The Design Of Embedded Weight-in-motion Meter

As is well known, the phenomenon of the vehicle with overload or over-limited becomes more and more serious in recent years, which has threatened the security of road infrastructure and the development of transportation, and even has disturbed the normal economy order of society. It is urgent for traffic control department to administer the vehicle with overload or over-limited. Practice proves that weight-in-motion system plays an important role in controlling the vehicle with overload or over-limited and investigating the traffic flow and so on.In this paper, an embedded weight-in-motion meter is designed to precheck high speed vehicles and to investigate the traffic flow. The embedded weight-in-motion meter has characteristics of strong ability to work independently, fast running, high measuring accuracy, good real time, low power consumption and stability. In this paper, the system structure of the embedded weight-in-motion meter adopts double CPU and Dual Port RAM; therefore, it can adequately meet the requirement of'collect along showing'; moreover, it not only can ensure the real-time capability, but also can supply the friendly human-machine interface.After analyzing the moving state of vehicles, the paper introduces the way that weight-in-motion meter calculates the weight, wheelbase, speed and other main datum of vehicles. And then, the paper proposes the scheme for the overall design of weight-in-motion meter. The scheme presents the design principle and target, general system design, software and hardware design of weight-in-motion meter. Hardware design includes core circuit design of front and rear processor, Dual Port RAM interface circuit design, signal isolating amplifier circuit design, A/D converting circuit design, power supply circuit design and anti-interference design of hardware. And correspondingly, software design consists of WinCE kernel customization, Dual Port RAM driver design, LPC2131 software and WinCE application software development. At the end of the paper, the software is tested and the result shows that the weight-in-motion meter designed in this paper achieves design requirements.Comparing to traditional weight-in-motion meter, the embedded weight-in-motion meter has outstanding characteristics, such as fast running, high accuracy, friendly human-machine interface, and so on. Especially the characteristic of working without computer, this will bring a broad application space for the weight-in-motion meter.