and a feasible solution for vehicle transmission shaft dynamic torque measuring was provided.