Abstract:Rydberg atoms are atoms in highly excited states with large principal quantum numbers n, and long lifetimes. The large Rydberg atom polarizability and strong dipole transitions between energetically nearby states are highly sensitive to electric fields. The new developed scheme for microwave electric field precision measurement is based on quantum interference effects (electromagnetically induced transparency and Autler-Townes splitting) in Rydberg atoms contained in a dielectric vapor cell. The minimum measured strengths of microwave electric fields of the new scheme are far below the standard values obtained by traditional antenna methods. And it has several advantages, such as self-calibration, non-perturbation to the measured field, a broadband measurement frequency range and so on, is next-generation electric field standard. In this review, we describe work on the new method for measuring microwave electric field based on Rydberg atoms. We introduce the basic theory and experimental techniques of the new method, and discuss the future development direction.

Abstract:In this paper, a measurement method based on multi base station laser tracker is proposed to meet the requirements of robot end-pose precision test. This method adopts the three-target measurement scheme, solves the transfer station parameters through the nonlinear least square method, and fuses the multi base station test data to realize the testing of the robots’ end pose accuracy. The measuring effect of this method is verified by experiments with linear guide rail and standard apparatus of turntable. The results show that the measurement positioning accuracy of this method is improved by 38.5% and repetitive positioning accuracy is improved by 42.2% compared with that of the single base station laser tracker. In addition, the multi base station measurement scheme is applied to test the IRB14000 robot and the measurement results of robot pose accuracy are obtained according to the national standard GB/T 12642: Industrial robots-Performance criteria and related test methods, which proved the feasibility of the method.

Abstract:When using theodolite and laser tracker for collaborative measurement, it is necessary to convert the measurement datum of different measurement systems. The traditional method of datum conversion is cumbersome and time-consuming. To solve this problem, this paper proposes a new portable reference conversion standard board, which is composed of a reference conversion component, a steering component and a tripod. The reference conversion is realized through the coordinate system constructed by the measuring target on the reference plate and the cubic mirror. When the laser tracker is used to verify the average position deviation of the standard board in different attitudes, the result is less than 0.01 mm, when the reference conversion standard board is used to verify the measurement deviation of the center point of the positioning hole of the theodolite system, the result is less than 0.06 mm, and the average absolute deviation of the normal vector of the cube mirror is less than 0.0043 °.The operation of the standard board is convenient and fast, which can meet the needs of benchmark conversion of theodolite and laser tracker collaborative testing under various working conditions, and has the value of application and promotion.

Abstract:Aiming at the field calibration problem of using thin-film thermocouple to measure the surface temperature, the CFD numerical simulation and Experimental Research on the measurement error caused by the thickness of adhesive layer under different surface temperatures are carried out. The corresponding relationship between the surface temperature, adhesive layer thickness and thermal resistance correction is obtained. On this basis, the thermal resistance correction model is established, which is represented by the curve. The experiments were designed to verify it. The results show that: under the same adhesive layer thickness, the temperature measurement deviation increases with the increase of the difference between the surface temperature and the ambient temperature, which is consistent with the experimental results; under the same surface temperature, the thinner the adhesive layer thickness, the smaller the temperature measurement deviation, which is also consistent with the actual situation.

Abstract:The process algorithm of the measurement data of the non-contact grind-fineness-gage measuring device based on the optical spectral confocal technology is studied. The Gauss filtering is used to filter and analyze the whole measurement data, and then the it is carried out in three sections of upper left plane, upper right plane and bottom surface of the chute. The surface roughness and waviness signals of the three measuring surfaces are separated and the roughness value is calculated. The least square method is used for fitting the Gaussian filter median line. The fitting results show the inclination of the straight line on the left and right upper planes in consistent and can be fitted into one straight line. The fitted straight line is used as the datum line, and the depth from the scanning point to the datum line is obtained, and the indicating error of the nominal value of the chute surface depth of 90μm is (0.27~1.97)μm. Compared with the contact measurement of an inductance micrometer, the results show that the data processing method for noncontact measurement is accurate and reliable.

Abstract:Modal mass and modal stiffness are very important on structural dynamics. They can be transformed by each other using modal frequency. This paper introduces the study on modal mass computation, focusing experiment method. The application on beam structure shows that the error of experiment method based on frequency change ratio is less than 20%, that can meet the engineering need.

Abstract:In order to meet the requirement of impulse pressure measurement and calibration in aerospace field, a generation method of medium and low gas impulse pressure was developed, which was based on the mode of outlet modulation, and the medium and low gas impulse pressure can be produced in the fixed cavity by motor motion.. Through the precision control of motor, the small impulse pressure was produced in the fixed cavity by motor motion. According to the motion state of the rotary valve and the change of the flow area of the valve port, the gas pressure relation was established. The feasibility of producing the gas impulse pressure by the rotary valve was verified by the simulation results. The experimental results showed that the impulse pressure amplitude was below 4 MPa and the impulse width was less than 15 ms. The influence of the device structure on the pulse pressure waveform was obvious. In the future, a more ideal impulse pressure waveform can be obtained by optimizing the device structure.

Abstract:Aiming at the requirement of dynamic calibration of pressure sensor in low temperature environment, the paper designs a sine pressure generator with bellows as the core components. The sine pressure generator has good tightness at either room temperature or low temperature and it can generates pressure ranging from positive to negative. Based on the adjustment of the structural parameters of the sine pressure generator and the further test, followed by the theoretical analysis of the experimental data, the empirical formula for calculating the amplitude of sine pressure is obtained. The feasibility of bellows as sine pressure generator is proved.

Abstract:Quartz tuning fork has the advantages of stable harmonic frequency and high quality factor, which is suitable for making atomic force microscope probe. In this paper, the driving circuit of quartz tuning fork probe, which includes preamplifier, self-excited oscillation and phase-locked loop (PLL) circuit system, is analyzed. The parameters of electronic devices that affect the performance of the circuit system are analyzed. In the drive circuit, the resonant frequency of quartz tuning fork can be detected and automatically compensated, and the PLL circuit is simulated and verified. The test results show that the circuit system meets the requirements of atomic force microscope.

Abstract:Aiming at the rotational inertia on-line measurement of the air-floating shaft system in the sine torque standard device, a non-contact flat spiral spring is designed according to the mechanical standard .Because the number of turns of the spring is less than the recommended turns in the design standard, the finite element analysis software ANSYS is applied to analyze the characteristic curve of the spring to verify whether the spring can stably provide sufficient reaction torque to drive the air shaft twisting. Experiments show that the results have good consistency and high accuracy by using the spring to measure the rotational inertia, which can meet the measurement requirements.

Abstract:This paper expounds the significance of the construction of the quality management system for calibration proficiency testing providers. It also introduces and analyzes the construction from the aspects of technical and management control, and puts forward the direction for the improvement and enhancement of the PTP from the perspectives of quality supervision delicacy and sample management informatization, under which the construction of the Quality Management System for Calibration Proficiency Testing Providers can be strengthened.