Abstract:Metrology and measurement are two different but closely related technologies that should not be mixed up. Building a technological system for transducers metrology examination on the basis of synthetic models is an important way to enhance transducer evaluation and support the research of transducer field calibration. The synthetic evaluation of experimental facilities should include evaluation of the quality of test data and evaluation of the quality of experimental environment simulation.

Abstract:Entropy as a basic concept in information theory has been widely concerned and studied. The principle of maximum entropy based on entropy has been developing in the research and application of many scholars and has gradually formed its own theoretical system, and has been widely used. For example, when the Bayesian method is used to evaluate the measurement uncertainty, the principle of maximum entropy can estimate the prior distribution. In this paper, Shannon entropy is taken as the main object, and the maximum entropy principle under different constraints involved in the current research is summarized, and sorted out into a relatively unified model. This paper discusses some methods to improve the traditional maximum entropy principle by using transformation function method and density kernel estimation method, and introduces their improvement ideas, theoretical models and application characteristics in detail. Finally, combined with practice, the improved methods of maximum entropy principle are summarized from the aspects of constraint selection, evaluation index and optimization algorithm, which will promote the further research and application of maximum entropy principle.

Abstract:With the increasing application of small-sized, high precision and intelligent MEMS devices, the research on MEMS metrology and testing technology is becoming more and more important. In order to improve China’s MEMS metrology and testing technology, the MEMS metrology plans that have been carried out by some overseas institutions and organizations are studied, the research works on advanced MEMS metrology and testing technology are reviewed, and the aspects in which China needs to learn from overseas research experiences and achievements are pointed out. This can help researchers in China to understand the research status of MEMS metrology and testing technology in other countries, so as to promote the development of MEMS metrology and testing technology in China.

Abstract:Focusing on the measurement and calibration of high-sensitivity magnetic sensors, a study on geomagnetic noise compensation based on cesium optical-pumping magnetometer was carried out. On the basis of the atomic spectrum lamp cesium optical-pumping magnetometer, the study replaced atomic spectrum lamp with laser as the light source of the cesium optical-pumping magnetometer, designed the laser optical-pumping magnetometer, and applied it to the geomagnetic noise compensation system. The magnetic field compensation capability of the optical-pumping magnetometers geomagnetic noise compensation system was analyzed through experiments on the two types of the optical-pumping magnetometers. Experimental results show that the geomagnetic noise compensation system based on the above two types of cesium optical-pumping magnetometers both can reproduce magnetic field with a noise power spectral density better than 0.5 pT/Hz1/2 @1 Hz and a noise peak-to-peak lower than 10.8 pT (10 Hz sampling rate), and the laser optical-pumping magnetometer has better compensation effect under large magnetic field. The results provide important reference for designing geomagnetic noise compensation systems for magnetic sensor metrology and calibration.

Abstract:In order to meet the comprehensive needs of inertial navigation equipment testing, the method to construct the control system of the single-axis turntable with angular position, angular velocity and angular vibration functions is studied. According to the functional requirements, the overall scheme design of the control system hardware and the selection of the main components have been carried out. Then the mathematical model of the turntable has been established, the principle and control algorithm of the motor servo drive have been analyzed, the control parameter setting method have been demonstrated, and the upper computer control software has been designed. After coordinate transformation, the three-phase permanent magnet synchronous motor can be converted into a DC motor (a second-order electromechanical system) which is controlled by the driver through the "position-speed-current" three-closed-loop control algorithm. A solution is given for the problem of vibration amplitude attenuation in high frequency angular vibration. The turntable that uses the designed control system can carry out high frequency angular vibration under large load, which is able to provide guarantee for the inertial navigation device test.

Abstract:The nondestructive connection brake device is an important component of the high torque in-situ calibration system for the transmission test bench. The device enables nondestructive connection braking of the high torque drive shaft of armored vehicles. In order to ensure the accuracy of in-situ calibration on the premise of meeting the site space requirement, the researcher designed a nondestructive connection brake system which matches the high torque power output device on site. The system suits the narrow space on site and provides matching transmission shaft holding force on the basis of the transmission device test bench output torque, so as to precisely control the drive shaft holding force. With field test, the correlation between the output torque of transmission device test bench and holding force has been built, and the requirement of braking without damaging the transmission shaft has been met. The test results show that the designed nondestructive connection brake system can achieve nondestructive connection brake when the pure torque that drives the transmission shaft is lower than 30000 N·m.

Abstract:Based on GJB1801-1993 testing methods of major performance for test equipments of inertial technology, the design of high-precision rate calibration system based on MSP430 was proposed to achieve high-precision rate measurement and presented examples of the test. The system used the method of measuring angle in gate time, with the thermostat TCXO clock as a time reference, MCU controlled HCTL-2032 to decode count grating encoder output signal, while the design of the hardware periodic synchronization circuit ensured the equal measurement precision in different rate. Finally, computer application software made the data processed and display, store, print statements. The experimental results show that: at the ultra low speed standard device of Beijing Great Wall measurement and Testing Technology Research Institute, angular rate calibration results for rate ranged from 0.001 ° / s ~ 600 ° / s, the highest precision at 360 ° interval to reach 3 × 10-7.

Abstract:Delay time is an important technical indicator of trailing cone system. In order to accurately predict the pipeline delay time of trailing cone system, a theoretical model of the trailing cone system was established based on the continuity equation and the momentum conservation equation with the influence of viscous resistance in pipelines under different flow states taken into consideration at the same time. The applicability of the model was improved and the accuracy of the model was verified by experiments, which makes the model applicable to practical engineering use. Moreover, the influence of the pipeline structural parameters and environmental parameters on the time delay of the trailing cone system was studied. The results show that the pipeline delay time increases with the increase of pipeline length and environmental pressure, and decreases with the increase of pipeline diameter, step pressure and environmental temperature.

Abstract:The structure of total pressure probe is the key factor affecting the probe performance. The structure greatly influences the total pressure coefficient and insensitive angle. In order to research the structural sensitivity of the performance of total pressure probe, different types of total pressure probes with different key dimensions are made, including convex-nosed total pressure probe and sleeve-type total pressure probe. The total pressure coefficient calibration test of these probes in calibration wind tunnel shows that the performance of rectifier-type probe is the best, shield-type probe takes the second place, and convex-nose type probe is the worst. By comparing the test results, the influence law of key dimensions of probe on its performance is obtained.

Abstract:Transfer alignment is greatly affected by lever arm effect in complex sea conditions, which is mainly reflected in the divergence degree of misalignment angle and the duration of alignment. In order to research the influence of different sea conditions on the lever arm effect, a ship six-degree-of-freedom model is established based on the idea of separated modeling, and an equivalent lever arm effect model is built on that basis. In simulation process, velocity matching transfer alignment is adopted in the equivalent lever arm effect model, and Kalman filter, Butterworth low-pass filter compensation and computational compensation methods are applied in comparative analysis. The simulation results show that the fifth grade sea state is the highest sea state grade for transfer alignment. The simulation results provide a theoretical basis for practical training, combat and mission execution, and also provide guidance for ship safety and the safety of carrier-based aircraft take-off and landing training.

Abstract:At present, the long-term stability parameter of the photoelectric pyrometer is usually tested manually, which has the problems of inefficient testing and complex data management. To solve this problem, designed a set of photoelectric pyrometer automatic test system. The system uses C# to realize the functions of process control, data acquisition and processing, fluctuation analysis and calculation, and historical data review. The test proves that the system has the function of automatic test, fluctuation automatically calculate, and store the test data in a unified format, which is convenient for data management, analysis and processing. The system has the advantages of simplifying the test process and improving work efficiency, also can effectively meet the needs of photoelectric pyrometer performance testing and analysis. The extended uncertainty of fluctuation is 0.015℃. It plays an important role in the environmental adaptability test and optimized design of photoelectric pyrometer.