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The use of remote teach controls for programming industrial robots has led to concern over programmer safety and reliability. The primary issue is the close proximity to the robot arm required for the programmer or maintainer to clearly see the tool actions, and it is feared that errors in robot control could result in injury. The further concern that variations in teach control design could cause "negative transfer" of learning has led to a call for standardisation of robot teach controls. However,at present there is insufficient data to provide suitable design recommendations. This is because previous researchers have measured control performance on very general, and completely different, programming tasks. This work set out to examine the motion control task, from which a framework was developed to represent the robot motion control process. This showed the decisions and actions required to achieve robot movement, together with the factors which may influence them. Two types of influencing factors were identified: robot system factors and human cognitive factors. Robot system factors add complexity to the control task by producing motion reversals which alter the control-robot motion relationship. These motion reversals were identified during the experimental programme which examined observers' perception of robot motion under different conditions of human-robot orientation and robot arm configuration. These determine the orientation of the robot with respect to the observer at any given time. It was found that changes in orientation may influence the observer's perception of robot movement producing inconsistent descriptions of the same movement viewed under different orientations. Furthermore, due to the strong association between perceived movement and control selection demonstrated n these experiments, no particular differences in error performance using different control designs were observed. It is concluded that human cognitive factors, specifically the operators' perception of robot movement and their ability to recognise motion reversals, have greater influence on control selection errors than control design per se.

This work describes the development of a technique for the evaluation of the performance of a product's physical user interface. The technique is intended to combine the best features cat conventional user group testing with those of computer based biomechanical modelling. A requirement for the new technique exists as social pressure demands that consumer products he optimised for users with a wide range of physical capabilities, while shortening product lifecycles leave less time for extensive user evaluation programmes. A demonstration system was developed, based upon the use of an electromagnetic tracking system to gather upper limb motion data and a two segment, rigid link biomechanical model. Experimental work was carried out to test the effectiveness of the system at following limb movements and average error in reconstruction of hand position from segment angle data was 62mm (Standard deviation 41 mm) The modelling system was applied to the assessment of two types of product: cutlery and drinking vessels and the effectiveness of various statistical techniques in allowing the rapid identification of important design parameters was assessed. The use of Taguchi's smaller-the-better signal to noise ratio was found to be effective for the measurement of the effect of product design on shoulder and elbow forces. Cutlery with enlarged handles designed to reduce grip strength requirements tended to increase forces at the shoulder. The method was also applied to an interface optimisation problem involving the design of a lever mechanism. Partial factorial design was used to minimise experimental cost during the assessment of multiple factors, but strong interactions were detected between interface parameters, reducing the value of the analysis. The overall height of the lever handle relative to the user's shoulder was found to be the most significant design factor, with an optimum operating situation existing where the lever was low enough to require almost full extension of the elbow during use. The work concludes that biomechanical analysis holds further promise for the optimisation of interface parameters, provided the high experimental cost involved with present techniques can be reduced.

The research involves the testing of Overall and Experimental Hypotheses concerning the nature of design activity and the relationship between designers' cognition and their use of CAD systems. In particular, a lack of understanding of the design process was perceived together with a need to utilize aspects of designers internal problem solving capabilities in the specification of electronio design aids. A multidisciplinary approach is used in review and experimental methods in order to associate theoretical aspects of design behaviour with the measurement of practice. The social, economic and industrial implications of new technology are reviewed in the light of their e~~ects upon intellectual industrial tasks, such as designing within the textile and other industries. Also considered are the theoretical aspects o~ designing and in particular the designers' cognitive activity is described in behavioural terms. Such theories are tested in experimental situations where the problem solving aspects are elicited from designers in relation to their internal schematic representation o~ design problems. Speci~ic conclusions in the area o~ person-system interaction concern both Hypotheses. Adaptation was ~ound to be best considered as another aspect of the holistio representation that a designer has of his task. This resulted ~rom a recognition o~ the individuals own methods o~ problem solving within the con~ines of the task. The use o~ repertory grid techniques ~or the investigation of designing did not prove however that a designer's internal spaoe is completely measurable. Indeed, it resulted that some phenomena associated with design appear ~undamentally subjective although it was £ound that identi~iable and individual oriteria are used by designers. The particular contribution that this work makes is in the assooiation o~ psychological, sociologioal and industrial aspects o~ designing in an approach to the adaptive behaviour of designers in their use of CAD "systems