Adaptable Prosthetic Foot Linkage System for Mediolateral Motion
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Solution Overview
Problem
Conventional prosthetic foot designs fail to adequately replicate the anatomical chain of movement, leading to issues with mediolateral stresses and discomfort, particularly on uneven surfaces, which can cause chronic disabilities and reduce physical performance.
Innovation Solution
The development of a prosthetic foot with a series of articulations enabled by linkage systems that allow for medial-lateral motion, including pronation and supination, mimicking the natural foot's movement to improve balance and stability on various terrains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional prosthetic foot designs are used, then the structure is simple and easy to manufacture, but the device cannot accommodate mediolateral motions and sideways stresses on uneven ground
Solution Approach 1:
The prosthetic foot is divided into multiple segments including a rearfoot assembly with heel assembly and rearfoot shell, a midfoot assembly with linkage systems, and a forefoot assembly. These segmented components are connected through articulations that enable independent motion in different planes, allowing the device to accommodate mediolateral motions while maintaining manageable structural complexity through modular design
Solution Approach 2:
The prosthetic foot incorporates dynamic linkage systems with articulations that allow the structure to adapt its configuration during use. The linkage systems include movable connections between the rearfoot, midfoot, and forefoot assemblies, enabling the device to dynamically respond to terrain variations and user movement patterns rather than maintaining a fixed rigid structure
2Object-affected harmful factors
If conventional prosthetic foot designs are used, then the manufacturing process is simple, but the device causes skin breakdown and pain at the residual limb due to shear stresses
Solution Approach 1:
The dynamic linkage systems with multiple articulations allow the prosthetic foot to adapt to uneven terrain and user movement, reducing shear stresses transmitted to the residual limb by distributing forces through the articulated structure rather than transmitting them directly through a rigid connection
Solution Approach 2:
The linkage systems act as intermediary elements between the ground reaction forces and the residual limb, with the articulated connections serving as force-distributing mechanisms that reduce peak shear stresses at the socket interface through mechanical advantage and force distribution across multiple connection points
3Adaptability or versatility
If conventional prosthetic foot designs are used, then the device structure is simple, but it cannot accommodate variations in leg position on uneven ground or during cognitive tasks
Solution Approach 1:
The prosthetic foot is segmented into rearfoot, midfoot, and forefoot assemblies that can move independently relative to each other through the linkage systems, allowing each segment to adapt to different positional demands while maintaining overall structural integrity
Solution Approach 2:
The articulated linkage systems provide dynamic adaptability allowing the prosthetic foot to accommodate variations in leg position during walking, running, dancing, and cognitive tasks by enabling real-time adjustment of foot orientation and position through the movable articulations
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
Enhances walking and running capabilities, reduces discomfort and skin breakdown, and allows for participation in recreational activities by accommodating uneven surfaces and variations in leg position, thereby improving overall physical performance and reducing the risk of chronic diseases.
Implementation Method 1
a first tension bearing element with a first end pivotally coupled to a first end of the first lower portion and a second end pivotally coupled to a second end of the first upper portion
Implementation Method 2
a first upper portion having a first contact surface, (ii) a first lower portion having a second contact surface, wherein the second contact surface contacts the first contact surface
Data Source
AI summary
A device is provided to allow adaptation of a prosthetic or robotic foot in the medial-lateral direction, including pronation and supination of the foot using a series of articulations. Articulations are permitted in the disclosed device due to linkage systems positioned at various locations of the prosthetic foot. In particular, the device includes multiple connected linkage systems each including upper and lower portions with an articulating contact surface designed for load carriage and stability. The point of contact between the contact surfaces of each linkage system comprises the position-dependent instantaneous center of rotation of the upper portion with respect to the lower portion. The device also includes a platform coupled between the linkage systems and a base.