Colin Harrison

Haptic interfaces for wheelchair navigation in the built environment

A number of countries have recently introduced legislation aimed at ending discrimination against disabled people; in the United Kingdom the Disability Discrimination Act (1995) provides the disabled community with new employment and access rights. The intention of the act is to help those who rely on wheelchairs for mobility and who frequently find that not all buildings provide conditions suited to easy access. Central to these new rights will be an obligation for employers and organizations to provide premises that do not disadvantage the disabled. This work reports on the development of instrumentation that allows wheelchair navigation within virtual buildings and can assist architects in identifying the needs of wheel-chair users at an early design stage. Central to this project has been the need to provide a platform that can accommodate a range of wheelchair types and will map intended wheelchair motion into a virtual space. This interface must have the capacity to provide feedback to the user reflecting constraints present in the physical world, including changes in floor surface characteristics, gradients, and collisions. Integrating visual and nonvisual sensory feedback correlating to the physical effort of wheelchair propulsion has been found to augment the perception of self-motion within the virtual world and so can create an effective instrument for use in the study of wheelchair accessibility within the built environment. This project represents a collaborative effort between architects and bioengineers engaged in research related to platform design, construction, and interfacing, while testing and evaluation has been accomplished with the assistance of user groups.

Enhancement of a Virtual Reality Wheelchair Simulator to Include Qualitative and Quantitative Performance Metrics

ABSTRACT The increasing importance of inclusive design and in particular accessibility guidelines established in the U.K. 1996 Disability Discrimination Act (DDA) has been a prime motivation for the work on wheelchair access, a subset of the DDA guidelines, described in this article. The development of these guidelines mirrors the long-standing provisions developed in the U.S. In order to raise awareness of these guidelines and in particular to give architects, building designers, and users a physical sensation of how a planned development could be experienced, a wheelchair virtual reality system was developed. This compares with conventional methods of measuring against drawings and comparing dimensions against building regulations, established in the U.K. under British standards. Features of this approach include the marriage of an electromechanical force-feedback system with high-quality immersive graphics as well as the potential ability to generate a physiological rating of buildings that do not yet exist. The provision of this sense of “feel” augments immersion within the virtual reality environment and also provides the basis from which both qualitative and quantitative measures of a buildings access performance can be gained.

Virtual Environments for Special Needs

The normal application of Virtual Reality is to the simulation of environments, which are in some way special - remote, hazardous or purely imaginary. This paper describes research and development work which changes the paradigm by simulating perfectly ordinary buildings for special people. Some 15% of the population have some form of physical impairment — a proportion which is likely to rise in line with an ageing population. New legislation, such as the UK Disability Discrimination Act places additional responsibility on building owners to ensure adequate access for people with an impairment and this in turn will place additional responsibility on the architect. Current methods of auditing access for new building are primitive and require the auditor to interpret plans/sections of the proposed building against a checklist of requirements specific to the special need. This paper reports on progress in the use of an immersive VR facility to simulate access to buildings for two broad classes of user:i) those with a mobility impairment; ii) those with visual impairment.

Dynamics characteristics of a micro-sheet-forming machine system

Dynamic characteristics of a micro-forming machine system are of significant importance to be considered if high-precision micro-parts are to be produced. This is because forming tolerances may be within a range of sub-microns up to 5-15% of the thickness of a thin sheet-metal (e.g. <100µm) being used in micro-sheet-forming. Achievability of the quality parts often vary with the machine-system performance and process parameters being set, and it largely depends on the understanding of the machine and tool system’s dynamic characteristics and effectiveness of the control of the machine and the process. Nevertheless, there has been lack of the effort in this field of research. Significant number of the efforts in this field were focused mainly on discrete and/slow processes where the dynamic characteristics of the forming systems were often neglected. This paper presents the dynamic characteristics of an autonomous micro-sheet-forming machine system and its effect towards the produced parts’ quality. These have been studied by combining finite element analysis and forming experiment, with a particular focus on the combined effects from the machine, tooling system and the sheet-metal feeding system (the strip feeder). The results showed that, besides importance of the dynamic performance of the machine and the tool-system, dynamic characteristics of the material-feeding plays an important part in determining the parts’ quality produced.

Design considerations for developing a new, ultra-high precision feeder for micro-sheet-forming applications

A recent review of micro-forming research and technological development suggested that the trend of the development is focused more on the manufacturing processes, machines and tooling, with efforts on the precision material handling being insufficient. Most of the developed machines were based on stand-alone concepts that do not support efficient integration to make them fully automated and integrated. Material feeding, in most cases, was not of sufficient precision and reliability for high throughput manufacturing applications. Precision feeding is necessary to ensure that micro-parts can be produced with sufficient accuracy, especially in multi-stage forming, while high-speed feeding is a necessity to meet production-rate requirements. Therefore, the design of a new high-precision and high-speed feeder for micro-forming is proposed. Several possible approaches are examined with a view to establishing feasible concepts. Based on the investigation, several concepts for thin sheet-metal feeding for micro-forming have been generated, these being argued and assessed with appropriate applied loads and force analysis. These form a basis for designing a new feeder.

Development of a New High-Precision Feeder for Micro-Sheet-Forming

Feeding the raw material accurately is essential in microsheet-forming, especially in multistage progressive forming operations and also when in particular, a certain feeding rate has to be maintained. Research into the microforming of thin sheet metals (< 100 mu m) led to investigations of the performance of existing sheet metal feeders, regarding their feeding accuracy and repeatability. The results indicated that the pursuance of greater feeding accuracy and repeatability, which was aimed at 5-15% of the strip thickness, was difficult to achieve with commercially-available feeders. A new high-precision and high-speed feeder was, therefore, developed for microsheet-forming. The feeder design was supported by motion analysis and feeding simulations. The feeder was constructed in collaboration with industrial partners. The conducted feeding tests and forming experiments demonstrated that greater feeding accuracy and repeatability can be achieved, compared to those of existing commercial feeders. This suggests a promising solution for high-precision strip feeding in microsheet-forming where thin sheet metals are to be fed.

Micro-sheet-forming and case studies

Various analytical rules of mixture are commonly used to take into account heterogeneous features of a material and to derive global properties. But, with such models, one may not be able to fulfil the requirements for separating appropriately the different lengthscales. This might be the case for some issues such as strain localisation, surface effect, or topological distributions. At an intermediate lengthscale, which we refer to as the mesoscopic scale, one can still apply continuum mechanics. So why not perform calculations using the finite element method on volumes of material to obtain the response of Representative Elementary Volumes (R.E.V.). The construction of digital microstructures for such calculations is performed in two steps. First, a series of R.E.V.s with statistics of features of real materials should be defined. Then, finite element meshes should be produced for these R.E.V.s and updated when calculations involve large strains. Powerful automatic three-dimensional mesh generators and remeshing techniques prove necessary for this latter task. This strategy is applied to create digital R.E.V.s which match statistical features of forgings. Measurements provide micromechanical parameters of each subvolume. As an example of calculations, numerical simulations provide the anisotropic fatigue properties of forgings.

Mechatronics applied to auditory localisation for telepresence

This paper describes the importance of the sense of hearing for immersive telepresence systems, and a fundamental approach to designing and implementing a binaural sensor system. This approach relies on knowledge of how the human auditory localisation mechanisms work to locate sounds in space, in order that a synthetic system can be derived. The most important of these mechanisms are explained. The Strathclyde auditory system is then described including ideas drawn from the literature to define a binaural approach. This novel system consists of a set of artificial pinnae and microphones mounted on a binocular stereo sensor platform capable of pan, tilt and roll which is slaved to a head tracking system. A set of preliminary experiments is described which test the performance of the system in practice, as a basis for further development.

Chapter 8 – Forming of Micro-Sheet-Metal Components

Sheet metal components are used extensively in various applications such as vehicles, aircraft, electronics products, medical implants and packaging for consuming goods, typical parts/components including car panels, aircraft skins, cans for food and drinks, frames for TV/computer screens/monitors/displays, etc. Basic process configurations for the forming of macro-products include shearing, blanking, bending, stamping, deep drawing (including mechanical and hydromechanical), hydroforming, stretching forming, super-plastic forming, age forming, spinning, explosive forming, and incremental forming. Some of these processes may be equally applied to the forming of miniature and even micro-products, if the issues related to “size effect” can be handled successfully. The manufacture of micro-sheet metal products, such as those used in electronics products and MEMS (micro-electric-mechanical systems), often needs bending to produce 3D profiles/sections. Typical applications include micro-electric contacts/fingers/switches, 3D profiles for mechanical and thermal-mechanical sensors and 3Dsheet metal frames/housing for optical devices and micro-sensors.

A Study on Automating Rolling-stock Maintenance in the Rail Industry using Robotics.

Maintenance cost of United Kingdom’s rail rolling stock is a substantial portion of its whole life costs. Therefore, it is vital to conduct these maintenance tasks in an efficient and cost-effective manner to minimize operational costs while maximizing safety, quality, and consistency of service. The introduction of robotics and other intelligent mechanisms to maintenance processes would be an ideal solution to these challenges. Hence, this research suggests introducing autonomous maintenance systems equipped with industrial robots to tasks within the railway system, specifically for rolling-stock maintenance. The paper summarizes on-going and future work of a case-study conduct in conjunction with a UK railway operator.