Actuated Prosthetic Ankle Adjusts Angle for Relaxed Posture
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Solution Overview
Problem
Conventional prosthetic and orthotic devices lack the ability to mimic the natural movement of a healthy ankle, leading to movement instability, high energy expenditure, and gait deviations in users, particularly for leg orthoses and prostheses.
Innovation Solution
A self-powered prosthetic or orthotic system with a sensor and control system that actively adjusts the angle between a foot unit and a lower limb member to mimic the natural movement of a healthy ankle, using an actuator and sensor assembly to monitor and process movement data for real-time adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional passive prosthetic and orthotic devices are used, then device simplicity is maintained, but movement stability and energy efficiency deteriorate
Solution Approach 1:
The prosthetic device uses the user's own movement to power the actuator through the energy storage mechanism, eliminating the need for external power sources. The system serves itself by converting the user's mechanical energy into controlled movement assistance, thereby improving movement stability without requiring complex external power systems
Solution Approach 2:
The device transitions from a static passive structure to a dynamic system that actively adjusts ankle angle in response to user movement. The actuator dynamically modifies the ankle angle based on real-time movement detection, enhancing movement stability while maintaining relatively simple device architecture through adaptive behavior
2Use of energy by moving object
If conventional passive devices are used, then device complexity is reduced, but energy expenditure by the user increases
Solution Approach 1:
The system captures and stores energy from the user's natural movement through the energy storage mechanism, then reusesthis energy to power the actuator that assists movement. This self-service energy management reduces the user's overall energy expenditure while avoiding the need for complex external power systems
Solution Approach 2:
The energy storage mechanism operates periodically, accumulating energy during certain phases of movement and releasing it during other phases. This periodic energy capture and release cycle reduces the user's energy expenditure while maintaining a relatively simple device structure without continuous power input
3Adaptability or versatility
If basic controllers are used, then device complexity is minimized, but adaptability to dynamic conditions deteriorates
Solution Approach 1:
The system incorporates sensors that detect user movement and provide feedback to the control mechanism. This feedback loop enables the actuator to adjust the ankle angle in response to dynamic conditions, significantly improving adaptability while adding only moderate complexity through the sensor-feedback-actuator integration
Data Source
AI summary
Systems and methods for sensing actuating a prosthetic ankle are disclosed. In one example, the system, such as an actuated prosthetic ankle joint, detects that the user has moved to a relaxed position, such as sitting, reclining, crawling, or leaning. In response, the actuated prosthetic ankle joint actively adjusts the angle between the members of the ankle to a relaxed state. The system may further detect when the user has moved to exit the relaxed position, and may actively adjust the angle between the members of the ankle to an exit state.