Research And Design Of Roadbed Temperature Acquisition System Based On AVR Microcontroller

Road quality is not only related to the quality of its construction, but also to its subgradestrength in permafrost and seasonal frozen regions.The strength and stability of roadbed isdetermined by the moisture and temperature,which the temperature is the power of moisturemigration in soil and important condition for moisture phase change.The analysis of thetemperature distribution and variation in the roadbed is the foundation of study the stability ofcement or asphalt pavement in seasonal frozen area.So a roadbed temperature acquisitionsystem that can get temperature variation in the freeze-thraw period of cold regionsautomatically and continuously will provide the basis for roadbed stability evaluation androad design and construction,which with important economic and scientific significance.For the demand of multi-channel automatic roadbed temperature acquisition,a roadbedtemperature acquisition system that can communicate with upper and lower computer isdesigned.Upper computer that written in LabVIEW data acquisition system achieve parametersetting and data acquisition with lower computer via the serial port. Lower computer usesPt100as temperature sensor,uses74LS138and74HC4051as multi-channel,uses ATmega16Aas MCU.ATmega16A communicate with AD7709and AT45DB041D through the SPIbus,connected PCF8563via I2C bus and achieve serial communication through theMAX3232.The power of system is supplied by a battery voltage of3.3V converted by thepower module.And complete the design of hardware circuit schematic and PCB board inAltium Designer to achieve a128-channel temperature acquisition system hardware design.Lower computer uses hibernate-interrupt operation mode to achieve lower poweconsumption.Modules such as clock module,multi-channel selection module,AD acquisitionmodule,data storage module, power detection module,the interrupt service module aredesigned by C language in AVR Studio.Through a custom serial communicationprotocol,upper computer management program by LabVIEW achieve system initialization,the clock parameter settings, alarm settings, memory data read and clear functions.Thendebugged and improved the software and hardware of the system through experiments.In order to achieve the roadbed temperature prediction function, a roadbed temperatureprediction model is put forward with artificial neural network model time series NAR network to achieve the roadbed temperature variation prediction. Experiments results show that themaximum relative error of0.443%of the predictive models with better prediction accuracy.The debug results show that the measurement error of the system meet the designrequirements with low cost,large collecte area,the user operability,ease of use,scalability,etc.advantages.The system can be used in the roadbed especially in permafrost areas to achievemulti-channel data acquisition efficiently and accurately.The long-term field workdemonstrated that the measurement system can long-term stable and reliable work,this systemnot only can realize the roadbed temperature multi-channel acquisition,but also can be appliedto other industries temperature data acquisition at the scene.