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Donaldson, J. A.

Publications and source records attributed to Donaldson, J. A..

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Mathematical analysis

Simple continuum models used in the design, analysis, and control of large space structures are examined. Particular emphasis is placed on boundary value problems associated with the Load Correction Method and control problems involving partial differential equations for the large space structure models. Partial differential equations will be used to model a large space structure, base the design of an optimal controller on this model, approximate the resulting optimal control model, and compare the results with data from other methods.

Donaldson, J. A.↗
NASA NTRS1981

Microprocessor-based cardiotachometer

Instrument operates reliably even with stress-test electrocardiogram (ECG) signals subject to noise, baseline wandering, and amplitude change. It records heart rate from preamplified, single-lead ECG input signal and produces digital and analog heart-rate outputs which are fed elsewhere. Analog hardware processes ECG input signal, producing 10-ms pulse for each heartbeat. Microprocessor analyzes resulting pulse train, identifying irregular heartbeats and maintaining stable output during lead switching. Easily modified computer program provides analysis.

Crosier, W. G.↗
NASA NTRS1980

Laser optical appraisal and design of a PRIME/Rover interface

An appraisal of whether to improve the existing multi-laser/multi detector system was undertaken. Two features of the elevation scanning mast which prevent the system from meeting desired specifications were studied. Then elevation scanning mast has 20 detectors, as opposed to the desired 40. This influences the system's overall resolution. The mirror shaft encoder's finite resolution prevents the laser from being aimed exactly as desired. This influences the system's overall accuracy. It was concluded that the existing system needs no modification at present. The design and construction of a data emulator which allowed testing data transactions with a PRIME computer is described, and theory of operation briefly discussed. A full blown PRIME/Rover Interface was designed and built. The capabilities of this Interface and its operating principles are discussed.

Donaldson, J. A.↗
NASA NTRS1979

A microprocessor-based cardiotachometer

The development of a highly accurate and reliable cardiotachometer for measuring the heart rate of test subjects is discussed. It measures heart rate over the range of 30 to 250 beats/minute and gives instantaneous (beat to beat) updates on the system output so that occasional noise artifacts or ectopic beats could be more easily identified except that occasional missed beats caused by switching ECG leads should not cause a change in the output. The cardiotachometer uses an improved analog filter and R-wave detector and an Intel 8080A microprocessor to handle all of the logic and arithmetic necessary. By using the microprocessor, future hardware modifications could easily be made if functional changes were needed.

Donaldson, J. A.↗