Design And Implementation Of Automotive Electronic Water Valve Based On UDS Protoco

With the development of automobile industry and the improvement of emission regulations and energy consumption requirements,efficient cooling system has become the key to improve engine performance.On the other hand,driven by the strategic development trend of "new four modernizations" of automobile,the rise of new energy electric vehicles,vehicle networking and automatic driving technology in recent years has greatly accelerated the development of automobile electronic technology.The number of ECU(electronic control unit)in automobile is increasing,and its function is becoming more and more complex.In order to cope with the cost pressure of software upgrade,bug repair and after-sales maintenance brought by many on-board ECUs,the OEMs put forward OTA(air upgrade)requirements for auto parts to meet the needs of vehicle software upgrade.In this context,as the core component of the cooling system,the functional requirements of the electronic water valve bootloader(start loader)are improved.It is gradually necessary to support OTA function through UDS(Unified diagnostic service)protocol.Based on the analysis of the functions and measurement and control requirements of automobile electronic water valve,an electronic water valve to meet the needs of vehicle OTA is designed based on MLX81332 chip,and a special measurement and control equipment for electronic water valve is developed.Firstly,based on the actual working environment of the electronic water valve,this paper analyzes its functional requirements,balances the cost while ensuring the performance,and selects the stepping motor as the driving motor.In order to reduce the motor noise and vibration caused by torque fluctuation and improve the motor operating characteristics and position accuracy,pulse width modulation(PWM)and software are used to realize the subdivision control of the motor.The electronic water valve control chip adopts MLX81332 chip with high integration.The chip has its own driver,which greatly reduces the complexity of the peripheral circuit,reduces the wiring area and better controls the cost.Secondly,in order to meet the functional requirements of electronic water valve for OTA,this paper designs and implements the bootloader program based on UDS on LIN.On the premise of ensuring that the software download and upgrade are realized according to the specified process,the software backup and automatic rollback functions are added to improve the fault tolerance rate of software upgrade and vehicle safety.In order to facilitate the function development and test verification of electronic water valve,according to its test requirements,a portable measurement and control device is designed and developed based on STM32f405 RG processor.The equipment simulates VCU to conduct joint commissioning of electronic water valve and other components.In terms of hardware,the equipment provides complete data acquisition,communication and control interfaces;In terms of software,Labview is used as the development platform to provide functions such as control command issuance,data processing and status display.Finally,based on the measurement and control equipment designed in this paper,an experimental test platform is built to verify the basic functions of the electronic water valve and the software functions of the bootloader.The test results show that the software and hardware design meets the design requirements and meets the needs of vehicle use.