Abstracts

Abstracts in this section are from papexs presented at:

IFAC SYMPOSIUM ON LOW COST AUTOMATION Vienna, Austria, 9-11 September 1992

Full papers appear in the Proceedings volume to which the page numbers relate, published by IFAC and available from Elsevier Science Ltd.

(ISBN: 0 08 041716 7)

001 New Techniques to Improve Performance of Simple Control Loops R. Ortega, pp 1-6

The authors present some recent developments in feedback control theory that, they believe, can have an immediate impact on low-cost automation ~q~plications, in

~ ticolar synthesis techniques for single-loop controllers. e paper fkst reviews the impommt area of controller

tuning, concentrating on gain-scheduling techniques, where new, insightful research has been reported. Next, some results in robust linear controller desi~n, are described, including designs that are robust v/s av ts either structured (parameUric) or unstructured (dynamic) uncertainty. Although the transition towards practical implementation is incomplete, particularly in low-cost automation, a fresh reconsideration of the subject can exploit new theoretical developments, while emphasizing their connection with engineering practice.

002 Low Cost PLC Design and Application H.P. J t rgl , G. Htld, pp 7-12

In recent years small PLCs have gained importance as true low-cost syst~.s for indus~al automation. Equipped with up to I00 digital I/Os, programmable timer and counter functions, PID-controller modules, analogue I/Os and communication ports, they are widely used for open- and closed-bop control of small machines and processes. In this paper, a short survey of the functionality of micro- PLCs with PID-control capabilities is given, and an application of a PLC in the field of small hydropowcr plant control is presented.

003 Neurofuzzy Controllers F. Gomide, A. Rocha, P. Albertos, pp 13-26

Fuzzy modelling and control is a technique for handling qualitative information in a formal way. The implementation of fuzzy control systems may reduce design complexity and solve previously intractable problems. Neural-net architectures can have massively parallel intezconnections of single, neuron-like processors. In control systems, they were first introduced to learn input-output mappings. This paper reviews the underlying ideas and applications of fuzzy and neural control systems. The key ideas behind neurofuzzy systems presently under development are outlined, and currently available hardware end support tools ere described. Finally, it is suggested how neurofuzzy systems may be used to construct control systems with improved capabilities.

004 "Low-Cost" Factory Automation P. Kopacek, pp 27-33

"Low cost" and intelligent automation is an efficient tool, especially for small and medium-sized companies today. While "low cost" devices and concepts for the automation of continuous processes are commercially available today, concepts for discontinuous processes, especially for manufacturing automation, are still under development. Therefore, in this paper a modular and open "low-cost" concept is presented and triefly discussed. It consists of a network of PCs superimposed on a host computer. The concept is illustrated by application examples.

005 Using Low-Cost Piezoelectric Ultrasonic Sensors for 3D Measurement in Robots G. Llndstedt, G. Olsson, pp 3540

The problem of measuring the distance between a robot gripper and an object is treated in this paper. The design, experimental verification and experience of alternative solutions using pulsed ultrasonics are reported. Ultrasonics are often superior to optical methods in rugged robot environments and have a relatively low cost. The developed sensor and methodology offer distance measurement capabilities, as well as space orientation and an object identification among a limited number of possible forms. The feedback potential is apparent. The system, which uses several different frequencies, has been built around a laboratory robot platform. Experimental experience of both object identification and sensor-baseA feedback are described.

006 A Simple Link Between Pole Shifting and Phase Margin A. Rachid, pp 41-43

This paper gives simple relations relating the phase margin and pole shifting for single-input systems. Some results are also presented in the context of optimal quadratic pole shifting.

007 A Design of Two Stepwise Optimal Controller Following the Reference Model Output Y. Yamane, P.N. Nikiforuk, pp 45-49

This pap~ desoribes a generalized model-matching controller with feedback and feodforward gains in its structure, and which holds the resultant transfer function of the plant equal to that of the reference model. Two different cost functions are chosen to switch the gains of

347