| Through the sand, snow, mud and other complex surface, in order to ensure safety and smooth passage of vehicle, the tires of the large-scale engineering vehicles, off-road vehicles and special vehicles, need to be inflated or deflated. Automatically adjusting the pressure can not be solved by the traditional Tire Pressure Monitoring System (TPMS).The tire pressure monitoring and adjusting system is an improvement TPMS. The pressure and temperature data of each tire are measured by the sensor which is installed within the tire, and transmitted to the central control unit via wireless communication. The data are received and processed in the central control terminal and displayed on the LCD screen for reference by the occupants view. When the user change the current road conditions, or the pressure, temperature anomalies, the system can carry out sound and light alarm, and open the valve automatically to adjust tire pressure or the tank valve to reduce tire temperatures. The tire pressure monitoring and adjusting system can guarantee that the vehicles normally drive under all kinds of complicated road, and enhance the mobility and off-road vehicle performance, at the same time improve the safety and comfort of vehicle, and have broad market prospects and significance.In this article the domestic and foreign status and development trends of tire preesure auto adjusting system are analyzed. Comparison of existing system and combined with the project's needs, based on the traditional Pressure-Sensor Based TPMS, a software and hardware design of tire pressure monitoring and adjusting system is proposed. The main chip selection and hardware circuit design of the central control and tire-side terminal are described. The central control terminal software design which is based on the embedded real-time operating systemμC/OS-II is described as the focus. In view of the system's real-time requirements and complexity, theμC/OS-II operating system and multi-task programming method are introduced. The whole system is divided into several tasks by the functionality and every task module design is completed. The cutting ofμC/OS-II and the mirgration process to the LPC2214 processor and the corresponding hardware device driver design are completed. Combination of system characteristics and experimental data, a safe and efficient tire pressure control algorithm enable to achieve the real-time tire pressure adjustment is proposed. According to the characteristics of embedded software, the software testing programs of several key modules of the system is designed. Finally, the physical map of each module of the system and the field test situation are introduced. |
