Alex Attridge

Virtual reality in engineering education: The future of creative learning

Virtual reality has achieved an adequate level of development for it to be considered in innovative applications such as education, training, and research in higher education. Virtual reality offers both opportunities and challenges for the educational sector. One of the challenges of virtual reality technology is the costs associated which have been unaffordable for educational institutes. However, in recent years, computer hardware and software development has made it more feasible to incorporate virtual reality technology into future teaching strategies. Despite the cost challenges, educational benefits of implementing virtual reality remain compelling. This paper explains virtual reality principle and describes the interactive educational environment developed at WMG, the University of Warwick. It also discusses the benefits of using state-of-the-art 3D photorealistic interactive and immersive virtual environment for engineering undergraduates and postgraduate teaching, learning and training.

Analysis of the effect of cone-beam geometry and test object configuration on the measurement accuracy of a computed tomography scanner used for dimensional measurement

Industrial x-ray computed tomography (CT) scanners are used for non-contact dimensional measurement of small, fragile components and difficult-to-access internal features of castings and mouldings. However, the accuracy and repeatability of measurements are influenced by factors such as cone-beam system geometry, test object configuration, x-ray power, material and size of test object, detector characteristics and data analysis methods. An attempt is made in this work to understand the measurement errors of a CT scanner over the complete scan volume, taking into account only the errors in system geometry and the object configuration within the scanner. A cone-beam simulation model is developed with the radiographic image projection and reconstruction steps. A known amount of errors in geometrical parameters were introduced in the model to understand the effect of geometry of the cone-beam CT system on measurement accuracy for different positions, orientations and sizes of the test object. Simulation analysis shows that the geometrical parameters have a significant influence on the dimensional measurement at specific configurations of the test object. Finally, the importance of system alignment and estimation of correct parameters for accurate CT measurements is outlined based on the analysis.

Assessing subjective response to haptic feedback in automotive touchscreens

The increasing use of touchscreen interfaces in vehicles poses challenges to designers in terms of optimizing safety, usability and affective response. It is thought that the application of haptic feedback to the touchscreen interface will help to improve the user experience in all of these areas. This paper describes the initial outcomes of a study to investigate user responses to haptic touchscreens using a simulated driving scenario based on the Lane Change Test, along with representative use case tasks. Results indicate preference for multi-modal feedback and user acceptance of the haptic feedback technology. Effects relating to multi-modal interaction and attentional demand are also observed.

Towards in-process x-ray CT for dimensional metrology

X-ray computed tomography (CT) offers significant potential as a metrological tool, given the wealth of internal and external data that can be captured, much of which is inaccessible to conventional optical and tactile coordinate measurement machines (CMM). Typical lab-based CT can take upwards of 30 min to produce a 3D model of an object, making it unsuitable for volume production inspection applications. Recently a new generation of real time tomography (RTT) x-ray CT has been developed for airport baggage inspections, utilising novel electronically switched x-ray sources instead of a rotating gantry. This enables bags to be scanned in a few seconds and 3D volume images produced in almost real time for qualitative assessment to identify potential threats. Such systems are able to scan objects as large as 600 mm in diameter at 500 mm s−1. The current voxel size of such a system is approximately 1 mm—much larger than lab-based CT, but with significantly faster scan times is an attractive prospect to explore. This paper will examine the potential of such systems for real time metrological inspection of additively manufactured parts. The measurement accuracy of the Rapiscan RTT110, an RTT airport baggage scanner, is evaluated by comparison to measurements from a metrologically confirmed CMM and those achieved by conventional lab-CT. It was found to produce an average absolute error of 0.18 mm that may already have some applications in the manufacturing line. While this is expectedly a greater error than lab-based CT, a number of adjustments are suggested that could improve resolution, making the technology viable for a broader range of in-line quality inspection applications, including cast and additively manufactured parts.

Evaluating user response to in-car haptic feedback touchscreens using the lane change test

Touchscreen interfaces are widely used in modern technology, from mobile devices to in-car infotainment systems. However, touchscreens impose significant visual workload demands on the user which have safety implications for use in cars. Previous studies indicate that the application of haptic feedback can improve both performance of and affective response to user interfaces. This paper reports on and extends the findings of a 2009 study conducted to evaluate the effects of different combinations of touchscreen visual, audible, and haptic feedback on driving and task performance, affective response, and subjective workload; the initial findings of which were originally published in (M. J. Pitts et al., 2009). A total of 48 non-expert users completed the study. A dual-task approach was applied, using the Lane Change Test as the driving task and realistic automotive use case touchscreen tasks. Results indicated that, while feedback type had no effect on driving or task performance, preference was expressed for multimodal feedback over visual alone. Issues relating to workload and cross-modal interaction were also identified.

Adding Depth: Establishing 3D Display Fundamentals for Automotive Applications

The advent of 3D displays offers Human-Machine Interface (HMI) designers and engineers new opportunities to shape the users experience of information within the vehicle. However, the application of 3D displays to the in-vehicle environment introduces a number of new parameters that must be carefully considered in order to optimise the user experience. In addition, there is potential for 3D displays to increase driver inattention, either through diverting the drivers attention away from the road or by increasing the time taken to assimilate information. Manufacturers must therefore take great care in establishing the ‘do’s and ‘don’ts of 3D interface design for the automotive context, providing a sound basis upon which HMI designers can innovate. This paper describes the approach and findings of a three-part investigation into the use of 3D displays in the instrument cluster of a road car, the overall aim of which was to define the boundaries of the 3D HMI design space. A total of 73 participants were engaged over three studies. Findings indicate that users can identify depth more quickly and accurately when rendered in 3D, indicating potential for future applications using the depth dimension to relay information. Image quality was found to degrade with increasing parallax and indications of a fatigue effect with continued exposure were found. Finally, a relationship between minimum 3D offset, parallax position and object type was identified.

Inconsistency in 9 mm bullets measured with non-destructive X-ray computed tomography

Fundamental to any ballistic armour standard is the reference projectile that is to be defeated. Typically, for certification, consistency of bullets is assumed. Therefore, practical variations in bullet jacket dimensions can have far reaching consequences. Traditionally, internal dimensions could only be analysed by cutting bullets which rules out any subsequent ballistic assessment. Therefore, the use of a non-destructive X-ray computed tomography (CT) method is explored in this paper. A set of 10 bullets (9 mm DM11) was taken for analysing both intra and inter bullet jacket thickness variation. CT measurements of jacket thickness were validated with high resolution scanning electron microscope (SEM) images. An image based analysis methodology has been developed to extract the jacket thickness map and the centre of gravity. Thickness variations of the order of 200 μm were found commonly across all the bullets along the length and an angular variation of up to 100 μm was found in a few bullets. Jacket thickness and centre of gravity were also calculated for the same bullets after impact and the variations between the pre- and post-impacted bullets were compared, by establishing a common physical reference. The results show that the proposed CT scanning approach and subsequent image analysis method can bring out the statistical variations in bullet geometry pre- and post impact effectively.

Effect of X-Ray Computed Tomography Scanning Parameters on the Estimated Porosity of Foam Specimens

X-Ray Computed Tomography (CT) scanning is an effective method for estimating the porosity of various engineering materials and biomedical specimens such as tissue scaffolds and bones. However, the scanning and analysis parameters play a significant role in the accuracy of the porosity value determined from CT scan. This paper presents details of an investigation carried out to understand the effect of system parameters, namely the voxel size, X-ray focal spot size and segmentation threshold, on the estimated porosity by taking an example of safety-critical foam used for impact protection applications. Different voxel resolutions and focal spot sizes are selected in a total of 12 scanning tests and the effect of segmentation threshold is analyzed on each of these tests. The study indicates that the obtained porosity value is greatly influenced by the choice of voxel size at larger spot sizes and less influenced at smaller spot sizes. The threshold also has significant effect on the porosity value, especially at larger voxel sizes.

Comparing the User Experience of Touchscreen Technologies in an Automotive Application

Touchscreen interfaces are increasingly used on a daily basis in both mobile devices and in cars. The majority of vehicles use resistive touchscreens which, while reliable and inexpensive, may not perform as well as alternative touchscreen technologies. A simulator-based user-centred study was conducted to compare the User Experience of resistive touchscreens against capacitive and infra-red variants in a range of automotive use cases. This paper details an initial treatment of the data focusing on touchscreen task performance and subjective usability measures. Findings identified that the resistive display was clearly least preferred, with capacitive offering the best overall performance.

The use of laser scanning technology to improve the design process

Benchmarking competitor products helps a company to identify opportunities to improve their product relative to their competitors. This allows a company to determine the basic requirements of a new product, and target potential areas for improvement, particularly within the automotive industry where there is considerable growth and competition. Automotive firms have been increasingly focusing on development processes. Reducing time to market and improving quality whilst minimising cost. Laser scanning technology enables companies to make design and engineering improvements through the ability to analyse a competitor’s design. A case study of this generic process will be presented in this paper. The results have revealed that a company can create significant value-added activity, reduce the need for physical prototype costs and time, improve quality in new product development introduction.