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Technical Paper

The Science of Testing: An Automotive Perspective

Increasing automation in the automotive systems has re-focused the industry’s attention on verification and validation methods and especially on the development of test scenarios. The complex nature of Advanced Driver Assistance Systems (ADASs) and Automated Driving (AD) systems warrant the adoption of new and innovative means of evaluating and establishing the safety of such systems. In this paper, the authors discuss the results from a semi-structured interview study, which involved interviewing ADAS and AD experts across the industry supply chain. Eighteen experts (each with over 10 years’ of experience in testing and development of automotive systems) from different countries were interviewed on two themes: test methods and test scenarios. Each of the themes had three guiding questions which had some follow-up questions. The interviews were transcribed and a thematic analysis via coding was conducted on the transcripts.
Technical Paper

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 user's 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 driver's 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’t's 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.
Technical Paper

A Pragmatic Model-Based Product Engineering Process

Complexity of electronics and embedded software systems in automobiles has been increasing over the years. This necessitates the need for an effective and exhaustive development and validation process in order to deliver fault free vehicles at reduced time to market. Model-based Product Engineering (MBPE) is a new process for development and validation of embedded control software. The process is generic and defines the engineering activities to plan and assess the progress and quality of the software developed for automotive applications. The MBPE process is comprised of six levels (one design level and five verification and validation levels) ranging from the vehicle requirements phase to the start of production. The process describes the work products to be delivered during the course of product development and also aligns the delivery plan to overall vehicle development milestones.
Journal Article

Robustness Testing of Real-Time Automotive Systems Using Sequence Covering Arrays

Testing real-time vehicular systems challenges the tester to design test cases for concurrent and sequential input events, emulating unexpected user and usage profiles. The vehicle response should be robust to unexpected user actions. Sequence Covering Arrays (SCA) offer an approach which can emulate such unexpected user actions by generating an optimized set of test vectors which cover all possible t-way sequences of events. The objective of this research was to find an efficient nonfunctional sequence testing (NFST) strategy for testing the robustness of real-time automotive embedded systems measured by their ability to recover (prove-out test) after applying sequences of user and usage patterns generated by combinatorial test algorithms, considered as “noisy” inputs. The method was validated with a case study of an automotive embedded system tested at Hardware-In-the-Loop (HIL) level. The random sequences were able to alter the system functionality observed at the prove-out test.
Technical Paper

3-D Numerical Analysis Investigating Distribution of Contact Pressures for a Number of Cylindrical Bearing Axial Profiles When Placed Under Radial Load Conditions

Increased torque values passing from engine to transmission have, increasingly become a problem regarding shaft misalignment. Engineers are restricted with regard to applying ISO standards when investigating bearing life cycles as they tend only to cover normal [radial thrust] load conditions. Depending on the application, the need has arisen for numerical models to determine reduction in normal life cycles due to abnormal running conditions. The Simulia Finite Element package Abaqus v6.7 provides trends in the deformations, contact pressures and their respective distribution. It was found the most efficient profile, with regards to a uniform contact pressure, under both radial and misaligned conditions is the toroidal profile.
Technical Paper

A Study of DeviceNet Technology for the Low Quantity Vehicle Industry

The popularity of CAN (Controller Area Network) in the production vehicles is well established. As a result, CAN has been developed for use in many non-automotive applications. This gave rise to the development of an open higher layer CAN protocol known as DeviceNet. With the popularity of DeviceNet for Automation Systems, this technology has drastically decreased in cost. Although DeviceNet is quite complex to develop, it easier to implement than SAE J1939 due to the large number of commercial off-the-shelf product that is available. Also, there are many configuration and diagnostic tools available by the same means. There are more than 300 vendors of DeviceNet product. Researchers at the University of Warwick have built a vehicle demonstrator using CAN/DeviceNet modules. This paper will illustrate the ease of vehicle system integration utilising this popular technology.
Technical Paper

Droplet Breakup in Turbulent Flows

For high Reynolds number flows, the fine structure turbulence is universal in the inertial subrange according to the Kolmogorov local isotropy theory; while for low-to-moderate Reynolds number flows, the turbulence tends to display a common structure for a particular type of shear flows from the Townsend structural similarity. The power laws for the turbulent flows reflect the similarity in the turbulence fine structure. The paper discusses the relationship between drop breakup and turbulence fine structure. A predictive formula for drop breakup in the turbulent flow is suggested based on the energy balance between turbulence separating kinetic energy (i.e. turbulence structure function) and surface tension. The model has been validated on a number of empirical relations for drop breakup in different turbulent flows. It is known that the drop size distribution in shear flows can be approximately expressed by a lognormal distribution.