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Research

DR. BROWN’s research interests lie in the general area of control theory. The main field of expertise is welding control, adaptive control, periodic disturbance cancellation and intermittent control. In addition Dr. Brown has interest in bioinformatics and modeling pf cellular signal transduction.

One major result, of Dr. Brown’s, in welding control is the realization that force, displacement and possibly cylinder air pressure during electrode contact provide a reliable way of detecting machine and part misalignment prior to the weld. It has been shown that these conditions significantly affect the appropriate choice of weld schedule. It is also possible that these signals can be used to dynamically detect weld electrode condition. Dr. Brown’s work in welding control has led to his serving on the Board of Directors of IRW, Inc. This was the automobile industry’s research consortium aimed at improving the state of the art for resistance spot welding. Up to 30% of spot welds made by the automobile industry are in excess of those required to meet structural integrity. If the industry could reduce the number of spot welds mad per year by 10%, the cost savings are estimated to be as high as 100 million dollars per year. The improved consistency of the welding process that can be delivered by dynamic detection of electrode and operating condition could make this a reality.

Intermittent Cancellation control is a control paradigm for canceling constant offsets and periodic disturbances via an open/closed loop strategy. This approach, for example, allows the benefits of integral control to be incorporated in a control strategy with out having to suffer the costs of the associated phase lag. In addition, Dr. Brown has shown the states of a simple internal model in IMC control strategies can be directly mapped to any error in the assumed frequency of a periodic disturbance. This error can be used to adaptively update the frequency in an internal model to generate superior adaptive notch filters and perfect periodic disturbance cancellation. The periodic control strategies being developed could find application for vibration cancellation in the semiconductor industry, for noise cancellation and in servo motor applications. An especially apt field for these algorithms is also in control algorithms for allowing read/write heads in disk drives to achieve greater precision in positioning. This is one of the requirements for continuing to achieve greater data densities.

The success of the human genome project is a milestone in human history. However, simply cataloging the human genome does not lead directly to new understanding. Dr. Brown has been working on methods and tools for deriving insight for genomic and proteomic data. Dr. Brown’s main approach involves dynamic models of signal transduction pathways. The components of these pathways are believed to represent over half of the human genome, and are vitally involved in critical issues such as cancer, pain, metabolism, etc. In addition Dr. Brown is developing visualization and analysis tools for developing insight of the high throughput data now becoming available to biologists.

Current Research Interests

• Control Theory
  • Welding Control
  • Adaptive Control
  • Periodic Disturbance Cancellation
  • Intermittent Control

My Research Group