Robot Arm Camera Target Mark Positioning
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Solution Overview
Problem
Existing methods for determining the positional relationship between a robot coordinate system and a machine tool coordinate system require expensive 3D sensors or extensive robot movement, making it difficult to perform measurements in restricted spaces.
Innovation Solution
A robot system equipped with a camera attached to its arm tip, using a target mark with a characteristic pattern, where the position and size of the mark are stored as reference data to calculate the target mark positions in both robot and machine coordinate systems, allowing for inexpensive and efficient 3D position measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive 3D sensors are used to measure the 3D position of target points, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent uses a 2D camera to capture images of a target mark and calculates 3D position information through image processing and coordinate transformation. Instead of using expensive 3D sensors, the system creates a computational model that copies the 3D measurement function using affordable 2D imaging equipment combined with mathematical calculations.
Solution Approach 2:
The patent replaces the mechanical/optical 3D sensing system with an imaging system combined with computational methods. By using a 2D camera to capture images and performing coordinate transformations based on known camera positions and target mark characteristics, the system substitutes complex 3D sensing mechanics with simpler imaging and calculation processes.
2Measurement precision
If the robot moves across a broad range of positions and postures to determine coordinate system relationships, then measurement accuracy is improved, but the measurement process becomes difficult in restricted spaces
Solution Approach 1:
The patent attaches the camera to the robot arm in advance and performs calibration to establish the relationship between the robot coordinate system and camera coordinate system before actual measurement. This preliminary setup creates a transformation model that can be used for 3D position calculation without requiring the robot to move extensively during the measurement process itself.
Solution Approach 2:
The patent introduces a target mark as an intermediary object between the robot and the measurement system. By capturing images of this known target mark and using its predetermined position and size information, the system can calculate 3D positions through coordinate transformation without requiring the robot to physically move to multiple measurement points.
3Device complexity
If a camera is used to capture images for 3D position measurement, then device cost is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent changes the parameters used for 3D position calculation by utilizing the predetermined position and size parameters of the target mark, combined with camera position information in the robot coordinate system. By transforming these parameters through coordinate systems and using image processing algorithms, the system achieves accurate 3D position measurement with a cost-effective 2D camera.
Data Source
AI summary
A robot system which is inexpensive and can easily measure a position of a target point. The system stores feature quantities of an image of a target mark included in an image acquired as reference data when the target mark is placed at a known first target mark position at the robot coordinate system and stores the first target mark position with respect to an arm tip as the position of the tool center point. The system compares the feature quantities obtained from the image acquired when the target mark is arranged at a second target mark position and the feature quantities of the reference data to make the arm tip move and calculates the second target mark position at the robot coordinate system based on a second robot position corresponding to the position of the arm tip after movement and the position of the tool center point.