Transfer Cart Vision Alignment for Defective Compensation Marks
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Solution Overview
Problem
Existing transfer devices struggle to accurately deliver articles to target devices when compensation marks are displaced or stained, as they cannot effectively cope with such defects in lighting and illumination conditions.
Innovation Solution
A transfer device equipped with a mobile cart, a robot arm, a camera capturing three compensation marks on the target device, and a control device that calculates the relative position and posture of the marks, determines positional relationships, and notifies potential displacement, enabling precise delivery by adjusting the robot arm's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera captures compensation marks for position correction, then the robot arm can be controlled to deliver articles at precise positions, but the system cannot appropriately cope with displacement or staining of the compensation marks
Solution Approach 1:
The patent divides the compensation mark recognition into two independent parts: (1) recognizing the position of each individual mark to calculate relative position for robot control, and (2) verifying the mutual positional relationship between marks to detect displacement or staining. This segmentation allows the system to handle mark defects by isolating the verification function from the position measurement function.
Solution Approach 2:
The patent implements a feedback mechanism where the control device verifies the mutual positional relationship between compensation marks and compares it against a reference relationship. When displacement or staining is detected through this verification, the system can notify external devices or halt operation, preventing erroneous delivery due to defective mark recognition.
2Manufacturing precision
If the system uses compensation marks for position correction, then delivery precision is improved, but the system becomes vulnerable to lighting and illumination conditions that may cause mark displacement or staining
Solution Approach 1:
The patent performs preliminary verification of the mutual positional relationship between compensation marks before using them for robot arm control. By checking whether the marks are properly positioned and visible before delivery operations, the system prevents lighting-related issues from affecting delivery precision, as defective marks are detected in advance.
Solution Approach 2:
The patent uses three compensation marks instead of the minimum two required for position calculation. This excessive number of marks provides redundancy, allowing the system to verify mutual positional relationships and detect displacement or staining even if one mark is affected by lighting conditions or other harmful factors.
Data Source
AI summary
A control device of a transfer device has: a mark relative position calculation unit which calculates a relative position of the three compensation marks relative to the cart, based on a captured image of the camera; a posture calculation unit which calculates a posture of the robot arm which arranges the article at the delivery position, based on a relative position of the three compensation marks calculated by the mark relative position calculation unit, and a teaching positional relationship which is taught in advance as a positional relationship between the three compensation marks and the delivery position; a reference positional relationship determination unit which determines whether a mutual positional relationship between the three compensation marks matches with a reference positional relationship set in advance, based on the relative positions of the three compensation marks calculated by the mark relative position calculation unit; and a displacement notification unit which notifies to outside of a possibility of displacement of the three compensation marks, in a case of the reference positional relationship determination unit determining that the mutual positional relationship of the three compensation marks does not match with the reference positional relationship.