Routing And ECU Flashing Method For In-vehicle CAN

With the advancement of the new four transformations in the automotive industry(electrification,connectivity,intelligence,and sharing),the concept of softwaredefined cars and standardized,platform-based hardware is gradually gaining popularity.Automotive manufacturers install high-performance hardware in vehicles during production and use Over-The-Air(OTA)technology to gradually release hardware functions and performance based on user needs during the vehicle’s lifecycle.As OTA technology is widely used,the frequency of software upgrades for Electronic Control Units(ECUs)on the Controller Area Network(CAN)in the vehicle is gradually increasing.This paper proposes a "high-level protocol" for ECU Firmware OTA(FOTA)on the CAN in the vehicle.The protocol is designed based on the physical and link layers of CAN and includes a network layer,transport layer,and application layer.The primary function of the protocol is to transmit firmware upgrade package data over CAN.Next,this paper proposes a user-unaware ECU flashing method based on a daemon thread,which achieves user-unaware ECU OTA upgrades in the vehicle,enhancing the user’s driving experience.The primary research content of this paper includes the following parts:(1)A FOTA-oriented CAN "high-level protocol" called ENCAP-CAN is proposed,which transmits firmware data over the CAN during ECU firmware upgrades.ENCAPCAN has a layered model,including a network layer,transport layer,and application layer.In the network layer,dedicated Interconnected Electronic Control Units are specified,and CAN message routing methods are designed.In the transport layer,single-frame and multi-frame message transmission methods are designed.In the application layer,FOTA-oriented commands are designed.(2)In order to optimize the user’s driving experience in OTA scenarios and achieve user-unaware ECU firmware upgrades,a user-unaware ECU flashing method based on a daemon thread is proposed.This method is designed based on the ECU’s software architecture,which refers to the Classic Platform(CP)architecture of AUTOSAR.The ECU storage partition is designed to carry different functions.An ECU firmware update daemon thread is designed,which is the core of this ECU flashing method.A Bootloader is designed to boot the firmware.(3)Experiments were conducted on the proposed firmware data routing and ECU flashing methods for the vehicle’s CAN.Functional testing was performed on the proposed methods in the experimental platform,confirming that the proposed method can achieve the desired functionality and make the firmware upgrade process transparent to users.Performance testing was then conducted,testing the time and space complexity,confirming that the proposed method can meet the requirements of actual application scenarios.The proposed firmware data routing and ECU flashing methods for the vehicle’s CAN can achieve user-unaware automotive software upgrades,reducing the impact of software upgrades on the user’s driving experience,and have practical application value.