Abstract:Aiming at the influence of the 12 bit quantization error on the four-parameter sinusoidal fittingaccuracy, the fitting error bounds were researched among the five parameters of effective bits, amplitude, frequency, initial phase and DC component. The selected condition variables are amplitude, the number of cycles of the waveform contained in the sequence, the initial phase, the DC component and the number of sequence data points. The error boundary search was carried out in a two-condition combination styles, and the error curves of the above five parameters were gained under each condition, including both the upper and the lower error bounds. The results can be used to estimate the error and uncertainty of the fitting parameters, or to construct the measurement conditions under the sitting fitting error and uncertainty.

Abstract:In order to realize the automatic verification of different steel tapes, a full-automatic device for ultra-long steel tape verification is designed in this paper. This device adds the structures for automatic loading tensile force, automatic rolling tapes, and automatic recognizing groove line on the basis of the measurement with limited length guide rail. So that a 100-meter steel tape can be verified efficiently on the much shorter guide rail.

Abstract:In order to reduce the uncertainty of the system, this paper analyzes the sources of the uncertainty of the steady-state pressure measurement system of the test-bed, analyzes the important factors of reducing the uncertainty of the steady-state pressure measurement system, and proposes the corresponding improvement methods. The in-site calibration method of pressure sensor is used to reduce the uncertainty caused by the difference between the measurement system and the calibration system. The cubic spline interpolation method is used to compensate the temperature of the pressure sensor and reduce the uncertainty of the influence of the working environment temperature on the pressure sensor. Through data verification, the two improved methods effectively reduce the uncertainty of the system. The improved method has important popularization and application value in other engine tests and related assembly tests.

Abstract:This paper presents the design and simulation of a lock-in amplifier(LIA) together with phase-shift function, applying in processing small signals buried in noises. A lock-in amplifier is equivalent to a narrow-band filter. It consists basically a phase sensitive detector followed by a low-pass filter. We designed the circuit based on the phase-sensitive detector AD630, together with a phase-shift circuit which can make the phase of reference signals coordinate with the phase of input signals. Simulation experiments verified the LIA can exstract useful signal from a noise signal approximately 1000 times in amplitude.

Abstract:In order to improve the dynamic measurement precision of sensor, a design method of dynamic compensator based on improved fireworks algorithm is presented. The optimal dynamic compensation system for the sensor is obtained by using the calibration data of the sensor and combining with the improved fireworks algorithm .The feasibility of the proposed method is verified by simulation experiments. And the experimental results show that the dynamic compensation method based on the improved fireworks algorithm can effectively improve the dynamic characteristics of Coriolis mass flowmeter transmitter, the dynamic response time was reduced by about 90%.

Abstract:The dynamic errors analysis and compensation of articulated arm measuring machine has become the focus of domestic and foreign scholars. In this paper, by analyzing the thermal deformation error, the measurement force error and the angle coding error, the optimal temperature value of the articulated arm measuring machine is obtained, and the three error factors representing its dynamic error, namely maximum positioning error (MPE), residual positioning error (RPE) and joint angle value (Ja), are obtained. In view of the above error factors, this paper proposes a new compensation method which combines the advantages of T-S fuzzy neural network (T-S FNN) in self-learning ability and large-scale operation, and the ability of simulated annealing (SA) to global optimization, and establishes the model. The orthogonal experiment shows that the error of dynamic process is reduced by 88.8%, 80.2% and 71.3% respectively by the proposed compensation method, which proves that the model can effectively improve the dynamic measurement accuracy of the measuring machine.

Abstract:For the detection of high pressure hydrogen leakage and diffusion, domestic and foreign scholars have carried out relevant research by using experiment and numerical simulation, and put forward some detection methods. These detection methods have reliable results, but generally have the shortcomings of slow response. In this paper, a fast visual detection method of high pressure hydrogen leakage based on light sheet is proposed. The laser is emitted by a semiconductor laser, and a laser sheet is formed after passing through a cylindrical lens group and a mirror. The high-pressure hydrogen leakage was identified after digital image processing. Based on this method, the layered flow model of high-pressure hydrogen jet is established. The experimental results are consistent with the previous experimental formula, which proves the feasibility of the method; the simulation experiments of 3, 5, 7 MPa pressure when the leakage diameter is 1 mm, and 0.5, 1, 1.5 mm leakage diameter when the pressure is 5 MPa are carried out The analytical relationship between the diameter of high pressure hydrogen leak and the specific height, the diameter of gas jet boundary layer, and the analytical relationship between the pressure of high pressure hydrogen and the diameter of jet boundary layer are obtained by the simulation experiment, which provides a strong support for the rapid and accurate detection of high-pressure hydrogen leakage.

Abstract:As a high-precision liquid level measurement device, magnetostrictive liquid level gauge is widely used. Aiming at the problems existing in the magnetostrictive liquid level meter calibration device, such as complex operation, large equipment area and relatively low accuracy, a vertical magnetostrictive liquid level meter calibration device is designed. The high-precision grating ruler is used as the measurement standard, the mechanical positioning method is used to realize the rapid adjustment of the liquid level meter, and the vertical guide rail system is used to automatically realize the float's up and down fixed-point movement, The automatic and accurate measurement of liquid level gauge is realized by special control software. The measurement uncertainty of the device is evaluated, which proves that it has good accuracy and reliability. It can effectively meet the calibration requirements of magnetostrictive liquid level gauge with the measurement range of 0 ~ 2 m in compact space, and has the value of technology promotion.

Abstract:In the process of high temperature eutectic point development, the common pouring methods include direct eutectic method and pre eutectic method. In this paper, two kinds of filling accessories are designed, one is direct eutectic crucible with long graphite liner, and the other is pre eutectic crucible with special structure. The experimental results show that the former can significantly improve the perfusion efficiency of direct eutectic method, and the latter can effectively avoid the eutectic bonding problem of pre eutectic method. Both of them have achieved the design purpose, and have played a promoting role in the development of high temperature eutectic point technology.

Abstract:With China officially entering the 5G commercial era, the digital transformation of traditional measurement industry ushered in new development opportunities, "5G + Intelligent Measurement" concept came into being. 5G technology, with the advantages of its three different application scenarios, uses key technologies such as network slicing and edge computing to enable intelligent measurement: on the one hand, the intelligent laboratory integrated with 5G communication can significantly improve the efficiency of traditional measurement; on the other hand, "5G +" mode, which combines artificial intelligence, Internet of things, cloud computing, big data and other technologies, will bring more intelligent measurement services and jointly promote the transformation of intelligent measurement.

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