US 12,742,632 B2Granted

Method and system for detecting positioning error of linear moving mechanism

AssigneeNanjing Kingyoung Intelligent Science & Technology Co.Ltd

InventorsChunmei Wang, Yi Huang, Cong Wang

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Abstract

A method and a system for detecting positioning error of a linear moving mechanism are provided, which includes a linear moving mechanism, a moving element, a visual sensor, a calibration object and a data processing system. The vision sensor is fixed on the moving element on the linear moving mechanism and is driven by the moving element to move on the linear moving mechanism. The calibration object is arranged in front of sight line of the visual sensor and used for calibrating posture of the visual sensor. The vision sensor shoots the calibration object at different moving positions on the linear moving mechanism, and the data processing system obtains shooting result, and calculates the coordinate system conversion matrix from the linear moving mechanism coordinate system at moving position point to the preset linear moving mechanism coordinate system, thereby analyzing the positioning error of the linear moving mechanism.

A method for detecting positioning error of a linear moving mechanism, comprising:

rigidly fixing a vision sensor on a moving element of the linear moving mechanism:
arranging a calibration object in front of sight line of the visual sensor;
arranging the vision sensor at a reference position, using the vision sensor to shoot the calibration object, and obtaining first shooting results of the calibration object;
controlling the linear moving mechanism to move, including driving the vision sensor to move along the linear moving mechanism by the moving element to a position point Pi, controlling the vision sensor to shoot the calibration object at the position point Pi, and obtaining second shooting results of the calibration object, wherein i≥1 and is an integer;
obtaining the first shooting results and the second shooting results by a data processing system, calculating a coordinate system conversion matrix HLine(i)/2Line(s) from a linear moving mechanism coordinate system to the preset linear moving mechanism coordinate system at moving position point Pi based on a formula (1) and a formula (2) and an installation posture of the vision sensor at the reference position in combination with the first shooting results and the second shooting results, and analyzing a positioning error of the linear moving mechanism using the calculated coordinate system conversion matrix HLine(i)/2Line(s):
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wherein Hcalib2cam(r) is a conversion matrix from the calibration object coordinate system to the vision sensor coordinate system at a selected reference position, and Hcalib2cam(i) is a coordinate system conversion matrix from the calibration object coordinate system to the vision sensor coordinate system at moving position point Pi, and Hcam(i)2Line(i) is a coordinate system conversion matrix between the vision sensor coordinate system when moving to position point Pi of the linear moving mechanism relative to the linear moving mechanism coordinate system after moving position point Pi, detecting an assembly error of the linear moving mechanism based on the analyzed positioning error, and repeatedly detecting and adjusting the assembly error to obtain a minimized assembly error, and correcting the linear moving mechanism based on the minimized assembly error to obtain a corrected linear movement mechanism, wherein the method further comprises when the moving element drives the visual sensor to move on the linear moving mechanism, setting the visual sensor to be soft triggered by a timer or hard triggered by a position sensor signal set on the linear moving mechanism.

144 more elements

Abstract

Claims8