Compliant End Effector for Ultrasonic Probe Contact Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In situations where the shape or position of the inspection target is not accurately grasped, there is a risk of the ultrasonic sensor being excessively strongly pressed against the target.

Innovation Solution

An end effector with an elastic member that allows displacement of the probe by compressing under the force applied from the inspection target, featuring multiple coil springs and rotating members to absorb and adjust forces, and an adjustment device to automatically or manually adjust the elastic forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the robot arm presses the ultrasonic sensor against the inspection target with strong force to ensure good contact, then the inspection accuracy is improved, but the risk of damaging the sensor or target increases when the shape or position is not accurately grasped

Engineering Contradiction:
Improveinspection accuracyVSAvoidexcessive force application
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an elastic member (spring) between the robot arm and ultrasonic sensor that acts as a cushioning element. This spring absorbs excessive forces before they reach the sensor or inspection target, preventing damage while maintaining adequate contact pressure for accurate inspection. The elastic member is specifically designed to compress under excessive force, providing beforehand protection against harmful force applications.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the mechanical stiffness parameter of the coupling between the robot arm and sensor by introducing an elastic member. This transforms the rigid connection into a compliant one, allowing the system to automatically adjust the contact force parameter based on the interaction with the inspection target, thereby preventing excessive force application while maintaining inspection accuracy.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the robot arm applies strong pressing force to ensure good ultrasonic wave transmission, then the signal quality is improved, but the probe may be damaged or the inspection target may be deformed

Engineering Contradiction:
Improvesignal qualityVSAvoidprobe durability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The elastic member serves as a cushioning element that protects the probe from excessive pressing forces. It absorbs the excess force through compression, ensuring that the probe is never subjected to forces beyond its structural limits, thereby maintaining probe durability while still allowing sufficient force transmission for high-quality ultrasonic signals.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The spring acts as an intermediary element between the robot arm's actuating force and the probe's contact force with the inspection target. It mediates the force transmission, allowing the robot arm to apply strong forces without directly transmitting those full forces to the probe, thus protecting the probe while maintaining signal quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the robot arm maintains rigid positioning of the ultrasonic sensor to ensure stable measurement, then the measurement stability is improved, but the system cannot adapt to variations in the inspection target's surface shape or position

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidadaptation to surface variations
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent transforms the rigid, static positioning system into a dynamic one by introducing the elastic member. This allows the probe position to dynamically adjust in response to variations in the inspection target's surface shape or position, while the robot arm maintains overall positional stability. The spring enables continuous adaptation without sacrificing measurement stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic member introduces compliance to the positioning system, changing the positional parameter from fixed to variable within elastic limits. This allows the system to adapt to surface variations by changing the probe's position parameter dynamically while maintaining stable measurement conditions through the elastic coupling.

Inventive Principle:
Principle #35Parameter changes

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

The end effector effectively suppresses the application of excessively large forces to the probe, ensuring appropriate force control during inspection, thereby preventing damage and ensuring accurate flaw detection.

Implementation Method 1

an elastic member that allows displacement of the probe by being compressed by a force that is applied from the inspection target to the probe

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

featuring multiple coil springs and rotating members to absorb and adjust forces

Methodology Applied
Scientific EffectSpring elastic force: Spring

Data Source

PatentEP4692782A1End effector, flaw detection system, and method for inspecting inspection target
Publication Date: 2026.02.11 MITSUBISHI HEAVY IND LTD
  • EP4692782A1 patent drawingFigure 1~2
  • EP4692782A1 patent drawingFigure 3~4
  • EP4692782A1 patent drawingFigure 5~6

AI summary

A robot arm (40) is provided with an end effector (70) that grips a probe so as to bring the probe (50) into contact with an inspection target. The end effector includes an elastic member that is compressed by a force applied to the probe from the inspection target, thereby allowing the probe to be displaced in the direction of the compression.