An online engine thrust and specific impulse estimation method and system

Abstract

Provided are an online estimating method and system for engine thrust and specific impulse. The method comprises the following steps: (1) according to a ground test result, determining estimated initial value for main engine thrust and specific impulse and initializing related parameters required by a subsequent iteration process; (2) combining additional acceleration generated by thrust directionof a main engine with quality consumption caused by an attitude control thruster in order to solve estimated initial value for main engine thrust and specific impulse, thereby achieving online estimate of engine thrust and specific impulse, wherein the attitude control thruster runs in the thrust direction of the main engine. Extra quality consumption and acceleration caused by air injection of other attitude control engines apart from the main engine are taken into consideration. Their impact is eliminated from an estimating equation. Ultimately, a method of least minimum square is recursedin order to acquire an accurate estimation result of the thrust of the main engine and the specific impulse. The advantage of the method is to perform operation in a real-time and online manner and remove adverse impact on operation of other engines to the estimation result.

Description

Technical field [0001] The invention relates to an online engine thrust and specific impulse estimation method and system, belonging to the field of spacecraft guidance and control. Background technique [0002] For spacecraft, the thrust and specific impulse of the main engine are the key parameters of various dynamic processes, such as the orbit control process, the lunar landing process, and the lunar ascent process, which affect the accuracy of the orbit strategy calculation or the guidance solution. [0003] At present, most spacecraft's engine thrust on-orbit calibration is done afterwards by using accelerometer measurement results during engine ignition. According to the physical theorem of thrust=mass×acceleration, the acceleration is measured with an accelerometer, and then the thrust can be calculated based on the mass (as a known quantity). Using the acceleration measurement for a period of time during the ignition process, the thrust can be estimated after smoothing an...

AI Technical Summary

Problems solved by technology

That is to say, the traditional method has two disadvantages: 1. The engine thrust cannot be estimated online in real time, but can only be estimated afterwards; 2. The specific impulse of the engine can only be estimated in advance by other methods, and cannot be estimated in real time during the ignition process.

But this method is flawed when the main engine parameters need to be obtained precisely

Images