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Gordon G. Johnson, Ph.D.
Professor of Mathematics
College of Natural Sciences and Mathematics, UH
Research will continue the investigation and study of a learning machine based upon primitive elements and ideas. Some of the ideas were first reported by the proposers at the ROBEX conference held at NASA/JSC in 1986 under the title, "Primitive Ideas in 'Intelligent' Thought."
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Leang S. Shieh, Ph.D.
Professor of Electrical and Computer Engineering
Cullen College of Engineering, UH
Most aerospace systems and industrial control process can be approximately described by uncertain linear models. The uncertainty in these systems arises from unmodeled dynamics, parameter variations, sensor noises, actuator constraints, load disturbances, and other characteristics. Since 1980, striking developments have taken place in the field of uncertain systems. During this period, advanced digital redesign techniques have been successfully developed for practical digital implementation of analogue controllers and for hybrid optimal control of nominal sampled-data systems with a zero-order hold and a relatively longer sampling period. Based on recent advances in the design of robust controllers and optimal digital redesign techniques for nominal/uncertain linear systems, initially developed by Shieh, this research project develops new robust optimal PAM (Pulse Amplitude Modulated) and PWM (Pulse Width Modulated) digital controllers for improving the performance and robustness of continuous-time uncertain aerospace systems and industrial control processes.
The main research problems are:
The proposed robust optimal PAM and PWM control design techniques will be applied to attitude control of the Space Shuttle with a payload extended on its Remote Manipulator System (RMS) and demonstrated using the high fidelity non-linear Interactive On-Orbit Simulator (IOS). The expected results of this proposed project are state-of-the-art PAM and PWM controllers for use in hybrid and modulated uncertain sampled-data systems, including both aerospace systems and industrial control processes. The transfer of this new technology will significantly benefit industry, military, aerospace, robotics, and academia by reducing design cycle costs and improving system performance and robustness.
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Wayne E. Wentworth, Ph.D.
Professor of Chemistry
College of Natural Sciences and Mathematics, UH
This research has the objective of designing, constructing, and evaluating an analyte selective photoionization-based ion mobility spectrometer (PI-IMS) for monitoring the contamination of ambient air by toxic and hazardous chemicals. The proposed PI-IMS would be suitable for use as a detector for measuring contaminants in the air sample after prior separation of the sample components by gas chromatographic methods and would incorporate the same ion separation technique used in a conventional chemical ionization-based ion mobility spectrometer (CI-IMS): separation based on ion drift time through a bath gas under the influence of an electrostatic field.
The proposed PI-IMS would, however, incorporate a new, patented photoionization source in place of the radioactive foil ionizer used in a conventional CI-IMS. University of Houston researchers have been developing this photoionization source for five years and have successfully incorporated it into other types of ionization detectors currently being produced as commercial products. It is anticipated that the proposed PI-IMS would provide significant advantages over the conventional CI-IMS. In particular, the proposed PI-IMS would
Contents
ISSO -- Institute for Space Systems Operations
1994-1995 Annual Report
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