Time filter

Source Type

Wang Z.,Northwestern Polytechnical University | Li Y.-J.,Northwestern Polytechnical University | Lei L.,Chinese Flight Test Establishment
Yuhang Xuebao/Journal of Astronautics | Year: 2011

Fault detection is important in satellite attitude control. Some great disturbance and model uncertainty make this task a difficult work. In the past, fault, input and disturbance are seen as a generalized input. Then residual is made close to fault by making infinite norm of gain minimum. In the past, the importance of fault, input and disturb is equal, which was not the best choice. So a novel method for designing a filter should be put out. The fault detection filter is designed by using the linear matrix inequality (LMI). This filter contains three different indexes. It is applied in an orbiting satellite model on witch fault may happen in its jet actuator. Parameters of the filter are calculated and simulation is done. Although three indexes can not be far less than 1, this filter still can be used for fault detection by using adaptive threshold. The result of the simulation is demonstrated.

Feng W.-Z.,Chinese Flight Test Establishment
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2014

The coolant flow in the aircraft liquid cooling system is usually regarded as an important parameter of the assessment of the system performance. With the aid of utilizing the diameter-variable ducts in the liquid cooling system as a throttling element, the coolant flow can be measured by using the differential pressure method. By applying data fitting to the experimental findings obtained from the groud calibration system, the characteristic curves of the coolant flow versus differential pressure for different temperature and pressure values were obtained. Furthermore, the formulate for the correction of calculated coolant flow were gained through linear interpolation. The flight test results indicate that the method is feasible for the measurement of the coolant flow of the aircraft liquid cooling system and, therefore, the problem of inconvenient refitting of flowmeter for the liquid cooling system has been solved.

Jiang Q.,Chinese Flight Test Establishment
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2013

High sink speed landing was discussed which was used to verify the strength and rigidity and shock-absorbing ability of landing gear in land-based airplane flight test. Sink speed was one of the key factors in landing gear design and verification. In fact, aircraft landing was effected by many factors, so it is very difficult and full of high risk for pilot to manipulate an aircraft to land at sink speed regulated by specifications. Landing and touchdown methods, such as floating-drop and direct-gliding and landing training were put forward and used in flight tests. According to this, the sink rate of a land-based airplane flight test in domestic reached 2.47 m/s, which is the maximum up to now. So the landing gears of this type aircraft satisfy relevant specifications.

Hou H.,Chinese Flight Test Establishment
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2015

The motion parameters of aircraft and its external store can be obtained by photoelectric theodolite in flight test, but due to large distance measured or target blocked, it's difficult to capture target very fast. After adding GPS receiver on the aircraft, we can get geodetic coordinate in real time. After the real-time acquisition data coded thought the telemetry channel, the ground machine can demodulate coordinate of the aircraft. The PCM data Stream can be received from the airborne transmission stream through the PCM telemetry receiving channel which is integrated on photoelectric theodolite. At the same time, the geodetic coordinate of aircraft can be demodulated from the data stream in real time. By this way, the external guide for photoelectric theodolite can be achieved after the data processed and transmitted to the control system of photoelectric theodolite. Application results show that the guided precision has good performance in the remote target capture and good results in practical application of this technique for photoelectric theodolite. ©, 2015, Chinese Academy of Sciences. All right reserved.

Yang Q.,Chinese Flight Test Establishment
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2015

For the purpose of complete flight test mission of a carrier-based aircraft, its arresting hook loads are measured using strain gage. A three-direction (longitudinal, lateral and vertical directions) load model of arresting hook is built through analyzing the loads in the arrest deck-landing process. Strain gages are designed and installed on the arresting hook. Ground calibration tests are implemented and load equations are constructed. Some typical loads of arresting hook in the process of carrier-based aircraft arrest deck-landing are also presented in detail, and the arresting energy and efficiency of arresting gear equipment are studied. Moreover, compared with the loads obtained by an ordinary single-direction load model, the three-direction load model is discussed. The results show that the load model and measurement methods are correct and credible, which can provide some references for the engineering practice. ©, 2015, AAAS Press of Chinese Society of Aeronautics and Astronautics. All right reserved.

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