Soft Buckling Linear Actuator Design for Precise Control
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Solution Overview
Problem
Existing soft actuators, such as McKibben actuators, face challenges including dry friction leading to heating and hysteresis, making precise positional control difficult, and they become stiff with decreasing specific tension at higher strains, while pneumatically actuated soft machines can burst under over-pressurization and increase in volume, limiting their application in confined spaces.
Innovation Solution
The development of soft buckling linear actuators that utilize buckling of elastic structural components to generate linear forces through fluid inflation or deflation, allowing for parallel actuation and mimicking biological muscle properties without volume expansion, enabling delicate object handling and sophisticated movements with simple pressure input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If McKibben actuators are used for soft actuation, then muscle-mimetic functionality is achieved, but dry friction causes heating and hysteresis making precise positional control difficult
Solution Approach 1:
The patent removes the fiber-reinforcing mesh from the traditional McKibben actuator design, extracting the source of dry friction and hysteresis. This leaves a smooth rubber balloon that can be precisely controlled while maintaining the fundamental muscle-mimetic contraction behavior
Solution Approach 2:
The patent replaces the mechanical fiber-reinforcing structure with a purely pneumatic system using a smooth rubber balloon. This substitution eliminates the mechanical friction between fibers and the surrounding mesh, replacing it with a friction-free pneumatic actuation mechanism that enables precise positional control
2Adaptability or versatility
If McKibben actuators are used, then soft actuation is achieved, but they become stiff and specific tension decreases at higher strains
Solution Approach 1:
The patent changes the material parameters by using a smooth rubber balloon with different elastic properties compared to traditional McKibben actuators. The balloon material is selected to maintain softness and high specific tension even at higher strains, fundamentally altering the stress-strain characteristics of the actuator
3Ease of operation
If conventional pneumatic soft actuators are used, then actuation is achieved, but they increase in volume when pressurized limiting use in confined spaces
Solution Approach 1:
The patent inverts the traditional pneumatic actuation approach by using negative pressure (vacuum) instead of positive pressure. The smooth rubber balloon contracts when vacuum is applied, eliminating the volume expansion problem that plagues conventional pneumatic actuators and enabling use in confined spaces
4Ease of operation
If conventional pneumatic soft actuators are used, then actuation is achieved, but they can burst when over-pressurized
Solution Approach 1:
The patent uses vacuum (negative pressure) actuation instead of positive pressure, fundamentally inverting the pressure approach. This eliminates the risk of bursting from over-pressurization, as the balloon cannot withstand negative pressure beyond its collapse point, providing inherent safety and reliability
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 soft buckling linear actuators provide efficient and precise control with scalable designs, maintaining force generation capabilities across a range of strains without volume expansion, suitable for applications requiring delicate handling and confined spaces, while maintaining thermodynamic efficiency and long-term reliability.
Implementation Method 1
utilize the buckling of one or more bucklable, elastic structural components in the actuators to generate a force
Implementation Method 2
bucklable, elastic structural components each having its longest dimension along a first axis
Implementation Method 3
actuated by deflating or over-inflating one or more cells which are inside the actuator body and structurally linked to the bucklable, elastic structural components
Data Source
AI summary
A soft buckling linear actuator is described, including: a plurality of substantially parallel bucklable, elastic structural components each having its longest dimension along a first axis; and a plurality of secondary structural components each disposed between and bridging two adjacent bucklable, elastic structural components; wherein every two adjacent bucklable, elastic structural components and the secondary structural components in-between define a layer comprising a plurality of cells each capable of being connected with a fluid inflation or deflation source; the secondary structural components from two adjacent layers are not aligned along a second axis perpendicular to the first axis; and the secondary structural components are configured not to buckle, the bucklable, elastic structural components are configured to buckle along the second axis to generate a linear force, upon the inflation or deflation of the cells. Methods of actuation using the same are also described.