Pressure Control of Gas Generator for Throttleable Ducted Rockets using Adaptive Control Theory

Sponsor: ROKETSAN A.S.

Throttleability provides a major superiority to rockets against their non-throttleable counterparts. This feature can be utilized at solid rocket motors by the help of changing the throat area of the nozzle at the outlet of the gas generator which generates fuel in gaseous form. In order to have a desired variable fuel mass flow rate and thus a desired variable thrust, the gas pressure in the gas generator chamber needs to be precisely controlled. In this research, the goal is to obtain precise control of pressure using the state of the art advanced control system technologies. In the existing literature, there are mostly constant gain or gain-scheduled controllers utilized for the purpose of pressure control. These approaches are not very successful in dealing with the nonlinear terms of the plant, or it is very time consuming to arrange look-up tables for gain scheduling. In this study, we eliminate the need for a precise system model for classical approaches. This is achieved by developing and utilizing a delay resistant adaptive controller which includes a unique combination of the elements of the Adaptive Posicast Controller (APC) with the ability to accommodate large delays and closed loop reference model (CRM) adaptive controller with improved transient response of closed loop adaptive system. Simulation and experimental results verifying the performance improvement of the delay resistant controller over the alternatives are obtained.

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