3 EXPERMENTAL RESULTS AND
ANALYSIS
3.1 Image acquisition scheme for crane grab
boom
The automatic grabbing device for segment beams is connected to the
automatic grabbing lifting tool through the crane’s crown block. The
bottom two sides of the lifting bracket are equipped with automatic
grabbing lifting rods, which are used to insert the segment beam lifting
hole to complete the grabbing task. After it is fully locked, the
position of the crown block and the posture of the lifting tool are
adjusted through the control system, and the segment beam can be grabbed
and placed in a designated area. The layout of the industrial camera is
shown in Figure 16. The camera is installed at the bottom of the hanger
at a 30 ° angle to the vertical direction. The industrial camera follows
the movement of the hanger and maintains its relative position with the
automatic grabbing boom, ensuring that the bottom of the automatic
grabbing boom is always in the center of the industrial camera’s field
of view.
Under working conditions, the overhead crane pulls the lifting tool to a
certain distance directly above the section beam to be grasped, adjusts
the posture to make it basically consistent with the posture of the
section beam to be grasped. The industrial camera automatically takes
photos and sends the captured image of the suspension rod back to the
local computer through the image transmission module. The method
described in this article is used for image processing, and the captured
photos are also transmitted to the crane driver’s cab for reference by
the operator. Using a local computer to calculate the intersection
coordinates of straight lines, provide image point coordinates for
photogrammetric 3D space calculation, and locate the 3D spatial position
of the lifting tool. Output the parameters to the control system, which
drives the adjustment mechanism of the suspension rod based on the
parameters to achieve precise alignment between the suspension rod and
the lifting hole. Finally, the lifting tool is lowered to achieve the
purpose of automatic grasping of the segmental beam.