bluuebunny/crossref_metadata_2025 huggingface dataset:
An explanation and critique of taguchi's contributions to quality engineering
Authors: Box George , Bisgaard Søren , Fung Conrad
Published: July 2007

Recently there has been much interest and some controversy concerning the statistical methods employed by Professor Genichi Taguchi of Japan for improving the quality of products and processes. These methods include the use of fractional factorial designs and other orthogonal arrays, parameter design to minimize sensitivity to environmental factors, parameter design for minimizing transmitted variation, signal‐to‐noise ratios, loss functions, accumulation analysis, minute analysis and the analysis of life test data. This paper explains some of Taguchi's contributions to quality engineering and also provides a critical evaluation of his statistical methods. Our conclusion is that although on the one hand, Professor Taguchi's quality engineering ideas are of great importance and should become part of the working knowledge of every engineer, on the other hand, many of the techniques of statistical design and analysis he employs to put these ideas into practice are often inefficient and unnecessarily complicated and should be replaced or appropriately modified. In this short article only an overview is attempted, but references are appended where these matters are discussed in greater detail.
Better than Taguchi orthogonal tables
Authors: Shainin Dorian , Shainin Peter
Published: July 2007

There has been a great amount of publicity about Taguchi orthogonal tables. This paper will evaluate the pros and cons of that approach. In addition an American approach, having the same initial goals of the Taguchi approach, will be presented in detail, representing a significant improvement in meeting those goals without confounding interactions with any main effect or with other interactions. In addition, this constructive alternative generally requires a much smaller number of tests.
Characterizing and optimizing multi‐response processes by the taguchi method
Authors: Logothetis N. , Haigh A.
Published: July 2007

In this paper we demonstrate the ability of the Taguchi technique accurately to characterize and successfully to optimize complicated multi‐response processes with the minimum of experiments, provided one uses simple statistical techniques which can ensure valid, and definitive results. We point out the usefulness of suitable data‐transformations, and we suggest a systematic procedure for establishing the optimal operating conditions and for carrying out confirmatory experiments.

For the particular case detailed in this paper (which is typical of multi‐response processes) the Taguchi technique achieved an improvement in uniformity of a factor of 2, together with optimized process control.
Estimating the error of an effect in unreplicated 2‐level fractional factorial designs
Authors: Wang Wenhao , Lawson John
Published: July 2007

Saturated fractional factorial experimental designs and orthogonal main effect plans are extremely valuable tools in quality engineering. However, one problem with these designs is that there are no replicate runs to be used for estimating experimental error. This note develops an estimator of the experimental error based on the hypothesis that not all factor effects will be non‐zero. A joint Bayesian prior distribution is presented for the experimental error variance of an effect, σ2, and the probability that each effect is non‐zero. From this prior distribution a posterior marginal distribution for σ2 is derived along with a direct estimate of σ2. This method is compared with the traditional methods of estimating σ2 in unreplicated designs through a numerical example.
Annotated bibliography of books on experimental design
Authors: Hahn G. J.
Published: July 2007

There is now a large number of books on experimental design on the market. This review provides an annotated bibliography of some texts. They have been selected for their general interest and relevance to industry, and are based in part upon information provided by the authors.

A summary table is included which indicates the major topic areas covered, the technical level, the emphasized field of application, and other pertinent information.

The determination of which books to include and exclude is necessarily a somewhat arbitrary one. In general the guide is limited to those that deal principally with ‘design of experiments’; thus books that are mainly concerned with analysing experimental data and linear models have been excluded.

Similarly, judgement was required in describing the books and in preparing the summary table.

Further information on other books that deal with ‘design of experiments’ is available in my contribution on the same topic as printed in the Encyclopaedia of Statistical Sciences, Vol. 2 (Wiley, 1982) of which this survey is an edited version. It is reproduced by kind permission of the editors of The Encyclopaedia of Statistical Sciences, Samual Kotz, Norman Johnson and Campbell B. Read.
Load‐strength simulation of plastic mouldings
Authors: Loll Valter
Published: July 2007

The load‐strength theory is used to simulate the relations between the reliability, the safety factors used in the mechanical design and the different material conditions caused by batch variations in raw material, the injection moulding process and the mould design.
Death by a thousand cuts: The physics of device failure through a series of activated, microscopic events
Authors: Holden A. J. , Allen R. W. , Beasley K. , Parker D. R.
Published: July 2007

A physical model describes device failure in terms of a series of n microscopic events (such as defect creation) which are describable in terms of an identifiable activation energy. The results show a ‘Weibull like’ time dependence, but the temperature dependence is not of the simple Arrhenius form. Application is made to the ‘dark’ leakage current in a PIN photodiode and to the deviation in threshold voltage in a MOSFET. In particular the threshold voltage is shown to depend on a series of activated processes, and the required number of such processes to cause failure increases with the width of the gate electrode.
A study of the quality management methods employed by U.K. automotive suppliers
Authors: Lascelles D. M. , Dale B. G.
Published: July 2007

This paper reports on the results of a postal questionnaire survey of quality management methods, awareness and attitudes of suppliers to three major companies in the U.K. automotive industry. The main issues discussed include the quality management systems operated by suppliers, the methods by which quality improvement is pursued, quality‐related training, and suppliers' interaction with both their own customers and vendors.

The findings to specific questions were disappointing and illustrate the poor state of quality management development in some suppliers; overall the survey evidence indicates that many suppliers have a traditional attitude towards quality management. For example: it is possible to inspect quality into a product; component quality can be graded at different levels according to individual customer requirements; if the customer does not return the product then quality must be satisfactory; the quality manager is responsible for the quality improvement programme. Quality management tools and techniques are often seen as an end in themselves rather than a means to an end, that of improvement. It is clear that a number of suppliers assume that introducing statistical process control is the same as developing a total approach to quality management. There also appears to be a dilution of the quality message as requirements are passed down the supply chain, and in general communication and feedback between customer and supplier is poor.
A two‐step methodology for CMOS VLSI reliability improvement: Step one
Authors: Davies M. S. , Miles R. E. , Postoyalko V.
Published: July 2007

Reliability improvement of CMOS VLSI circuits depends on a thorough understanding of the technology, failure mechanisms, and resulting failure modes involved. Failure analysis has identified open circuits, short circuits and MOSFET degradations as the prominent failure modes. Classical methods of fault simulation and test generation are based on the gate level stuck‐at fault model. This model has proved inadequate to model all realistic CMOS failure modes.

An approach, which will complement available VLSI design packages, to aid reliability improvement and assurance of CMOS VLSI is outlined. A ‘two‐step’ methodology is adopted. Step one, described in this paper, involves accurate circuit level fault simulation of CMOS cells used in a hierarchical design process. The simulation is achieved using SPICE and pre‐SPICE insertion of faults (PSIF). PSIF is an additional module to SPICE that has been developed and is outlined in detail. Failure modes effects analysis (FMEA) is executed on the SPICE results and FMEA tables are generated.

The second step of the methodology uses the FMEA tables to produce a knowledge base. Step two is essential when reliability studies of larger and VLSI circuits are required and will be the subject of a future paper. The knowledge base has the potential to generate fault trees, fault simulate and fault diagnose automatically.
Proper subgroup size for statistical process control
Authors: Holmes Donald S. , Mergen A. Erhan
Published: July 2007

This paper deals with an approach for choosing the proper subgroup size for control charts. The approach is particularly appropriate for batch industries where some batch‐to‐batch variation is to be expected and should be accommodated. It uses two tests to evaluate the proper subgroup sizes. The tests are ANOVA for testing that the process mean is in control and Bartlett's test for testing that the process variance is in control. Besides the two tests the width of the process from measurements based on the selected subgroup size needs to be compared with the desired specification limits. An example is included to illustrate the use of the approach.
A quality growth model and its application to initial production process control
Authors: Yamada Shigeru
Published: July 2007

During initial production of a new product prior to actual production, the decrease in the fraction defective of units produced can be observed as personnel gather experience and the faults in the product's design, manufacturing, etc. are removed. This paper discusses an initial production process control based on a quality growth model proposed here. The model describes a continuing reduction in the cumulative defect rate defined by the ratio of the cumulative number of defective units to that of produced units. A stopping rule is also investigated for determining when to discontinue the initial control of the production process and proceed to the actual production stage. Further, a numerical example of the application is presented.
Reliability‐enabled changes in the design and manufacture of commercial electronic products
Authors: Ganter William A.
Published: July 2007

It has now become possible to design electronic products that have only a small probability of failing in a period of technologically useful life, if these products are to be used in an environment controlled for human comfort. Such product designs, even ones containing considerable complexity, can use combinations of ASIC and semi‐custom VLSI devices, damage‐resistant packaging and fault‐tolerant techniques to achieve breakthrough reliability. The theme of this paper is that once field failures can be reduced to small fractions of the units produced, by means of such design approaches, then major changes and their accompanying cost savings become possible in the manufacture and support of these electronic products. Although some extra design validation steps will be needed, the resulting opportunities can be very significant for companies that design and manufacture electronic products. This reliability‐enabled strategy is fully described in this paper.
A multi‐failure additive dependability model for transit system effectiveness analysis
Authors: Rapone Mario , Calabria Raffaela , Pulcini Gianpaolo
Published: July 2007

Dependability has been recognized in the transportation reliability literature as an effective measure of transit system service quality. Dependability models link system dependability with reliability and maintainability characteristics of subsystems, incorporating special operating characteristics and recovery policy from failure of each particular transit system. In this paper a new transit system dependability model is proposed, which considers the possibility that a passenger may be delayed by the occurrence of more than one failure in a trip. The mathematical difficulties associated with the algebra of random variables are overcome by using the Monte Carlo method. The results of the proposed model are compared with those relative to different modelling approaches in the literature, by applying the model to a common test scenario.
Reliability of plastic‐encapsulated logic circuits
Authors: Olsson Christer
Published: July 2007

Families of plastic‐encapsulated logic circuits have been subjected to a qualification procedure. The aim was to qualify them for use in telecommunication equipment in a central office environment. The qualification was based on a large number of reliability tests performed by the Ericsson failure analysis laboratory and by the vendors themselves. Reliability monitoring data from the testing of more than 150,000 devices during the period 1984 to 1985 have been analysed. Life tests, such as ‘high temperature operating life’, ‘high humidity operating life’, and temperature cycling have been performed. A comparison between life‐test data and field data from telephone exchanges in service has also been made. An average activation energy of 0.5 eV has been shown to be useful in such a comparison for the best LS vendors and 0.3 eV for the best HCMOS vendors.
Some supplier quality assurance assessment issues
Authors: Singer A. J. , Churchill G. F. , Dale B. G.
Published: July 2007

An investigation has been carried out in thirteen suppliers of plant systems and equipment for one‐off construction projects, to determine the benefits and problems of applying quality assurance. This paper reports the findings of the investigation. These suppliers and the major purchasing agents are confronted with special quality assurance problems such as multiple auditing and inspection which are allied to the one‐off nature of the items supplied. It is pointed out that this sample of suppliers is commonly encountering four to five external audits each year and that there is some dissatisfaction with the professional competence of some auditors and many inspectors employed on non‐nuclear contracts.
Graphical and computer‐aided approaches to plan experiments
Authors: Joglekar Anand M. , Kacker Raghu N.
Published: July 2007

Design of experiments is a quality technology to achieve product excellence, that is to achieve high quality at low cost. It is a tool to optimize product and process designs, to accelerate the development cycle, to reduce development costs, to improve the transition of products from R & D to manufacturing and to troubleshoot manufacturing problems effectively. It has been successfully, but sporadically, used in the United States. More recently, it has been identified as a major technological reason for the success of Japan in producing high‐quality products at low cost.

In the United States, the need for increased competitiveness and the emphasis on quality improvement demands a widespread use of design of experiments by engineers, scientists and quality professionals. In the past, such widespread use has been hampered by a lack of proper training and a lack of availability of tools to easily implement design of experiments in industry.

Three steps are essential, and are being taken, to change this situation dramatically. First, simple graphical methods, to design and analyse experiments, need to be developed, particularly when the necessary microcomputer resources are not available. Secondly, engineers, scientists and quality professionals must have access to microcomputer‐based software for design and analysis of experiments.1 Availability of such software would allow users to concentrate on the important scientific and engineering aspects of the problem by computerizing the necessary statistical expertise. Finally, since a majority of the current workforce is expected to be working in the year 2000, a massive training effort, based upon simple graphical methods and appropriate computer software, is necessary.2

The purpose of this paper is to describe a methodology based upon a new graphical method called interaction graphs and other previously known techniques, to simplify the correct design of practically important fractional factorial experiments. The essential problem in designing a fractional factorial experiment is first stated. The interaction graph for a 16‐trial fractional factorial design is given to illustrate how the graphical procedure can be easily used to design a two‐level fractional factorial experiment. Other previously known techniques are described to easily modify the two‐level fractional factorial designs to create mixed multi‐level designs. Interaction graphs for other practically useful fractional factorial designs are provided. A computer package called CADE (computer aided design of experiments), which automatically generates the appropriate fractional factorial designs based upon user specifications of factors, levels and interactions and conducts complete analyses of the designed experiments is briefly described.1 Finally, the graphical method is compared with other available methods for designing fractional factorial experiments.
A practical assessment of current plastic encapsulated microelectronic devices
Authors: Hughes John
Published: July 2007

The use of plastic encapsulated devices (PEDs) for a variety of market sectors has been the subject of much discussion over the past two decades. The advantages of lower cost together with the inherent mechanical ruggedness of these non‐cavity packages have been weighed against the concerns over quality and reliability and, in particular, electrical operation at extremes of temperature. This paper presents the results of some practical work undertaken on a modern LSI device in a plastic leaded chip carrier package. It then discusses British Telecom's experience with PEDs to date and concludes with some general considerations on the quality assurance requirements a purchaser may place on vendors of such devices.
Testing control chart subgroups for rationality
Authors: Holmes Donald S. , Erhan Mergen A.
Published: July 2007

One of the key issues in statistical process control (SPC) is the forming ‘rational subgroups’. Rational subgroups are defined as

Subgroups displaying only random within‐variation.

Subgroups having small within‐variation to compare with variation between subgroups.

In a previous paper1 we developed an approach of choosing the proper subgroup size for control charts for statistical process control. The approach is particularly appropriate for batch industries where some batch‐to‐batch variation is to be expected and should be accommodated. In this paper we will deal with the question of whether or not subgroups are rational. A randomness test can be used to verify rationality. The measure selected is the ratio of several different variance estimators. An example is provided to demonstrate the application of the measure.
The role of SPC in printed circuit board manufacture
Authors: Manson M. M. , Dale B. G.
Published: July 2007

This paper reports on research which examined the use of statistical process control (SPC) in the quality improvement process of a printed circuit board (PCB) manufacturer. The implementation of SPC is discussed along with the difficulties encountered and benefits achieved. The findings indicate that SPC is a tool which can be of considerable assistance in the quality improvement process of PCB manufacture. However, the variety of manufacturing technologies used and the number of interconnecting processes makes the application of SPC more difficult than in other traditional industries. The lessons learned include that the introduction of SPC must not be rushed, that discipline and support from all levels in the organization are crucial to its success, that SPC cannot be used in isolation—it needs the structure of a continuous improvement initiative, and that getting processes in a state of statistical control and capable, and keeping them there, is a difficult task which involves considerable effort and patience.
Fault diagnosis as an aid to process machine reliability
Authors: Denis Summers‐Smith J.
Published: July 2007

Identification of the reasons for failures of process plant machines is the first step in obtaining increased reliability. Weibull analysis of the service life obtained from maintenance records requires a minimum of only five incidents and provides an insight into the failure mechanism. Two examples are given where Weibull analysis of maintenance records helped identify the cause of failure and was instrumental in achieving enhanced reliability of process plant machines.
Proportional hazards analysis of diesel engine failure data
Authors: Jardine A. K. S. , Ralston P. , Reid N. , Stafford J.
Published: July 2007

Canadian Pacific Rail's diesel engines undergo scheduled major overhaul at intervals of approximately four years. Between these overhauls the condition of an engine is monitored by a series of physical tests and spectroanalysis carried out on samples of lubricating oil. At present the results of these tests are interpreted by the combination of skilled oil‐analyst technicians and an expert system. The success rate of this is over 70 per cent, where success is defined to mean that the oil‐analyst/expert system recommends that the engine should be scheduled for maintenance and it does indeed subsequently show evidence of an imminent failure. The purpose of the paper is to report on an examination of the method of proportional hazards modelling to determine whether or not PHM could improve on the accuracy of the oil‐analyst/expert system in determining the risk of failure of a diesel engine.
The efficient maintenance of offshore structural integrity using reliability analysis
Authors: Kam J. C. P.
Published: July 2007

Efficient maintenance of offshore structures is one of the priority development areas of the offshore industry world‐wide. The maintenance of the installations in a hostile environment such as the North Sea poses a particular problem. Owing to the large number of wave‐induced stress cycles experienced by the structures, the integrity is subject to progressive degradation under fatigue crack growth. If cracks are discovered in service, the operators of the structures will need to decide on the appropriate course of action. The priorities for actions will also need to be determined for cracks of various sizes found in different locations of the structures.

In the past, the above decisions have depended very much on engineering judgement. However, the latest developments in reliability fracture mechanics (RFM) analysis have for the first time provided an objective criterion for this type of decision making. Moreover, this criterion is consistent with the established structural design criteria based on reliability analysis of strength—load interaction. Therefore, it has become a real possibility to incorporate structural integrity considerations by design.

The reliability‐fracture‐mechanics‐based fatigue analysis includes studies on the uncertainties of load history, materials crack growth behaviour, fracture mechanics modelling, non‐destructive inspection and other environmental factors. This paper will review the development in this methodology.

In order to integrate the above analysis into the overall design process, it is useful to carry out reliability analysis for the complete structural system. The current state of the art of structural system reliability analysis is therefore briefly reviewed. The necessary development in order to accommodate fatigue reliability degradation is then discussed.
Proportional hazards modelling of aircraft cargo door complaints
Authors: Leitao A. L. F. , Newton D. W.
Published: July 2007

Proportional hazards modelling is a powerful technique which can be used to investigate the effects of various explanatory variables on the life length of equipment. In this paper the analysis of aircraft cargo door complaints is considered, as this can cause serious delay problems. Particular attention is given to the assumptions supporting the application of the model. Consideration is given to problems in the choice of the appropriate basic metric time, definition of covariates and adapting the methodologies to this particular problem. Emphasis is placed upon the validation of the results by attempting several different structures of the dependent variables.
An iterative approach for estimating component reliability from masked system life data
Authors: Usher John S. , Guess Frank M.
Published: July 2007

Life data from systems of components are often analysed to estimate the reliability of the individual components. These estimates are useful since they reflect the reliability of the components under actual operating conditions. However, owing to the cost or time involved with failure analysis, the exact component causing system failure may be unknown or ‘masked’. That is, the cause may only be isolated to some subset of the system's components. We present an iterative approach for obtaining component reliability estimates from such data for series systems. The approach is analogous to traditional probability plotting. That is, it involves the fitting of a parametric reliability function to a set of nonparametric reliability estimates (plotting points). We present a numerical example assuming Weibull component life distributions and a two‐component series system. In this example we find estimates with only 4 per cent of the computation time required to find comparable MLEs.
Fuzzy logic approach to ic quality assurance plan selection
Authors: Kohoutek Henry J.
Published: July 2007

The problem of selection of a proper quality assurance and control programme for manufacturing of microelectronics devices is usually solved empirically by analogy with existing situations, or those experienced in the past. This problem is characterized by incomplete comprehension of influencing variables, unknown relationships among them, and their often vague definitions. This makes it an almost perfect candidate for application of methods from the theory of fuzzy sets and approximate reasoning. One such reasoning process is described here using familiar terms from the MIL‐HDBK‐217E, and is illustrated by an ASIC MOS device example.
Imaging of packaging‐related problems in electronic components by scanning acoustic microscopy
Authors: Wilson K. J. , Sutherland R. R. , Videlo I. D. E. , Wakefield B.
Published: July 2007

Low‐frequency (50 MHz) scanning acoustic microscopy has been applied to the problem of imaging defects in semiconductor packages. The results have been compared with the more established technique of X‐ray shadow imaging. The scanning acoustic microscope has been found to be able to image a greater variety of defects than X‐ray shadow imaging, although the acoustic image could often only be fully interpreted after comparison with the corresponding X‐ray image. Scanning acoustic microscopy is now proving to be a valuable analysis technique for the detection and characterisation of packaging related problems.
A review of reliability evaluation techniques applied to ingaas pin photodiodes, germanium apds and ingaas apds
Authors: Stokoe J. C. D. , Putland P. A. , Sutherland R. R.
Published: July 2007

This paper reviews current life‐testing practices applied to photodiodes, illustrated with examples from some recent work on commercial components. A description is given of the types of photodiode tested, followed by an explanation of the basic princples of life‐testing. Comparisons of biasing methods are made and the difficulties of testing certain photodiodes are discussed. It is shown that it is impossible to demonstrate high reliability in fibred packages (without using a very large number of devices on test), because of life‐test temperature limitations. Similarly, it is difficult to demonstrate high reliability for germanium avalanche photodiodes (APDs). It is also shown that it can be very difficult to demonstrate high reliability in devices which reach wear‐out within short times at relatively low life‐test temperatures. Recent results are presented which demonstrate that planar PIN photodiodes are superior to mesa PINs, and that planar InGaAs APDs can have an acceptable reliability.
Some problems encountered in the construction and interpretation of control charts
Authors: Dale B. G. , Shaw P.
Published: July 2007

This paper reports the typical problems encountered in the construction and interpretation of control charts for use in the motor industery. The main findings include the fact that the data used to construct the initial control limits sometimes fail to give a true picture of process performance, the statistical theory underlying the design of control charts is often not considered and understood by users, and the taking of samples involving attribute data appears, on occasions, to be more prone to difficulties than is the case with measured data. A list of dos and don'ts is given which may help companies avoid some of the trap encountered in the construction of control charts.
Metal–GaAs interaction and contact degradation in microwave MESFETs
Authors: Zanoni Enrico , Callegari Alessandro , Canali Claudio , Fantini Fausto , Hartnagel Hans L. , Magistrali Fabrizio , Paccagnella Alessandro , Vanzi Massimo
Published: July 2007

This work reports and critically reviews failure mechanisms induced by metal‐GaAs interaction and contact degradation in low and medium power GaAs MESFETs in the framework of a comprehensive reliability evaluation test plan, performed mainly on commercially purchased devices manufactured by different technologies. The results show that, at least as regards contact degradation phenomena, these technologies have reached sufficient maturity, and significant reliability levels have been achieved even for the most severe application and environments. Devices coming from some suppliers still suffer from reliability problems. such as ‘sinking’ of Au‐based gate metallization into the active channel. Al electromigration, Al/GaAs interdiffusion enhanced by high contacts electromigration, surface metal migration and short circuiting of closely spaced electrodes on GaAs with a non‐suitable surface preparation and/or passivation. All these failure mechanisms have been identified by means of suitable microanalytical techniques, correlated with device electrical degradation and thoroughly discussed in this paper by comparison with results previously reported in the technical literature.
Analysis of a memory module failure pattern
Authors: Hale P. W. , Mactaggart I. K.
Published: July 2007

Memory modules used in personal computers were discovered to have a potential reliability defect caused by a fault in the module manufacturing process.

In order to assess the eventual impact on personal computer reliability, should it be decided to use these modules, thermal stress testing and subsequent analysis of the results was performed.

Several approaches were employed in the calculation of the relevant statistical parameters which would describe the failure pattern; and the validity of each approach was assessed by comparing predicted with actual results. The optimum approach was used in making a projection to normal operating conditions.

Finally the analysis was developed to account for the configuration of modules as assembled in the personal computer. This last stage of the analysis allowed the definition of the expected failure pattern of the machine due to defective memory modules.
The use of visual feedback for the acquisition of pseudorandomly oriented parts
Authors: Driels Morris , Huang Mingzen , Liscano Ramiro , Michael Kim
Published: July 2007

The problem of picking up single cylindrical objects using a robot equipped with a vision system is investigated. Explanation of how the robot defines the position of objects located within the workcell is provided. Image analysis, camera calibration, and algorithm specification are also defined.
The creation of line drawings as a basis for feature‐based stereo vision
Authors: Van Gool L. , Van Thillo M. , Akkermans M. , Oosterlinck A.
Published: July 2007

In this article an algorithm for the creation of line drawings of polyhedral scenes is described. It finds the two‐dimensional position of the vertices and it generates a topological description of the scene in terms of the connectiveness of the vertices by edges. Application of this algorithm on a stereoscopic pair of views yields the basis for the range data acquisition. The algorithm is far from complete yet, but the results are promising.
Sensor‐based obstruction avoidance technique for a mobile robot
Authors: Ahluwalia R. S. , Hsu E. Y.
Published: July 2007

This article describes a sensor‐based obstruction avoidance technique. This technique, if implemented on the on‐board computer of a mobile robot, would enable the robot to move through an unknown environment. The proposed approach is driven by sensory data. The robot thus senses and adapts to the changes in the environment. The software also does path planning. As more information about the environment is obtained the robot's path planning capabilities improve. Illustrative examples are used to describe the algorithms.
Detection of an ellipse by use of a recursive least‐squares estimator
Authors: Nagata Tadashi , Tamura Hirotoshi , Ishibashi Kohichi
Published: July 2007

A method for detecting an ellipse in an image by use of a recursive least‐squares estimator is described. This method is based on classifying the behavior of parameters in a quadratic equation estimated by the estimator. The segmentation of an image is executed using a statistical measure called the adjacent separability factor. Noise elimination is performed by the expansion‐contraction method and a contour for each region is extracted. Points on the contour are supplied to a recursive least‐squares estimator in succession and the parameters in a quadratic equation are estimated recursively. It is possible to decide whether the contour is an ellipse by analyzing the behavior of an estimated parameter. A main feature of this method is the generality and the simplicity of the procedure.
A simplified visual inspection system using a personal computer
Authors: Nakajima T. , Kamei M. , Inari T.
Published: July 2007

For a practical visual inspection system, data processing in real time, flexibility for variety of products, and cost performance have been required. This article describes a simplified visual inspection system that has well‐balanced performance that meets these requirements. Inspection data processing by software makes the inspection system flexible. Development of a simplified pattern matching method based on limiting the inspection within the area pointed by an user and direct memory access of binary image data performs a high speed inspection function. By using a personal computer as a processor of this system, a cost effective inspection system is realized.
An approach to software organization for control of industrial robots
Authors: Nagamatsu Ikuo , Tomiyama Toshihide , Tanaka Masato , Kyura Nobuhiro
Published: July 2007

This article describes a philosophy and practical application of software organization for control of industrial robots. In order to apply an industrial robot to a work cell as a component or device, not only is a language to command the robot motion necessary, powerful functions of the robot to realize a robot work cell with a hierarchical structure are also required.

First, we discuss an outline of industrial robot control and select required functions. Second, we discuss software organizations and significant points to realize them. Finally, as a practical application we introduce a robot system using a personal computer that is widely available in Japan.
A solution to the inverse kinematics of redundant manipulators
Authors: Benhabib B. , Goldenberg A. A. , Fenton R. G.
Published: July 2007

A solution to the inverse kinematics is a set of joint coordinates which correspond to a given set of task space coordinates (position and orientation of end effector). For the class of kinematically redundant robots, the solution is generically nonunique such that special methods are required for obtaining a solution. The method addressed in the paper, introduced earlier and termed “generalized inverse,” is based on a certain partitioning of the Jacobian functional corresponding to a nonlinear relationship of the inverse kinematics type. The article presents a new algorithm for solving the inverse kinematics using the method of generalized inverse based on a modified Newton‐Raphson iterative technique. The new algorithm is efficient, converges rapidly, and completely generalizes the solution of the inverse kinematics problem for redundant robots. The method is illustrated by numerical examples.
Modeling and feedback control of a flexible arm
Authors: Sakawa Yoshiyuki , Matsuno Fumitoshi , Fukushima Shigenobu
Published: July 2007

When a flexible arm is rotated by a motor about an axis through the arm's fixed end, transverse vibration may occur. The motor torque should be controlled in such a way that the motor rotates by a specified angle, while simultaneously stabilizing vibration of the flexible arm so that it is arrested as soon as possible at the end of rotation. In this paper, we first derive a partial differential equation and a set of boundary conditions governing the vibration. Then, a feedback control system which incorporates a dynamic compensator is designed using sensor outputs. A set of experiments has been constructed to demonstrate control strategies for a flexible arm, where a strain gage was used as a vibration sensor and a microcomputer was equipped as a controller. Several satisfactory experimental results are shown.
Duty‐cycle analysis of a human‐controlled manipulator
Authors: Stoughton Robert S. , Martin H. L.
Published: July 2007

The duty cycles of a human‐controlled servomanipulator system have been experimentally measured revealing how humans use manipulators to perform tasks. The use of the kinematic ranges, in both joint and Cartesian space is valuable to engineers in the kinematic design of servomanipulators. The working volume of human manipulation presented here is also of interest to designers of prosthetic systems. These results illuminate the relative merits of various system drive configurations. A graphical representation of mechanical power usage, which displays the total operation time as a function of torque and velocity, is presented for each manipulator joint. These data are compared with data representing idealized joint performance resulting in design criteria for quantitative improvements in joint torque and velocity capacities. A generalized method for applying this representation to any robotic system is discussed.
Dynamic omnidirectional vision for mobile robots
Authors: Cao Zuo L. , Oh Sung J. , Hall Ernest L.
Published: July 2007

Mobile robotic devices hold great promise for a variety of applications in industry. A key step in the design of a mobile robot is to determine the navigation method for mobility control. The purpose of this paper is to describe a new algorithm for omnidirectional vision navigation. A prototype omnidirectional vision system and the implementation of the navigation techniques using this modern sensor and an advanced automatic image processor is described. The significance of this work is in the development of a new and novel approach—dynamic omnidirectional vision for mobile robots and autonomous guided vehicles.
Contribution to synthesis of manipulator control
Authors: Goldenberg A. A. , Bazerghi A.
Published: July 2007

The article addresses the control problem associated with tracking a trajectory which is predefined by the desired position and orientation of the end‐effector tip (stage of nominal control). The problem is compounded by the assumption that variations in system parameters may occur thereby requiring that the nominal control be complemented with a controller (stage of perturbed control) which would regulate the disturbance produced by the variation in system parameters. A new formulation of the robot model for control synthesis is presented. The new formulation facilitates the synthesis of regulators for parameter variations using a robust servomechanism approach or a force feedback approach. The two approaches are illustrated using examples. The first example uses robust regulation to reject step input disturbances. The second example simulates the operation of peg‐in‐hole insertion using force feedback with an LQ controller.
Binocular stereo vision system using an eye and neuron model
Authors: Ohmori Takashi
Published: July 2007

Humans have two eyes and see objects binocularly. The three‐dimensional sensing capacity of humans depends both on the eyes and the neuron system controlling them. In this article, we made a model of the human visual system, including eye movement, and tried to realize the capacity in an artificial sensor. For this, the visual system is separated into two parts—the Eye System and the Neuron System. The former is realized by the sensor mechanisms that are similar to human eyes and the latter by the Neuron Simulator which consists of sixty‐four microprocessors. This system can be used as a passive three‐dimensional sensor in unarranged surroundings such as the outdoors.
New type of miniaturized optical range‐sensing methods RORS and RORST
Authors: Idesawa Masanori , Kinoshita Gen‐Ichiro
Published: July 2007

Two types of miniaturized optical range‐sensing methods have been developed. The first is called RORS (Riken Optical Range‐Sensing Scheme). In this method, a mirror tunnel is first placed between an objective lens and an object to be measured; a bright spot is then projected onto the object through the objective lens. This spot is observed through the objective lens after reflection with the mirror tunnel, and range information is determined by the triangulation. The width of an optical system can be reduced remarkably smaller than the effective base line length of the triangulation. Therefore, it is suitable to miniaturize a range‐sensing system such as an optical stylus and a proximity sensor. The second method, RORST (Riken Optical Range Sensing Method for Surface Tracing), projects an axially symmetrical light sheet onto an object and a ring pattern is produced. The ring pattern image is then projected onto the observation plane by the objective lens, radii of the ring pattern image for different azimuths are detected, distances corresponding to the specified azimuths are determined by the triangulation, and thus the information of partial inclination can be obtained.
A prototype of optical proximity sensor based on RORS
Authors: Kurahashi A. , Adachi M. , Idesawa M.
Published: July 2007

In an effort to develop a practical implementation of the RORS (Riken Optical Range Sensing Method), a prototype was developed. An evaluation was performed with this prototype in combination with an Integrated Circuit intended for use in an auto‐focus camera. The sensor was developed for use in noncontact robot sensor applications and is thus compact, low cost, and easily available. This sensor system consists of a head section and a processing/display section. The size of the sensor head section is 16 mm in dia and 23.5 mm in length, and is capable of measuring the distance from top of the sensor head to a target in 0–6 mm range. The distance signal is obtained as a dc voltage of 90 mV/mm and a digital signal which divides the measuring range into eight levels is also available.
A study on robot path planning from a solid model
Authors: Itoh Y. , Idesawa M. , Soma T.
Published: July 2007

CAD/CAM technologies have been developed and are beginning to penetrate rapidly into industries. At present, however, there are many problems that should be solved before CAD/CAM technologies can play their proper role in the total process. In an effort to improve CAD/CAM current circumstances, a trial CAE system which generates an operation path of a robot from a solid‐model built‐in CAD process, has been examined. In this system, solid models are built by performing set operations such as addition, subtraction, intersection between several primitives or solid models. Processing is made for a solid model represented by B‐rep (boundary representation). To ease the processing, curved faces such as spherical, cylindrical, or conical surfaces, are approximated by several flat planes. As a first step, by assuming Gaussian spatial distribution for a painting gun, path planning of a painting robot for a convex solid body has been examined. A scanning plane is defined for each flat plane and a path of robot effector is generated on this plane.
Integrated design of an end effector for a visual servoing algorithm
Authors: Palm William J. , Liscano Ramiro
Published: July 2007

An algorithm is presented for using a robot system with a single camera to position in threedimensional space a slender object for insertion into a hole; for example, an electrical pin‐type termination into a connector hole. The algorithm relies on a control‐configured end effector to achieve the required horizontal translations and rotational motion, and it does not require camera calibration. A force sensor in each fingertip is integrated with the vision system to allow the robot to teach itself new reference points when different connectors and pins are used. Variability in the grasped orientation and position of the pin can be accommodated with the sensor system. Performance tests show that the system is feasible. More work is needed to determine more precisely the effects of lighting levels and lighting direction.
Robotic range sensor with projection of bright ring pattern
Authors: Kinoshita Genichiro , Idesawa Masanori , Naomi Shigeo
Published: July 2007

A new type of optical range sensor is being proposed as a robotic sensor. The range sensor consists of the projection subsystem of an axially symmetrical light sheet and the detection subsystem for monitoring the focussing process of a lens. The projection subsystem produces a bright ring pattern through an objective lens on the surface of an object. Next, the distance from the range sensor to the surface of an object is calculated from the position of the lens. The prototype range sensor is able to measure the distance in the range of 430 to 570 mm with an accuracy of 0.3 mm. As the position of the objective lens is controlled so that the ring pattern projected on the surface of an object becomes a fine spot, the detection subsystem finds the position of the objective lens on which the output of photodiode comes to be maximum.
Exact solution to the inverse kinematics problem of a standard 6‐axis robot manipulator
Authors: Shahinpoor M. , Jamshidi M. , Kim Young T.
Published: July 2007

Presented are four sets of exact solutions for the vector of the joint angles {θi} pertaining to the inverse kinematics problem of a standard 6‐axis robot manipulator with two different kinds of gripper configurations. Here a standard 6‐axis robot is meant to be a general computer‐controlled revolute robot with base, shoulder, elbow, wrist pitch, wrist yaw, wrist roll, and gripping action.

Explicit solutions are obtained using Denavit‐Hartenberg homogeneous transformations. Furthermore, the inverse solutions are examined by means of a direct kinematic computer program.