为适应基于通信的列车运行控制(CBTC, communication based train control)系统从车地模式向车车通信模式发展的趋势,针对多周期性应用并发的车载安全计算机的时间约束性,提出了基于时间Petri网的安全计算机时间约束性验证方法.以车载2乘2取2安全计算机为例,通过分析安全计算机多周期应用的并发性质,采用时间Petri网(TPN, time Petri net)推算其时间可调度区间,并在此基础上进行实例分析.分析和验证结果表明, 在单核主频1GHz的条件下,车载安全计算机能满足3个以上周期性安全关键应用的时间约束性,表明TPN在验证和评估安全计算机中周期性应用的时间约束性方面的有效性.%In order to adapt to the development trend of the communication based train control (CBTC) system from train-ground communication mode to train-to-train communication mode, a verification approach for time constraints of multi-period applications concurrence on-board safety computer based on time Petri net was proposed. By taking the double 2 out of 2 on-board safety computer as an example, the multi-period applications concurrence nature of the safety computer was analyzed. Time Petri net (TPN) was utilized to calculate the time schedulable interval. Then several cases were analyzed based on the inference of this approach. The analysis and verification results indicate that onboard safety computer can meet the time constraints of more than three periodic safety-critical applications under the condition of single-core with main frequency of 1GHz, which demonstrates the effectiveness of verifying and evaluating the time constraints of safety computer periodic applications using TPN.
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