Rotating Head Calibration Using Multi-Camera Pose Alignment
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Solution Overview
Problem
Existing rotating head systems face challenges in achieving precise and efficient positioning of the head relative to the vehicle body, leading to potential collisions and incorrect stud placement during the manufacturing process, particularly after maintenance.
Innovation Solution
A method involving a rotating head system that calibrates its pose by capturing images from multiple cameras positioned at different angles around the rotation point, determining deviations using a transformation matrix, and adjusting the head's position to align with a target pose, ensuring precise and collision-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the head is positioned using traditional calibration methods, then the positioning process is simpler, but the positioning precision is insufficient leading to collisions and wrong stud placement
Solution Approach 1:
A reference object with known geometry is introduced as an intermediary between the rotating head system and the measurement process. The reference object serves as a mediator that enables precise pose determination through multiple camera views without requiring complex direct measurement systems
Solution Approach 2:
The patent replaces traditional mechanical positioning and calibration methods with an optical measurement system using multiple cameras. Instead of relying on mechanical fixtures and manual alignment, the system uses optical fields from K cameras to capture images and compute the head's pose through image processing and transformation matrices
2Measurement precision
If multiple cameras are used to improve positioning accuracy, then the measurement precision increases, but the device complexity and calibration time increase
Solution Approach 1:
The reference object is pre-positioned in a known pose before the calibration process begins. This preliminary setup with known geometry allows the system to rapidly compute transformations without requiring time-consuming iterative adjustments during calibration
Solution Approach 2:
The system captures multiple images of the same reference object from different camera angles simultaneously. By copying the reference object's appearance in K different views, the system can compute the head's pose through multi-view geometry without requiring sequential positioning operations
3Reliability
If the head position is not precisely calibrated, then the system operation is simpler, but collisions occur and stud placement accuracy deteriorates
Solution Approach 1:
The system computes the actual pose of the rotating head by comparing measured positions with the target pose, determining an offset that provides feedback on positioning accuracy. This feedback mechanism enables collision prevention and accurate stud placement while maintaining operational simplicity through automated compensation
Data Source
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AI summary
A method (300) for operating a rotating head system (110), e.g. a manipulator or a robot, comprising a head (111), e.g. an end-effector, which is configured to be rotated around a rotation point (121). The method (300) comprises: rotating (301) the head (111) into K different orientations (211, 212, 213, 214) to face K different cameras (201, 202, 203, 204), respectively, with K>3; capturing (302) K images using the K different cameras (201, 202, 203, 204), respectively; determining (303) K deviations of a reference point (112) of the head (111) from a target position (211) within the K images, respectively; and determining (304) an offset of an actual pose of the head (111) from a target pose based on the K deviations using a transformation matrix. The method is directed at calibrating the rotating system (110) relative to one or more products on an assembly line. The rotating system (110) may also perform a welding operation.