Variable Stiffness Prosthetic Foot Plate for Lateral Roll-Over
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional prosthetic feet lack the ability to simulate natural lateral rotation and adapt to uneven terrain, leading to an unnatural feel and balance issues due to their unitary design and inability to mimic the medial to lateral roll-over motion of a natural foot.
Innovation Solution
A prosthetic foot with a variable stiffness sole plate featuring a layer with laterally varying stiffness, including a softer instep and stiffer out-step, allowing for smooth multi-axial rotation and natural roll-over on uneven surfaces, achieved through a composite material construction with a leaf spring and urethane layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a unitary foot design is used, then the structure is simple and easy to manufacture, but the foot cannot rotate laterally to accommodate uneven terrain
Solution Approach 1:
The foot plate is divided into multiple regions with different stiffness properties - a softer medial portion and a stiffer lateral portion - allowing independent rotation and adaptation to terrain variations while maintaining overall structural integrity
Solution Approach 2:
Different portions of the foot plate are assigned different stiffness characteristics to match the natural foot's behavior, with the medial side being softer for rotation and the lateral side being stiffer for stability during lateral roll-over
2Adaptability or versatility
If the forefoot is split longitudinally to create toes, then lateral rotation is enabled, but the foot bends independently in each region causing unnatural feel and balance issues
Solution Approach 1:
The foot plate incorporates regions of varying stiffness rather than splitting the structure, allowing controlled lateral rotation through material property gradients while maintaining continuous structural integrity and balanced weight distribution
Solution Approach 2:
The foot plate uses composite material construction with varying stiffness properties across different regions, enabling lateral rotation capability while maintaining overall structural stability and natural feel through carefully engineered material distribution
3Adaptability or versatility
If a unitary sole plate is used, then manufacturing is simple, but the foot cannot provide smooth multi-axial rotation on uneven terrain
Solution Approach 1:
The sole plate's stiffness parameter is varied laterally across its width, creating a gradient from softer medial regions to stiffer lateral regions that enables smooth multi-axial rotation while maintaining a relatively simple monolithic structure that can be manufactured as a single piece
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
Enables the prosthetic foot to maintain balance and maneuver effectively on varied terrain by providing a natural medial to lateral roll-over motion, enhancing the user's ability to navigate uneven surfaces during walking and physical activities.
Implementation Method 1
The lateral portion can have a stiffness different than a stiffness of the medial portion... providing a relatively softer instep and a relatively stiffer out-step... providing smooth and steady multi-axial rotation laterally across the forefoot region
Data Source
AI summary
A foot plate for a prosthetic foot includes a sole plate and a layer with laterally variable stiffness disposed above the sole plate. The layer has a medial portion and a lateral portion. The lateral portion has a stiffness different than a stiffness of the medial portion, such as a greater stiffness to provide a relatively softer instep and a relatively stiffer out-step.