C. D. Johnson, PhD, Distinguished Professor
Field of interest: Control of Dynamical Systems in the Face of Uncertain Disturbances and Parameter Variations.

Y. B. Shtessel, PhD, Associate Professor
Field of interest: Sliding Mode Control with Applications to Space and Flight Control.

For the past 35 years Dr. Johnson has been actively involved in the development of new approaches to the design of high-performance stabilization, set-point regulation, servo-tracking, guidance laws and adaptive control systems for rockets, missiles and other dynamical systems which must operate in environments with uncertain, persistently-acting disturbances and parameter-variations. These research efforts have led to the development of a wide variety of new control techniques including the theories of: subspace-stabilization control, disturbance-accommodating control, Chebyshev-minimax control, optimal bang-bang control, optimal linear-saturating control, optimal disturbance-utilizing control, linear adaptive control, inter-sample control for discrete-time systems, "smart" active-control of vibrations and structures, inverse-system realization methods, new methods for real-time system identification and deconvolution, singular-solution methods in optimal control, optimal real-time allocation of scarce resources, and exact time-varying eigenvalue methods for linear time-varying dynamical systems. Dr. Johnson published over 200 technical papers

Presently, Dr. Shtessel is actively involved in a reusable launch vehicle (RLV) trajectory control, aircraft control reconfiguration addressing aircraft damage and actuator saturation, and satellite attitude control via sliding modes. Employing a time scaling concept a new two/three-loop structure of the control system for an RLV has been developed for ascend and descend modes. Continuous sliding mode controllers, including the continuous finite-reaching-time sliding mode controllers have been designed to robustly enforce the given close-loop RLV dynamics. Simulations of the X33 launch vehicle showed an accurate, robust tracking performance in ascend and descend modes. This project is sponsored by NASA via 1997 summer fellowship and Graduate Student Research Grant, 1997-2000. Improving a tailess aircraft control the continuous finite-reaching-time sliding mode controller has been developed and tailored to the dynamic prioritization algorithm for the control allocator design. Improving an aircraft tracking performance recovery from the damage to an aircraft a reconfigurable continuous sliding mode controllers have been designed with a direct adaptation taking into account the actuator saturation. This project is sponsored by AFOSR via 1997 summer fellowship. Dr. Shtessel published over 100 technical papers.

Contact Information email: