针对S3PR网的死锁预防问题,提出一种基于信标的最大许可死锁控制策略.采用迭代方法对网系统中存在的所有可清空严格极小信标添加一组广义互斥约束,使信标的标志数不超过某个上限值,将基于信标的死锁预防控制转化为禁止状态监控问题,使得受控网系统的所有禁止状态不可达,从而保证受控网具有最大许可行为.通过柔性制造系统实例验证了该策略的有效性,该算法尤其适用于结构相对简单的可达状态性能要求比较高的网模型.%To solve the problem of deadlock prevention for System of Simple Sequential Process with Resources (S3PR),a policy to design the deadlock-free supervisor with the maximum permissive system was proposed based on siphons.Using the iterative method,a set of Generalized Mutual Exclusion Constraints(GMEC) were added into all emptiable Strict Minimal Siphons (SMS) existed in the net system so as to make the number of siphons constrained in a given up-limited value,which transformed the siphon based deadlock prevention strategy into the monitoring problem of forbidden state.Thus all forbidden states in the controlled net system could not be reached,and the controlled network had maximum permissive behavior.The effectiveness of proposed policy was verified by examples of flexible manufacturing system,and it was especially suitable for the net model with relatively simple structure and high quality requirement of the reachable states.
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