Crane static stiffness measuring method and device

Abstract

The invention discloses a crane static stiffness measuring method, which belongs to the technical field of digital close range measurement. Digital images of a crane girder before and after loading ofthe crane are acquired respectively, based on a digital speckle correlation measurement technology, the number of moving pixels of steel beam digital images before and after deformation on the targetsurface of an image plane image sensor is calculated, an image distance and an included angle between an image acquisition system and a horizontal plane are measured, the system magnification is calculated, the actual displacement before and after loading of the crane girder is thus calculated, and a girder stiffness numerical value is obtained. The method and the device have the advantages of long distance, non contact and no need of pasting of a marker, and can be applied to displacement measurement under effects of displacement load along any point under the crane girder, the test result is high in precision, the use is convenient, and the test speed is quick.

Description

technical field [0001] The invention belongs to the technical field of digital close-range measurement, and in particular relates to a static stiffness measurement method and device. Background technique [0002] Stiffness is an important technical indicator for the safety of hoisting machinery, especially for large-span cranes, which have higher requirements for stiffness. Static stiffness is not only one of the main technical indicators for the design and control of hoisting machinery, but also an important basis for judging whether the hoisting machinery can operate safely At the same time, it is also a major item of daily inspection and testing. In the inspection, the measurement result of the static stiffness of the crane girder (inspecting the mid-span and lower deflection of the girder) is the most important judgment index to measure the safety performance of the crane girder. [0003] Traditional hoisting machinery static stiffness measurement methods include laser r...

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Problems solved by technology

[0003] Traditional hoisting machinery static stiffness measurement methods include laser ranging system method, theodolite method, total station method, etc., but these methods have certain disadvantages. The vertical distance h1 between the plate and the ground, then lift the rated load, and read the vertical distance h2 between the ground and the lower cover plate of the girder displayed on the laser ranging system again, then h1-h2 is considered to be the maximum static deflection of the girder. The method has obvious shortcomings, because the rated load is located directly below the mid-span of the girder, the laser ranging system can only be placed on the side of the rated load, and the measured girder deflection value is not the maximum girder deflection value, so the measurement results are quite different. Large deviation; In addition, a small deviation in the vertical direction of the laser ranging system will also bring a large measurement error

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