Abstract:Industrial robots have become one of the key research directions of industrial intelligence in China because of their high degree of automation and positioning accuracy. Industrial robots would gradually replace manual labor and play an irreplaceable role in the field of intelligent manufacturing. However, in the process of use, many factors may reduce the accuracy of industrial robots, which would directly affect their application in high-precision fields, such as blade grinding and high-precision drilling and riveting. To address the above problems, on the basis of summarizing the common calibration model of industrial robots, the current situation and problems of calibration technology and error compensation methods for industrial robots are analyzed, and the future development trend of calibration methods for industrial robots is elaborated to provide reference for the subsequent development of online calibration and error compensation methods and specification standards for industrial robots.

Abstract:In order to solve the problem of checking the conversion efficiency of the conversion furnace of the nitrogen oxide (NOx) analyzer, a quantitative analysis of the existing calculation model of the conversion efficiency of nitrogen oxides was carried out, and combined with the meaning of errors in the measurement work,two concepts of nitrogen dioxide conversion error and nitric oxide detection error during the detection process of nitrogen oxide analyzer were defined. The principle of non-spectroscopy infrared method detection of nitrogen oxide analyzer and the necessity of conversion efficiency check are introduced. The conversion efficiency of nitrogen oxide analyzer is checked using an ozone generator. A second-order calculation model of conversion efficiency based on the conversion error of nitrogen dioxide and the detection error of nitric oxide is proposed, and the principle of stepwise regression is used to determine the independent variables in the model and estimate the parameters. The research results show that, compared with the calculation model embedded in the nitrogen oxide analyzer and the first-order calculation model, the degree of multiple coefficient of determination of the fitting equation close to 1 increased by 96.8% and 51.5% on average, and the residual sum of squares decreased by 85.1% and 31.7% on average, so that the nitrogen oxide analyzer can more accurately and reliably detect the concentration of nitrogen oxide in the exhaust gas of the vehicle.

Abstract:In order to investigate the influence of accelerometer error due to asymmetry coefficients in overloading-vibration compound environment, a mathematical model of the vibration rectification error including the accelerometer model asymmetry is established, and the simulation is carried out with the model and given values. Simulation results show that the vibration rectification error induced by accelerometer asymmetry coefficients can be omitted when the overload is no less than the vibration amplitude. Otherwise, the vibration rectification error caused by accelerometer asymmetry is less than 1% of the total vibration rectification error.

Abstract:Thermocouples have been widely applied in the measurement of temperature uniformity of vacuum furnaces. The effects of geometry and emissivity of thermocouple on the temperature uniformity measurement have not been sufficiently investigated. These effects have been investigated by numerical simulation method in this paper. The results show that the influence of diameter of thermocouple on the steady-state temperature of commonly used thermocouples is close to the influence of emissivity. The 0D model analysis shows that the sensitivity of thermocouple temperature to the relative change rate of diameter is equal to the sensitivity to the relative change rate of emissivity, which verifies the accuracy of the numerical simulation conclusions. This article provides a theoretical guidance and technical reference for temperature measurement of vacuum furnace.

Abstract:In view of the current situation that the range of the existing sinusoidal force calibration device can not fully meet the requirements of dynamic force calibration, a (2.5 ~ 250) kN sinusoidal force calibration device has been developed in order to expand the calibration range and reduce the measurement uncertainty of the sinusoidal force. After the development of this new device, the dynamic force traceability system in China will be more perfect and a series of high-precision sinusoidal force standards will be established based on this device.

Abstract:In order to meet the pressure measurement requirements in high temperature environments, a high temperature F-P（Fabry-Perot） optical fiber pressure sensor based on CO2 laser welding was developed. The manufacturing process of the MEMS（Micro Electro Mechanical Systems）pressure sensitive structure was introduced, the welding process between the sensor components was studied, and the no-adhesive packaging of the high temperature F-P optical fiber pressure sensor was achieved. On this basis, the temperature characteristics and high temperature pressure performance of the sensor were studied. The research results showed that the sensor packaged by CO2 laser welding has high reliability，and the sensor signal was transmitted normally at high temperature with no spectral energy attenuation phenomenon. In the environment of 300℃, the measurement error of the sensor in the pressure range of (0~2.5) MPa was less than 0.2% FS, which realized the accurate measurement of high temperature pressure. However, the influence of temperature on the sensor cannot be ignored, and the sensor needs to be temperature compensated in the application.

Abstract:At present, the maximum upper limit of dew point temperature traceability in China's humidity measurement is 80℃. In order to meet the demand of humidity parameter traceability at higher dew point temperature, a high dew point humidity standard device set based on the principle of double temperature and double pressure method is developed. The device consists of the constant temperature system, pre-saturation system, saturation system, measuring chamber and temperature, pressure measurement and control system. It can produce the dew point temperature of 80~150℃, the corresponding measuring temperature range is 80~200℃, the absolute pressure range is 0~1MPa, and the expanded uncertainty is 0.34~0.80 ℃ (k=2). The device has good accuracy, convenience to operate and important technical application value.

Abstract:A laser five-degree-of-freedom motion error measurement system based on the principle of laser collimation is designed. Based on the collimation principle of double parallel beams, the system measures the horizontal straightness, vertical straightness, yaw, pitch and roll angle error synchronously. The self-calibration of the core device parameters of the system's straightness, yaw and pitch angle error measurement is carried out. Aiming at the problem that the double beam is difficult to level and affects the roll angle error measurement, it is proposed to use a level to compensate and correct the roll angle error. Finally, an accuracy comparison experiment is carried out on the entire system. The results show that the accuracy of the straightness, yaw and pitch angle and roll angle measured by the system can reach 0.8μm, 0.8" and 1.5" respectively. The system provides a powerful reference for the research of machine tool geometric error measurement.

Abstract:Dynamic pressure testing is more and more widely used in the industrial field, and reliable calibration technology is the guarantee of accurate dynamic pressure value. Traceability has always been the bottleneck of the development of dynamic pressure calibration technology. This paper takes the traceable dynamic pressure measurement method based on laser interference as the research object. According to the characteristics of liquid pulse pressure, a measurement model based on Newton's second law is established, and the errors caused by various influencing factors are analyzed and tested. Through the calibration test of pressure sensor, the feasibility verification of laser interference measurement and the analysis of measurement uncertainty are completed, and the pulse pressure calibration is realized Reliable traceability.

Abstract:In order to solve the technical problem of I-V curve tester in terms of quantity transmission and traceability, the author has realized the online measurement of the open circuit voltage (Voc) and short circuit current (Isc) parameters of I-V curve tester through the research and development of solar cell’s Voc and Isc measurement method and technology, thus completing the system online calibration of the I-V curve tester. The relative indication errors of Voc and Isc online calibration are 0.45% and 0.20% respectively. This work meets the demand of traceability of related equipment in photovoltaic industry, and provides the technical support for the healthy development of the industry.

Abstract:In order to improve the calibration ability of the micro gas flow and expand the lower limit of the flow calibration range, the passive piston glass volume tube master standard was used as the research object, and a method of using a laser interferometer to measure the displacement of the piston in real time to calculate the standard flow was proposed. This method extended the lower limit of the flow range from 1 mL/min to 0.01 mL/min. The research performed flow repeatability test and standard flow uncertainty analysis. The results show that the standard has good measurement performance in the extended micro flow range, meets the traceability calibration requirements, and achieves a technological breakthrough in micro-upgrading micro gas flow calibration.

Abstract:To implement the relevant regulations on laboratory accreditation, a comprehensive evaluation and qualification accreditation of the laboratory management level and technical ability is conducted by a third party organization to prove to the relevant parties that the laboratory has a certain technical ability and qualification. At the same time, the management level and technical capabilities of the laboratory can be improved. In order to pass the laboratory accreditation, adequate preparations should be made in terms of organizational structure, personnel capacity, facilities and equipment, and effective operation of the quality management system.