Sensor-Based Prosthetic Digit Control via Motion Path Detection
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Solution Overview
Problem
Conventional upper limb prostheses rely on muscle flexion to generate electrical signals for digit movement, lacking the ability to automatically move digits based on predetermined user movements sensed by sensors.
Innovation Solution
A prosthetic apparatus with sensors that detect user movements and provide a sensed path output, allowing a processor to actuate the digits in a predetermined fashion, enabling automatic movement without user muscle activation, using a combination of sensors like accelerometers, gyroscopes, and magnetometers for precise movement tracking and wireless communication for control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If myoelectric signals from muscle flexion are used to control digit movement, then the prosthesis can be actuated by the user's residual limb, but the control requires active muscle engagement and does not enable automatic movement based on natural body gestures
Solution Approach 1:
The patent replaces the myoelectric control system (which requires muscle flexion) with a sensor-based system that detects natural body movements. Sensors attached to the user's body track movement paths and trigger prosthesis actions automatically, substituting the mechanical muscle-flexion interface with a non-invasive motion detection system that enables more intuitive and automatic control.
Solution Approach 2:
The system enables the user's natural body movements to directly control the prosthesis without requiring additional active effort. The sensors automatically detect and interpret the user's gestures, and the processor autonomously translates these into appropriate prosthesis actions, making the system serve itself by leveraging the user's natural motion patterns.
2Extent of automation
If sensors are used to detect user movement paths, then automatic prosthesis actuation is enabled, but the system complexity increases with multiple sensors and processing requirements
Solution Approach 1:
The patent employs multiple sensors (accelerometers, gyroscopes, magnetometers) that serve multiple functions: they detect movement paths, determine orientation, track position, and identify gesture types. This multi-functional approach allows a single sensor suite to handle various control requirements, reducing the need for separate specialized components and managing system complexity through functional integration.
Solution Approach 2:
The processor acts as an intermediary that receives raw sensor data, interprets movement paths, compares them against stored reference paths, and generates appropriate control signals. This intermediary layer simplifies the overall system by centralizing the complex decision-making logic, allowing the sensors and actuators to remain relatively simple while the processor handles the intelligence required for automatic actuation.
3Measurement precision
If the prosthesis requires precise sensor movement detection for automatic actuation, then movement precision is improved, but the system becomes more sensitive to measurement errors and environmental interference
Solution Approach 1:
The patent combines multiple sensor types (accelerometers for acceleration, gyroscopes for rotation, magnetometers for orientation) to create a complementary sensor system. Each sensor type measures different aspects of movement, and their combined data provides a more robust and accurate representation of the user's gesture. This fusion of multiple measurement modalities improves reliability by compensating for the limitations and vulnerabilities of individual sensors.
Solution Approach 2:
The system continuously monitors sensor output and compares actual movement paths against predetermined reference paths stored in the processor. This feedback mechanism allows the system to verify that detected movements match intended gestures, filter out noise and erroneous readings, and make real-time adjustments to maintain accurate control despite measurement uncertainties or environmental interference.
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 automatic and precise movement of prosthetic digits in response to predetermined user movements, enhancing functionality and independence from muscle-activated control methods, allowing for complex gestures and actions like pointing or grasping without manual actuation.
Implementation Method 1
The at least one sensor may comprise an accelerometer. The accelerometer may be operative to sense the inclination of movement.
Implementation Method 2
The at least one sensor may comprise a magnetometer. The magnetometer may be operative to sense the azimuth (i.e. compass direction) of movement.
Implementation Method 3
The at least one sensor may comprise a gyroscope. The gyroscope may be operative to sense a direction of movement.
Data Source
Figure 1
AI summary
The invention provides a prosthetic apparatus (10) and method of operating the same. The prosthetic apparatus (10) includes an upper limb prosthesis (12) comprising at least one mechanically operable digit (14) and at least one sensor configured to be disposed on the user. The at least one sensor being operative to sense a path described by the sensor during movement thereof by the user and to provide a sensed path output in dependence upon the path. The apparatus (10) also includes a processor (24) operative to provide for actuation of the at least one digit (14) in dependence on the sensed path output having a predetermined characteristic and such that the at least one digit (14) moves in a predetermined fashion.