Robot Tool and Work Object Calibration With Geometry Constraints
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Solution Overview
Problem
Existing calibration methods for robot tools and work objects are performed separately, leading to error propagation that limits the robot's absolute position accuracy and path accuracy.
Innovation Solution
A method for simultaneous calibration of both the tool and work object using a geometry constraint-based objective function, which determines touch points and calibration parameters through a single process, reducing error propagation and optimizing calibration performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tool calibration and work object calibration are performed as two individual steps, then the calibration process is simpler to implement, but error propagation occurs between the two calibrations which limits robot position accuracy and path accuracy
Solution Approach 1:
The patent merges tool calibration and work object calibration into a single simultaneous calibration process. The system performs both calibrations together using a unified mathematical model that accounts for tool errors during the work object calibration, eliminating error propagation between separate calibration steps while improving overall measurement precision.
2Measurement precision
If tool calibration is performed first to establish relative position and rotation, then the tool coordinate system is calibrated, but the tool error is propagated and accumulated into the subsequent work object calibration
Solution Approach 1:
The patent implements feedback by using the calibrated tool coordinate system and its associated error parameters during the work object calibration process. The system feeds back the tool error information into the work object calibration mathematical model, allowing the work object calibration to compensate for tool errors rather than propagating them, thereby improving reliability and accuracy.
Data Source
AI summary
Example embodiments of the present disclosure relate to calibration of a tool and a work object for a robot. The method includes determining a geometry constraint from a set of candidate geometry constraints as a physical closure for the calibration; determining a set of touch points of the tool with the work object based on a performance criterion and an objective function, wherein the objective function is constructed for the tool and the work object based on the selected geometry constraint; and obtaining calibration parameters of the tool and the work object according to the objective function based on observations from the robot with the set of touch points.