New method for measuring screw pitch of propeller blades

Abstract

The invention provides a new method for measuring the screw pitch of propeller blades, which takes an image as a basis to carry out non-contact measurement of the screw pitch of the propeller blades. The method comprises the following steps: firstly, collecting the images of the propeller blades by utilizing equipment such as a computer, a camera and the like; acquiring a coordinate of a two-dimensional image coordinate system of the points to be measured of the blades by taking a digital image processing technology as a basis; calculating a coordinate of a three-dimensional real-world coordinate system of the points to be measured of the blades by utilizing a camera calibration model; and finally calculating the screw pitch of the propeller blades by utilizing the computer.

Description

Technical field: [0001] The invention belongs to the related field of propeller measurement, in particular to a new method for image-based propeller blade pitch measurement. technical background: [0002] The propeller provides thrust for the ship's navigation and is a key part of the ship's propulsion system. The quality of the propeller directly affects the propulsion efficiency of the ship. In order to ensure the manufacturing quality of propellers, the State Bureau of Technical Supervision has issued national standards on the technical requirements of metal propellers, which regulate many technical indicators including the pitch of propeller blades. Therefore, in order to control the quality of the propeller during the propeller manufacturing process, it is necessary to repeatedly measure the pitch parameters of the propeller blades. The measurement of propeller blade pitch parameters can provide a basis for accurate adjustment of blade processing volume to meet the te...

AI Technical Summary

Problems solved by technology

It is time-consuming and labor-intensive to measure propeller blades with existing coordinate measuring machines in the propeller manufacturing process

In the measurement process, the existing coordinate measuring machine needs to determine each section and the position of the measurement point one by one, and the heavy workload caused by this often leads to human measurement errors

In addition, the measuring head of the existing coordinate measuring machine needs to contact the metal surface of the blade, and the wear caused by long-term use will also cause measurement errors

Therefore, the above factors affect the accurate measurement of the propeller blade by the existing coordinate measuring machine

In addition, the existing coordinate measuring machine uses the rotating shaft system, the cantilever beam type cross arm and the sliding frame to support and move the measuring head of the measuring rod to measure different sections of the propeller. The nonlinear deformation of the cross arm and other structures due to factors such as self weight , also affect the further improvement of measurement accuracy

The contact method used by the existing coordinate measuring machine to measure the pitch of propeller blades requires a huge workload and takes a long time

In addition, the existing coordinate measuring machine contact measurement method is still difficult to provide means for online measurement during propeller processing

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