Robot Arm Contact Change Detection with Force-Acceleration Validation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing robot arm systems face challenges in accurately and reliably detecting contact with external objects due to the limitations of force/torque sensors, which often result in false positives and are not suitable for precise contact detection.

Innovation Solution

A method that combines force and acceleration sensing to detect changes in contact by comparing the direction of contact force and part acceleration, providing a robust and accurate indication of contact occurrence between the robot arm and an external object.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If force/torque sensors are used to detect contact between robot arm and external objects, then contact detection capability is provided, but false positives occur and detection reliability deteriorates

Engineering Contradiction:
Improvecontact detection reliabilityVSAvoidcontact detection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent combines force sensing and acceleration sensing into a unified contact detection system. The controller integrates data from both force/torque sensors and acceleration sensors to determine contact occurrence, leveraging the complementary strengths of each sensor type to achieve more reliable and precise detection than either sensor could provide alone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system continuously monitors both force and acceleration signals, using feedback from acceleration data to validate force sensor readings. When a force change is detected, the system checks corresponding acceleration patterns to confirm actual contact occurrence, creating a feedback loop that eliminates false positives and improves detection reliability.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If force/torque sensors are used for contact detection, then contact information is obtained, but detection accuracy deteriorates due to false positives

Engineering Contradiction:
Improvecontact detection accuracyVSAvoiddetection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent merges force sensing and acceleration sensing into a unified contact detection system. The controller integrates data from both force/torque sensors and acceleration sensors to determine contact occurrence, leveraging the complementary strengths of each sensor type to achieve more reliable and precise detection than either sensor could provide alone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system continuously monitors both force and acceleration signals, using feedback from acceleration data to validate force sensor readings. When a force change is detected, the system checks corresponding acceleration patterns to confirm actual contact occurrence, creating a feedback loop that eliminates false positives and improves detection reliability.

Inventive Principle:
Principle #23Feedback

3Device complexity

If only force sensing is used for contact detection, then system complexity is reduced, but detection robustness deteriorates

Engineering Contradiction:
Improvesensing system complexityVSAvoiddetection robustness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent combines force sensing and acceleration sensing into a unified contact detection system. The controller integrates data from both force/torque sensors and acceleration sensors to determine contact occurrence, leveraging the complementary strengths of each sensor type to achieve more reliable and precise detection than either sensor could provide alone.

Inventive Principle:
Principle #5Merging (Combining)

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

This approach enables fast, accurate, and robust detection of contact changes, allowing for reliable contact-based programming of robot arms and reducing false indications, thereby improving the precision and safety of robotic operations.

Implementation Method 1

obtaining a contact force provided at a contact part of a robot arm by sensing a force provided to a part of the robot arm

Methodology Applied
Scientific EffectForce sensing: Force

Implementation Method 2

obtaining the acceleration of the contact part of the robot arm by sensing the acceleration of the part of the robot arm

Methodology Applied
Scientific EffectAcceleration sensing: Accelerometer

Data Source

PatentEP3976322B1Detection of change in contact between robot arm and an object
Publication Date: 2024.12.04 UNIVERSAL ROBOT
  • EP3976322B1 patent drawingFigure 1
  • EP3976322B1 patent drawingFigure 2
  • EP3976322B1 patent drawingFigure 3a~4c

AI summary

A method of detecting change in contact between a contact part of a robot arm and an object as defined by the independent claims, by obtaining a contact force provided at the contact part of the robot arm by sensing a force provided to a part of said robot arm; and by obtaining the part acceleration 5 of the contact part of the robot arm by sensing the acceleration of at least a part of the robot arm and then indicate if a change in contact between the contact part of the robot arm and the object has occurred based on the obtained contact force and the obtained contact part.