The Study Of Wireless Passive Sensor For Tire Pressure And Temperature Measurement And Its Monitoring System

The tire performance directly influences the safety of driving. Tire PressureMonitoring System (abbreviations: TPMS) is a kind of device which can reflect real-timepressure and temperature information, and also can effectively avoid traffic accidentcaused by the tire problems. Current TPMS usually works in active sensing mode whichneeds power module to provide energy. This mothod has many defects such as powerchange trouble and uneasy adjusting balance due to too large volume and quality.According to these shortcomings, the study of passive sensors is the inevitable trend ofTPMS development. Consider the comprehensive sensors work environment, SurfaceAcoustic Wave（abbreviations: SAW）sensors are considered to be the most promisingwireless sensor which could take the place of the active device. This paper focuses onrealization of wireless and passive tire pressure monitoring system as the main question,including that SAW sensors is not easy to simultaneously measure temperature andpressure information, the accuracy and reliability of RF transceiver system and monitoringsystem and so forth. Regarding the referred issues，this paper carries out the followingstudies:（1）Firstly, based on the SAW and SAW delay line principle and theory, this paperdescribes the design methodology of a new SAW, which is able to measure temperatureand pressure value simultaneously. By improving structure of sensors, the SAW is dividedinto two areas, one of which is temperature-influenced, and the other is influenced by bothtemperature and pressure. By import a weighted factor in the measurement parameterscalculation of SAW sensor, the effect of the temperature on the phase shift can beeliminated, so the phase shift induced by the pressure can be detected independently bythe sensor. The function between the temperature pressure and RF pulse echo signal ofSAW sensor are derivate, therefore, with this novel design, the SAW sensor is capable ofmeasuring both the temperature and the pressure simultaneously and accurately.（2）the hardware of the monitoring system is designed, in accordance with the signalgenerating, amplifying, filtering, interception, receiving, quadrature phase detection, dataprocessing and so forth. The hardware part is divided into a radio frequency module anddata processing module. The design of the software part includes process flow of timingsequence, RF transceiver module and signal processing module.（3）This paper analyses the electromagnetic environment of TPMS and elaboratesthe system hardware and software design on the electromagnetic compatibility designlevel. According to the system’s requirements of the measurement data，multi-sensorfusion technology processing data is used in this paper in order to achieve the TPMSaccurate alarm and avoid false negative and false positive alarm signal.