Research On Pressure-sensor Based Tire Pressure Monitoring System

Many highway traffic accidents major caused by tire blowouts which is mainly the consequences of under-inflation, high pressure of tire and so on. How to prevent tire blowouts has become an important issue for driving safety. Tire Pressure Monitoring System (TPMS) is a new and effective automotive safety device preventing from tire blowouts. The system can alarm by monitoring tire pressure when one or more of a vehicle's tires become abnormal to ensure driving security. TPMS enhances vehicle security, it can also improve control performance, reduce fuel economy, and increase tread life. Pressure-Sensor Based (PSB) TPMS is the mainstream automobile tire pressure monitoring system. It relies on the sensors installed on the tire to directly access the tire pressure and temperature values. And it communicates via wireless RF-transmission with central receiver module installed on body. The United States has legislated mandatory installation of TPMS. And TPMS in Europe and the United States have developed rapidly. But the research on TPMS in China is relatively late, and the technology is slower. Study on PSB TPMS with independent intellectual property rights for increasing domestic automobile safety and automobile industry international competitiveness is become of great significance.This paper first outlined the important role of TPMS, introduced the operating principle and characteristics of PSB and Wheel-Speed Based (WSB) TPMS, then focused on PSB TPMS, described its status quo, profoundly analyzed the key technologies-reliability, power, location and installation of tire-monitoring module, and described the future development trend.In view of the current PSB TPMS, there are some shortcomings and this paper proposed a scheme to improve the system design. First the design requirement of the system was brought forward. Then with comparing two PSB TPMS scheme, one-way communication system and two-way communication system, the system architecture has been proposed. And then the paper introduced the selection of system core chip, and put forward the solutions for the location of tire-monitoring module, low-power dissipation, signal collision-free design as well as installation outside tire valve.According to the system schema, the software and hardware design for every module were accomplished. On the one hand, the schematic circuits and printed circuit board was designed, including the periphery circuits for tire-monitoring module's single chip microcomputer named AVR ATmega48 automotive and tire receiver module's named AVR ATmega162, and the circuits for sensor dectecting, wireless communication with single chip transceiver named nRF401, CAN communication, and the serial communication between single chip microcomputer and PC used for display module. On the other hand, system software was designed, including the detailed design of low-power dissipation and signal collision-free, the establishment of wireless communication protocol, the SPI communication between sensor and single chip microcomputer, the serial communication between wireless single chip transceiver and single chip microcomputer, CAN communication, the serial communication between PC and single chip microcomputer, and the design of display module.Finally, a TPMS prototype composed of tire-monitoring module, central receiver module and display module has been made. Then the physical construction of TPMS's tire-monitoring module was designed. And then the power dissipation of tire-monitoring module was analyzed. In the end, the system hardware and software was debugged on the TPMS prototype.