Soft Pneumatic Prosthetic Fingers for Low-Pressure Hand Actuation
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Solution Overview
Problem
Current prosthetic devices for upper limb amputees are either aesthetically appealing but non-functional or high-cost, high-weight robotic devices that are not widely adopted due to their limitations in light weight actuation methods.
Innovation Solution
A prosthetic hand with soft pneumatic fingers using fluidically interconnected extensible segments and a control system that employs compressors and valves to pressurize the fingers, allowing for lightweight and efficient actuation, incorporating a microprocessor for muscle voltage sensing and actuator control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional robotic actuators are used in prosthetic hands, then motor control and strength are improved, but weight and cost increase significantly
Solution Approach 1:
The patent employs pneumatic actuators using soft elastomeric material with embedded inextensible layers. Compressed air or gas is introduced into chambers within the elastomeric structure to generate actuation forces for finger movement, replacing traditional heavy robotic motors with lightweight pneumatic systems.
Solution Approach 2:
The actuator uses soft elastomeric material as a flexible shell that can deform under pneumatic pressure. The elastomeric material forms the structural basis of the actuator, allowing bending and articulation while maintaining structural integrity through embedded inextensible layers.
2Weight of moving object
If pneumatic actuators are used in prosthetic hands, then weight is reduced, but actuation pressure requirements increase
Solution Approach 1:
The actuator combines soft elastomeric material with embedded inextensible layers (such as fabric, mesh, or rigid strips) to create a composite structure. The inextensible layers provide structural support and constrain deformation, allowing the pneumatic system to achieve effective actuation at lower pressures by preventing unwanted expansion and directing force efficiently.
Solution Approach 2:
The patent modifies the physical parameters of the actuator structure, including the thickness and distribution of elastomeric material, the configuration of inextensible layers, and chamber geometry. These parameter changes optimize the pressure-displacement characteristics to reduce required actuation pressure while maintaining effective finger movement.
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 solution provides a lightweight and efficient prosthetic hand capable of mimicking natural hand movements with reduced pressure requirements, suitable for wider adoption and improved functionality in prosthetic devices.
Implementation Method 1
fingers which are pneumatic/hydraulic actuators that bend when filled with pressurized gas/liquid from compressors/pumps
Implementation Method 2
fingers which are pneumatic/hydraulic actuators that bend when filled with pressurized gas/liquid
Implementation Method 3
the extensible segments comprise at least one fluidically interconnected inflatable chamber, and the extensible segments comprise an outer wall selected to constrain radial expansion
Implementation Method 4
an inextensible layer connected to the extensible segments at a base of the extensible segments, the inextensible layer comprising a flexible polymer and having an embedded inextensible layer that extends along the length of the finger actuator
Data Source
Figure 1
Figure 2A~2C
Figure 3A
AI summary
A finger actuator, includes a plurality of fluidically interconnected inflatable chambers, wherein each chamber comprises outer walls having an embedded extensible layer selected to constrain radial expansion and freestanding inner walls; and an inextensible layer connected to the chambers at a base of the chambers, the inextensible layer comprising a flexible polymer and having an embedded inextensible layer that extends along the length of the finger actuator.