The selection of narrow band filter＇s center wavelength has an important influence on the quality of the weld pool image captured in passive vision mettmd for controlling arc welding process. In this paper, 29 narrow...The selection of narrow band filter＇s center wavelength has an important influence on the quality of the weld pool image captured in passive vision mettmd for controlling arc welding process. In this paper, 29 narrow band filters with different center wavelengths ranging from ultraviolet to near infrared wavelength were used to capture images of weld pool during both the peak current period and the base current period of P-GMA W （ pulsed gas metal arc welding）. The experimental results showed that the filters with near infrared center wavelength could weaken the arc most during the peak current period, while during the base current period the entire weld pool could be seen with the filters with wavelength above 600 nm. The camera spectral response and the radio of arc to weld pool emission were considered to analyze the phenomenon of experimental results.展开更多
Wire and arc additive manufacturing(WAAM) shows a great promise for fabricating fully dense metal parts by means of melting materials in layers using a welding heat source. However, due to a large layer height produce...Wire and arc additive manufacturing(WAAM) shows a great promise for fabricating fully dense metal parts by means of melting materials in layers using a welding heat source. However, due to a large layer height produced in WAAM, an unsatisfactory surface roughness of parts processed by this technology has been a key issue. A methodology based on laser vision sensing is proposed to quantitatively calculate the surface roughness of parts deposited by WAAM.Calibrations for a camera and a laser plane of the optical system are presented. The reconstruction precision of the laser vision system is verified by a standard workpiece. Additionally, this determination approach is utilized to calculate the surface roughness of a multi-layer single-pass thin-walled part. The results indicate that the optical measurement approach based on the laser vision sensing is a simple and effective way to characterize the surface roughness of parts deposited by WAAM. The maximum absolute error is less than 0.15 mm. The proposed research provides the foundation for surface roughness optimization with different process parameters.展开更多
A sensing system is developed to measure the weld pool boundary and pool suoface deformation in gas tungsten arc welding. LaserStrobe technique is used to eliminate the strong arc light inteoference, and specular refl...A sensing system is developed to measure the weld pool boundary and pool suoface deformation in gas tungsten arc welding. LaserStrobe technique is used to eliminate the strong arc light inteoference, and specular reflection from the pool suoface is sensed to describe the relation between the deformed stripes and pool surface depression. Clear images of both the pool boundary and the deformed stripes edges are obtained during gas tungsten arc welding process, which lays foundation for realtime monitoring the pool suoface depression and weld penetration.展开更多
Diagnosing the operational status of High-voltage circuit breakers(HVCBs)is crucial for ensuring the safe and stable operation of the grid.Mechanical characteristic parameters are effective indicators for evaluating t...Diagnosing the operational status of High-voltage circuit breakers(HVCBs)is crucial for ensuring the safe and stable operation of the grid.Mechanical characteristic parameters are effective indicators for evaluating the performance of HVCBs.Recent studies have shown that the actions of the springs and cams in HVCBs can be used to detect the operational status of the mechanical mechanisms,which occur extremely quickly,usually in the speed of m/ms.In this paper,dynamic vision sensing technology was employed to rapidly and dynamically capture the movements of the springs and cam of the HPL245B1 HVCB.The data volume of a single experiment is less than 100 MB,whereas the data collected by a high-speed camera at the same frame rate exceeds 1 GB.Action data streams of the springs and cam were obtained and images were reconstructed from the event streams.The Lucas-Kanade optical flow algorithm and the normalised cross-correlation algorithm are applied to calculate the parameters of spring deformation characteristics and cam rotation characteristics for mechanical feature detection of HVCBs.This is the first attempt to utilize brain-inspired hardware technology for the status monitoring of electrical equipment.The advantages of dynamic vision sensing technology,such as high dynamic range,low data transmission,and low energy con-sumption,also offer significant benefits for air discharge monitoring and status moni-toring of electrical equipment.展开更多
基金Acknowledgement The authors are grateful to the financial support for this project from the National Natural Science Foundation of China under grant No. 51005069.
文摘The selection of narrow band filter＇s center wavelength has an important influence on the quality of the weld pool image captured in passive vision mettmd for controlling arc welding process. In this paper, 29 narrow band filters with different center wavelengths ranging from ultraviolet to near infrared wavelength were used to capture images of weld pool during both the peak current period and the base current period of P-GMA W （ pulsed gas metal arc welding）. The experimental results showed that the filters with near infrared center wavelength could weaken the arc most during the peak current period, while during the base current period the entire weld pool could be seen with the filters with wavelength above 600 nm. The camera spectral response and the radio of arc to weld pool emission were considered to analyze the phenomenon of experimental results.
基金Supported by National Natural Science Foundation of China(Grant Nos.51505394,61573293)Key Technologies R&D Program of Sichuan Province of China(Grant No.2015GZ0305)
文摘Wire and arc additive manufacturing(WAAM) shows a great promise for fabricating fully dense metal parts by means of melting materials in layers using a welding heat source. However, due to a large layer height produced in WAAM, an unsatisfactory surface roughness of parts processed by this technology has been a key issue. A methodology based on laser vision sensing is proposed to quantitatively calculate the surface roughness of parts deposited by WAAM.Calibrations for a camera and a laser plane of the optical system are presented. The reconstruction precision of the laser vision system is verified by a standard workpiece. Additionally, this determination approach is utilized to calculate the surface roughness of a multi-layer single-pass thin-walled part. The results indicate that the optical measurement approach based on the laser vision sensing is a simple and effective way to characterize the surface roughness of parts deposited by WAAM. The maximum absolute error is less than 0.15 mm. The proposed research provides the foundation for surface roughness optimization with different process parameters.
文摘A sensing system is developed to measure the weld pool boundary and pool suoface deformation in gas tungsten arc welding. LaserStrobe technique is used to eliminate the strong arc light inteoference, and specular reflection from the pool suoface is sensed to describe the relation between the deformed stripes and pool surface depression. Clear images of both the pool boundary and the deformed stripes edges are obtained during gas tungsten arc welding process, which lays foundation for realtime monitoring the pool suoface depression and weld penetration.
基金National Natural Science Foundation of China,Grant/Award Numbers:52077118,62411560155Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2024A1515012597。
文摘Diagnosing the operational status of High-voltage circuit breakers(HVCBs)is crucial for ensuring the safe and stable operation of the grid.Mechanical characteristic parameters are effective indicators for evaluating the performance of HVCBs.Recent studies have shown that the actions of the springs and cams in HVCBs can be used to detect the operational status of the mechanical mechanisms,which occur extremely quickly,usually in the speed of m/ms.In this paper,dynamic vision sensing technology was employed to rapidly and dynamically capture the movements of the springs and cam of the HPL245B1 HVCB.The data volume of a single experiment is less than 100 MB,whereas the data collected by a high-speed camera at the same frame rate exceeds 1 GB.Action data streams of the springs and cam were obtained and images were reconstructed from the event streams.The Lucas-Kanade optical flow algorithm and the normalised cross-correlation algorithm are applied to calculate the parameters of spring deformation characteristics and cam rotation characteristics for mechanical feature detection of HVCBs.This is the first attempt to utilize brain-inspired hardware technology for the status monitoring of electrical equipment.The advantages of dynamic vision sensing technology,such as high dynamic range,low data transmission,and low energy con-sumption,also offer significant benefits for air discharge monitoring and status moni-toring of electrical equipment.
