Microprocessor-controlled Systems Research Articles

Design and Initial Evaluation of a Low-Cost Microprocessor-Controlled Above-Knee Prosthesis: A Case Report of 2 Patients

For prosthesis users, knee units can range from simple devices costing $2000 up to $45,000 for high-end, microprocessor-controlled systems. These higher-end electronic knees provide significant advantages in stability, gait, and metabolic rate compared to their passive or mechanical counterparts. However, the high cost of such systems makes them inaccessible to most amputees. In this study, it was hypothesized that a microprocessor knee could be manufactured for less than $1000, with comparable stability and user experience to a high-end industry standard device. A prototype (E-Knee) was designed with a specific emphasis on stance stability, and was tested during patient gait trials. The gait trials used a repeated measures design to compare three knee devices (a simple passive knee, the prototype E-Knee, and a high-end knee). Ground reaction forces and a functionality questionnaire were used to compare devices. A microprocessor locking test was used to evaluate the prototype’s ability to prevent falls. Building on the LIMBS M3, a passive four-bar polycentric device, the E-Knee added sensing, computing, and controlling capabilities for a material cost of $507. Initial data from a two-subject trial served as proof-of-concept to validate the prototype and found that it improved gait by providing more stability than the M3 and had more gait-pattern similarities to the Ottobock C-Leg than to the M3. Patients reported no perceived differences in stability between the E-Knee and the C-Leg. Patient trials supported that the E-Knee prototype behaved more naturally than the low-end M3 device and had similar ground reaction forces to the C-Leg.

Design and Construction of A Two Axes Sun Tracker Prototype with A Real Time Controller and Hybrid Stepper Motors (Dept.M)

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Адаптивная кратность форсировки по току синхронных генераторов с тиристорными системами самовозбуждения

The voltage decreases significantly at the generator leads if a short circuit occurs near the power rails of a power plant. In this case thyristor self-excitation system that use rated algorithms and forcing-state parameters in some cases might not be able to force by raising the voltage and the excitation current. Voltage collapses, and the generator loses its excitation and turns off. It is not difficult to alter the forcing algorithm in microprocessor-controlled systems. It is therefore interesting to find out whether it is possible to save the generator in the power system by using a higher-than-2x current-forcing ratio or a ratio that adapts to the resulting system impedance. The paper investigates how generator-lead voltages depend on the resulting system impedance in case of short-circuits; analysis is done for various current-forcing ratios, with analyzed generators varying both in power and by the excitation system type. It is shown that ratios or current-forcing durations might be altered to expand the zone wherein short-circuits do not result in voltage collapse and excitation loss. Altering the generator forcing ratio can make power plants and systems generally more reliable.

On the performance improvement of the optimal-sampling-inspired self-triggered control at implementation stage

The self-triggered control includes a sampling strategy that focuses on decreasing the use of computational resources (processor and network) while preserving the same control performance as the one obtained via a controller with periodic sampling. Within this framework it has been developed recently a self-triggered control technique inspired by a sampling pattern whose optimal density minimizes the control cost, this approach is called “optimal-sampling inspired self-triggered control”. However, the strategies used to implement it on microprocessor-controlled systems working under perturbation are still unclear; this paper addresses some techniques to organize and improve the implementation on actual controllers. The proposed solution comprises both the formulation of two algorithms to organize the implementation and the insertion of a closed-loop observer to deal with the perturbation that normally appears on real plants. Regarding the former, certain computationally expensive processes involved in the implementation of this control technique are treated through their replacement by lightweight polynomials fitted at design stage. Simulations and practical experiments confirm the solution is effective and there could be an open research topic concerning observation in optimal-sampling self-triggered control strategies.

Surgical Simulation: Where Have We Come From? Where Are We Now? Where Are We Going?

It is now clear to most stakeholders that acquisition of surgical psychomotor skills is best achieved outside of the clinical operating room, in the context of a simulated environment. Endoscopic simulation can be accomplished using simple “box” simulators or video trainers, and virtual reality simulation is now possible using microprocessor-controlled systems. Structured surgical training performed outside of the operating room environment is relatively new to health care, a circumstance different from the process of pilot training, in which simulation has been a mainstay for more than 75 years and in which virtual reality simulation is now the norm. Those charged with surgical education are faced with a dilemma as, while attempting to understand the basic goals of simulation, they are simultaneously faced with choice between relatively inexpensive video trainers and the often prohibitively expensive virtual reality systems. This article explores the history of simulation, reports the results of a modified systematic review of currently available systems and performance, and identifies the gaps in current research and development. It is apparent that available video trainers provide the opportunity for skill development that at present is not surpassed by virtual reality systems. In the future, there will likely be an increasing role for virtual reality; however, challenges remain that include determination of the appropriate metrics and system design, and the fiscal resources necessary for the required hardware and related software development.

Coulometric determination of the flow rate of small masses of substances II. Application to on-line measurement of the EOX-parameter

Today’s microprocessor-controlled coulometric systems can generate complex functions obtained from the response of the microcoulometric cell. A previously developed procedure for determining the flow-rate (mass per unit time of detected species) has been accomplished by integrating, in the software, the full time dependence of the reaction of the coulometric cell and their electrodes, as well as of the titration curve. This leads to a time dependence of the measured signal, which has a fast response time without any delay. The titration curves are determined by means of various procedures. The applicability of the method is demonstrated for the case of the continuous analysis of the EOX-parameter (Extractable Organic Halogens X=Cl, Br, I) by coupling the coulometric detection with a FIA system. Results of continuous measurements of aqueous samples containing different chlorinated compounds as analytes are presented by taking into account different flow velocities in the FIA system as well as different measuring times. Recovery yields of the FIA system better than 70% have been obtained.

Suppression of image frequency mode in microprocessor-controlled frequency synthesising systems

A simple method of starting a new acquisition cycle in microprocessor-controlled frequency synthesising systems in order to suppress the image frequency mode is described. The image frequency detector built into the 305–415 kHz first local oscillator – frequency synthesiser of a 20 Hz – 110 kHz selective voltmeter, supported by an Intel 80C39 microcontroller, identifies the appearance of the image frequency mode in the system and generates a signal to start the procedure carried out by the microcontroller. The microcontroller changes the reference frequency to suppress the signal at the variable input of the phase detector of the phase locked loop (PLL) containing a frequency mixer. This, in turn, forces the phase detector of this PLL to generate an increased voltage, up to 12 V, across the associated varactor diode and, by increasing the loop frequency, restore proper functioning of the synthesiser.

Development of a Service Support System for Microprocessor-Controlled Vehicle Electrical Systems

This paper describes the development of a diagnostic system for the service support of the microprocessor-controlled electrical systems for the Jaguar XJ40. It includes details of the system concept, specification, hardware, software structure and operator interfaces.

How to Develop Reliable Microprocessor Software Systems for Process Control

The triumphal march of innovative microelectronics continues. The rapidly increasing industrial use of microprocessors not only poses technical problems for the development of machines, products and installations, but also the organisation of development, support and maintenace, as well as the training of qualified workers, call for engagement and considerable investment. The central task is the development of especially reliable software.The lecture touches on the situation regarding the development of microprocessor-controlled systems and demonstrates how to keep development risk and costs under control by using specialized development systems: the UNIX-based, universally-usable tools system CAMIC/S will be presented; its successful use in industry will be proved using facts and figures.

Software-Development for Microprocessor Applications

The industrial use of microprocessors is increasing rapidly. Innovative microelectronics Dose not only technical problems for developers of machines, Products and installations; the organisation of development, support and maintenance as well as the training of qualified workers also calls for a lot of engagement and considerable expense. With special development systems, the risks and cost of projects using intelligent microelectronics can be brought under control. The lecture touches on the situation regarding the development of microprocessor-controlled systems and presents a universally-usable tool system: the UNIX-based CAMIC/S.

Spectral information from fourier analysis of digitized quartz grain profiles

Fourier analysis of closed curves defining two-dimensional images has emerged as a promising new tool for the quantification of projected shape in detrital quartz grains. The Fourier method has received added impetus with the introduction of microprocessor-controlled video imaging systems that permit automated acquisition and processing of digital information for hundreds of grains in a few hours. Although new methods and technology have removed much of the tedium and subjectivity associated with older representations of particle shape, other problems are introduced during the acquisition and interpretation of Fourier shape spectra that find their analog in conventional time series analysis. These include the aliasing problem and the treatment of quantization errors which attend the digitization process, along with decisional problems regarding the selection of harmonics and the smoothing of spectral power estimates from individual grain shapes. Our work with quartz grain shapes suggests that bandwidth averaging of power estimates over four adjacent harmonics is an effective smoothing procedure and that harmonics 18 through 21 may constitute a suitable standard band for multiple study comparisons.

Videotape Editing Systems Using Microprocessors

Following a short overview of videotape editing history, the modern approach is described — using a controller built around a microprocessor or “computer on a chip” rather than hardwired logic. A good editing controller should be directly interfaced with the individual editing machine; it must “know” all the relevant characteristics of the machine for correct control and at the same time must have easily understandable displays and a simple, functional control panel for easy operation. Two specific microprocessor-controlled editing systems designed to operate with the TR-600 quadruplex VTR are discussed; these are the AE-600, a sophisticated time-code editing system (able to control up to eight TR-600's) using the Intel 8080 microprocessor with 15K bytes of memory, and the SE-1 “simple editing system” using the CDP1802 microprocessor with 2K bytes of memory. The mechanics of editing with time code are discussed briefly.

A Method for Implementing Microprocessor-Controlled Systems

Techniques for both hardware and software development of microprocessor systems are discussed. A crossassembler, written for execution on a 16-bit control computer, is used to assemble programs and produce binary output tapes for programming read-only memories. A modular 8-bit microprocessor system has been developed that includes a bus-oriented card file and a group of analog and digital I/O interface cards. This has proved to be a flexible and inexpensive method of implementing a variety of one-of-a-kind microprocessor applications in a laboratory environment.