| With the improvement of automotive intelligence and the continuous popularization of electric vehicles,automotive sensors are gradually developing in the direction of miniaturization,intelligence,and high integration.MEMS pressure sensors have become the most used sensors in automobiles.Compared with consumer pressure sensors,the working environment of automotive pressure sensors is more demanding.It is difficult for the sensors to maintain high precision output in a wide temperature range with working temperature ranging from-40℃ to 125℃.Therefore,this paper designs and implements a pressure sensor signal transmission calibration system that can be used in a wide temperature range for automotive sensors based on a pressure sensor signal conditioner and transmission system chip developed by the laboratory.Focusing on the temperature compensation in the wide temperature region of vehicle sensors,this paper proposes a calibration model of the fourth-order curved surface fitting based on the least square method.The new model has fewer calibration parameters,bettter fitting effect and fewer hardware requirements,and it solves the problem that the calibration effect of the second-order curved surface fitting calibration model is not ideal in the temperature region.And the theoretical calibration accuracy reaches 0.3325%FS in the range of-40℃～125℃.Aiming at the problems of multiple sensor testing equipments and complex calibration process,this paper designes a set of upper computer software based on Lab VIEW,realizes the acquisition and processing of the raw data of the sensors and the download of calibration parameters,complete the automatic calibration of the sensors,and simplified the calibration process.At the same time,an interface conversion circuit based on STM32F105 chip is designed to realize the information transfer between the upper computer and the Sensor Signal Conditioner.In this paper,the hardware and software design of the pressure sensor signal transfer calibration system that can be used in a wide temperature range is completed based on STM32F105 and Lab VIEW.A test platform is built based on GB/T 15478-2015 standard to complete the calibration of the sensor and the functional verification of the pressure sensor signal transfer calibration system.The test result shows that the measured accuracy of the sensor in the environment of-40℃～125℃ is improved from 20.8%FS to 0.484%FS,and the temperature drift is 0.16%FS.It meets the calibration accuracy requirements of automotive sensors and achieves the design goals. |
PDF Full Text Request