Prosthetic Foot With Removable Blades for Adjustable Gait Stability
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Solution Overview
Problem
Prosthetic feet often lack the ability to provide stability and energy absorption during the gait cycle, and do not adequately adapt to individual user needs in terms of weight, height, stride length, and activity level, with limited adjustability and variable stiffness.
Innovation Solution
A prosthetic foot design featuring flexible members between joints, adjustable stiffness control, and an actuator that can be manually or automatically controlled to enhance stability and energy conservation, allowing for medial-lateral and twist movements, and incorporating sensors for adaptive adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a prosthetic foot uses fixed rigid structure, then manufacturing is simple, but it cannot provide stability and energy absorption during gait cycle
Solution Approach 1:
The prosthetic foot is divided into multiple segments including a rigid shell and flexible members (blades) that can move independently. The flexible members are segmented into multiple blades that can flex and rotate relative to each other, allowing the structure to adapt to gait requirements while maintaining manufacturing simplicity of individual components.
Solution Approach 2:
The prosthetic foot transitions from a static rigid structure to a dynamic system where flexible members can rotate and flex during the gait cycle. The blades are designed to rotate about axes and flex under load, providing energy absorption and stability adaptively during different phases of walking.
2Adaptability or versatility
If a prosthetic foot uses fixed stiffness, then device complexity is low, but it cannot adapt to individual user needs and activity levels
Solution Approach 1:
The stiffness of the prosthetic foot is adjusted by changing the position of adjustable members along the flexible blades. By moving these adjustable members to different positions, the effective length and stiffness of the blades can be modified to match different user weights, activity levels, and gait requirements.
Solution Approach 2:
The prosthetic foot design incorporates multiple flexible blades that can be independently adjusted, allowing a single device to serve multiple users with different requirements. The same basic structure can be adapted for various activity levels from walking to running by adjusting the blade configurations.
3Loss of energy
If a prosthetic foot absorbs and returns elastic energy, then energy conservation is enhanced, but device complexity increases due to spring and resilient members
Solution Approach 1:
The flexible members are constructed as thin blade-like structures that can bend and flex under load. These blades act as elastic energy storage elements, absorbing energy during loading and returning it during push-off, without requiring complex spring mechanisms or resilient materials.
Solution Approach 2:
The flexible blades are designed to dynamically respond to loading conditions, flexing under weight bearing to store elastic energy and then recovering to return that energy during the propulsive phase of gait. This dynamic behavior provides energy conservation through the natural elasticity of the blade structures.
4Reliability
If a prosthetic foot provides medial-lateral and twist movement, then stability during stance is improved, but control precision becomes more difficult
Solution Approach 1:
The flexible foot is divided into multiple blades that can move independently in different directions. Each blade can rotate about its axis and flex laterally, allowing the system to accommodate complex movements including medial-lateral motion and twisting while maintaining control through the segmented modular structure.
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 design provides improved stability and energy efficiency during ambulation, accommodating individual user needs through adjustable stiffness and sensor-driven adaptations.
Implementation Method 1
the resilient member can be a linear or non-linear spring or other resilient member configured to absorb and return elastic energy
Implementation Method 2
a friction member, such as a friction disc or friction pad, that provides frictional resistance to movement of the flexible element in a direction transverse to its longitudinal axis
Data Source
AI summary
A prosthetic foot can include an attachment member, at least one first brace, at least one first flexible member, an unpowered actuator, at least one second brace, and at least one second flexible member. The attachment member can include a connector configured to connect the attachment member to a user or another prosthetic device. The at least one first brace can mount to the attachment member and the at least one first flexible member can connect to the attachment member by the at least one first brace such that a force between the ground and the attachment member can be supported by the at least one first flexible member. The unpowered actuator can mount to the attachment member and the at least one second brace can be mounted to the actuator. The at least one second flexible member can connect to the attachment member by the at least one second brace such that a force between the ground and the attachment member can be supported by the at least one second flexible member.