RIA: Real-Time Discrete Event Control and Its Application toAutomated Manufacturing Systems

Kumar 9409712离散事件系统是指那些涉及具有离散值集的量的系统，这些量除了在系统中发生事件的离散时间外是恒定的。 例子包括通信网络、智能车辆高速公路系统、制造系统和计算机程序。 监督控制理论的发展提供了一个数学框架，为这样的系统，以满足各种定性或不定时的约束控制器的设计。 已经提出了一种统一的方法，其中既可以实现逻辑规范，也可以实现性能规范。 我们建议使用定时状态机来表示实时工厂以及所需的行为。 定时状态机的优先级同步组合已经被提出作为表示被控对象和控制器的各个子系统之间的相互作用的机制，并且还作为表示各种定性规范的组合的机制。 建议的监督也能够对控制规范的变化作出反应，因为它计算的控制策略的基础上可变有限的前瞻性，这种随时间变化的规格是相当常见的在一个实际的设置。 故障检测和恢复的问题也将通过定义“安全”的行为，并考虑“收敛”到这样的行为发生故障进行调查。 为了将我们的理论应用到自动化制造设备中，我们将获得工厂中各种机器的时间状态机模型，制定适当的定性和定量控制规范，并使用我们的理论制定控制策略。 我们还将研究这种方法的计算复杂性。 ***

Kumar 9409712 Discrete event systems are those systems which involve quantities which take on a discrete set of values and which are constant except at discrete times when events occur in the system. Examples include communication networks, intelligent vehicle highway systems, manufacturing systems and computer programs. Supervisory control theory was developed to provide a mathematical framework for the design of controllers for such systems in order to meet various qualitative or untimed constraints. A unified approach in which both logical as well as performance specifications can be achieved has been proposed. We propose to use timed state machines to represent the real-time plant as well as the desired behavior. Prioritized synchronous composition of timed state machines has been proposed as the mechanisms for representing interaction among various subsystems of the plant and the controller, and also as the mechanisms of representing composition of various qualitative specifications. The proposed supervisor is also able to react to changes in control specifications since it computes the control policy based on variable limited look-ahead; such time-varying specifications are quite common in a practical setting. The issues of failure detection and recovery will also be investigated by defining "safe" behavior and considering "convergence" to such behavior upon occurrence of failure. In order to apply our theory to the automated manufacturing facility, we will obtain timed state machine models of various machines on the factory, formulate appropriate qualitative and quantitative control specifications, and develop control policies using our theory. We will also investigate the computational complexity of this approach. ***