Research on adaptive pressure control for rockets by Asst. Prof. Yıldıray Yıldız of the Department of Mechanical Engineering and his student Anıl Alan was featured as the cover article in the October 2018 issue of leading control journal IEEE Control Systems Magazine. The work was conducted in collaboration with Roketsan, Inc., where the contributing engineer was Ümit Poyraz.
The published research focuses on the pressure control problem of gas generators employed in variable-speed rockets. The ability to change speed during operation enables these rockets to adjust to the demands of different types of maneuvers and varying flight conditions. As a result, speed-controllable rockets provide a dramatic advantage over their alternatives with fixed-speed profiles. In throttleable ducted rockets, speed variation is achieved by changing the fuel flow rate, which is achieved using closed-loop control.
The article provides a detailed review of the current state of rocket propulsion control and the main challenges in the field. A controller that has a unique combination of features, such as fast adaptation, delay compensation and a smooth response, is introduced as a solution to the pressure control problem in air-breathing rocket propulsion. The resulting design, called a delay-resistant closed-loop reference model adaptive controller, combines delay compensation and adaptive transient performance improvement. The superior performance of the controller, compared to existing alternatives, is demonstrated through experimental tests, using a test setup provided by Roketsan.
The discussion in the article on the employment of advanced control methodologies is indicated as being of potential benefit to practitioners whose goal is to obtain a fast system response in safety-critical applications where nonlinear dynamics, time-varying parameters and time delays pose significant challenges.