Workpiece Removal Robot System Avoiding Interference
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Solution Overview
Problem
Existing workpiece taking out robot systems face interference issues when trying to remove multiple randomly located workpieces, as the detection method from above can lead to failure in extracting lower workpieces due to interference with the upper ones, and registering three-dimensional models of various workpieces is labor-intensive.
Innovation Solution
A system and method that utilize a vision sensor to obtain height distribution information, calculate the initial position/orientation of workpieces, and convert it to a second position/orientation based on orientation conversion information, such as radius and rotation angle, to avoid interference, allowing the robot to take out workpieces without obstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the robot takes out workpieces based on detection results from above, then the detection process is simple, but interference occurs when taking out lower workpieces due to upper workpieces blocking access
Solution Approach 1:
The patent changes the detection dimension from top-down (2D) to side-view (3D depth information included). The sensor is positioned to detect workpieces from the side, obtaining depth information that reveals the stacked arrangement of workpieces. This dimensional change allows the system to identify which workpieces are accessible and which are blocked, enabling reliable selection of target workpieces for removal.
2Reliability
If three-dimensional models of workpieces are registered to specify grippable portions, then interference can be avoided, but the registration process becomes labor intensive
Solution Approach 1:
The system uses the sensor-detected depth information and workpiece arrangement data to automatically determine grippable portions and safe grip paths. Instead of requiring manual registration of 3D models, the system self-generates the necessary geometric information from the detected workpiece positions, orientations, and stacking relationships, eliminating labor-intensive model registration while maintaining reliable grip operations.
3Productivity
If multiple workpieces are taken out in priority order, then systematic removal is achieved, but lower workpieces remain inaccessible due to upper workpiece interference
Solution Approach 1:
The system performs preliminary analysis of the workpiece stack arrangement using depth information before initiating removal operations. It identifies which workpieces are blocked and determines the optimal sequence of removal to maximize accessibility. By planning the removal sequence in advance based on detected positions and orientations, the system ensures that removing one workpiece will expose previously inaccessible workpieces below, maintaining continuous productivity.
Data Source
AI summary
A robot system and a method, by which a robot can effectively and sequentially take out a plurality of randomly located workpieces, while avoiding interference by a simple calculation. A first detection coordinate system for determining the motion of the robot is defined on the lateral surface of the workpiece. The first detection coordinate system is translated by a predetermined distance in the negative direction of a Z-axis, and then an X-Z plane is rotated about an X-axis of the workpiece so that the X-Z plane is perpendicular to an X-Y plane of a robot coordinate system, whereby a work coordinate system is obtained. Next, the work coordinate system is rotated about the X-axis by a target angle, and then is translated by a distance corresponding to a radius of the workpiece in the positive direction of the Z-axis, whereby a second detection coordinate system is obtained and output.