Pushing the Limits by Gaining Control
Bitmead named Cymer, Inc. Professor of High Performance Dynamical Systems Modeling and Control

Robert Bitmead

Understand the dynamics of an engineered system, and you have the power to increase performance. That is Robert Bitmead’s central tenet of control theory and one he has applied most recently in his work with the General Electric Global Research Center on an Air Force-funded project aimed at producing a next-generation turbine jet engine controller for the U.S. Air Force’s F-15 and F-16 planes.

He’s been developing a control system that should dramatically increase performance, provide more rapid acceleration, require less maintenance, and be completely reconfigurable in real-time — all without rebuilding the engine itself.

“The traditional approach to accelerating a jet engine is to introduce more fuel. But at some point, gunning the fuel can overheat and damage the turbine,” explains Bitmead. “So, engineers have set conservative guidelines on how much fuel can be added. We've created a dynamic feedback control system which senses the current condition of the engine, feeds that information into a mathematical model for the optimal performance of the engine, and then adjusts the release of fuel accordingly.”

Bitmead is confident that once this dynamic feedback system is introduced, jet engines will perform better, last longer and require less extensive maintenance. “You can make adjustments as you go along. When more power and acceleration are needed, the constraints can be modified. If you find that a compressor is not working as efficiently as it should, maybe because it has not been overhauled for a while, but the turbine is running very efficiently, you might operate in a different ratio by driving the turbine harder and relaxing the compressor a little. These decisions and modifications can be made during operation.” The bottom line is that you have more control without extensive redesign.

Bitmead says his dynamic feedback control system can be applied to a variety of engine types, and the theories behind it can even be used in other industries such as telecommunications, where it can manage network congestion.