Rotational fluid flow experiment: WPI/MITRE advanced space design GASCAN 2

The design and implementation is examined of an electro-mechanical system for studying vortex behavior in a microgravity environment. Most of the existing equipment was revised and redesigned as necessary. Emphasis was placed on the documentation and integration of the mechanical and electrical subsystems. Project results include the reconfiguration and thorough testing of all the hardware subsystems, the implementation of an infrared gas entrainment detector, new signal processing circuitry for the ultrasonic fluid circulation device, improved prototype interface circuits, and software for overall control of experiment design operation

Development of a software interface for optical disk archival storage for a new life sciences flight experiments computer

The current Life Sciences Laboratory Equipment (LSLE) microcomputer for life sciences experiment data acquisition is now obsolete. Among the weaknesses of the current microcomputer are small memory size, relatively slow analog data sampling rates, and the lack of a bulk data storage device. While life science investigators normally prefer data to be transmitted to Earth as it is taken, this is not always possible. No down-link exists for experiments performed in the Shuttle middeck region. One important aspect of a replacement microcomputer is provision for in-flight storage of experimental data. The Write Once, Read Many (WORM) optical disk was studied because of its high storage density, data integrity, and the availability of a space-qualified unit. In keeping with the goals for a replacement microcomputer based upon commercially available components and standard interfaces, the system studied includes a Small Computer System Interface (SCSI) for interfacing the WORM drive. The system itself is designed around the STD bus, using readily available boards. Configurations examined were: (1) master processor board and slave processor board with the SCSI interface; (2) master processor with SCSI interface; (3) master processor with SCSI and Direct Memory Access (DMA); (4) master processor controlling a separate STD bus SCSI board; and (5) master processor controlling a separate STD bus SCSI board with DMA

PenDraw - A Language for Improving Take-Up of SVG

The case is presented for preferring a dedicated Computer Graphics (CG) language to the traditional conventional language plus add-on. PenDraw is presented as an existing language that overcomes many problems of CG add-ons, providing compile-time checking and reduced need for run-time debugging. PenDraw produces well-formed SVG. Evidence is given that PenDraw decreases development costs. Evidence is presented that PenDraw has brought CG programming to a wider ability range of potential users than professional programmers. It is argued that, given its qualities, PenDraw should be able to improve the take-up of CG programming. Such take-up is expected to be slow at first, given the market-place focus on interactivity and 3D. But it is believed that PenDraw's expressive power and cost benefits should lead to growth in its use, and in use of SVG

Towards composition of verified hardware devices

Computers are being used where no affordable level of testing is adequate. Safety and life critical systems must find a replacement for exhaustive testing to guarantee their correctness. Through a mathematical proof, hardware verification research has focused on device verification and has largely ignored system composition verification. To address these deficiencies, we examine how the current hardware verification methodology can be extended to verify complete systems

Self-tuning digital controllers for servo systems

Adaptive self-tuning systems have been the subject of a great deal of research effort in recent years. Practical applications have lagged behind such work, in the main being applied in the process industries. Few serve applications have been reported, the wide bandwidths and demanding performance specifications raising problems not found in the process world. The research project described here is concerned with the use of self-tuning digital controllers applied to servo systems, specifically an electro-mechanical actuation unit. Practical limitations, such as stiction, friction and velocity saturation effects are taken into account. [Continues.

Core component choices in single-user computer systems : a home office user\u27s perspective

The home office is a rapidly growing segment of the business environment. The trend toward two-income families and concerns over quality of life have made the office at home increasingly attractive alternative business style. The evolution of technology during the past ten years has opened up a broad array of choices. The introduction of the IBM personal computer in the fall of 1981 provided the technological nucleus. Other office products aimed at the individual user such as personal copiers, facsimile machines, smart typewriters, and multi-function telecommunications products have grown around it. The evolution of personal computer technology has been accelerating since its introduction; the home office user has a broad and confusing array of choices at varying levels of technological development and intercompatibility

Design and construction of a laboratory system for neuromuscular stimulation of the lower extremities during cycling

Functional Neuromuscular Stimulation (FNS) is a method by which paralyzed muscles are stimulated electrically in order to produce a useful movement. The design and testing of a laboratory system for the modulated control of the lower extremities during FNS-induced cycling on an exercising device (Paracycle) is described. The system hardware, which is designed around a standard IBM compatible Personal Computer, features six independent stimulation channels. Waveform characteristics such as pulse frequency, width and amplitude are defined as a function of the crank position of the Paracycle for each channel. An extensive software package allows programmability of the waveform parameters and supports the user in the definition of stimulation sequences. The effective performance of the complete FNS-controller/ Paracycle system has been demonstrated during a controlled case study with two paraplegic subjects

X.25 traffic generator

Due to the lower cost and error free data transmission capabilities offered by packet switching, numerous countries have installed national packet switched networks. The South African packet network, SAPONET-P, became operational in 1982 and has been growing rapidly, creating a need for network test equipment. This thesis describes the design of a high speed traffic generator which can be used to test and monitor the throughput capabilities of equipment or part of the network as a whole. To meet the main requirement of the traffic generator, that it should support a number of high speed X.25 lines, a multiprocessor architecture was chosen to cope with the high data throughput. An IBM PC was used as the base system, with several specially designed X.25 cards being installed in its expansion slots. The major part of the work done was on the design and development of the X.25 cards, each of which provides two high speed (64 Kbps) X.25 links. In order to achieve this throughput, the card uses three processors coupled on a local bus to a 256K multi-port memory. Two WD25ll processors implement the link level of the X.25 packet switching protocol (LAPB), with the required software being micro-encoded on the chip. An 8088 processor, the same as is used in the PC, implements the packet level, the traffic generator and overall control of the card. Extensive use was made of programmable array logic (PAL) devices to implement the system logic required. All programs for the traffic generator are written in the modern and powerful c language which is ideally suited to the application. The software was written in a modular fashion with the various modules being linked together by means of a set of common data structures. Use was made of packet buffers and job queueing to allow the traffic generator to cope with very high peak data rates. As well as programs for the X.25 cards, a monitor program runs on the PC and allows the· user to view statistics screens and modify the traffic generator configuration. While primarily designed for the,traffic generator application, the X.25 card may also be configured for a variety of other networking applications. By substituting a local area network (LAN) processor for the X.25 one, the card can be used as a low cost network card or as a network file server. The card can also be configured to provide a low cost means of connecting a PC based workstation to the packet switching network. As all programs are downloaded onto the cards from the PC, it is relatively easy to modify or upgrade the software. Thus while meeting the original project requirements, the traffic generator design has a flexible and expandible nature

Computer Aided Industrial Design

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