Robot Coordinate Alignment Using 3D Flange Marker Measurement

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Solution Overview

Problem

Existing robot systems face difficulties in accurately setting a coordinate system when measurement points on the reference plane and reference reflectors are obstructed by peripheral devices, making it challenging to correct the robot coordinate system.

Innovation Solution

A robot installation position measurement device that includes a first position information acquisition unit, a second position information acquisition unit, and a coordinate system correction unit, which utilize a three-dimensional measurement instrument to acquire and correct the robot coordinate system by minimizing differences in position information across multiple poses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If measurement points on the reference plane and reference reflectors are used to set the coordinate system, then the robot coordinate system can be corrected, but measurement is difficult when obstructed by peripheral devices

Engineering Contradiction:

Improvecoordinate system correction accuracyVSAvoidmeasurement accessibility

Core Design Contradiction:

Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a measurement marker as an intermediary object that is attached to the robot flange. This marker serves as a mediator between the robot and the three-dimensional measurement instrument, allowing coordinate system measurement without requiring direct access to the robot's reference reflectors or measurement points on the reference plane. The measurement marker can be positioned in spaces that are accessible to the measurement instrument even when the robot is surrounded by peripheral devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a virtual model of the measurement marker in the simulation environment that corresponds to the physical marker attached to the robot. This virtual copy allows the coordinate system to be measured and corrected in the simulation based on the physical marker's position, enabling coordinate system correction without direct measurement of the robot's internal reference points.

Inventive Principle:

Principle #26Copying

2Productivity

If the robot is surrounded by peripheral devices in complex production cells, then productivity is maintained, but coordinate system measurement becomes difficult

Engineering Contradiction:

Improveproduction cell complexityVSAvoidcoordinate system correction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The measurement marker attached to the robot flange acts as an intermediary that can be measured even when the robot is surrounded by peripheral devices. The marker is positioned on the robot's exterior surface, making it accessible to the three-dimensional measurement instrument from various angles without requiring disassembly or reconfiguration of the production cell.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from measuring the robot's internal reference points in three-dimensional space to measuring the external measurement marker's position and orientation. This dimensional approach allows the coordinate system to be determined by measuring the marker's six-degree-of-freedom pose (position and orientation) rather than requiring direct access to the robot's internal reference reflectors.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If reference reflectors on the robot base are used for measurement, then coordinate system can be set, but measurement is obstructed by peripheral devices

Engineering Contradiction:

Improvecoordinate system setting accuracyVSAvoidmeasurement operation difficulty

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The measurement marker serves as an external intermediary that replaces the need to measure the robot's internal reference reflectors. The marker is attached to the flange and can be measured from the outside, eliminating the operational difficulty of accessing hidden reference reflectors behind peripheral devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of measuring the robot's fixed reference points directly, the patent inverts the approach by attaching a measurable marker to the robot and measuring that marker's position relative to the production cell coordinate system. This inversion transforms an inaccessible measurement problem into an accessible one.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12479096B2Robot installation position measurement device, installation position measurement method, robot controller, teaching system, and simulator

Publication Date: 2025.11.25 FANUC LTD

AI summary

A robot installation position measurement device includes a first position information acquisition unit that acquires first position information, which is a three-dimensional command position of a tool center point fixed with respect to a flange at a tip of a robot, in a state in which the robot is positioned in a desired pose, a second position information acquisition unit that acquires, by a three-dimensional measurement instrument installed with a predetermined measurement coordinate system, second position information, which is a three-dimensional actual position of the tool center point in the pose, and a coordinate system correction unit that corrects a robot coordinate system, with which the robot operates, such that a difference between pieces of the first position information and pieces of the second position information acquired in states in which the robot is positioned in multiple different poses becomes small.