数据包丢失对列车控制系统的影响

Effect of Data Packet Dropout on Trains' Control System

基于通信的列车控制(CBTC)系统中的车-地通信是利用WLAN技术传输列车的状态和控制命令。列车控制系统的性能取决于通信链路数据传输的准确、实时、可靠,而WLAN技术并不是为城市轨道交通快速运行的环境而设计的,因此,在传输过程中出现传输延时和数据包丢失等情况,导致列车运行性能的下降。把列车控制系统等效为网络控制系统,对于车地通信无线传输过程中,出现随机延时大于其采样周期而导致传输的数据包丢失情形,采用补偿策略估计列车的系统状态并对其进行了分析,提出了改善数据包丢失的列车控制方法。

Train-ground communication based on CBTC u- ses WLAN technology to transfer status and control com- mands of the train. The performance of train control sys- tem depends on the accurate, real-tme and reliable data transmission in communication links. WLAN technology, however, is not originally designed for the high mobility en- vironment of mass transit. Thus, when random delay and data drop happens in transmission process will result in the degraded train performance. In the paper, train control sys- temis modeled as a networked control system, and in the train-ground transmission process, when the random delay is greater than a sampling period which causes the transmis- sion data drops, a compensation scheme is proposed to e- valuate the system state of train, and through analysis of the fault, some improvement measures are put forward.