Robot Teaching with Detachable Vision Sensor Calibration
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Solution Overview
Problem
Existing robot teaching methods suffer from reduced accuracy due to errors in the posture of the robot, which are propagated to the attached vision sensor, affecting the calibration and precision of the teach position.
Innovation Solution
A method involving a detachable stereo camera vision sensor that measures a reference object and calibrates its relative relationship with the robot, allowing for accurate teaching by referencing this relationship after attachment, thereby isolating errors in the robot's posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the vision sensor is attached to the robot for teaching, then the robot can perform work with high accuracy, but the error in posture of the robot affects the accuracy of calibration
Solution Approach 1:
The calibration process is segmented into two independent stages: first calibrating the vision sensor relative to the robot base coordinate system when the robot is in a known reference posture, then using this pre-calibrated sensor for teaching operations. This segmentation isolates the calibration accuracy from robot posture errors during teaching.
Solution Approach 2:
The calibration between the vision sensor and robot base coordinate system is performed in advance before the actual teaching operations. By completing the calibration preliminarily when the robot is in a controlled reference posture, the system establishes an accurate coordinate transformation relationship that can be reused during teaching, preventing posture errors from affecting calibration accuracy.
2Measurement precision
If the robot posture has errors, then the vision sensor attached to the robot also has errors in position and orientation, but the patent needs high accuracy for teaching
Solution Approach 1:
The robot base coordinate system serves as an intermediary reference frame. The vision sensor is calibrated relative to this base coordinate system rather than directly to the robot's moving coordinate system. This intermediary reference allows the system to compensate for robot posture errors by using the stable base coordinate system as the foundation for all measurements and teachings.
Solution Approach 2:
The patent creates a virtual model of the workpiece with precise three-dimensional coordinates based on measurements taken by the calibrated vision sensor. This virtual model serves as an accurate copy or representation of the physical workpiece, allowing teaching operations to reference the precise virtual model rather than being affected by robot posture variations during physical manipulation.
Data Source
AI summary
A robot system includes a robot, a vision sensor, and a controller. The vision sensor is configured to be detachably attached to the robot. The controller is configured to measure a reference object by using the vision sensor and calibrate a relative relationship between a sensor portion of the vision sensor and an engagement portion of the vision sensor, and teach the robot by referring to the relative relationship and by using the vision sensor, after the vision sensor is attached to the robot.