Asymmetric Soft Robotic Actuators for Tunable Pressure Bending

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Solution Overview

Problem

Existing soft robotic manipulators have limited motion capabilities and are not suited for delicate or varied object manipulation due to their rigid skeletons, and there is a need for actuators with adaptable dynamics and design frameworks for quantitative modeling.

Innovation Solution

A soft robotic actuator with a flexible elongate body that can bend by varying internal pressure, featuring a repeating wall portion with adjustable parameters such as wall height, pitch, and thickness, allowing for tunable pressure sensitivity and multi-directional actuation, and can incorporate features like suction cups and granular materials for enhanced functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid robotic skeletons are integrated with soft skins, then structural strength is improved, but adaptability and ease of operation deteriorate due to limited motion capabilities

Engineering Contradiction:
Improvestructural strengthVSAvoidmotion capabilities
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent replaces rigid skeletons with flexible elastomeric bodies that can be actuated through pneumatic pressure. The soft robotic actuator comprises an elastomeric body with internal chambers that can be inflated and deflated to produce bending and motion, eliminating the need for rigid structural support while maintaining sufficient strength for the application.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses pneumatic actuation where pressurized air is introduced into internal chambers of the elastomeric body to generate motion. The flexible actuator can be inflated to a first volume for one configuration and deflated to a second volume for another configuration, enabling adaptable motion without rigid components.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Speed

If McKibben actuators are used for soft robotic actuation, then actuation speed is improved, but motion versatility deteriorates due to single-mode contraction and extension

Engineering Contradiction:
Improveactuation speedVSAvoidmotion modes
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The patent divides the elastomeric body into multiple internal chambers that can be independently actuated. By selectively inflating or deflating different chambers, the actuator can produce various motion modes including bending in different directions, twisting, and elongation, going beyond the single contraction mode of McKibben actuators.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables multi-directional actuation by arranging chambers in three-dimensional space within the elastomeric body. By pressurizing specific chambers, the actuator can bend toward different directions or twist, adding rotational and multi-planar motion capabilities that McKibben actuators lack.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If repeating wall portions with variable parameters are incorporated, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvepressure sensitivityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent incorporates repeating wall portions with variable geometric parameters such as wall height, pitch, and thickness along the length of the actuator. By changing these parameters, the actuator can be tuned to have different pressure sensitivities in different regions, enabling controlled bending and multi-directional actuation while maintaining a relatively simple overall structure.

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 actuator achieves a broad dynamic range with reduced strain and improved reproducibility, enabling complex motions and reduced mechanical interference, suitable for various applications including medical devices and surgical instruments.

Implementation Method 1

a flexible or elastic elongate body that defines a sealed void which can be pressurized or depressurized relative to the environment surrounding the actuator

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

When the internal bladder is pressurized, the pressurized air pushes against the inner bladder surface and external shell, causing the bladder to expand

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Implementation Method 3

the braided mesh shell shortens in a scissor- like action due to the non-extensibility of the threads

Methodology Applied
Scientific EffectMechanical constraint:

Data Source

PatentEP3152446B1Soft robotic actuators utilizing asymmetric surfaces
Publication Date: 2021.04.07 SOFT ROBOTICS INC
  • EP3152446B1 patent drawingFigure 1A~1D
  • EP3152446B1 patent drawingFigure 2A~2D
  • EP3152446B1 patent drawingFigure 3A~3C

AI summary

A soft robotic actuator is disclosed. The actuator includes a first portion with a substantially constant profile and a second portion with a regularly varying profile, and bends in a pressure-dependent fashion as the internal pressure within the actuator is increased or decreased. The present invention addresses the needs described above by providing actuators that are configured to perform new fundamental motions through the inclusion of design elements which can be configured, through the manipulation of a relatively short list of parameters, to undergo specific pressure-actuated changes which can be designed using quantitative modeling techniques.