Abstract:Aeronautic sensor is an important guarantee for safe flight, ground test and flight test. By analyzing the existing problems of aeronautic sensor in actual working environment, this paper expounds the necessity of the performance evaluation of aeronautic sensor in actual working environment. Combining with the comparative study of the performance evaluation methods of aeronautic sensor at home and abroad, the development trend of research on the performance evaluation of aeronautic sensor in actual working environment is predicted.

Abstract:In order to suppress the very directional vibration of a wind tunnel model sting system, the active vibration control method was proposed based on non-collocated configuration negative acceleration feedback (NAF) control algorithm. The very directional character of the lower-order modes was obtained by modal analysis, and the active wind tunnel model vibration control system with structural coupling embedded piezoelectric ceramic stack actuators was proposed. Based on the non-collocated configuration NAF control algorithm, the single-modal NAF control algorithm for the second-order mode and the dual-modal NAF control algorithm for the first two-order modes were proposed. The impact test shows that the dual-modal NAF control algorithm is more effective than the single-modal NAF control algorithm. Through the dual-modal NAF control algorithm, the damping ratio of the first two-order modes increases by nearly 13 times and 40 times respectively, and the setting time shortens by nearly 11s and 26s respectively.

Abstract:With the expansion of application fields, the forms of turntables have become diversified, and the traditional precision calibration methods of turntables have limitations. A calibration method for positioning accuracy of turntables based on coordinates is proposed. It measures the coordinate values of the positioning point with a coordinate measuring device, uses the least square method to obtain the space circle equation, uses the uncertainty weight fusion algorithm to optimize the objective function, and eliminates the axial error by coordinate system transformation to obtain the angle value of the turntable movement. The factors affecting the calibration accuracy are analyzed, and an optimization method is proposed. The method is applied to the calibration experiments of one-dimensional and three-dimensional turntables, and the results prove the usability and portability of the method.

Abstract:In the linear accelerometer dynamic calibration of double centrifuge, three-parameter cosine algorithm runs through the entire test of the amplitude frequency characteristic, phase frequency characteristic and amplitude linearity. This paper describes the concept and the derivation process of the three-parameter cosine algorithm, its practical application in computational process of dynamic calibration of double centrifuge linear accelerometer, and the implementation of three-parameter cosine algorithm. And the paper introduces the selection method of collection points in the amplitude frequency characteristic and phase frequency characteristics, so as to reduce the impact of different selection methods on data fitting accuracy. Taking a linear accelerometer as an example, double centrifuge were used for dynamic calibration, and the accelerometer data are collected and calculated to give the fitting curve and the result, which verifies the feasibility of the three-parameter cosine algorithm program.

Abstract:Aiming at the calibration problem of single beam pulse laser velocimeter in laboratory environment, this paper presents a design and implementation method of moving target simulator, which is based on the generation principle of high-precision pulse sequence with time delay. In this paper, a specific delay pulse sequence is designed. Through software programming, the data timing generator is controlled as the hardware circuit generating equipment. The storage and distribution of the delay pulse sequence and the circuit generation are completed. The universal moving target simulator with any standard speed is realized, and the laser velocimeter verification device is constructed. The experimental results show that the device has good repeatability.

Abstract:Multispectral temperature measurement is an important method for measuring the surface temperature of the hot end of engines and heavy-duty gas turbines. However, due to the unfavorable factors such as large temperature difference in the background environment, uncertain humidity and electromagnetic interference, the weak signal processing of the multispectral surface thermometer is very difficult. This article focuses on the design of weak signal conditioning circuits for multispectral surface thermometers in complex environments. The near infrared detector which is suitable for multispectral surface thermometer is studied and selected. The accuracy of signal amplification is improved because of the technologies of guard ring and kelvin switch. The selection method of circuit board sheet, the circuit three anti-technology and the specific implementation of anti-electromagnetic interference are introduced. The experiment results show that the multispectral surface thermometer meets the measurement needs and has certain environmental adaptability.

Abstract:In the in-situ calibration of rotor balance, the accurate loading of calibration force is an important factor to improve the calibration accuracy. The structural deformation of the calibration device will cause errors in the loading of the calibration force and affect the calibration accuracy. In order to solve this problem, a force calibration system for rotor balance is designed. The system uses laser triangulation method to measure the micro-displacement, and calculates the displacement of force loading point by measuring the change of spatial position of cubic target. A mathematical model is established to analyze the influence of structural deformation on the loading of calibration force and to measure the calibration force. Experiments show that the system can eliminate the influence of structural deformation, measure the calibration force accurately and improve the loading accuracy of the calibration force.

Abstract:A multichannel high-speed FBG sensor interrogation system based on wavelength-scanning fiber laser and field programmable gate array (FPGA) is developed. The system utilizes a semiconductor optical amplifier (SOA) and a fiber Fabry–Perot tunable filter (FFP-TF) to generate a wavelength-scanning fiber laser with a sweep rate of 1 kHz. By combining the symmetric triangular waveform technique and the fast FPGA based signal processing algorithm, the FBG interrogation system realizes a demodulation speed of 2 kHz and a multiplexing performance of 16 channels simultaneously. In addition, the interrogation wavelength-range can reach 80 nm.

Abstract:The unified glare rating (UGR) is an important parameter to characterize the degree of glare and visual comfort of indoor lighting, which is widely used in indoor lighting detection and lighting design. At present, the tracing method of the glare tester in China only uses the brightness standard device to calibrate the brightness value, but there is no relevant calibration for the brightness distribution and geometric position information of the lighting source, resulting in the inaccuracy and inconsistency of the glare measurement results. In order to solve this problem, this paper developed a set of UGR calibration device, introduced the principle and structure of the device, and analyzed its uncertainty. The development of the device plays an important role in ensuring the accuracy and unity of the glare measurement results, effectively improving the lighting design quality and protecting the visual health.

Abstract:In order to solve the technical problem of evaluating the accuracy of the open channel flowmeter in the on-line wastewater automatic monitoring system, a set of on-line calibration device of the open channel flowmeter with high-precision pipeline flowmeter as the standard meter is designed. A special on-site flow signal acquisition and measurement system is developed. The hardware circuit is designed, and the matching upper computer operation software is developed by QT. Through a large number of field comparative tests under different conditions, the reliability of the system and the effectiveness of the device are verified, providing a technical basis for the accurate online monitoring of wastewater flow.

Abstract:Aiming at the problem of calibrating the full-range air pressure sensitivity of inertial devices, an air pressure box structure capable of resisting high centrifugal acceleration is invented, and a centrifugal-air pressure composite calibration device is developed to realize the calibration of the air pressure characteristics of inertial devices under the condition of large g value. Two working modes are designed based on the centrifugal-air pressure compound calibration device. When the centrifuge is stationary, the precise pressure control of the centrifugal-air pressure compound calibration device is realized by using precise pressure measurement and control systems such as vacuum pump and high-precision pressure sensor. When the centrifuge is working, the pressure maintaining scheme of the centrifugal-air pressure composite calibration device is realized through sealing technology and the like. Therefore, the device organically integrates high linear acceleration and air pressure environment by precisely controlling the air pressure in the experimental box installed on the centrifuge, and provides a reliable acceleration and air pressure compound metering calibration environment for the accelerometer. The experimental results verify that the designed air pressure box structure can realize precise control of the air pressure in the range of 1 kPa to 100 kPa and the air pressure deviation is better than 10 Pa.

Abstract:Dynamic flow measurement is becoming more and more important in the process of research and development of production. In order to test the dynamic response characteristics of the flowmeter, the dynamic measurement of the piston displacement of the active piston prover is carried out by using the laser interferometer, and the step characteristics of the prover are analyzed. The test results show that the time constant is between 7 ~ 60 ms in a certain step flow range. It is suggested that the transmission structure and servo control parameters of the prover be further optimized to improve the step characteristics of the device.

Abstract:In order to realize the condensation measurement of the cold mirror dew point meter with high accuracy, a photoelectric identification method based on the discrimination of two pairs of photoelectric pair tubes is proposed. One pair of the tubes is directly radiated in the measuring cavity where the cold mirror is located as the environmental control group, and the other pair of the tubes is reflected by the cold mirror surface with semiconductor refrigeration. The zero point of the third derivative curve of the photoelectric signal value is used to distinguish the time of condensation on the whole surface of the cold mirror. The experimental results show that this method can meet the needs of dew point humidity gas condensation measurement in the temperature range of - 20 ~ 25 ℃, which has technical reference significance.

Abstract:In order to solve the problem that the performance of the grating card in the active volume tube flow standard device is not stable and sometimes the data cannot be locked, a method of measuring the standard volume value by using a counter instead of the grating card is proposed. The active volume tube uses grating ruler as the measurement standard. According to the characteristics of grating ruler signal, double timing method is adopted to realize grating ruler signal acquisition. The problem of missing pulse in signal acquisition is solved by using the self-made synchronous circuit and ADAM4080 counter, which ensures the accuracy of flow measurement. The experimental results show that the difference between the developed system and the original system in standard flow collection is less than 0.005%, which verifies the feasibility of the scheme.

Abstract:The mechanical environment of tilt or swing can produce additional forces and torques on military equipment. This situation can lead to an accident caused by abnormal equipment. This paper mainly studies the calibration method of tilt and swing test bench to ensure the accuracy and reliability of experiment results, and to meet the requirements for traceability during the test on ships, submarines, aircraft carriers and other equipment.

Abstract:封面目录