Preface
This report is about my seven month stay at the National Institute of Standards & Technology in Gaithersburg, Maryland U.S.A. In these months I have worked in the Tactile Graphics project group, pursuing the development of a Tactile Graphic Display. This display is to be used to aid visually impaired persons in recognizing images and mathematical diagrams. Unfortunately my internship ended before a fully functioning prototype was built, but I hope this report will prove to be a sufficient guide to future project members to successfully continue our work and succeed in making the tactile technology available for those who need it.
Enschede, October 2001
V.J.T. Min
Summary
This report reflects the research and work done in building a refreshable Tactile Graphics Display (TGD). It is to be used by visually impaired people as a replacement for paper or plastic sheet embossed graphics, like art, maps and mathematical graphics to save both resources and time. A prototype was designed with a 5” by 7” size grid of pins with a density of 100 dots per square inch. Simple test patterns have been ‘written’ on the display in the first tests. Some elements still need to be constructed to finish a fully functioning device and also additional tests need to be done with respect to robustness and durability. Literature research on the physiology of the touch sensors in the fingers is described, as well as an extensive description of a possible follow-up project involving a fingertip size display. The description includes design issues, integration in Virtual Reality systems and good collaboration candidates.
Acknowledgements
I would like to thank Dr Victor McCrary, Dr Xiao Tang and John Roberts for the confidence they showed in me and my work during my stay. It has been a tremendous learning experience that I will never forget.
Furthermore I would like to thank my fellow project team members: Oliver Slattery, Michael Sutton, Brett Swope, David Kardos, Tracy Comstock and Gina Rodgers. It was great working with all of them, as well as with the rest of the division.
I would also like to thank John Roberts, Tracy Comstock and Susan Polman for their efforts in reviewing my report.
Table of contents
Summary / 2
Acknowledgements / 2
Table of content / 3
Chapter 1: NIST Overview
- A brief history of NIST
- NIST today
- NIST organizational chart
§ Information Technology Laboratory (ITL)
§ Convergent Information Systems Division
- CISD projects
§ NIST Electronic Book (E-Book) Project
§ The NIST Rotating-Wheel Based Refreshable Braille Display / 5
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Chapter 2: Preliminary research and literature
2.1 A survey of tactile technology
- The 400 pin tactile Simulator Array
- Tele-Taction system
- TIGER Advantage
- ALVA 570 Satellite Pro
- NOMAD Talking Touch Pad
2.2 Important aspects of touch
- Mechanoreceptors
- Temperature sensors
- Pain sensors
- Discussion and Conclusion
2.3 The tactile display: first prototype
- Description
- Performance
- Conclusions
- Recommendations
2.4 Basic alternatives for an enhanced graphics tactile display
- Design issues
- Design alternatives: Locking mechanisms
§ Alternative 1: ‘Array lock’
§ Alternative 2: ‘Strip lock’
§ Alternative 3: ‘Rod lock’
§ Alternative 4: ‘Hairpin’ method
§ Alternative 5: ‘Screw lock’
§ Alternative 6: ‘F-lock’
- Design alternatives: Actuation mechanisms
§ Alternative 1: full grid
§ Alternative 2: line driven
§ Alternative 3: X-Y table driven
- Overview table / 10
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Chapter 3: Design process of the 2nd generation prototype
3.1 Design issues
3.2 Design description
3.3 Current status and (dis)assembly.
3.4 Overview of the project management and time line. / 28
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Chapter 4: The Fingertip Display
4.1 Setting up a fingertip display (FTD) project
- FTD description
- Example case
- Force Feedback integration
- The Virtual Environment
4.2 Co-operation candidates
- Force Feedback collaboration: Immersion
- Virtual Environment for the FTD / 37
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Conclusions / 42
Self-reflection / 43
References/ Picture Sources / 44
Appendix A: First prototype, the conversion circuit / 45
Appendix B: First prototype, the software / 47
Appendix C: Specifications of Immersion products: / 48
Appendix D: Second prototype, design drawings / 50
Chapter 1: NIST Overview[1]
- A brief history of NIST
The National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards (NBS), was established by Congress in 1901 to support industry, commerce, scientific institutions, and all branches of Government. For nearly 100 years the NIST/NBS laboratories have worked with industry and government to advance measurement science and develop standards.
NBS was created at a time of enormous industrial development in the United States to help support steel manufacturing, railroads, telephone, and electric power, all industries that were technically sophisticated for their time but lacked adequate standards. In creating NBS, Congress sought to redress a long-standing need to provide standards of measurement for commerce and industry and support the "technology infrastructure" of the 20th Century.
In its first two decades, NBS won international recognition for its outstanding achievements in physical measurements, development of standards, and test methods - a tradition that has continued ever since. This early work laid the foundation for advances and improvements in many scientific and technical fields of the time, such as standards for lighting and electric power usage; temperature measurement of molten metals; and materials corrosion studies, testing, and metallurgy.
Both World Wars found NBS deeply involved in mobilizing science to solve pressing weapons and war materials problems. After WWII, basic programs were instituted in nuclear and atomic physics, electronics, mathematics, computer research, and polymers as well as instrumentation, standards, and measurement research.
In the 1950s and 1960s, NBS research helped usher in the computer age and was employed in the space race after the stunning launch of Sputnik. The Bureau's technical expertise led to assignments in the social concerns of the Sixties: the environment, health and safety, among others. By the Seventies, energy conservation and fire research had also taken their place at NBS. The mid-to-late 1970s and 1980s found NBS returning with renewed vigor to its original mission focus in support of industry. In particular, increased emphasis was placed on addressing measurement problems in the emerging technologies. Many believe that the Stevenson-Wydler Act implemented, throughout the federal laboratories, the practices that had been developed at NBS over the years: cooperative research and technology transfer activities.
The Omnibus Trade and Competitiveness Act of 1988 - in conjunction with 1987 legislation - augmented the Institute's uniquely orchestrated customer-driven, laboratory-based research program aimed at enhancing the competitiveness of American industry by creating new program elements designed to help industry speed the commercialization of new technology. To reflect the agency's broader mission, the name was changed to the National Institute of Standards and Technology (NIST).
These efforts, and the organizational changes brought by the NIST Authorization Act for 1989 which created the Department of Commerce's Technology Administration to which NIST was transferred, served as a critical examination of the role of NIST in economic growth. These mission and organizational changes, initiated under the Bush Administration were reaffirmed and strengthened by the Clinton Administration.
In addition to the reviews by Congress, the Administration, and the Department of Commerce, the Visiting Committee on Advanced Technology (VCAT) of NIST reviews and makes recommendations regarding the general policy, organization, budget, and programs of NIST. The VCAT holds four business meetings each year with NIST management, and summarizes its findings each year in an annual report that is submitted to the Secretary of Commerce and transmitted by the Secretary to Congress.
As an agency of the U.S. Department of Commerce's Technology Administration, NIST's primary mission is to promote U.S. economic growth by working with industry to develop and apply technology, measurements, and standards. It carries out this mission through a portfolio of four major programs:
· Measurement and Standards Laboratories that provide technical leadership for vital components of the nation's technology infrastructure needed by U.S. industry to continually improve its products and services;
· A rigorously competitive Advanced Technology Program providing cost-shared awards to industry for development of high-risk, enabling technologies with broad economic potential;
· A Manufacturing Extension Partnership with a network of local centers offering technical and business assistance to smaller manufacturers;
· A highly visible quality outreach program associated with the Malcolm Baldrige National Quality Award that recognizes business performance excellence and quality achievement by U.S. manufacturers, service companies, educational organizations, and health care providers.
- NIST today
· BUDGET: $760 million (FY 1999 estimated operating resources from all sources).
· STAFF: About 3,300 scientists, engineers, technicians, and support personnel, plus some 1,550 visiting researchers. NIST also partners with 2,000 manufacturing specialists and staff all around the country.
· SITES: Gaithersburg, Maryland (headquarters - 234-hectare campus) and Boulder, Colorado (84-hectare campus).
- NIST organizational chart
Information Technology Laboratory (ITL)
About 60 percent of all U.S. workers have jobs that depend on the information they generate and receive on advanced information networks. Innovations in computer hardware, software, and digital communications will challenge managers to apply new technology for productivity increases throughout the American economy in the coming years and will have pervasive effects on industry structure as well as on the quality of government services. Also, since computers will be distributed throughout society, both at home and in the workplace, computer integration, interoperability, usability, reliability, and security will become even more important.
NIST's Information Technology Laboratory (ITL) concentrates on developing tests and test methods for information technologies that are still in the early stages of development-long before they are available in new products. But even after information technology products are available, tests developed by ITL provide impartial ways of measuring them so developers and users can evaluate how products perform and assess their quality based on objective criteria.
Technical research, industry collaborations, and standards-related work of ITL address issues emerging from today's information revolution.
Convergent Information Systems Division:
The mission of this ITL division is to conduct research and development into integrated systems, architectures, applications and infrastructure for the exchange, storage, and manifestation of digital content and to explore their scalability, feasibility, and realization for new applications.
CISD is divided into two groups:
· Distributed Systems Technologies Group (DST)
The DST group leverages its competence in smart software development and distributed computing architectures in research on performance measurement methods to support massively parallel systems, scaleable computing using emerging network and workstation technology, and interactive digital television.
· Information Storage & Integrated Systems Group (ISIS)
The ISIS group maintains a competence in hardware design, graphics design, performance, and reliability. Projects at ISIS are focused on testbed and hardware prototypes to facilitate effective collaboration between industry, government, and universities to focus on the development of software and device standards for information storage and systems integration.
- CISD projects
NIST Electronic Book (E-Book) Project
The NIST Electronic Book (E-Book) Project was started in January 1997. At that time, the project was focused on the investigation of ways to implement new features in an electronic book reader. This led to the development of an electronic book prototype to demonstrate these new features and to the filing of a patent application, NIST #98017, "Modular Electronic Book".
In 1998 several new commercial eBook devices were announced, so the focus of the project shifted to bringing together all participants in the eBook industry (device manufacturers, software companies, publishers, libraries, end users, and so on) to discuss the issues and to determine whether standardization would be desirable. To enable this process, NIST organized and hosted the world's first-ever electronic book workshop, Electronic Book '98. At this workshop there was a call for an "Open Electronic Book Publication Structure" (OEBPS) specification, a file interchange format that would work across different hardware platforms for electronic books. The Open eBook Forum (OEBF) was formed to develop this specification and Dr. Victor McCrary of NIST has served as Chair, to facilitate the work of the Forum. At the Electronic Book '99 workshop, held at NIST in September 1999, the Open eBook Forum presented Version 1.0 of the Open Electronic Book Publication Structure specification.
The NIST Rotating-Wheel Based Refreshable Braille Display
NIST has developed a unique refreshable Braille technology that can reduce cost by a factor of 10 or more. It will make possible high performance Braille displays for $1000 or less, and enable high speed reading devices about the size of a portable CD player. While existing displays put Braille on a linear array of dots, this design puts the Braille on the rim of a rotating wheel, which moves the text past the user's fingers. Users can adjust wheel speed, or can pause the wheel for stationary reading. Tests thus far indicate a high degree of readability. With advice from many Braille users and accessibility organizations, a working second-generation prototype was first shown at the Electronic Book 2000 conference in September 2000, hosted by Victor McCrary. NIST has filed a patent, and is in discussion with manufacturers to add this technology to their product lines. We have also started work on refreshable tactile graphic technology, and hope to make an announcement in November 2000.
The NIST design is intended to enable lower cost and greater compactness. By placing the Braille text on a rotating wheel, it is no longer necessary to provide a separate actuator for every dot. The working prototype uses just three low-voltage solenoids to set all the Braille dots as they move past one point in the rotation of the wheel. (The prototype produces 6-dot Braille; an 8-dot display would use four solenoids instead of three, since 8-dot Braille has four rows of dots.) Where a conventional display uses a rounded pin driven by an actuator for each dot, the dots in the NIST design are simple rounded pins with a head (like a nail) on the other end. The pins are placed in the holes in the wheel, with the heads of the pins toward the axis of the wheel. If the rounded tip of a pin sticks out of the surface of the wheel, the user will feel a dot. If the pin stays further inside the wheel, the tip does not stick out of the rim of the wheel, and the user will not feel a dot. A set of non-rotating tracks or slots inside the rotating wheel provides two positions for each of the pins to ride around with the rotating wheel, either sticking out of the wheel (to form a dot) or not sticking out of the wheel (no dot). The non-rotating tracks prevent the heads of the pins from moving from one position to the other as the wheel rotates, so the pattern of dots representing the current Braille text is preserved as it moves across the reading area. This method of creating an extended reading area is called the passive pin control system, because it uses no powered components to hold the pins in place - even if the display power is turned off, the text will remain in place in the reading area. An additional benefit of this approach is that since the pins are held in place by metal tracks, finger pressure will not make the dots go back into the display. The dots are thus very "strong" compared to dots driven by piezoelectric actuators. The "sharpness" of the dots depends on the shape of the rounded tips of the pins, which can be selected by the manufacturer for the degree of sharpness desired by the user. The height of the Braille dots is determined by the dimensions of the non-rotating tracks.