Asymmetric Soft Robotic Actuators for Pressure-Driven Bending
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Solution Overview
Problem
Existing soft robotic manipulators have limited actuation capabilities and are not well-suited for applications requiring delicate object manipulation or handling objects with significant part-to-part variance, as they often rely on rigid skeletons that can only perform contraction and extension.
Innovation Solution
The development of soft robotic actuators with a flexible or elastic elongate body that can be pressurized or depressurized to bend, featuring a repeating variable wall portion and tunable parameters such as wall thickness and pitch, allowing for specific pressure-actuated changes and designed using quantitative modeling techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid skeletons are used in soft robotic manipulators, then structural strength is improved, but actuation capability and adaptability deteriorate
Solution Approach 1:
The patent employs flexible elastomeric shells with asymmetric wall thicknesses to replace rigid skeletons. The thin film structure allows the manipulator to conform to delicate objects while maintaining sufficient structural integrity through strategic thickness variation, resolving the contradiction between strength and adaptability.
Solution Approach 2:
The patent varies wall thickness parameters asymmetrically across different regions of the elastomeric shell. By changing the thickness parameter from uniform to asymmetric distribution, the structure achieves both mechanical strength where needed and flexibility where required, enabling diverse actuation capabilities.
2Ease of operation
If McKibben actuators are used, then contraction and extension capability is improved, but mode of actuation diversity deteriorates
Solution Approach 1:
The patent introduces asymmetric wall thicknesses in the elastomeric shell, creating inherent geometric asymmetry that enables bending and directional actuation. This asymmetric design allows the same pressurized structure to produce multiple motion modes (bending, twisting, elongation) rather than just contraction, diversifying actuation capabilities.
Solution Approach 2:
The patent creates dynamically adaptable structures where the elastomeric shell can transition between different actuation modes based on pressure distribution and wall thickness variations. The structure is not fixed to a single motion type but can dynamically adjust its actuation mode to suit different task requirements.
3Ease of manufacture
If uniform wall thickness is used in elastomeric bodies, then manufacturing simplicity is improved, but pressure sensitivity and actuation precision deteriorate
Solution Approach 1:
The patent applies different wall thicknesses to different local regions of the elastomeric shell. This local quality variation creates asymmetric structures that are highly sensitive to pressure changes in specific areas, enabling precise control and actuation while maintaining overall manufacturing feasibility through additive or layered fabrication approaches.
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
These actuators can perform new fundamental motions, offer a broad and tunable dynamic range, reduce strain, and enhance reproducibility, making them suitable for various applications including medical devices and surgical instruments with improved control and reduced mechanical interference.
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
Data Source
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.