Robot Vision Position Correction for Machine Tool Layout Flexibility
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Solution Overview
Problem
In production systems with machine tools and robots, positional displacement between the robot and machine tool leads to inaccurate operations, and existing methods for correcting this displacement are either cumbersome or time-consuming, especially when the layout changes, and are affected by factors like vibration and cutting oil.
Innovation Solution
A production system that includes a visual target on the machine tool and a vision device on the robot to measure and correct the positional relationship between the robot and machine tool, allowing for precise positioning without the need for strong floor fixation using anchor bolts, utilizing a scheduling part to initiate measurements at strategic processing times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the robot and machine tool are fixed to the floor using anchor bolts, then the placement positions are stable and do not displace during operation, but it becomes very troublesome to refix them when layout changes are needed
Solution Approach 1:
The patent replaces the mechanical fixation system (anchor bolts) with a vision-based measurement and correction system. The robot uses a vision device to detect the position of a visual target on the machine tool and corrects its own motion positions based on detected positional displacements, eliminating the need for strong mechanical fixation and enabling easy layout changes.
2Measurement precision
If the robot is moved to grip the workpiece after the workpiece is captured by the camera, then the taught coordinate position can be corrected based on the image obtained by the camera, but the robot cannot be moved during the camera captures the workpiece and/or during the obtained image data is processed, whereby a cycle time of the robot is extended
Solution Approach 1:
The patent performs position measurement of the machine tool using the vision device and visual target before the robot executes its workpiece handling operations. The robot measures the positional relationship between itself and the machine tool in advance, corrects its motion positions based on the measurement results, and then proceeds with workpiece supply and ejection without waiting for measurement during operation, thereby reducing cycle time.
Solution Approach 2:
The patent introduces a visual target as an intermediary object placed on the machine tool. The vision device captures images of this visual target to determine positional relationships, rather than directly capturing the workpiece. This intermediary approach allows for faster, more reliable position detection without requiring the robot to pause during workpiece handling operations.
3Measurement precision
If the robot moves close to the workpiece to capture it with the camera, then the workpiece position can be measured, but the camera is likely to be affected by cutting oil
Solution Approach 1:
The patent uses a visual target attached to the machine tool as an intermediary for position measurement. Instead of having the camera directly capture the workpiece in the cutting oil environment, the camera captures the visual target which is positioned on the machine tool exterior or in a cleaner environment. This intermediary approach maintains measurement capability while avoiding contamination of the camera by cutting oil.
4Measurement precision
If a camera is attached to the front end of the robot to detect the position of the workpiece and jig, then the operation position can be corrected based on the detection result, but it takes time to supply or eject the workpiece after the position is measured
Solution Approach 1:
The patent performs position measurement and correction in advance before the robot executes workpiece supply and ejection operations. By measuring the positional relationship between the robot and machine tool using the visual target and vision device beforehand, and correcting the robot's motion positions based on these measurements, the system eliminates delays during the actual workpiece handling operations, thereby reducing overall cycle time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise and efficient supply and ejection of workpieces with reduced cycle time and flexibility in factory layout changes, as the system can measure and correct positional relationships before each operation, improving overall production efficiency.
Implementation Method 1
a vision device arranged on a movable part of the robot, the vision device being configured to measure a positional relationship between the robot and the machine tool by capturing the visual target
Data Source
AI summary
A production system in which a position of a robot relative to a machine tool can be measured and an operation position of the robot can be corrected based on the measurement result, by using a simple configuration. The robot has a vision device attached to a movable part such as a robot arm. The machine tool has a visual target arranged on an outer surface of the machine tool. An image of the visual target captured by a camera is processed by a robot controller or an image processor. Due to such image processing, the position of the robot relative to the machine tool can be measured. Further, the production system has a correcting part which corrects a position of a motion of the robot regarding supplying and ejecting a workpiece, based on the positional relationship between the robot and the machine tool.