Variable-Stiffness Prosthetic Foot for Gait Stability and Energy Return
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Prosthetic feet often lack the ability to provide stability throughout the gait cycle, absorb and return elastic energy, and adapt to individual user needs, including varying weights, heights, stride lengths, and activity levels.
Innovation Solution
A prosthetic foot design featuring flexible members between joints, an actuator, and a variable stiffness control mechanism that allows for adjustable stiffness based on user-specific parameters, such as activity level and gait phase, enhancing stability and energy return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a prosthetic foot uses rigid structure to provide stability, then stability during stance phase is improved, but energy absorption and return capability deteriorates
Solution Approach 1:
The patent applies dynamics by making the prosthetic foot structure adaptable and variable rather than fixed. The system transitions between rigid and flexible states based on gait phase, using actuators to adjust the stiffness of structural elements. This allows the foot to be rigid during stance for stability and flexible during swing for energy efficiency, resolving the contradiction between stability and energy loss.
Solution Approach 2:
The patent changes physical parameters of the prosthetic foot structure dynamically. Specifically, it adjusts the stiffness parameter of structural elements using actuators and elastic components. By varying the stiffness parameter between rigid and flexible states, the system achieves both stability during stance and energy absorption during movement, resolving the contradiction between these two requirements.
2Ease of manufacture
If a prosthetic foot is designed with fixed stiffness, then manufacturing simplicity is improved, but adaptability to individual user needs deteriorates
Solution Approach 1:
The patent implements a dynamically adjustable stiffness mechanism using actuators and elastic components. This allows a single prosthetic foot design to adapt to different users and activities by changing its mechanical properties in real-time, rather than requiring multiple fixed-stiffness models. The system maintains manufacturing simplicity while achieving high adaptability through active control.
Solution Approach 2:
The patent creates a universal prosthetic foot design that can serve multiple users with different needs through its variable stiffness capability. The same basic structure can be adjusted to accommodate different weights, heights, activity levels, and gait patterns, making one design universally applicable rather than requiring user-specific customizations.
3Loss of energy
If a prosthetic foot uses passive elastic elements, then energy return is improved, but control and stability during gait cycle deteriorates
Solution Approach 1:
The patent incorporates feedback control through sensors that detect gait phase and mechanical state, feeding this information to actuators that adjust the stiffness of elastic elements in real-time. This feedback loop ensures that passive elastic elements provide energy return only when appropriate, while maintaining control and stability by actively regulating their engagement based on sensed conditions.
Solution Approach 2:
The patent uses actuators as intermediary components between the passive elastic elements and the user's movements. These actuators mediate the interaction by selectively engaging or disengaging the elastic elements, allowing energy return when beneficial while preventing instability when the elements would be detrimental. The actuator serves as a controlled intermediary that manages the passive elastic components.
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 conservation during ambulation by allowing for adjustable flexibility and resistance, accommodating individual user needs and gait patterns.
Implementation Method 1
a resilient member (e.g., a spring or elastic material) that is configured to assist with plantarflexion motion
Implementation Method 2
a magnetic component with an adjustable magnetic force
Data Source
AI summary
A prosthetic foot comprises an attachment member and two or more flexible members. The attachment member can include a connector configured to connect the attachment member to a user or another prosthetic device. The two or more flexible members can be rotatably attached to the attachment member by rotatable joints such that the flexible members can both rotate and flex relative to the attachment member when the prosthetic foot contacts the ground.