高精度微推力测量方法及实验研究
HIGH-PRECISION MICRO-THRUST MEASUREMENT METHOD AND EXPERIMENTAL RESEARCH
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摘要: 微推力器是实现卫星姿态与轨道控制不可或缺的执行机构, 精确测量其推力性能至关重要. 针对传统微推力测量装置存在的推力力臂难以精确测定, 羽流随扭摆转动而偏转以及装配调试复杂等问题, 设计并研制了一种基于罗伯威尔平衡结构的新型微推力测量装置. 该装置的推力力臂长度固定, 不受微推力器安装位置的干扰, 有效消除了力臂测量引入的不确定度, 同时降低了微推力器的装配与调试难度. 此外, 该装置确保了推力羽流在扭摆转动过程中不发生偏转, 便于同步监测推力器羽流信息. 本研究利用电磁标准力对其开环和闭环两种测量模式开展了性能测试与评估, 并使用该装置对一套冷气微推力器进行了标定. 性能测试结果显示, 在开环模式下, 该装置量程为2 mN, 分辨力优于1 μN, 包含因子为3时的测量不确定度为 2.33 \text μN + 0.99\text% T (其中 T 为实测力值). 在闭环模式下, 测量量程达到100 mN, 分辨力优于5 μN, 测量不确定度则为 18.00 \text μN + 0.31\text% T . 该装置可满足多种微牛级至毫牛级微推力器的推力测量需求, 为我国商业航天的快速发展提供助力.Abstract: Micro-thrusters serve as indispensable actuators for satellite attitude and orbit control. Precise measurement of their thrust performance is essential for the success of space missions. Conventional micro-thruster measurement devices face several challenges, including the difficulty in accurately determining the thrust arm length, plume deflection during pendulum motion, and intricate assembly and adjustment procedures. To address these technical limitations, a novel micro-thrust measurement device has been designed and developed, based on the fundamental principles of the Roberval balance mechanism. This innovative device features a fixed thrust arm length that remains unaffected by the installation position of micro-thrusters. This feature significantly reduces the uncertainties associated with thrust arm measurements and, in turn, simplifies the complexity of micro-thruster assembly and adjustment. Additionally, the device effectively eliminates thrust plume deflection during pendulum motion, allowing synchronous monitoring of thruster plume behavior in online measurements. This paper elaborates on the measurement principle and design scheme of the proposed device. Electromagnetic standard force was employed to conduct performance tests and evaluations under both open-loop and closed-loop measurement modes. And a cold gas micro-thruster was successfully calibrated through this device. The performance test results indicate that in the open-loop mode, the device achieves a measurement range of 2 mN with a resolution better than 1 μN. With a coverage factor of 3, the measurement uncertainty is expressed as 2.33 \text μN + 0.99\text% T (where T represents the measured thrust). In the closed-loop mode, the measurement range is extended to 100 mN with a resolution better than 5 μN, and the measurement uncertainty is determined to be 18.00 \text μN + 0.31\text% T . This device provides a robust solution for accurate thrust measurement of micro-thrusters with thrust ranges from micro-newtons to milli-newtons, covering the diverse needs of modern space propulsion systems. It is expected to contribute to the development of China's commercial aerospace industry by supporting the rapid iteration and engineering implementation of micro-propulsion systems.