Corrugated Soft Robotic Actuator for Low-Pressure Force Output

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Solution Overview

Problem

Conventional soft pneumatic actuators face limitations such as low force output, high energy losses, and limited design complexity due to material constraints like silicone and thermoplastic polyurethane (TPU).

Innovation Solution

The development of a soft robotic actuator comprising a corrugated sleeve made of TPU and a bladder made of silicone rubber, where the bladder is detachably secured inside the corrugated sleeve, allowing for controlled extension and bending by inflating/deflating the bladder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If silicone is used for soft pneumatic actuators, then high deformation properties are achieved, but force output is limited due to low Young's Modulus

Engineering Contradiction:

Improvedeformation propertiesVSAvoidforce output

Core Design Contradiction:

ShapeVSForce

Solution Approach 1:

The patent uses composite materials by combining silicone rubber (for high deformation) with TPU fabric layers (for structural support and force transmission). The multi-layer composite structure allows the actuator to achieve both high deformation properties and sufficient force output, resolving the contradiction between material softness and force generation capability.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If TPU is used for hermetic sealing, then repeatable manufacturing is achieved, but very high-pressure requirements and high energy losses occur due to increased stiffness

Engineering Contradiction:

Improvemanufacturing repeatabilityVSAvoidenergy losses

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent applies local quality by using TPU fabric layers specifically at strategic locations within the multi-layer structure where hermetic sealing and structural support are needed, rather than making the entire actuator from stiff TPU. This localized application maintains manufacturing repeatability while reducing overall stiffness and energy losses.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The multi-layer composite structure combines TPU fabric layers with silicone rubber layers, creating a hybrid material system that leverages the manufacturing advantages of TPU while mitigating its high stiffness and energy loss characteristics through the compliant silicone matrix.

Inventive Principle:

Principle #40Composite materials

3Loss of energy

If TPU-backed fabrics are used with heat sealing, then lower energy losses are achieved, but design complexity is limited and seam rupture occurs at pressures above 150 kPa

Engineering Contradiction:

Improveenergy lossesVSAvoidpressure tolerance

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent segments the hermetic sealing function from the structural function by using multiple discrete TPU fabric layers embedded within the silicone rubber matrix, rather than relying on single-layer heat-sealed fabric. This segmentation distributes stress across multiple interfaces and eliminates seam rupture issues while maintaining low energy losses.

Inventive Principle:

Principle #1Segmentation

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 configuration enables the robotic actuator to achieve desired motion and force output with lower fluid pressures, reduced energy losses, and increased design complexity, addressing the limitations of conventional actuators.

Implementation Method 1

when a fluid medium is supplied into the bladder, the bladder is inflated, thereby compressing against the interior passageway, deforming the corrugated sleeve and providing a force output at the robotic actuator

Methodology Applied

Scientific EffectPneumatics:

Implementation Method 2

deforming the corrugated sleeve and providing a force output

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

deforming the corrugated sleeve

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS20250025999A1Soft Robotic Modular and Reconfigurable Actuator

Publication Date: 2025.01.23 NATIONAL UNIVERSITY OF SINGAPORE

AI summary

The present invention describes soft robotic actuators (300,400). Each robotic actuator (300,400) is made up of a corrugated sleeve (110,110a,210,210a), an expandable blabber (120,220) and a lock member (370,480). The corrugated sleeve (110,110a,210,210a) has a hollow passageway (111,211) with a plurality of folds (112,212) extending along the passageway, with the hollow passageway extending along a length of the corrugated sleeve. The expandable blabber (120,220) is detachably inserted inside the hollow passageway (111,211) and being kept inside the corrugated sleeve (110,110a,210,210a) by the lock member (370,480). In a use application, a fluid medium is communicable into the bladder under pressure through a tubing opening formed on the lock member (370,480) results in reversible inflation of the bladder (120,220). Inflation of the bladder causes the bladder to press against and deform the corrugated sleeve, thereby generating a force output and controlled extension/bending of the robotic actuators (300,400).