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Showing papers presented at "International Symposium on Industrial Electronics in 1994"


Proceedings ArticleDOI
25 May 1994
TL;DR: Complex graphic signal flow graphs are suited to visualize the dynamic performance of AC machines and can assist to form an understanding of the internal dynamic processes of a machine and their interactions with external controls.
Abstract: Induction motors represent nonlinear higher-order dynamic systems of considerable complexity They are well amenable to a formal mathematical analysis It has proved more difficult, however, to comprehend and penetrate in an imaginative way the principles of their operation under transient conditions Complex graphic signal flow graphs are suited to visualize the dynamic performance of AC machines They can assist to form an understanding of the internal dynamic processes of a machine and their interactions with external controls >

66 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: In this article, a model-based control method for transportation control of a rectangular tank, considering the suppression of sloshing, is presented by means of a 2D distributed parameter model and a modal model.
Abstract: This paper presents a model-based control method for transportation control of a rectangular tank, considering the suppression of sloshing, i.e. liquid oscillations. Sloshing phenomena as caused by horizontal motion are analysed by means of a 2D distributed parameter model and a modal model. The latter is used for generating an optimal open-loop control input which reduces sloshing and provides savings in total transportation time. Furthermore, H/sup /spl infin feedback control is incorporated in the neighborhood of the target location, in case more precise control is needed. Key points for transportation control of a cart-based rectangular tank are clarified. >

32 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: The authors present a method designed to solve the problem of automatic color grading for industrial inspection and presents results of correctly grading a series of ceramic tiles, the differences of which were at the threshold of the human perception.
Abstract: The authors present a method designed to solve the problem of automatic color grading for industrial inspection. By far the most important obstacle to the solution of this problem is the temporal constancy of the image capturing conditions. They discuss the problems they were confronted with in that respect and the ways they dealt with them. Finally, they present results of correctly grading a series of ceramic tiles, the differences of which were at the threshold of the human perception. >

25 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, an artificial neural network (ANN) approach suitable for online faults detection of induction machines was presented. But the results proved the feasibility of to tool arranged by means of artificial neural networks for a fast and accurate detection of stator faults in induction machines.
Abstract: The paper deals with the analysis of an artificial neural network (ANN) approach suitable for online faults detection of induction machines. The aim of this paper is to develop an alternative with respect to traditional fault detector techniques that overcomes the limitations of present technology. After an analytical discussion about theoretical principles and relations used for the diagnosis of electrical machines failures, a simple ANN algorithm is presented and tested. The results prove the feasibility of to tool arranged by means of artificial neural network for a fast and accurate detection of stator faults in induction machines. Furthermore a good accuracy of the results have been achieved notwithstanding the great simplicity of the algorithm with respect to a complete model arranged by a space vector analysis. >

16 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: A soft-sensor, or virtual sensor, is a system designed to substitute the momentary or permanent unavailability of a sensor in a plant as discussed by the authors, which may be required because the actual sensor has failed or because it has been removed for maintenance.
Abstract: A soft-sensor, or virtual sensor, is a system designed to substitute the momentary or permanent unavailability of a sensor in a plant. This substitution may be required because the actual sensor has failed or because it has been removed for maintenance. It may also happen that the real sensor is used in a time-sharing way. Topics involved in the use of soft-sensors including new developments are reviewed. Experimental results obtained from applications to industrial plants are given, and related pending R&D subjects are presented. >

15 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: A novel technique to perform on-line remote monitoring and diagnosis of industrial and manufacturing systems based on Bayesian belief networks and genetic algorithms is described.
Abstract: Remote diagnosis of industrial and manufacturing facilities constitutes a feasible alternative at high-risk or remote sites where unmanned operation is preferred. Computer-aided diagnostic tools can reduce downtime by providing support to remote monitoring centers and on-site plant operators. This paper describes a novel technique to perform on-line remote monitoring and diagnosis of industrial and manufacturing systems based on Bayesian belief networks and genetic algorithms. An implementation of the methodology in a chemical process industry is presented and potential applications for different types of industrial systems are discussed. >

14 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, an economic performance analysis of harness assembly methods is presented, which will aid the designer to select the most economical harness assembly method for a particular application. But, the analysis is limited to a single harness.
Abstract: Due to expanding electronic features in most equipment, the role of the wire harness is becoming more and more prominent in many manufacturing fields. Furthermore, wire harness assembly is certainly one of the most difficult and time consuming assembly phases in manufacturing. This article presents an economic performance analysis of harness assembly methods. It is hoped that this will aid the designer to select the most economical assembly method. >

14 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: In this article, the authors presented a laboratory assembly to perform three-phase squirrel cage induction motor load tests using a 12-bit data acquisition system, a software controlled electronic driving system, temperature sensors and a microcomputer.
Abstract: This paper presents a laboratory assembly to perform, automatically, three-phase squirrel cage induction motor load tests. Besides the motor, mechanical load (fan), drive and electrical protection equipment, the assembly comprises a 12 bits data acquisition system, a software controlled electronic driving system, temperature sensors and a microcomputer. It is useful for fast and reliable motor part temperatures acquisition during any load test proposed via a computer keyboard allowing for the data storage for motor thermal behavior studies. The performance of the assembly was checked by performing load tests according to the duty types proposed in IEC Publ. 34-1, Rotating electrical machines, Part 1: Rating and Performance, 8th edition, 1983. >

14 citations


Proceedings ArticleDOI
G.T. Heydt1, S.P. Hoffman1, A. Risal1, R.I. Sasaki1, M.J. Kemper1 
25 May 1994
TL;DR: In this article, a discussion of several energy saving technologies and their impact on electric power distribution systems is presented. But the main focus of the discussion relates to ASD heat pumps and electronic ballast fluorescent lighting.
Abstract: This paper contains a discussion of several energy saving technologies and their impact on electric power distribution systems. The reduced power demand of these energy saving devices reduces the peak system demand. However, there are increased distribution transformer and distribution network losses due to the distorted load current waveshape. These losses, when integrated over many services and over the year, represent a significant cost due to fuel costs and higher peak. The main focus of the discussion relates to ASD heat pumps and electronic ballast fluorescent lighting. >

13 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, a 3D extension of Bresenham's algorithm and its implementation in the linear trajectory interpolation of CNC paths is described and applied to a CNC milling machine that uses stepper motors as actuators, resulting in minimal contour errors for a given step motor resolution.
Abstract: This article describes a 3D extension of Bresenham's algorithm and its implementation in the linear trajectory interpolation of CNC paths. The resulting algorithm has been successfully applied to a CNC milling machine that uses stepper motors as actuators, resulting in minimal contour errors for a given step motor resolution. A numerical control system that uses the algorithm implementation has been built as part of a wider effort which is to test the feasibility of building or retrofitting machine tools with CNC capabilities at an affordable price tag for a developing country. >

11 citations


Proceedings ArticleDOI
25 May 1994
TL;DR: In this article, a compact single-ended MOSFET inverter with a switching snubber operating at a frequency of 1 MHz, which generates an RF power of 600 W when an ultrasonic transducer with a characteristic impedance of 1 ohm is connected to the inverter.
Abstract: Described is a compact single-ended MOSFET inverter with a switching snubber operating at a frequency of 1 MHz, which generates an RF power of 600 W when an ultrasonic transducer with a characteristic impedance of 1 ohm is connected to the inverter. The inverter has a power conversion efficiency of 67% at 1 MHz when a DC voltage of 70 V is supplied to the inverter. The inverter is 22 cm/spl times/l7 cm/spl times/9 cm in dimensions and 2 kg in weight. >

Proceedings ArticleDOI
25 May 1994
TL;DR: A method for detecting and following a half-faded lane on an asphalt road using image processing based on a template matching with the "lane mark model" and a method for the motion control of the robot which is based on the "look-ahead model".
Abstract: In this paper, the authors propose a method for detecting and following a half-faded lane on an asphalt road using image processing. It ensures reliable detection and high speed following in ordinary outdoor scenes. The method of the image processing is based on a template matching with the "lane mark model". They also propose a method for the motion control of the robot which is based on the "look-ahead model". The feedback law adopted is PID (proportional-integral-derivative) control. The authors built a testbed robot, which aims to paint a half-faded lane mark semi-automatically. The details of this testbed robot and experimental results of a half-faded lane mark detection and following are described. Experimental results (trajectories of this robot) for an actual half-faded lane mark show the applicability of this method. >

Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, a three-phase inverter with insulated gate bipolar transistors (IGBTs) is presented, where the modulation strategy considers the calculation of the on-times of the different voltage vectors that must be applied to the load, to generate the voltage vector required by the speed control system of the machine.
Abstract: This work presents the design of a three-phase inverter with insulated gate bipolar transistors (IGBTs). The pulse width modulation technique based on the space vector theory is analysed in detail. The modulation strategy considers the calculation of the on-times of the different voltage vectors that must be applied to the load, to generate the voltage vector required by the speed control system of the machine. These times are calculated previously and stored in a ROM, producing a simple, reliable, compact and low cost digital modulator. The inverter behaves as a voltage source with variable amplitude and frequency. By using the space vector theory, the number of commutations in the inverter is minimized, reaching a reduction in the switching frequency and in the current distortion. >

Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, an automatic seam detection and recognition system interfaced to a robot that uses ultrasonic sensors for obtaining the seam position and orientation, and its geometrical features, is described.
Abstract: In robotic arc welding, sensors must be used to detect the position and orientation of a weld seam and determine its shape in order to carry out the weld parameter control. Useful measurements are the seam width and the volume of the seam that must be filled. With these measurements it is possible to set the welding parameters for each condition. In this paper an automatic seam detection and recognition system interfaced to a robot that uses ultrasonic sensors for obtaining the seam position and orientation, and its geometrical features, is described. The echo signals are digitized and through an analytical method the echo envelope and the moment of the arrival of the echo are precisely calculated. Echo amplitude is obtained searching the maximum of its envelope, and the range measurement is obtained known the starting time of the echo. >

Proceedings ArticleDOI
25 May 1994
TL;DR: Although all the concepts and methods are feasible for any kind of digital electronic system, ASICs (Application Specific Integrated Circuits) are specially considered.
Abstract: The design process based on hardware description languages is described. The most important stages of the design flow and the tools involved are presented, from the specification to the final implementation. The advantages of using hardware description languages are highlighted, as well as the problems that may appear by their use. Although all the concepts and methods are feasible for any kind of digital electronic system, ASICs (Application Specific Integrated Circuits) are specially considered. >

Proceedings ArticleDOI
25 May 1994
TL;DR: A novel and more robust controller is proposed, viz a numerical-based fuzzy PID controller or extremities PID controller, which combines classical PID concepts with fuzzy arithmetics.
Abstract: The employment of PID controllers for automated processes has been widely accepted in industry. The main problems associated with classical PID controllers are tuning and robustness in case of changes in system conditions. In this paper, a novel and more robust controller is proposed, viz a numerical-based fuzzy PID controller or extremities PID controller, which combines classical PID concepts with fuzzy arithmetics. For the purpose of investigating the basic performance of the newly developed controller, two laboratory-scale plants are used, viz a simple series RLC network and a microcomputer-based dual-converter DC drive. Experimental results, including comparisons with a classical PID controller, are also presented. >

Proceedings ArticleDOI
25 May 1994
TL;DR: The Weighted Mahalanobis Distance Hough Transform (WMDHT) as discussed by the authors was proposed to improve the efficiency, accuracy and reduce the size of the accumulator arrays by combining with extended Kalman filter refinement.
Abstract: The paper presents a new parameter space approach, called the Weighted Mahalanobis Distance Hough Transform (WMDHT) whose main merit is to incorporate formal stochastic image and feature noise models. It is aimed at improving the efficiency, accuracy and reducing the size of the accumulator arrays by combining it with extended Kalman filter refinement. It works by detecting image feature points in the neighbourhood of a contour instead of exactly on the contour through a Mahalanobis distance measure modified by a weight function inversely proportional to the distance between the point and an ideal contour. The method is applicable to geometric features of any dimensionality and the paper illustrates it by considering detection of straight and circular segments. >

Proceedings ArticleDOI
25 May 1994
TL;DR: A biologically-inspired visual pattern recognition system, namely the Cyvis-1, is reported, which is composed of a series of modularized processing specializations dedicated to the processing of a specific image attribute such as edge-elements, color, regions, texture and movement.
Abstract: A biologically-inspired visual pattern recognition system, namely the Cyvis-1, is reported. The system is composed of a series of modularized processing specializations, each one dedicated to the processing of a specific image attribute such as edge-elements, color, regions, texture and movement. These specialized processing pathways are interconnected among themselves at their many hierarchical levels in order to speed up the recognition process. The biological principles that have been adopted as well as the functional structure of the proposed system and the data structures and processing strategies to be used in each of the processing specialization, are also discussed. >

Proceedings ArticleDOI
25 May 1994
TL;DR: The results show that a low power laser cutting machine with three degrees of freedom is feasible at a reasonable cost for applications where speed and repeatability are more important than high precision and power.
Abstract: This article describes the design and construction of a low power laser cutting machine with three degrees of freedom for applications such as wood, textile fabrics and the like. An available 10 Watt laser gun is used to provide the cutting mechanism. The results show that such a machine is feasible at a reasonable cost for applications where speed and repeatability are more important than high precision and power. >

Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, the dependence of losses and efficiency on design characteristics of a squirrel cage induction motor fed by a voltage source inverter, is analyzed in a model based on harmonic equivalent circuits.
Abstract: The dependence of losses and efficiency on design characteristics of a squirrel cage induction motor fed by a voltage source inverter, is analysed in this paper. A model based on harmonic equivalent circuits is used to study the influence of circuital parameters and motor geometry on the magnitude of losses. An analysis of parameter sensibility shows that a motor with large leakage inductance presents an important reduction of losses and an insignificant reduction of fundamental torque. Thus, it is found that motors with a small number of stator and rotor slots, deep slots and large diameter/axial length ratio, present low losses and high efficiency. >

Proceedings ArticleDOI
25 May 1994
TL;DR: Task Planning for Manufacturing Systems (TPMS) as discussed by the authors is a system that automatically generates programs or sets of commands for robots, AGVs, numerical control machines and other components of the system without the need of programming the flexible manufacturing system (FMS) components.
Abstract: This paper describes a system named TPMS (Task Planning for Manufacturing Systems). The final goal of this system is to automatically generate programs or sets of commands for robots, AGVs, numerical control machines and other components of the system without the need of spending much time programming the flexible manufacturing system (FMS) components. The sequence of operations to be handled by the manufacturing system depends on the constraints for the task. Three types of constraints are defined and explained: processing constraints; feasibility constraints and geometric constraints. The symbolic plan for the task is represented in the form of a precedence graph. High level operations can be converted into programs or sets of instructions to control the manufacturing system's equipment. The main contributions of TPMS are the following: to put together symbolic planning and execution planning; it is being developed to work for complete manufacturing systems (and not for controlling only one robot); different industrial operations (assembly, welding, drilling, etc.) can be considered at the same time. >

Proceedings ArticleDOI
25 May 1994
TL;DR: A moving corner detector for analysis of traffic movements is introduced which comprises a corner response calculation component and a spatial temporal analysis part and is reasonably successful in separating stationary corners from moving ones.
Abstract: Corners have become now one of the most commonly used features in image analysis, in particular, in motion analysis and stereo vision. There are many corner detection algorithms which can be classified into two groups. One is based on the extraction of object contours and followed by the analysis of their structures. The other works directly on the local grey values. In this paper, a moving corner detector for analysis of traffic movements is introduced which belongs to the second category. It comprises a corner response calculation component and a spatial temporal analysis part. The corner response calculation uses only the first order image derivatives, which is detected from Harris and Stephens' combined corner edge detector. Spatio-temporal analysis combines both spatial and temporal information to suppress noise and is achieved through more than two images. Apart from some random noises digitization, there are some slight shifts in space from frame to frame. These cause some stationary corners with high contrast being picked up as moving corners. Results showed that this moving corner detector is reasonably successful in separating these stationary corners from moving ones. >

Proceedings ArticleDOI
25 May 1994
TL;DR: Experimental efforts to combine the power of genetic algorithms and the practical applications of fuzzy controllers, are described.
Abstract: Fuzzy controllers are based on a rule set that describe the strategy applied to control a plant. Some rules are obvious but in many cases to choose a set of rules is not a very easy task. Almost all fuzzy consumer products on the market rely on rules supplied by a human expert. Tuning the rules is a lengthy and cumbersome process, and some effort has been made toward the automation of this process. Self-organizing-controllers (SOC) and neural networks are examples. Another approach is found in genetic algorithms, which make it possible to explore a great range of solutions. The advantage is that little has to be known about the plant to be controlled and also about the best set of rules. When applied to servo-systems like positioning systems for NC machine tools, some obvious rules may, or even have to, be used, but a final set may be implemented by the algorithm. In this paper, some experimental efforts to combine the power of genetic algorithms and the practical applications of fuzzy controllers, are described. >

Proceedings ArticleDOI
25 May 1994
TL;DR: In this article, the authors proposed a scheme for on-line fault detection and diagnosis using an expert system, which is being tested at a beet-sugar factory in Spain.
Abstract: The article proposes a scheme for on-line fault detection and diagnosis using an expert system. This approach is being tested at a beet-sugar factory in Spain. A great deal of critical situations may arise in the normal operation of such a process. They are now managed by plant operators and cover both cases: faulty equipment diagnosis, which requires module substitution, as well as the detection of major improper control actions that may cause plant problems in the long run. This prototype not only comprises aspects related with fault detection and diagnosis but also is responsible for supervisory tasks to improve the whole process performance. The paper includes a description of the system architecture, a detailed presentation of the fault detection and diagnosis modules, and some evaluation of the results obtained by the system operation at the factory. >

Proceedings ArticleDOI
25 May 1994
TL;DR: Three trends that are described at length are the increasing use of microsensors, the techniques that are used in the handling of partial or uncertain data, and the application of neural network techniques for sensor fusion.
Abstract: The need for intelligent systems that can operate in an unstructured dynamic environment has created a growing demand for the use of multiple, distributed sensors. While most research in multisensor fusion has revolved around applications in object recognition-including military applications for automatic target recognition-developments in microsensor technology are encouraging more research in affordable, highly-redundant sensor networks. Three trends that are described at length are the increasing use of microsensors, the techniques that are used in the handling of partial or uncertain data, and the application of neural network techniques for sensor fusion. >

Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, an extended state equation (ESE) was proposed for finding firing sequences for the reachability problem in Petri nets, which is formulated as an integer programming problem whose solution can provide sufficient information on the firing sequences.
Abstract: Finding firing sequences for the reachability problem can be regarded as one of the most important issues associated with Petri nets. The purpose of this study is to develop a new method for finding firing sequences by defining an extended state equation. The proposed method is formulated as an integer programming problem whose solution can provide sufficient information on the firing sequences. First, the optimization problem is approached with a linear programming technique. Evaluating the reduced-cost and activeness of every variable, one can systematically sort out the irrelevant variables to be neglected in the integer programming problem of the succeeding stage. In this paper, the usefulness of the proposed method is demonstrated with the evaluation of a couple of simple examples. >

Proceedings ArticleDOI
25 May 1994
TL;DR: The authors have implemented a distributed universal fuzzy controller capable of adapting itself to deal with a specific process, which can run sequentially and in parallel on a network of transputers, its performance is being tested in an industrial application: the tuning of high frequency amplifiers.
Abstract: The authors have implemented a distributed universal fuzzy controller capable of adapting itself to deal with a specific process. Due to its distributed nature the controller can run sequentially, in a processor, or in parallel, in a net of processors when the application requires it. In order to implement the distributed universal fuzzy controller the authors have developed a system with the following components: (1) a language to describe the control problem in terms of fuzzy inputs, outputs and rules, defined by a Pb-grammar; (2) a language to represent internally the control problem in terms of elementary fuzzy processes defined by a Pe-grammar; (3) a library of the elementary fuzzy processes, mentioned in (2); and (4) a set of software tools. Among the software tools there are an extractor, a loader and an ender procedure. The extractor identifies the elementary and independent processes in which the fuzzy controller can be divided. This extractor receives the Pb-description of the control problem and it provides the Ps-description. The loader receives the Ps description and puts the elementary processes into the physical processors and also it starts its execution. When the user wants to finish the control task, the ender turns off the set of processes. The distributed universal fuzzy controller has been implemented sequentially and in parallel on a network of transputers, its performance is being tested in an industrial application: the tuning of high frequency amplifiers. >

Proceedings ArticleDOI
25 May 1994
TL;DR: In this paper, a speed estimation method based on the introduction of a constant frequency carrier signal is presented, which produces a constant speed rotating field from which the speed information in a wide range is obtained.
Abstract: A speed estimation method, based on the introduction of a constant frequency carrier signal, is presented. This frequency carrier signal produces a constant speed rotating field from which the speed information in a wide range is obtained. The speed is estimated through the detection of irregularities in the rotor. These irregularities generate frequency pulsations proportional to the rotor speed, which are independent of the parameters of the machine. Because these signals are extremely low, special electronic circuits, implemented with analog multipliers and filters, have been designed, and they are able to measure very low speed values. Computer simulations and some experiments have been carried out, and they have shown that it is possible to measure speeds as low as 20 RPM. >

Proceedings ArticleDOI
25 May 1994
TL;DR: This paper proposes to reduce execution time and to gain predictability by making use of a concurrent hardware software scheme for memory hierarchies that is composed by specially designed memory controllers connected to a dedicated bus.
Abstract: In this paper, we propose to reduce execution time and to gain predictability by making use of a concurrent hardware software scheme for memory hierarchies. Making use of memory hierarchies will allow reducing memory access time while concurrency will relax memory bandwidth resource constraint. The software part of the scheme makes a static analysis of the real time application and generates a file containing special controller instructions. These instructions are generated and scheduled using artificial intelligence optimization techniques so to assure an optimal concurrent management scheme of the memory hierarchy. The hardware part is composed by specially designed memory controllers which are connected to a dedicated bus which allows access to all the memory hierarchy levels. These controllers will execute the instructions associated to the application concurrently with the execution of the application on the microprocessor. Bus contention is avoided between the microprocessor executing the real time application and the controllers on the dedicated bus due to the good scheduling generated at compile time. >

Proceedings ArticleDOI
25 May 1994
TL;DR: A fast and robust algorithm is presented for training multilayer feedforward neural networks as an alternative to the backpropagation algorithm, known as the "predictor of linear output" (PLO), in terms of its function.
Abstract: A fast and robust algorithm is presented for training multilayer feedforward neural networks as an alternative to the backpropagation algorithm. The number of iterations required by the new algorithm to converge is less than 10% of what is required by the backpropagation algorithm. Also, it is less affected by the choice of initial weights and setup parameters. The algorithm uses a modified form of the backpropagation algorithm to minimize the mean-squared error between the desired and actual outputs with respect to the inputs to the nonlinearities. This is in contrast to the standard algorithm which minimizes the mean-squared error with respect to the weights. The new algorithm is known as a "predictor of linear output" (PLO), in terms of its function. Estimated linear signals, generated by the modified backpropagation algorithm, are used to produce an updated set of weights through a system of linear equations (which has an easy resolution) at each node. >