Myoelectric Postural Controller for Prosthetic Hand

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Traditional prosthetic devices allow only a single posture or a limited number of pre-defined postures, restricting the functionality and versatility of multi-function prostheses, especially in controlling joint angles and postural adjustments.

Innovation Solution

A myoelectric postural controller system that uses EMG signals to determine desired joint angles through a postural control space, allowing for continuous morphing between postures, incorporating a conversion module and joint angle transformer to map EMG signals to joint angles, and a feedback controller to adjust the prosthetic device's actuators, enabling a wide range of postures without the need for trigger commands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional prosthetic devices use pre-defined postures with trigger commands, then the device complexity is reduced, but the adaptability and versatility of the prosthesis are limited

Engineering Contradiction:

Improveposture versatilityVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic posture control by allowing continuous adjustment of joint angles through EMG signal processing. The system transitions from static pre-defined postures to dynamic, real-time posture generation by mapping EMG signals to joint angle space and allowing morphing between postures based on user intent.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the control parameter from discrete trigger commands to continuous EMG signal amplitudes. By processing EMG signals through a postural controller that maps to joint angle space, the system enables continuous variation of posture parameters rather than switching between fixed states.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the prosthesis allows continuous morphing between postures, then the ease of operation is improved, but the device complexity increases due to additional controllers and processors

Engineering Contradiction:

Improveposture control intuitivenessVSAvoidcontroller structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The postural controller serves multiple functions: it processes EMG signals, maps them to joint angle space, determines desired postures, and generates control commands for multiple actuators. This multi-functional controller consolidates what would otherwise require separate systems for signal processing, posture determination, and actuator control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces a postural controller as an intermediary between the EMG signal processing module and the actuators. This intermediary component translates physiological signals into meaningful posture commands, bridging the gap between user intent and mechanical actuation without requiring complex direct control of each actuator.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If traditional prostheses use a single posture or limited pre-defined postures, then the reliability of the control system is improved, but the functional capability is reduced

Engineering Contradiction:

Improvecontrol system stabilityVSAvoidfunctional capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system implements feedback control by continuously monitoring EMG signals and adjusting joint angles in real-time. The postural controller receives processed EMG signals, determines desired postures based on current muscle activation patterns, and generates control commands that maintain stable operation while adapting to changing user needs.

Inventive Principle:

Principle #23Feedback

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

Enables intuitive and precise control of multi-function prosthetic devices, allowing users to achieve limitless postures and functional grasps, improving biomimetic control and robustness against real-world scenarios like electrode shift and sweat, without requiring training or advanced mathematical processes.

Implementation Method 1

The set of electrodes can be used to monitor muscle contractions and generate electromyographic (EMG) signals

Methodology Applied

Scientific EffectElectromyographic signal detection:

Data Source

PatentUS20230023282A1Systems and methods for postural control of a multi-function prosthesis

Publication Date: 2023.01.26 THE REGENTS OF THE UNIVERSITY OF COLORADO

AI summary

Systems and methods for postural control of a multi-function prosthesis are provided. Various embodiments provide for a postural controller that use EMG signals to drive a point in a posture space and outputs continuously varying joint angles for a powered prosthetic hand. The postural controller can include an EMG signal processing unit to receive signals from electrodes for processing (e.g., band pass filtering, rectification, root mean square averaging, dynamic tuning, etc.). The processed EMG signals can then be combined or converted to produce a point in the postural control domain. The PC domain map defines the posture that corresponds to each PC cursor coordinate. This map can have limitless possible postures and limitless possible positions of the postures. The Joint Angle Transform converts the PC cursor coordinate into the joint angle array which is sent to the prosthetic hand thereby creating more natural movements.