U. Brunner

DESIGN OF A DISCRETE EVENT CONTROLLER FOR A MODEL RAILWAY

A framework is described to design a real-time discrete event control system. Extensions to Discrete Event Systems (DES) theory are developed to include probability measures in the plant model to describe features of a manufacturing system that are best represented in a stochastic setting. Job completion is modeled by a stopping rule for the plant in conjunction with an event cost function. An optimal stopping problem is formulated. A simple example is provided to demonstrate the proposed approach for a model railway project.

Observer models for real-time traffic control

The control of traffic lights today is mostly done by program selection depending on the daytime or of the average traffic flow. Flow models are the basis for the offline optimization. These rough models cannot be applied for real-time traffic control to achieve time-critical goals. In this paper different observer models for noiseless detectors are described. The identification of the model parameters is done. Verification and validation are subject of future work. Robustness can be obtained by an adequate error model.

Traffic Control Using Graph Theory

Abstract In this paper the design of a controller crossing is presented by means of an example. The controller to be developed has to minimise the waiting time of the public transportation while maintaining the individual traffic flowing as well as possible. First, the model of the chosen traffic crossing is derived. Then, using a combination of ‘Dynamic Programming’ and ‘Branch and Bound’ the control algorithm is presented. A visualization of the algorithm is given by means of graphs, complexity issues are investigated, and computational refinements proposed. Simulation results are shown at the end. The actual implementation of the control algorithm for the example shown is under way and carried out in co-operation with the Transportation Authority of the city of Zurich. The work presented here is part of a bigger project. The overall goal is to provide the traffic engineer with a tool for designing ‘intelligent’ controllers for traffic lights.

Design of a Discrete Event Controller for a Model Railway

Abstract A framework is described to design a real-time discrete event control system. Extensions to Discrete Event Systems (DES) theory are developed to include probability measures in the plant model to describe features of a manufacturing system that are best represented in a stochastic setting. Job completion is modeled by a stopping rule for the plant in conjunction with an event cost function. An optimal stopping problem is formulated. A simple example is provided to demonstrate the proposed approach for a model railway project.

MAXX: a manufacturing oriented simulator

MAXX is a manufacturing oriented simulator designed for detailed modeling and analysis of a manufacturing line. MAXX Version 4 is designed to evaluate a manufacturing line not only for steady-state long-term performance, but also for transient performance based on short-term production schedules. At the same time, it is easy and efficient to use. A methodology for dealing with the tradeoff is described. Central to the methodology is bottom-up design, which involves understanding the customers needs and incremental enhancement. A secondary concept in the methodology is systems integration. These concepts are explained in the development methodology for MAXX.<<ETX>>

NATURALLY MOTIVATED PROCEDURE FOR THE DESIGN OF A REDUCED-ORDER CONTROLLER

Abstract The old problem of designing reduced-order controllers has been addressed from many different angles. This paper offers an alternative approach to design reduced-order controllers for SISO systems. (The MIMO case is currently under development.) The new design technique lies between the two common design methods. The first common design method obtains the controller based on a reduced-order process model. The second one obtains the controller by designing a controller for the full-order process model and by then reducing the order of this controller. Unlike those two ‘open-loop’ methods the method presented in this paper works directly with the closed-loop system during the design, thus ensuring that the reduced-order controller achieves a performance similar to that of a full-order controller. Roughly speaking, the proposed procedure computes the reduced-order controller by approximating an equivalent closed-loop state feedback system and then performing an inverse operation.

Using the MAXX simulator for electronic card manufacturing

MAXX is a manufacturing-oriented simulator designed for detailed modeling and analysis of a manufacturing line. It is capable of evaluating both steady-state long-term performance and transient performance based on short-term production schedules for many types of manufacturing systems. It requires no programming by a user; instead, users interact with MAXX through menus, tables, forms, and a graphical routine editor. It is shown how MAXX can be used to model an electronic card manufacturing line and simulation results are presented for an example model.<<ETX>>

New method for the design of a reduced-order controller

The old problem of designing reduced-order controllers has been addressed from many different angles. This paper offers an alternative approach to design reduced-order controllers for S1SO systems (the MIMO case is currently under development). The new design technique lies between the two common design methods. The first obtains the controller based on a reduced-order process model. The second obtains the controller by designing a controller for the full-order process model and by then reducing the order of this controller. Unlike those two ‘open-loop’ methods the method presented in this paper works directly with the closed-loop system during the design, thus ensuring that the reduced-order controller achieves a performance similar to that of a full-order controller. Roughly speaking, the proposed procedure computes the reduced-order controller by approximating an equivalent closed-loop state feedback system and then performing an inverse operation.

A Method for Approximating Linear Controllers

Abstract By introducing an approximation parameter k, a weighted consideration of the transmission zeros of a system can be obtained when applying “modal” order reduction methods, and thus an approximation of its closed-loop characteristics can be achieved. Using this approximation with a suitable k, which can be found iteratively, we propose a method for the simplification of linear controllers.