Robot Calibration via Visual Sensor and Multi-Position Measurement

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional robot systems face challenges in achieving accurate coordinate calibration due to mechanical errors and operator-dependent calibration methods, which require manual teaching operations and result in longer calibration times and varying accuracy levels.

Innovation Solution

A robot system that performs coordinate calibration without manual teaching by measuring reference members at multiple position and orientation groups using a visual sensor, calculating calibration values, and activating the robot body using these values to improve accuracy and reduce calibration time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual teaching operation is used for coordinate calibration, then calibration accuracy can be improved, but operation time increases

Engineering Contradiction:

Improvecalibration accuracyVSAvoidoperation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The robot body performs calibration measurements automatically without operator intervention. The control apparatus autonomously controls the robot body to move to predetermined positions and orientations, and the visual sensor automatically measures the reference member, eliminating the need for manual teaching operations while maintaining calibration accuracy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Multiple position and orientation data are predetermined in advance for the calibration process. The control apparatus uses these predetermined positions to automatically guide the robot body through the calibration sequence, reducing operation time while ensuring accurate calibration through pre-planned measurement points

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If single position and orientation calibration is performed, then calibration process is simple, but accuracy is insufficient due to motion errors

Engineering Contradiction:

Improvecalibration process complexityVSAvoidcalibration accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The calibration process is divided into multiple independent position and orientation measurements. Instead of a single calibration point, the robot body is measured at multiple predetermined positions and orientations, allowing the system to account for motion errors across different configurations and improve overall calibration accuracy

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs more calibration measurements than the minimum single position required. By measuring at multiple positions and orientations beyond the basic requirement, the system compensates for motion errors and mechanical variations, achieving higher accuracy at the cost of increased process complexity

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If automated calibration is implemented, then operation time is reduced, but accuracy may vary depending on operator skill level

Engineering Contradiction:

Improvecalibration speedVSAvoidcalibration consistency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The calibration system operates autonomously without requiring operator skills for manual teaching. The control apparatus automatically executes the calibration sequence using predetermined position and orientation data, ensuring consistent results regardless of operator expertise level and eliminating variability in calibration quality

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Manual operator operations are replaced with automated control system operations. The control apparatus uses visual sensor data and predetermined position information to automatically perform calibration, replacing the mechanical teaching process with an automated computational process that ensures consistent, repeatable results

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9221176B2Robot system and method for controlling the same

Publication Date: 2015.12.29 CANON KK

AI summary

A robot system which requires no manual teaching operation in acquiring calibration values for coordinate transformation, and improves the calibration accuracy includes a robot body, a camera, and a control apparatus. The control apparatus measures, via the camera, a calibration plate at each position and orientation of a first position and orientation group including a reference measurement position and orientation and a position and orientation within a first offset range, calculates a first calibration value based on the measurement value, measures, via the camera, the calibration plate at each position and orientation of a second position and orientation group including a reference operation position and orientation different from the reference measurement position and orientation, and a position and orientation within a second offset range, calculates a second calibration value based on the measurement value, and activates the robot body by using the first and second calibration values.