The rising number of electronic control units （ECUs） in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the ...The rising number of electronic control units （ECUs） in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the explicit calibration protocol （XCP） and J1939 communication protocol to satisfy the need of calibrating multiple ECUs simultaneously. The messages in the controller area network （CAN） are defined in the J1939 protocol. Each CAN node can get its own calibration messages and information from other ECUs, and block other messages by qualifying the CAN messages with priority, source or destination address. The data field of the calibration message is designed with the XCP, with CAN acting as the transport layer. The calibration sessions are setup with the event-triggered XCP driver in the master node and the responding XCP driver in the slave nodes. Mirroring calibration variables from ROM to RAM enables the user to calibrate ECUs online. The application example shows that the multi-ECU calibration system can calibrate multiple ECUs simultaneously, and the main program can also accomplish its calculation and send commands to the actuators in time. By the multi-ECU calibration system, the calibration effort and time can be reduced and the variables in ECU can get a better match with the variables of other ECUs.展开更多
对一种全新的拥塞控制协议XCP(eXplicit Control Protocol)进行了研究。在分析传统TCP的拥塞控制机制不足的基础上,对XCP协议的拥塞头格式进行了剖析,给出了基于XCP协议实现拥塞控制的基本原理。最后通过对比实验,验证了XCP协议在拥塞...对一种全新的拥塞控制协议XCP(eXplicit Control Protocol)进行了研究。在分析传统TCP的拥塞控制机制不足的基础上,对XCP协议的拥塞头格式进行了剖析,给出了基于XCP协议实现拥塞控制的基本原理。最后通过对比实验,验证了XCP协议在拥塞控制性能上比传统的TCP协议更优越。展开更多
现有TCP协议的拥塞控制机制存在很多不足,XCP(eXplicit Control Protocol)协议采用显式反馈的方式有效地克服了这些缺陷。XCP协议能容忍数据流之间一定的RTT差异,但当这种差异超出一定范围时,XCP协议性能恶化,变得不稳定。通过分析XCP...现有TCP协议的拥塞控制机制存在很多不足,XCP(eXplicit Control Protocol)协议采用显式反馈的方式有效地克服了这些缺陷。XCP协议能容忍数据流之间一定的RTT差异,但当这种差异超出一定范围时,XCP协议性能恶化,变得不稳定。通过分析XCP协议路由控制周期与数据流RTT的关系,提出了一种控制周期根据RTT差异程度而自适应调整的方法,消除了系统振荡。仿真数据表明,该方法能有效地提高XCP协议在数据流RTT差异较大的环境下的鲁棒性,同时不给路由器带来过大的计算负担。展开更多
文摘The rising number of electronic control units （ECUs） in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the explicit calibration protocol （XCP） and J1939 communication protocol to satisfy the need of calibrating multiple ECUs simultaneously. The messages in the controller area network （CAN） are defined in the J1939 protocol. Each CAN node can get its own calibration messages and information from other ECUs, and block other messages by qualifying the CAN messages with priority, source or destination address. The data field of the calibration message is designed with the XCP, with CAN acting as the transport layer. The calibration sessions are setup with the event-triggered XCP driver in the master node and the responding XCP driver in the slave nodes. Mirroring calibration variables from ROM to RAM enables the user to calibrate ECUs online. The application example shows that the multi-ECU calibration system can calibrate multiple ECUs simultaneously, and the main program can also accomplish its calculation and send commands to the actuators in time. By the multi-ECU calibration system, the calibration effort and time can be reduced and the variables in ECU can get a better match with the variables of other ECUs.
文摘现有TCP协议的拥塞控制机制存在很多不足,XCP(eXplicit Control Protocol)协议采用显式反馈的方式有效地克服了这些缺陷。XCP协议能容忍数据流之间一定的RTT差异,但当这种差异超出一定范围时,XCP协议性能恶化,变得不稳定。通过分析XCP协议路由控制周期与数据流RTT的关系,提出了一种控制周期根据RTT差异程度而自适应调整的方法,消除了系统振荡。仿真数据表明,该方法能有效地提高XCP协议在数据流RTT差异较大的环境下的鲁棒性,同时不给路由器带来过大的计算负担。
