Design And Application Of The Embedded Weigh-In-Motion System Of Vehicles

Based on the project of electronic toll collection on the highway toll station, this paper places the emphasis on R&D of the weigh in motion system of vehicle with ARM processor and RTOS, which can reach the requirement of real-time, high-precision and high-reliability.First, we devoted ourselves to the analysis of the current status of the weigh in motion technology at home and abroad. Then the ARM embedded system is put forward according to the requirement. But the reliability of software will deteriorate with the increase complexity of system. Using the real time operation system can reduce the complexity of debug process and improve the maintenance and reliability.Second, the application status and future of embedded system ,real time operation system and Bluetooth wireless communications protocol are summarized. After the proper embedded ARM , RTOS and Bluetooth module are selected according to the requirement of the weigh in motion, the software and hardware of embedded system are narrated in detail.We tested the stability and the precision of the WIM system on the spot and made some measures like lightening-protection, anti-electromagnetic interference and so on. Especially, according to the characteristics of the highway station environment, we set up the data buffer separately in the lower and the higher position machines, which can store the vehicle data. The data can be kept after power cuts or equipment resets. Moreover, we designed the dynamic link library to provide the application programming interface for the third-party software.Finally, this embedded ARM system is applied in the weigh in motion system on the highway toll station. It is real-time, highly stable and reliable in practice. Simultaneously, a practical, complete data-processing algorithm and its running results are introduced in this paper.