Decomposition-based real-time control of multi-stage transfer lines with residence time constraints

2020 ◽  
pp. 1-17
Author(s):  
Feifan Wang ◽  
Feng Ju
Keyword(s):  
Real Time ◽  
Residence Time ◽  
Time Constraints ◽  
Real Time Control ◽  
Transfer Lines ◽  
Time Control ◽  
Multi Stage

Real-Time Scheduling and Control of Single-Arm Cluster Tools With Residency Time Constraint and Activity Time Variation by Using Resource-Oriented Petri Nets

2019 ◽  
pp. 850-886
Author(s):  
Yan Qiao ◽  
NaiQi Wu ◽  
MengChu Zhou
Keyword(s):  
Real Time ◽  
Time Variation ◽  
Sojourn Time ◽  
Control Policy ◽  
Time Constraints ◽  
Activity Time ◽  
Real Time Control ◽  
Time Control ◽  
Cluster Tool ◽  
Residency Time

In semiconductor manufacturing, when a wafer is processed, it requires unloading from its process module in a given time interval, otherwise it is scraped. This requirement is called wafer residency time constraints. Thus, it is crucial to schedule a cluster tool such that the wafer sojourn time in a process module is within a given time window to satisfy the wafer residency time constraints. Besides wafer residency time constraints, in a cluster tool, the activity time is subject to variation. The activity time variation can make a feasible schedule obtained under the assumption of deterministic activity times become infeasible. To solve this problem, it is important to reveal the wafer sojourn time fluctuations with bounded activity time variation. Such an issue is addressed in this chapter for single-arm cluster tools. A single-arm cluster tool is modeled by a resource-oriented Petri net to describe the wafer fabrication processes. Based on it, a real-time control policy is proposed such that it offsets the effect of the activity time variation as much as possible. Then, the wafer sojourn time delay in a process module is analyzed and analytical expressions are derived to calculate the upper bound. With the help of the real-time control policy and wafer sojourn time delay analysis results, schedulability conditions and scheduling algorithms for an off-line schedule are presented in this chapter. The schedulability conditions can be analytically checked. If schedulable, an off-line schedule can be analytically found. The off-line schedule together with the real-time control policy forms the real-time schedule for the system. It is optimal in terms of cycle time minimization. Examples are given to show the application of the proposed approach.

Real-Time Scheduling and Control of Single-Arm Cluster Tools with Residency Time Constraint and Activity Time Variation by Using Resource-Oriented Petri Nets

2013 ◽  
pp. 178-210
Author(s):  
Yan Qiao ◽  
NaiQi Wu ◽  
MengChu Zhou
Keyword(s):  
Real Time ◽  
Time Variation ◽  
Sojourn Time ◽  
Control Policy ◽  
Time Constraints ◽  
Activity Time ◽  
Real Time Control ◽  
Time Control ◽  
Cluster Tool ◽  
Residency Time

In semiconductor manufacturing, when a wafer is processed, it requires unloading from its process module in a given time interval, otherwise it is scraped. This requirement is called wafer residency time constraints. Thus, it is crucial to schedule a cluster tool such that the wafer sojourn time in a process module is within a given time window to satisfy the wafer residency time constraints. Besides wafer residency time constraints, in a cluster tool, the activity time is subject to variation. The activity time variation can make a feasible schedule obtained under the assumption of deterministic activity times become infeasible. To solve this problem, it is important to reveal the wafer sojourn time fluctuations with bounded activity time variation. Such an issue is addressed in this chapter for single-arm cluster tools. A single-arm cluster tool is modeled by a resource-oriented Petri net to describe the wafer fabrication processes. Based on it, a real-time control policy is proposed such that it offsets the effect of the activity time variation as much as possible. Then, the wafer sojourn time delay in a process module is analyzed and analytical expressions are derived to calculate the upper bound. With the help of the real-time control policy and wafer sojourn time delay analysis results, schedulability conditions and scheduling algorithms for an off-line schedule are presented in this chapter. The schedulability conditions can be analytically checked. If schedulable, an off-line schedule can be analytically found. The off-line schedule together with the real-time control policy forms the real-time schedule for the system. It is optimal in terms of cycle time minimization. Examples are given to show the application of the proposed approach.

A Layered, Multi-Agent System for Intelligent Control

1992 ◽  
Vol 4 (2) ◽  
pp. 152-158
Author(s):  
Takuya Ishioka ◽  
◽  
Morikazu Takegaki
Keyword(s):  
Real Time ◽  
Intelligent Control ◽  
Time Constraints ◽  
Multi Agent System ◽  
Real Time Control ◽  
Agent Model ◽  
Intelligent Control System ◽  
Time Control ◽  
Rule Set ◽  
Multi Agent

We propose a layered, multi-agent model as a method for establishing an intelligent control system. The model handles each task, which constitutes control processing, as a group of agents operating autonomously, and organizes the agents in a layered structure from the viewpoint of real-time constraints. This enables real-time control processing and knowledge information processing simultaneously. We will describe a method for building the layered multiagent model using a concurrent rule set. The concurrent rule set can be processed by extending the expert shell and can realize the layered agent model in various computer environments through the use of the shell.

A Real Time Control Architecture for Continuously Managing Patients in a Care Unit

1995 ◽  
Vol 34 (05) ◽  
pp. 475-488
Author(s):  
B. Seroussi ◽  
J. F. Boisvieux ◽  
V. Morice
Keyword(s):  
Real Time ◽  
Linear Time ◽  
Treatment Plan ◽  
Control Architecture ◽  
Real Time Control ◽  
Time Representation ◽  
Time Control ◽  
Continuous Support ◽  
Definition Of ◽  
Computerized System

Abstract:The monitoring and treatment of patients in a care unit is a complex task in which even the most experienced clinicians can make errors. A hemato-oncology department in which patients undergo chemotherapy asked for a computerized system able to provide intelligent and continuous support in this task. One issue in building such a system is the definition of a control architecture able to manage, in real time, a treatment plan containing prescriptions and protocols in which temporal constraints are expressed in various ways, that is, which supervises the treatment, including controlling the timely execution of prescriptions and suggesting modifications to the plan according to the patient’s evolving condition. The system to solve these issues, called SEPIA, has to manage the dynamic, processes involved in patient care. Its role is to generate, in real time, commands for the patient’s care (execution of tests, administration of drugs) from a plan, and to monitor the patient’s state so that it may propose actions updating the plan. The necessity of an explicit time representation is shown. We propose using a linear time structure towards the past, with precise and absolute dates, open towards the future, and with imprecise and relative dates. Temporal relative scales are introduced to facilitate knowledge representation and access.

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