Browsing by Subject "Throttleable ducted rockets"

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Open Access
Gas generator pressure control in throttleable ducted rockets: a classical and adaptive control approach
(American Institute of Aeronautics and Astronautics (AIAA), 2015) Alan, Anıl; Yıldız, Yıldıray; Poyraz, Ü.; Olgun, U.
This paper describes the control of gas generator pressure in throttleable ducted rockets using nonlinear adaptive control as well as classical control approaches. Simulation results using the full nonlinear and time-varying dynamics of the gas generator are reported in both classical controller and adaptive controller cases. "Closed-loop Reference Model" structure is used together with the adaptive controller to improve transient response. Controllers are simulated to test their robustness by introducing uncertinities, disturbances and noise to the system. Cold Air Test Plant (CATP) is used as the test facility to compare the controllers and validate the results from simulations. Moreover, damping effect of CRM to oscillations in adaptive controller case is observed in CATP tests.
Open Access
Pressure control of gas generator in throttleable ducted rockets: a time delay resistant adaptive control approach
(2017-06) Alan, Anıl
Having variable thrust during the operation of a rocket provides tremendous advantages while chasing down a target. For ducted rockets, the key factor to obtain variable thrust is the precise pressure control inside the gas generator, which is one of the main elements of a throttleable ducted rocket and utilized to generate the fuel in gaseous form for combustion. However, the inherent nature of the system makes the control problem di cult due to time varying parameters, nonlinearities and time delays. Furthermore, disturbances and uncertainties exist due to challenging operation conditions. All these challenges make it necessary to design an advanced control approach. Therefore, a delay resistant closed loop reference model adaptive control is proposed in this thesis to address the control problem. The proposed controller combines delay compensation and adaptation with improved transient response. The controller is successfully implemented using an industrial grade cold air test setup, which is a milestone towards obtaining a fully developed throttleable rocket gas generator controller. Simulation and experimental comparisons with alternative adaptive approaches and a xed controller demonstrate improved performance and e ective handling of time delays and uncertainties. A step by step design methodology, covering robustfying schemes, selection of adaptation rates and initial controller parameters, is also provided to facilitate implementations.