Research On Passive Tire Pressure Monitoring System Based On Delay-line Surface Acoustic Wave Sensor

With the increase of car’s ownership, the situation of car’s security is facing increasingly serious challenges. Up to70%due to traffic accidents caused by tire problems.The tire pressure monitoring system is an active safety system, which is used to provide pressure and temperature in the vehicle, provides the implementation of monitoring, warning and alarm to ensure traffic safety.Based on the background of the current tire pressure monitoring system, this passage amplifies the concept of tire pressure monitoring system, and describes the research status of the tire pressure monitoring system. According to the deficiencies of the existing tire pressure monitoring systems, this paper point out the development trend of the future tire pressure monitoring system is passive measure. This paper presents a passive solution of tire pressure monitoring system. Finally, it’s a brief introduction of the contents of this article.(1) With the summary of the concept of the surface acoustic wave, SAW’s propagation characteristics are researched. Several SAW devices and the principles of they work. This chapter focuses on the research of structure and characteristics of the delay line surface acoustic wave sensor. Two key parts:the interdigital transducer and the metal reflector grid are researched. Sensor processing and packaging technics were also researched.(2) Aiming at the existing gaps, this paper proposed a new type of passive sensor structure of the program, and researched its measure principle of temperature and pressure. Finally, according to the assumptions and formulas, it preceded theoretical analysis of the measurement principle, and determined the ultimate principle of the formula.(3) This chapter researched simulation models of the SAW sensor, based on the contrast of the advantages and disadvantages of various models and determined the coupling model (COM). It identified the model of each correlation matrix, gave the relevant formulas. Finally, according to the new passive sensor program design parameters and material parameters, preceded the model simulation, and obtained the simulation results. The simulation confirmed the accuracy of the models and theories. It provides a theoretical basis for the production, testing and application of the sensor element.(4) This paper proposed the overall design scheme of the new type of passive tire pressure monitoring system, researched various parts of the hardware. This chapter described how the system works and the echo signal processing principles, and preceded hardware simulation test of the entire measurement system, got ideal temperature and pressure measurement curve.