Supervisory control of a rapid thermal multiprocessor

Abstract

An apblication of supervisory control theory to a semiconductor manufacturing piece of equipment is presented. This approach allows the flexible design and reliable update of processing "retipes" to accommodate frequently changing manufacturing requirements. An input-output interpretation of supervisory control theory is given. This interpretation leads to a generic implenientation scheme for manufacturing systems. A synthesis fixpoint algorithm implementation using binary decision diagrams enables the design of supervisors of realistic size. A sample synthesis for an oxide growth recipe is performed on a state space of the order of lo6 states. The actual implementation of the logk sequencing control software for the application under investigation is described.study on how to apply supervisory control to the management of manufacturing workcells [41. Other related work includes the automatic verification of controllers, instead of their automatic synthesis. Here, the supervisor design is performed on a trial and error basis. Verification can be done using techniques originally developed for the formal verification of logic circuits, protocols, and logic programs [51-[7]. Recently, modelchecking verification approaches have been applied to the verification of supervisors for an automated highway car platoon system [81.

Supervisory synthesis for product-driven automation and its application to a flexible assembly cell

“…As a result, the concept of global controllability and uncontrollability of events is absent from the synthesis processes. This corresponds in fact to an input/output interpretation of SCT theory as proposed by Balemi et al (1993).…”

“…The gap between interpretations of the supervisor in SCT and the controller in the forcing events approaches (Marikar et al 1998) can be bridged by an input-output interpretation of the SCT controllable and uncontrollable events (Balemi et al 1993). Such an interpretation can be direct (Nourelfath and Niel 2004) if the supervisor sequences contain at least one controllable event between two uncontrollable events.…”

Synthesis of supervised controller based on Boolean constraints and Boolean automata

“…To reflect the interactions between the Grafcet controller and the plant, we chose the interpretation of Balemi (Balemi et al, 1993), where the controllable events Σ c represents the inputs process and the uncontrollable events Σ u their outputs. The controller can consequently force the input process at any moment and the generation of events is initiated jointly by the process and/or the controller.…”

Decomposing Controllers into Non-conflicting Distributed Controllers

“…While the state transition diagrams may look complex, they illustrate the available symmetry which is actually exploited in the decomposition process. Issues related to the realisation of synthesised controllers are discussed in [Zha96].…”