Dynamic modelling of a small scale turbojet engine

Thrust vector can effectively improve the fighter´s maneuverability and flight safety, increasing the survival rates in the air combat. As the key component of thrust vectors, the turbojet engine´s dynamics and characteristics have a great influence on the performance and control of thrust vectors. This paper would model the dynamics of a small scale turbojet engine through experiment and identification. An experiment platform of the turbojet engine was developed to test its dynamic responses and characteristics. Through the analysis of the experiment data, we find that the dynamics of the turbojet engine can be divided into two parts: the dynamic response from the throttle commands to the engine rotor speed and the nonlinear function between the rotor speed and the engine thrust. The proposed model was checked and verified through the experiment data, and the results show that the model can accurately and effectively represent the turbojet engine´s dynamics and characteristics. The model describes the turbojet engine´s input/output response with only two parameters, which is simple and convenient for us to understand its input/output characteristics and make appropriate usage.