Methods for measuring inner profile of thin-walled composite tubular component with large length-to-diameter ratio

A method for measuring an inner profile of a thin-walled composite tubular component with a large length-to-diameter ratio, comprising:

• installing a contact probe, and calibrating a fixture coordinate system through the contact probe;
• acquiring an outer profile point cloud map of a tubular component to be inspected, wherein the outer profile point cloud map refers to a point cloud map under the fixture coordinate system;
• determining a discrete point regarding an outer profile of the tubular component to be inspected, acquiring probe coordinates of the discrete point, and measuring a thickness value of the discrete point;
• wherein the measuring a thickness value of the discrete point includes:
• selecting a plurality of inspection points at two ends of the tubular component to be inspected;
• measuring a thickness at each of the plurality of inspection points through a micrometer to acquire a standard thickness value d1;
• measuring the thickness at the each of the plurality of inspection points through a thickness measuring device to be calibrated to acquire a measured thickness value d2;
• calibrating the thickness measuring device to be calibrated by combining the standard thickness value d1 and the measured thickness value d2;
• and
• measuring a thickness at the discrete point through the calibrated thickness measuring device to acquire a thickness value w of the discrete point;
• acquiring a normal vector of the discrete point according to the outer profile point cloud map, compensating the probe coordinates according to the normal vector, and acquiring outer profile coordinates of the discrete point;
• calculating inner profile coordinates corresponding to the discrete point according to the normal vector, the thickness value, and the outer profile coordinates of the discrete point;
• selecting a plurality of discrete points, repeating, for each of the plurality of discrete points, the operations of the determining a discrete point regarding an outer profile of the tubular component to be inspected, acquiring probe coordinates of the discrete point, and measuring a thickness value at the discrete point;
• and
• constructing an inner profile of the tubular component to be inspected based on inner profile coordinates of the plurality of discrete points.