Material-Mapped Soft Actuator for Artery Navigation

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Solution Overview

Problem

Conventional robots are stiff and unsuitable for navigating through narrow passages or being used within human arteries, as they may puncture artery walls, and existing fiber-reinforced elastomeric enclosure (FREE) actuators do not fully address the physical constraints of soft robot usage environments.

Innovation Solution

A material-mapped actuator with spatially varying mechanical properties that can change shape in response to an actuation medium, incorporating locally-oriented fibers or meshes, allowing for desired anisotropies and strain limiting behaviors, and a method for designing and manufacturing such actuators using inverse design techniques and additive/subtractive processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional robots are used, then structural strength is maintained, but the robot cannot navigate through narrow passages or bends and may puncture artery walls

Engineering Contradiction:

Improveability to navigate passagesVSAvoidpuncture risk to artery walls

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a soft robotic body constructed from flexible elastomeric materials with embedded fiber reinforcement. The fiber orientation and density are spatially varied to provide directional stiffness while maintaining overall flexibility, enabling the robot to conform to narrow passages and bends without puncturing artery walls.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The robotic structure implements locally-varying mechanical properties through strategically oriented fiber reinforcements in different body regions. This allows specific areas to have enhanced stiffness for structural support while other areas remain compliant for safe navigation through biological passages, resolving the contradiction between strength and adaptability.

Inventive Principle:

Principle #3Local quality

2Shape

If fiber-reinforced elastomeric enclosure (FREE) actuators are used, then uniform shape change is achieved, but physical constraints of soft robot usage environments are not fully addressed

Engineering Contradiction:

Improveuniform shape changeVSAvoidresponse to environmental constraints

Core Design Contradiction:

ShapeVSAdaptability or versatility

Solution Approach 1:

The patent extends the FREE actuator concept by implementing spatially-varying fiber orientation and density throughout the elastomeric body. This creates regions with different mechanical properties that can respond differently to actuation pressures, enabling complex non-uniform shape changes and adaptive behaviors necessary for navigating constrained biological environments.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The robotic system employs dynamically adjustable mechanical properties through programmable fiber reinforcement patterns. The varying fiber orientations allow different body segments to exhibit different degrees of compliance and stiffness, enabling the robot to adapt its physical characteristics in response to environmental constraints while maintaining controlled shape changes.

Inventive Principle:

Principle #15Dynamics

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

Enables soft robots to conform to complex shapes, such as those found in human arteries, without damaging the walls and to perform specific tasks by transitioning through multiple shapes and orientations, ensuring safe navigation and effective procedure execution.

Implementation Method 1

the fiber orientation of pitch is free to vary in any direction along the actuator body

Methodology Applied

Scientific EffectMaterial anisotropy: Anisotropy

Implementation Method 2

In the presence of a fluid medium, the FREE actuator experiences uniform change in shape

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS10760597B2Soft robots, soft actuators, and methods for making the same

Publication Date: 2020.09.01 REGENTS OF THE UNIVERSITY OF MINNESOTA

AI summary

A material-mapped actuator useful as, or as part of, a soft robot along with automated methods of design and manufacture. The actuator exhibits mechanical properties that spatially vary along a coordinate system of the actuator. The actuator body has an initial shape with a corresponding initial map of mechanical attributes consisting of locally-varying stiffness at each point in a volume of the actuator body. The actuator is configured to change to a different shape or distribution of mechanical properties upon being activated by an actuation medium. The map of mechanical attributes influences and determines the new shape or distribution. The material-mapped actuator can incorporate a spatially-varying distribution of mechanical properties that dictates multiple desired shapes as the actuation medium is applied, including an actuation sequence in which the actuator transitions from a first shape to a desired intermediate shape(s), and from the intermediate shape to a desired final shape.