Thumb Sensor Controls Prosthetic Grip Patterns
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Solution Overview
Problem
Current prosthetic devices with individual digit control require multiple sensors and complex control systems to interpret patient myoelectric signals, leading to clumsiness and increased errors due to the vast array of possible positions and movements.
Innovation Solution
An electronic or electromechanical thumb sensor is used to determine the position of the thumb, which serves as an indicator for specific gripping patterns, allowing the control system to reduce the complexity of movements and enable precise control with a limited number of sensors by interpreting the thumb position and adjusting the other digits accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensors and complex control systems are used to control individual digit movement in prosthetic devices, then the device can achieve a vast array of positions and movements, but the system becomes cumbersome and prone to increased errors
Solution Approach 1:
The patent extracts the thumb from the group of digits and provides it with independent control through a dedicated sensor. This separates the control of the most versatile digit from the other digits, allowing the thumb to independently select from multiple gripping patterns while the other digits are controlled more simply, thereby reducing overall system complexity while maintaining versatility
Solution Approach 2:
The control system is segmented into two parts: thumb control and other digit control. The thumb sensor independently determines gripping patterns, while the other digits are positioned according to the selected pattern. This segmentation reduces the complexity of the control system by dividing the control tasks into manageable segments
2Measurement precision
If multiple sensors are added to monitor patient myoelectric signals for accurate control of multiple digits, then positioning accuracy improves, but the system becomes more cumbersome and inconvenient for the patient
Solution Approach 1:
The patent extracts the thumb control function from the group of digits and provides it with a dedicated sensor. This allows accurate thumb positioning to be achieved with a single sensor rather than requiring multiple sensors for each digit, thereby improving positioning accuracy while maintaining patient convenience
Solution Approach 2:
The thumb position is determined first as a preliminary action that establishes the gripping pattern. This preliminary determination of thumb position allows the system to pre-select from available gripping patterns, simplifying subsequent control of other digits and reducing the number of sensors needed
Data Source
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AI summary
A method and system for determining a grip or grasp pattern of a prosthetic terminal device or other orthotic device using the position of the thumb or other digit as the initial determination of the grasping function. The system comprising sensors, an electronic control system and a motor drive.