Calibration device and calibration method for non-contact photographic hole measurement

A calibration method for non-contact photographic hole measurement, wherein the calibration method is implemented by adopting a calibration device for non-contact photographic hole measurement;

• the calibration method comprises:
• step S101, leveling an overall reference of the calibration device;
• using a fine-tuning unit of a base to adjust a surface flatness based on a probe or a micrometer, and making a surface flatness of the calibration device less than 0.005 mm;
• step S102, adjusting a depth of parallelism of an installation platform;
• using a first servo motor of the base to adjust a depth of parallelism based on the probe or the micrometer, and making the depth of parallelism of the installation platform less than 0.005 mm;
• step S103, leveling a calibration assembly;
• using a second servo motor of the installation platform to adjust the surface flatness based on the probe or the micrometer, and making a surface flatness of the calibration assembly less than 0.005 mm;
• step S104, applying the calibration device based on a Numerical Control program;
• in response to that a camera lens moves at different rotation angles according to the Numerical Control program, the calibration device rotates synchronously cooperatively according to calculation rules, and makes a matte plate in the calibration assembly be parallel to the camera lens;
• step S105, photographing a matte calibration ball and calculating three-dimensional coordinates of a center position of a ball contour by a camera system;
• photographing the matte calibration ball in the calibration assembly in combination with a camera system, and adopting an image recognition technology to complete a calculation of the three-dimensional coordinates of the center position of the ball contour at different rotation angles;
• step S106, performing a compensation iteration for a moving position of the camera system;
• on a basis of a calibration ball contour position in an initial state, determining whether a degree of accuracy of all ball's center positions in step S105 meets a tolerance band requirement of 0.01 mm;
• in response to that the degree of accuracy of all the ball's center positions in step S105 do not meet the tolerance band requirement of 0.01 mm, a deviation between an actual value of a calibration ball contour center and a theoretical value of the calibration ball contour center is configured as a compensation value for correcting a movement displacement of the camera system at different rotation angles, and repeating step S104 and step S105;
• in response to that the degree of accuracy of all the ball's center positions in step S105 meet the tolerance band requirement of 0.01 mm, exiting the iteration;
• step S107, outputting camera system movement compensation values of step S106 at different angles of the Numerical Control program, which is configured for a compensation of the Numerical Control program when the camera system is measuring a metal skin maintenance hole, and realizing a precise Computer Numerical Control countersinking of a metal skin;
• wherein
• in the step S104, the calculation rules of the calibration device comprise:
• in response to that rotation angles of a machine tool's rotation axis are angle A and angle C, directly applying the angle A and the angle C to a rotation of the calibration device around a Z axis and a rotation of the calibration device around an X axis;
• in response to that the rotation angles of the machine tool's rotation axis are the angle A and angle B, first inversely solving the angle A and the angle B into vectors I, J, K, then recalculating the I, J, K as the angle C and the angle A, A=arccos(K) and C=arctan(−I/J);
• after obtaining a new angle A and a new angle C, applying the new angle A and the new angle C to the rotation of the calibration device around the Z axis and the rotation of the calibration device around the X axis;
• and
• in response to that the rotation angles of the machine tool's rotation axis are the angle B and the angle C, directly determining that the angle B=the angle A, which is applied to the rotation of the calibration device around the Z axis and the rotation of the calibration device around the X axis;
• the calibration device for non-contact photographic hole measurement comprises the base, the installation platform, and the calibration assembly,
• the base comprising a base body, the first servo motor and a bull gear plate, wherein the first servo motor is provided at one side of the base body, the bull gear plate is provided at an upper surface of the base body, and the first servo motor is meshed with the bull gear plate and is configured to drive the bull gear plate to rotate around the Z axis;
• the installation platform comprising an U-shaped base, the second servo motor, a bevel gear pair and a worm wheel and worm, wherein the U-shaped base is provided at an upper surface of the bull gear plate;
• the second servo motor, the bevel gear pair and the worm wheel and worm are all provided at the U-shaped base;
• the second servo motor is connected to the bevel gear pair, and the bevel gear pair is connected to the worm wheel and worm;
• and
• the calibration assembly comprising the matte plate and the matte calibration ball, wherein the matte plate is provided at the U-shaped base and is connected to the worm wheel and worm, the matte calibration ball is provided at the matte plate;
• the ball's center position of the matte calibration ball is provided at an intersection position of a rotation center of the base and a rotation center of the installation platform;
• the calibration assembly is configured to rotate around the X axis driven by the worm wheel and worm.