Volitional Controller for Powered Prosthetic Leg Adaptation

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Solution Overview

Problem

Existing powered prosthetic controllers struggle to adapt effectively to the variability of real-world environments, such as changes in speed and incline, and often require manual tuning, which is time-consuming and not clinically viable.

Innovation Solution

The volitional controller, comprising one or more processors and hardware storage devices, determines a global shank orientation and calculates target ankle and knee torques based on virtual damping and biarticular torques, allowing for continuous adaptation without enforcing specific prosthesis positions or torques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual tuning of control parameters is used for discrete gait phases, then adaptability to specific thresholds is improved, but time consumption and device complexity increase

Engineering Contradiction:

Improveadaptability to discrete gait phasesVSAvoidtime for manual tuning

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The controller automatically adapts to gait phases and terrain changes without requiring manual tuning. The system uses sensors to detect gait phase transitions and terrain variations, then autonomously adjusts control parameters for impedance, torque, and position to match real-world conditions.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system transitions from static manual tuning to dynamic automatic adaptation. Control parameters such as impedance and torque are continuously adjusted in real-time based on detected gait phase and terrain conditions, allowing the prosthesis to adapt to varying speeds and inclines without manual intervention.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If data-driven controllers continuously adapt to speed and incline changes, then adaptability to real-world variability is improved, but loss of user-specific customization occurs

Engineering Contradiction:

Improvecontinuous adaptation to speed and inclineVSAvoiduser-specific preference alignment

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The controller dynamically changes control parameters including impedance, torque, and position based on detected gait phase and terrain conditions. These parameter adjustments enable continuous adaptation to speed and incline variations while maintaining a personalized control strategy for each user.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses sensor feedback to continuously monitor gait phase transitions and terrain variations. This feedback loop enables the controller to automatically adjust parameters in real-time, maintaining adaptability to real-world conditions while preserving user-specific customization through personalized control strategies.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the number of discrete thresholds is increased to improve function, then adaptability to different conditions is improved, but device complexity and manual tuning requirements increase

Engineering Contradiction:

Improvefunction across different conditionsVSAvoidnumber of thresholds and control parameters

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system replaces static discrete thresholds with dynamic continuous adaptation. Instead of defining separate control modes for different conditions, the controller continuously adjusts impedance, torque, and position parameters based on real-time detection of gait phase and terrain, simplifying the control architecture while improving adaptability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A single unified control algorithm handles multiple gait phases and terrain conditions without requiring separate threshold-based control modes. The controller universally adapts to various conditions through a consistent parameter adjustment strategy, reducing complexity while maintaining comprehensive functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250107907A1Powered knee and ankle prosthesis controller for adaptive ambulation

Publication Date: 2025.04.03 UNIV OF UTAH RES FOUND

AI summary

Disclosed are embodiments of a volitional controller and prosthetic leg system comprising a volitional controller and a powered prosthetic leg. The volitional controller may be configured to control a powered knee joint and a powered ankle joint to enable a user to walk at different speeds and inclines. The orientation of the components of the powered prosthetic leg may be monitored continuously to enable the system to adapt to changes in the duration of the user's gait. The volitional controller may be configured to determine a target knee torque and a target ankle torque that may be based on the global shank orientation, a prosthetic knee velocity, and a prosthetic ankle velocity.