3D Workpiece Holding Control for Accurate Magnetic Placement
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Solution Overview
Problem
Existing workpiece holding apparatuses struggle to accurately calculate and place workpieces with high precision when the holding position changes three-dimensionally, such as when a workpiece is attracted by a magnet, leading to potential inaccuracies in placement.
Innovation Solution
A workpiece holding apparatus that includes holding means, first information acquisition means for acquiring three-dimensional information of the workpiece, position calculation means to determine the lowest center point as position information, and control means to move the workpiece to a calculated placement position, utilizing a robot arm and vision sensors to ensure accurate placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnet is used to hold the workpiece, then the workpiece can be held securely, but the holding position changes three-dimensionally making accurate placement difficult
Solution Approach 1:
The patent transitions from two-dimensional alignment mark reading to three-dimensional point cloud acquisition. By using a 3D camera to capture the workpiece from multiple angles and generate a point cloud, the system can accurately determine the workpiece position in three-dimensional space, including the height direction, thereby resolving the positioning inaccuracy caused by magnetic holding effects.
2Device complexity
If alignment mark reading is used to calculate holding position, then the method is simple, but accuracy is insufficient when three-dimensional position changes occur
Solution Approach 1:
The patent replaces the traditional mechanical/optical alignment mark reading system with a vision-based three-dimensional measurement system. A 3D camera captures the workpiece geometry and generates a point cloud, which is then processed to extract precise three-dimensional position information, substituting simple 2D image processing with advanced 3D vision technology.
3Measurement precision
If three-dimensional information acquisition is implemented, then holding position accuracy improves, but system complexity increases
Solution Approach 1:
The 3D camera serves multiple functions: it captures the workpiece geometry for position calculation, acquires alignment mark information, and generates three-dimensional spatial data. This multi-functional approach consolidates what would otherwise require separate sensing systems into a single device, reducing overall system complexity while maintaining high measurement precision.
Data Source
AI summary
To calculate a holding position of a workpiece with high accuracy and place the workpiece in a placement position with high accuracy based on the holding position. A workpiece holding apparatus includes: holding means for holding a workpiece; first information acquisition means for acquiring three-dimensional information of the workpiece held by the holding means; position calculation means for calculating a lowest center point of the workpiece as position information of the workpiece based on the three-dimensional information of the workpiece acquired by the first information acquisition means; and control means for calculating a placement position where the workpiece is to be placed based on the position information of the workpiece calculated by the position calculation means and controlling, based on the placement position, the holding means so as to move the workpiece to the placement position and place the workpiece in the placement position.