In order to make the power level angle(PLA)have the same bijection relationship with the thrust when the environment changes before operational limit exceedance,and ensure the pilot's ability of unrestricted throt...In order to make the power level angle(PLA)have the same bijection relationship with the thrust when the environment changes before operational limit exceedance,and ensure the pilot's ability of unrestricted throttle movement as well as the safety of the engine,a method used to design a constant thrust power schedule was proposed.The research was based on a simulink turbofan engine model and the results were organized as look-up tables in different structures with limitations.Simulation was done to confirm the validity and demonstrate the effectiveness of the schedule obtained with the approach.The constant thrust takeoff schedule,constant thrust idle schedule and constant thrust part power schedule with the present constant thrust control(CTC)method were proved to be valid.The results can be applied to this specific engine but the method can be applied to any areoengine and can be even extended to the unmanned plane.展开更多
A robust constant thrust rendezvous approach under thrust failure is proposed based on the relative motion dynamic model. Firstly, the design problem is cast into a convex optimization problem by introducing a Lyapuno...A robust constant thrust rendezvous approach under thrust failure is proposed based on the relative motion dynamic model. Firstly, the design problem is cast into a convex optimization problem by introducing a Lyapunov function subject to linear matrix inequalities. Secondly, the robust controllers satisfying the requirements can be designed by solving this optimization problem.Then, a new algorithm of constant thrust fitting is proposed through the impulse compensation and the fuel consumption under the theoretical continuous thrust and the actual constant thrust is calculated and compared by using the method proposed in this paper. Finally, the proposed method having the advantage of saving fuel is proved and the actual constant thrust switch control laws are obtained through the isochronous interpolation method, meanwhile, an illustrative example is provided to show the effectiveness of the proposed control design method.展开更多
An improved constant volume cycle(CVC) model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine(PDRE).Theoretically, this model shows that the thrust coeffi...An improved constant volume cycle(CVC) model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine(PDRE).Theoretically, this model shows that the thrust coefficient/specific impulse of PDRE is a function of the nozzle contraction/expansion ratio and the operating frequency. The relationship between the nozzle contraction ratio and the operation frequency is obtained by introducing the duty ratio, by which the key problem in the theoretical design can be solved. Therefore, the performance of PDRE can be accessed to guide the preliminary shape design of nozzle conveniently and quickly. The higher the operating frequency of PDRE is, the smaller the nozzle contraction ratio should be. Besides, the lower the ambient pressure is, the larger the expansion ratio of the nozzle should be. When the ambient pressure is 1.013 × 105 Pa, the optimal expansion ratio will be less than 2.26.When the ambient pressure is reduced to vacuum, the extremum of the optimal thrust coefficient is 2.236 9, and the extremum of the specific impulse is 321.01 s. The results of the improved model are verified by numerical simulation.展开更多
文摘In order to make the power level angle(PLA)have the same bijection relationship with the thrust when the environment changes before operational limit exceedance,and ensure the pilot's ability of unrestricted throttle movement as well as the safety of the engine,a method used to design a constant thrust power schedule was proposed.The research was based on a simulink turbofan engine model and the results were organized as look-up tables in different structures with limitations.Simulation was done to confirm the validity and demonstrate the effectiveness of the schedule obtained with the approach.The constant thrust takeoff schedule,constant thrust idle schedule and constant thrust part power schedule with the present constant thrust control(CTC)method were proved to be valid.The results can be applied to this specific engine but the method can be applied to any areoengine and can be even extended to the unmanned plane.
基金supported by the National Natural Science Foundation of China (No. 61304088)the Fundamental Research Funds for the Central Universities of China (No. 2013QNA37)
文摘A robust constant thrust rendezvous approach under thrust failure is proposed based on the relative motion dynamic model. Firstly, the design problem is cast into a convex optimization problem by introducing a Lyapunov function subject to linear matrix inequalities. Secondly, the robust controllers satisfying the requirements can be designed by solving this optimization problem.Then, a new algorithm of constant thrust fitting is proposed through the impulse compensation and the fuel consumption under the theoretical continuous thrust and the actual constant thrust is calculated and compared by using the method proposed in this paper. Finally, the proposed method having the advantage of saving fuel is proved and the actual constant thrust switch control laws are obtained through the isochronous interpolation method, meanwhile, an illustrative example is provided to show the effectiveness of the proposed control design method.
基金supported by the National Natural Science Foundation of China(No.11472167)
文摘An improved constant volume cycle(CVC) model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine(PDRE).Theoretically, this model shows that the thrust coefficient/specific impulse of PDRE is a function of the nozzle contraction/expansion ratio and the operating frequency. The relationship between the nozzle contraction ratio and the operation frequency is obtained by introducing the duty ratio, by which the key problem in the theoretical design can be solved. Therefore, the performance of PDRE can be accessed to guide the preliminary shape design of nozzle conveniently and quickly. The higher the operating frequency of PDRE is, the smaller the nozzle contraction ratio should be. Besides, the lower the ambient pressure is, the larger the expansion ratio of the nozzle should be. When the ambient pressure is 1.013 × 105 Pa, the optimal expansion ratio will be less than 2.26.When the ambient pressure is reduced to vacuum, the extremum of the optimal thrust coefficient is 2.236 9, and the extremum of the specific impulse is 321.01 s. The results of the improved model are verified by numerical simulation.
