Bolt axial force monitoring system and monitoring method based on visual deep learning

Abstract

The invention belongs to the technical field of bolt axial force information monitoring, and discloses a bolt axial force monitoring system and method based on visual deep learning. The method comprises the steps that: a camera takes a picture or record a video of a bolt, and the video can be decomposed into images in a frame format; a bolt marking device is installed in a visual range near bolt connection, and the marking device can uniquely determine one or more bolt connections and is used for shooting a plurality of bolts at different angles to identify and measure different bolt individuals; and a bolt axial force monitoring module automatically identifies and extracts bolt connection in the image through a deep learning algorithm, measures the reverse rotation angle of the nut, calculates the elongation change of the bolt, and obtains a bolt axial force attenuation value, wherein the corresponding relationship between the bolt elongation and the bolt axial force is calibrated andobtained by an ultrasonic bolt axial force measurement technology. According to the invention, a visual non-contact mode and a deep learning algorithm are utilized to detect or monitor the axial force or attenuation condition of a bolt or a bolt group.

Description

technical field [0001] The invention belongs to the technical field of bolt axial force information monitoring, and in particular relates to a bolt axial force monitoring system and monitoring method based on visual deep learning. Background technique [0002] At present, bolted connections are affected by external factors, such as: vibration, thermal shock, axial force relaxation, premature failure and fracture. Structures often have many or even a large number of bolt connections. For contact monitoring methods of bolt axial force, such as: ultrasonic, force ring, strain gauge, grating, etc., under the constraints of economy and engineering, it is impossible to measure the quantity. Numerous bolts are used for axial force monitoring, which greatly reduces the application significance of monitoring. [0003] In summary, the problems in the prior art are: [0004] (1) High monitoring cost: Using contact-type bolt axial force monitoring technologies such as ultrasound, forc...

AI Technical Summary

Problems solved by technology

[0004](1) High monitoring cost: using contact-type bolt axial force monitoring technologies such as ultrasound, force rings, strain gauges, and gratings, it is necessary to increase the number of monitored bolts For the sensor part, the monitoring of a large number of bolts will lead to a substantial increase in cost;

[0005](2) The project implementation is complex: for each bolt using the contact bolt axial force monitoring technology, it is necessary to use wires or wireless methods, resulting in on-site construction Complexity and substantial increase in engineering costs;

[0006] (3) Changing the bolt connection structure: Some contact bolt monitoring technologies, such as strain gauges, gratings, and force rings, will change or damage the bolt connection structure, so that the necessity of bolt monitoring is greatly reduced;

[0007](4) Quantity of monitoring bolts: Due to the limitation of monitoring cost, the contact bolt monitoring technology can only conduct sampling monitoring on bolts, and it is impossible to monitor the large Some bolts are monitored, which greatly reduces the significance of monitoring

[0009] Bolted connection is the most widely used assembly and assembly method in the industry. Its axial force is an important indicator of structural health. However, due to the design of bolted connection and the quality of bolts Due to reasons such as fastening process, the quality of bolted connections is often difficult to control, and a large number of structural failures are caused by the failure of bolted connections; due to the huge number of bolted connections, it is difficult to quickly, effectively and low-cost the axial force attenuation. Geometry, making it a thorny problem for industry

Due to the inherent limitations of contact bolt axial force monitoring technology, all contact bolt monitoring technologies cannot solve the above 1-4 problems, resulting in contact bolt axial force measurement technology can only be used in the design verification and prototype stage of product structure , but it is difficult to use it on a large scale in engineering practice

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