Variable Stiffness Device Using Shape-Memory Pipe and Segmented Heating

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Solution Overview

Problem

Existing variable stiffness devices for flexible members, such as endoscopes, lack efficient mechanisms to dynamically adjust stiffness in response to temperature changes, leading to limited control over bending properties and responsiveness.

Innovation Solution

A variable stiffness device comprising a first elongated member with alternating high and low bending stiffness portions and a shape-memory pipe, heated by a second elongated member's heater, allowing phase transition between low and high stiffness states, enabling controlled stiffness adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a shape-memory member is used to provide variable stiffness, then the stiffness can be changed between soft and hard states, but the response time and controllability are limited

Engineering Contradiction:

Improvestiffness adjustment capabilityVSAvoidresponse time

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The shape-memory member is divided into multiple independent heating zones along its length, allowing different sections to be heated independently. This segmentation enables localized and rapid stiffness adjustment, improving response time while maintaining the overall variable stiffness capability of the member.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heating element applies periodic or pulsed heating to the shape-memory member rather than continuous heating. This periodic action accelerates the phase transition response time by delivering concentrated thermal energy in controlled intervals, enabling faster stiffness changes while improving energy efficiency.

Inventive Principle:

Principle #19Periodic action

2Strength

If the shape-memory member is heated to increase stiffness, then high stiffness state is achieved, but energy consumption increases

Engineering Contradiction:

Improvebending stiffnessVSAvoidheating energy consumption

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

Instead of heating the entire shape-memory member uniformly, the heating element applies heat only to specific localized zones where stiffness adjustment is needed. This local quality approach reduces overall energy consumption while achieving the required high stiffness state in the necessary regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The heating element applies just enough thermal energy to trigger the phase transition to the high stiffness state, avoiding excessive heating. By controlling the heating duration and intensity to match the minimum requirement for phase transition, energy consumption is minimized while still achieving the desired stiffness increase.

Inventive Principle:

Principle #16Partial or excessive action

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 device provides responsive and controlled stiffness variation, allowing for easy deformation in low stiffness states and high resistance in high stiffness states, enhancing the flexibility and durability of flexible members like endoscopes.

Implementation Method 1

a second elongated member including a heater, disposed inside an inner circumference of the first elongated member... The heater extends through an inner space of the shape-memory pipe and configured to heat the shape-memory pipe

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The first elongated member includes a shape-memory pipe... One of the first elongated member and the second elongated member includes a shape-memory pipe. The heater extends through an inner space of the shape-memory pipe and configured to heat the shape-memory pipe to increase stiffness of the shape-memory pipe

Methodology Applied

Scientific EffectPhase transition: Phase Change

Data Source

PatentUS11596294B2Variable stiffness device and method of varying stiffness

Publication Date: 2023.03.07 OLYMPUS CORPORATION(JP)

AI summary

A variable stiffness device includes a first elongated member in a hollow shape extending along a longitudinal axis, and a second elongated member including a heater, disposed inside an inner circumference of the first elongated member, and extending in parallel to the first elongated member along the longitudinal axis. The first elongated member includes a high bending stiffness portion and a low bending stiffness portion alternately aligned along the longitudinal axis. One of the first elongated member and the second elongated member includes a shape-memory pipe. The heater extends through an inner space of the shape-memory pipe and configured to heat the shape-memory pipe to increase stiffness of the shape-memory pipe.