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A case study is expected to capture the complexity of a single case, which should be a functioning unit, be investigated in its natural context with a multitude of methods, and be contemporary. A case study and, normally, history focus on one case, but simultaneously take account of the context, and so encompass many variables and qualities. When a physical artefact is the case the gap between case study and history tends to diminish and case studies often become more or less historical case studies. Case study methodology also bridges the gap between quantitative and qualitative methods in the social sciences. Still the different concepts of validation in quantitative and qualitative research sometimes create confusion when they are combined, as they often are in case studies.

The case might be studied with an intrinsic interest in the case as such, or with an interest in generalising. When a generalisation is based on the deductive principle, the procedure of testing hypothesis is used. A second mode of generalisation is inductive theory-generation, or conceptualisation. The third mode depends on the principle of abduction. Abduction is the process of facing an unexpected fact, applying some rule and, as a result, positing a case that may be. But there are two kinds of abduction: One is when a case is created from a few facts; for instance, historical data or clues. The other is operative when generalisations are made from known cases and applied to an actual problem situation by making appropriate comparisons. This is also called naturalistic generalisation. In a case study, the different modes of generalisation are often combined.

The conclusion is that case studies has the potential for further development through the mastery of the combination on different levels of techniques, methodologies, strategies, or theories, like; the combination of case study and history, which is important when the case is an artefact; the combination of differing quality standards in qualitative and quantitative research, which are difficult to codify; and the combination of different modes of generalisation.

This study aims to enable robotic friction stir welding (FSW) in practice. The use of robots has hitherto been limited, because of the large contact forces necessary for FSW. These forces are detrimental for the position accuracy of the robot. In this context, it is not sufficient to rely on the robot’s internal sensors for positioning. This paper describes and evaluates a new method for overcoming this issue.

A closed-loop robot control system for seam-tracking control and force control, running and recording data in real-time operation, was developed. The complete system was experimentally verified. External position measurements were obtained from a laser seam tracker and deviations from the seam were compensated for, using feedback of the measurements to a position controller.

The proposed system was shown to be working well in overcoming position error. The system is flexible and reconfigurable for batch and short production runs. The welds were free of defects and had beneficial mechanical properties.

In the experiments, the laser seam tracker was used both for control feedback and for performance evaluation. For evaluation, it would be better to use yet another external sensor for position measurements, providing ground truth.

These results imply that robotic FSW is practically realizable, with the accuracy requirements fulfilled.

The method proposed in this research yields very accurate seam tracking as compared to previous research. This accuracy, in turn, is crucial for the quality of the resulting material.

Presents an approach to improved performance and flexibility in industrial robotics by means of sensor integration and feedback control in task‐level programming and task execution. Also presents feasibility studies in support of the ideas. Discusses some solutions to the problem using six degrees of freedom force control together with the ABB S4CPlus system as an illustrative example. Consider various problems in the design of an open sensor interface for industrial robotics and discusses possible solutions. Finally, presents experimental results from industrial force controlled grinding.

In the western world the vehicle industry is declining yet Volvo, now the largest industrial enterprise in Scandinavia, has increased both its sales volume and market shares. What is the secret?

The British Robot Association annually awards a Travel scholarship. The 1986 winner from Imperial College reports on the first stage of his tour, to Sweden

The article describes a digitisation project in which Göteborg University Library, Sweden, is publishing a collection of eighteenth century manuscripts on the Internet, in collaboration with its history department. The aims of the project are to make one virtual collection of documents owned by different institutions, to give free and open access to the collection, to save heavily used documents from wear and tear, and to let users enrich the collection by subject indexing and by their own research findings. The texts are the scattered remains of the archives of the Swedish East India Company (1732 ‐1813). These documents, which are in great demand by academic users as well as by the general public, are being digitised as high quality images. Instead of text encoding, indexing is used to provide searchable entries for words in document titles, names of people, and subjects.

Describes the assembly process at Volvo′s Uddevalla plant. Considers the layout, management of materials, flexibility, training, working conditions, and teamwork, as well as the historical reasons for adopting the coach‐built assembly principle. Surmises that the new plant has advantages in assembly cost, ergonomics and working conditions, and flexibility over conventional line assembly plants.

Dates: 29–31 May 1991 Venue: De Doelen Conference Centre, Rotterdam, The Netherlands The Benelux Chapter of the International Society for Hybrid Microelectronics will be organising the 8th European Microelectronics Conference. The event will take place at ‘De Doelen’, Rotterdam, The Netherlands, from 29 to 31 May 1991.

Delta robot is a parallel robot specifically designed for high-speed pick and place tasks. However, sometimes they are asked to perform additional assembling and squeezing actions, which is beyond the capability of position-controlled Delta robots. Force sensors may be expensive and add mass to the system. Therefore, the purpose of this paper is to study sensorless force control of Delta robots using limited access interface.

Static force analysis is performed to establish a relation between joint torques and external forces. The joint torques are observed from signals provided by motor drivers. A distributed mass model is proposed to compensate the gravity of upper arms and forearms. To minimize the effect of backlash and nonlinear frictions brought by gearboxes, model parameters are calibrated in two separated modes: “LIFTING” and “LOWERING”. Finally, a hybrid force estimation model is built to deal with both cases simultaneously. Surrogate model-based force control law is proposed to increase the force control loop rate and handle the force control problem for discrete position-controlled Delta robots.

The results show that the force estimation model is effective and mode separation can significantly improve the accuracy. The force control laws indeed stabilize the robot in desired states.

The proposed solution is based on position-controlled commercial Delta robot and requires no additional force sensor. It is able to extend Delta robots’ capability and meet requirements of emerging complex tasks.