A Rotary Axis Calibration Method Based on Line Laser Vision Sensor

Abstract

The invention relates to a method for calibrating a rotating shaft based on a line laser vision sensor, comprising the following steps: (1) installing the line laser vision sensor; (2) setting a calibration tool; (3) determining an external coordinate system; (4) calibrating Determine the coordinates of the center of the circle in the external coordinate system; (5) analyze and calculate the coordinates of the calibration circle center in the online laser sensor coordinate system: fit the calibration circle on the image collected by the line laser vision sensor to obtain the calibration circle center online laser coordinates in the sensor; (6) perform a fitting operation to obtain the best value of the transformation relationship between the coordinates in the calibration circle center line laser sensor and the coordinates in the external coordinate system. The use of the present invention solves the problem of camera calibration in a non-standard space Cartesian coordinate system (when one coordinate axis is a rotation axis), the calibration process is simple, and the calibration accuracy is high. At the same time, the present invention broadens the application of line lasers in the field of industrial robots scope.

Description

technical field [0001] The invention belongs to the technical field of sensor calibration, in particular to a method for calibration of a rotating shaft based on a line laser vision sensor. Background technique [0002] The line structured light sensor is a non-contact measuring device, mainly composed of a camera and a line laser. It has the advantages of simple structure, non-contact, fast measurement speed and high precision, and has a large number of application requirements in high-precision measurement in the industrial field. Before using the line laser sensor, it needs to be calibrated first, and the calibration accuracy will directly affect the accuracy and safety reliability of casting grinding. At present, the line laser is widely used in high-precision measurement, and the line laser used in the present invention mainly It is used in the field of robot industrial intelligence application, which has high requirements for the calibration accuracy of the sensor. ...

AI Technical Summary

Problems solved by technology

However, the above method has the following defects: the existing line laser static calibration method either needs a special mechanical motion actuator to carry the calibration plate to move within the field of view of the laser camera, needs to add an additional high-precision motion mechanism, or requires multiple Robots work together to complete hand-eye calibration. In practical applications, there may not be so many robots for use

Without the help of a second robot and an additional motion actuator, it is necessary to install a tooling or workpiece with a known positional relationship at the end of the robotic arm, and it is necessary to have multiple obvious features on the tooling or workpiece. This method requires more preparatory work. Many, additional specially designed equipment is required, and it is difficult to operate when the robot carries the tooling and the line laser cooperates to scan the image

When using external tooling or workpiece for calibration, it is affected by the machining accuracy of the calibration point features, which affects the calibration accuracy

The calibration process is complicated, limited by the line of sight of the laser, the movement range of the motion mechanism is also limited during calibration, and the calibration accuracy is low, so this calibration method is rarely used

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