Robot Calibration Using Mark Imaging and Coordinate Correlation
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Solution Overview
Problem
Conventional robot systems require a pattern plate for calibration, which is burdensome for users to store and prepare for each calibration operation.
Innovation Solution
A robot system with a movable component having a mark attached, a control unit, and a digital camera that creates a transformation parameter to correlate a two-dimensional image data coordinate system with a three-dimensional coordinate system, eliminating the need for a pattern plate by using image data from the mark at different positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pattern plate is used for calibration, then the calibration operation can be performed, but the user has to store and prepare the pattern plate for each calibration which is burdensome
Solution Approach 1:
The robot arm itself serves as the calibration object by attaching a mark to its end effector. The system uses the robot's own movement capabilities to perform calibration, eliminating the need for external pattern plates. The robot arm moves to predetermined positions and the digital camera captures the mark's position, allowing the system to calculate the transformation parameter between the robot's coordinate system and the camera's coordinate system.
2Measurement precision
If a pattern plate is used for calibration, then coordinate systems can be correlated, but the device complexity increases due to additional calibration components
Solution Approach 1:
The invention extracts the essential calibration element (the mark) from the complex pattern plate structure. Instead of using a full pattern plate with multiple features, only a simple mark is attached to the robot arm's end effector. This extracted mark is sufficient for calculating the transformation parameter, significantly reducing the complexity of calibration components while maintaining calibration accuracy.
3Measurement precision
If a pattern plate is used for calibration, then the transformation parameter can be calculated, but the calibration process becomes time-consuming due to preparation requirements
Solution Approach 1:
The robot arm is pre-programmed with predetermined positions for calibration. During the calibration process, the robot arm automatically moves to these predetermined positions, and the digital camera captures images at each position. This preliminary setup of movement paths eliminates the need for manual pattern plate preparation and positioning, significantly reducing calibration time while ensuring accurate transformation parameter calculation.
Data Source
AI summary
A robot system includes a movable component with a mark thereon, a control unit that controls the movable component in a three-dimensional coordinate system on the basis of control information, a digital camera that outputs image data by imaging a range of movement of the mark, and a calibrator that creates a transformation parameter for correlating a two-dimensional coordinate system of the image data with the three-dimensional coordinate system on the basis of the image data obtained by imaging the mark at different positions and the control information.