Dr. Lee Keel
- EDUCATION
Ph.D, Electrical Engineering, Texas A&M University, College Station,
Texas, 1986.
M.S. Electrical Engineering, Texas A&M University, College Station,
Texas, 1983..
B.S. Electronic Engineering, Korea University, Seoul, Korea, 1978.
- AREAS OF RESEARCH
Robust Control, Controls and Structures, Computational Methods, Computer
Aided Control Systems Design.
- PAST AND CURRENT RESEARCH PROJECTS
Robust Parametric Control Applications to Space Structures
Recent developments in robust parametric control are being studied for
their application to the problem of position control and vibration control
of a space platform including the LAN-7 satellite, flexible slewing beam,
and large space structures.
This research is funded by NASA Headquarters.
Fault and Damage Detection
Structural fault/damage detection research consists of trying to
detect and isolate, if possible, fault/damage in the structures so that
the structures can perform normal operation. The methodologies investigating
here are based on the observation of behavioral changes of the structures.
These changes may be effectively monitored by detecting whether the responses
of the structures are within a predetermined response set which is described
in terms of a transfer function family.
This research is funded by NASA Headquarters.
Robotic Telescope Scheduling Problem
The Center operates four remote telescopes, they are the VU/TSU
16 inch, TSU/ASO 32 inch, SAO/TSU 30 inch, and Fairborn 10 inch telescopes.
Two more telescopes, the AST 2 meter and AIT 24 inch, are currently under
construction. All of these are robotic telescopes which are remotely controlled
from the Center located in Nashville, Tennessee. In order to achieve better
utilization of the telescopes' time, we are currently developing a new
state-of-art optimal scheduling mechanism which will eventually
replace the scheduler our astronomers are presently using.
This research is funded by NASA Ames
Research Center.
Low Order and Parametrically Less Sensitive Controller Design
It is found that controllers that robustly stabilize a plant against
plant uncertainty are usually high order and extremely sensitive with respect
to controller parameter perturbations. To overcome this problem, the research
aims to develop new control design methodologies that can result in a low
order controller which tolerates some degree of controller perturbations.
Stable Robust Adaptive Control Using Neural Networks
The development of stable adaptive algorithms for the control of
a class of nonlinear interval plants using neural networks.
Funded by Center of Excellence in Information Systems at Tennessee State
University.
- REFEREED PUBLICATIONS
L.H. Keel, K. Lim, and J.-N. Juang, "Robust Eigenvalue Assignment
with Maximum Tolerance to System Uncertainties", AIAA Journal of
Guidance, Controls and Dynamics, vol. 14, no. 3, pp. 615 - 620, May-June
1991.
L.H. Keel and S.P. Bhattacharyya, "Frequency Domain Design of Interval
Controllers", Control of Uncertain Dynamic Systems, pp. 423
- 438, CRC Press, 1991.
L.H. Keel and S.P. Bhattacharyya, "Extremal Gain and Phase Margins
for Interval Plants", International Workshop on Robust Control,
San Antonio, TX., March 1991.
L.H. Keel and S.P. Bhattacharyya, "Optimum Design of Robust One-Parameter
Controllers for Interval Plants", Proceedings of the 1991 IFAC
Symposium on Design Methods for Control Systems, Zurich, Switzerland,
September 4 - 6, 1991.
L.H. Keel and S.P. Bhattacharyya, "Extremal Gain and Phase Margins
for Interval Systems", Proceedings of the 1991 AIAA Guidance, Navigation
and Control Conference, New Oleans, LA., August 1991.
H. Chapellat, L.H. Keel and S.P. Bhattacharyya, "Stability Margin
for Multilinear Interval Control Systems", Proceedings of the 1991
IEEE Conference on Decision and Control, Brighton, United Kingdom,
December 1991.
S.P. Bhattacharyya and L.H. Keel, "Robust Stability and Control of
Linear and Multilinear Interval Systems", Control and Dynamic Systems,
vol. 51, Part 2, pp. 31 - 77, Academic Press, 1992.
S. Ahmad, L.H. Keel and S.P. Bhattacharyya, "Computer Aided Robust
Control Design for Interval Control Systems", Proceedings of the
1992 IEEE Symposium on Computer Aided Control System Design;, Napa,
CA., March 1992.
L.H. Keel, J. Shaw and S.P. Bhattacharyya, "Robust Control of Interval
Systems", in Robust Control, pp. 24 - 31, Springer Verlag,
1992.
S. Ahmad, L.H. Keel, and S.P. Bhattacharyya, "Robust PID Control and
Lead-Lag Compensation for Linear Interval Systems", Robustness
of Dynamic Systems with Parameter Uncertainties, pp. 251 - 260, Birhauser
Press, 1992.
H. Chapellat, L.H. Keel, and S.P. Bhattacharyya, "Robustness Properties
of Multilinear Interval Systems", Robustness of Dynamic Systems
with Parameter Uncertainties, pp. 73 - 80, Birhauser Press, 1992.
L.H. Keel and S.P. Bhattacharyya, "Control System Design for Parametric
Uncertainty", Proceedings of the 1st Quantitative Feedback Theory
Symposium, Wright Pattersen Air Force Base, OH, August 3 - 4, 1992.
L.H. Keel and S.P. Bhattacharyya, "Stability Margins for Multilinear
Interval Systems via Phase Conditions: A Unified Approach", Proceedings
of the 1993 American Control Conference, San Francisco, CA, June 2
- 4, 1993.
L.H. Keel and S.P. Bhattacharyya, "Vertex Results in Robust Stability",
Proceedings of the 1993 IFAC World Congress, Sydney, Australia,
July 19 - 23, 1993.
L.H. Keel and S.P. Bhattacharyya, "Parametric Stability Margin for
Multilinear Interval Control Systems", Proceedings of the 1993
American Control Conference, San Francisco, CA, June 2 - 4, 1993.
J.S. Lew, L.H. Keel, and J-N. Juang, "Quantification of Model Error
via an Interval Model with Nonparametric Error Bound", Proceedings
of the 1993 AIAA Guidance, Navigation, and Control Conference, Montery,
CA, August, 1993.
S.P. Bhattacharyya and L.H. Keel, "Comments on `Extreme Point Results
for Robust Stabilization of Interval Plants with First Order Compensators",
IEEE Transactions on Automatic Control, vol. 38, no. 11, pp. 1734
- 1735, November 1993.
S. Bhattacharyya, L.H. Keel, and S.P. Bhattacharyya, "Robust Stabilizer
Synthesis for Interval Plants Using Nevanlina-Pick Theory", Proceedings
of the 32nd IEEE Conference on Decision and Control, San Antonio, TX,
December 15 - 17, 1993.
L.H. Keel and S.P. Bhattacharyya, "Control System Design for Parametric
Uncertainty", International Journal of Robust and Nonlinear Control,
vol. 4, pp. 87 - 100, April 1994.
J.S. Lew, T.L. Link, E. Garcia, and L.H. Keel, "Interval Model Identification
for Flexible Structures with Uncertain Parameters", Proceedings
of the 1994 AIAA/ASME Adaptive Structures Forum, Hilton Head, SC, April
21 - 22, 1994.
H. Chapellat, L.H. Keel, and S.P. Bhattacharyya, "Extremal Robustness
of Multilinear Interval Systems", Automatica, vol. 30, no.
6, pp. 1037 - 1042, June 1994.
L.H. Keel, J.S. Lew, and S.P. Bhattacharyya, "System Identification
Using Interval Dynamic Models", Proceedings of the 1994 American
Control Conference, Baltimore, MD, June 29 - July 1, 1994.
L.H. Keel and S.P. Bhattacharyya, "Robust Stability of Interval Matrices:
A Computational Approach", Proceedings of the 1994 Asian Control
Conference, Tokyo, Japan, July 27 - 30, 1994.
L.H. Keel and S.P. Bhattacharyya, "Robust Stability of Interval Matrices:
A Computational Approach", Proceedings of the 1994 Asian Control
Conference, Tokyo, Japan, July 27 - 30, 1994.
L.H. Keel and S.P. Bhattacharyya, "Robust Parametric Classical Control
Design", IEEE Transactions on Automatic Control, vol. 39, no.
7, pp. 1524 - 1530, July 1994.
J.S. Lew, L.H. Keel, and J-N Juang, "Quantification of Model Error
via an Interval Model with Nonparametric Error Bound", AIAA Journal
of Guidance, Controls, and Dynamics, vol. 17, no. 6, pp. 1212 - 1218,
November - December 1994.
L.H. Keel and S.P. Bhattacharyya, "Phase Properties of Hurwitz Polynomials",
Proceedings of the 34th IEEE Conference on Decision and Control,
New Orleans, LA, December 13 - 15, 1995.
L.H. Keel and S.P. Bhattacharyya, "Robust Stability of Interval Matrices:
A Computational Approach", International Journal of Control,
vol. 62, no. 6, pp. 1491 - 1506, December 1995.
L.H. Keel and S.P. Bhattacharyya, "Phase Properties of Hurwitz Polynomials",
IEEE Transactions on Automatic Control, vol. 41, no. 5, pp. 733
- 734, May 1996.
Y.C. Kim and L.H. Keel, "Robust Stabilization of a Magnetic Levitation
Vehicle", Proceedings of the 1996 International Symposium on Intelligent
Automation and Control, Montpellier, France, May 27 - 30, 1996.
T.L. Link, J.S. Lew, E. Garcia, and L.H. Keel, "Interval Model Identification
and Robustness Analysis for Uncertain Flexible Structures", IEEE
Transactions on Control Systems Technology, vol. 4, no. 4, pp. 411
- 418, July 1996.
L.H. Keel, J.W. Howze, and S.P. Bhattacharyya, "Robust Tracking and
Disturbance Rejection with Two DOF Controllers and Distributed Internal
Models", Proceedings of the 1997 American Control Conference,
Albuquerque, NM, June 4 - 6, 1997.
L.H. Keel and S.P. Bhattacharyya, "Robust, Fragile or Optimal?",
Proceedings of the 1997 American Control Conference, Albuiquerque,
NM, June 4 - 6, 1997.
- CONTACT
keel@gauss.tsuniv.edu