A new approach to synthesis problems in timed discrete-event systems

A method for the modular synthesis of controllers for timed discrete-event systems

“…The framework lent itself to exploiting arithmetic properties for our control purposes. Based on the work by Ramadge and Wonham (1987 b), Ho (2000) introduced the notion of controlinvariant state predicates for TDES and a fixed point algorithm to calculate a control-invariant state subpredicate of a given state predicate. The most difficult part of this approach was to find conditions under which a control strategy employing forcing as a means of control can be generated.…”

“…The objective of this paper is to extend the centralized synthesis method by Ho (2000) to a modular synthesis method as an alternative strategy for control synthesis for large systems. The reasons for doing so are similar to those in the works by Wonham and Ramadge (1988) and by Brandin et al (1992).…”

“…Hence Ho (2000) developed an alternative method for yielding solutions to a class of synthesis problems without enumerating the detailed event trajectories of the system. The control objective was to synthesize a centralized controller such that the closed-loop behaviour of TDES satisfies a state predicate specification expressed in terms of the avoidance of forbidden state conditions.…”

Grid automata and supervisory control of dense real-time discrete event systems

“…This model specifies a priori the smallest measurable time unit [21,6,17]. A conceptual global digital clock is used to generate a fictitious event tick at a constant frequency.…”

A New Class of Supervisors for Timed Discrete Event Systems Under Partial Observation

“…L m ðGÞ-closure, controllability, and observability serve as necessary and sufficient conditions for the existence of a nonblocking supervisor for TDESs under partial observation (Lin and Wonham, 1995). Some other supervisory control problems such as modular supervisory control (Brandin and Wonham, 1993), hierarchical supervisory control (Wong and Wonham, 1996), stabilization (Yang et al, 1997), robust supervisory control (Takai, 2000), state based supervisory control (Ho, 2000), and reduced supervisor design (Gohari and Wonham, 2003) have been studied in the TDES framework of Brandin and Wonham. In this paper, we study supervisory control of TDESs under partial observation. Lin and Wonham's supervisor (Lin and Wonham, 1995) decides to enable or disable the event tick as well as controllable events.…”