Hand Prosthesis Single Drive Grip Control
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Solution Overview
Problem
Existing hand prostheses require high control effort, are complex, and prone to failure due to integrated drives in each finger, making them costly and unreliable for realistic gripping functions.
Innovation Solution
A hand prosthesis with a common drive system that couples force transmission devices to finger prostheses in a way that different grip angles are achieved through directional rotation, allowing for simple control of 'lateral' and 'pointed' grips using a single drive housed in the chassis, with mechanical coupling and spring preloading for efficient movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate drives are integrated in each finger prosthesis, then different grip situations can be implemented, but the control effort increases and the device complexity increases
Solution Approach 1:
Multiple separate finger drives are merged into a single common drive unit. The drive shaft connects to multiple force transmission devices (cables, belts, or linkages) that simultaneously actuate multiple fingers. This consolidation reduces the number of motors and control units while maintaining the ability to perform different grip patterns through coordinated mechanical transmission.
Solution Approach 2:
The single common drive is designed to perform multiple functions by controlling different fingers for various grip patterns. Through the mechanical coupling of force transmission devices to different fingers, one drive unit can implement pointed grips, lateral grips, and other grasping motions that previously required separate drives for each finger.
2Adaptability or versatility
If separate drives are integrated in each finger prosthesis, then different grip situations can be implemented, but the susceptibility to failure increases
Solution Approach 1:
By consolidating multiple independent drive units into a single common drive, the system reduces the number of potential failure points. Fewer motors, control circuits, and power sources mean lower overall susceptibility to failure, while the mechanical force transmission mechanisms maintain the versatility needed for different grip patterns.
3Device complexity
If a common drive is used for multiple fingers, then the device complexity is reduced, but the control precision for individual fingers may be compromised
Solution Approach 1:
While using a single common drive, the force transmission to individual fingers is segmented through separate force transmission devices (individual cables, belts, or linkages) for each finger. This allows independent adjustment and optimization of each finger's mechanical advantage and movement range, maintaining control precision despite the simplified drive architecture.
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 reliable, inexpensive, and efficient gripping with reduced control effort by using a single drive for multiple fingers, achieving common grip states with minimal secondary forces and secure grip functionality.
Implementation Method 1
at least one finger prosthesis has a spring element which can be preloaded with force in the course of the movement and which can effect a restoring movement via spring preloading
Implementation Method 2
different adjustment angles can be implemented by rolling a power transmission device onto a cam disk, the radius of which is different for each direction of rotation
Data Source
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AI summary
The invention relates to a hand prosthesis comprising a chassis to which a plurality of finger prostheses are articulated, said finger prostheses being movable about at least one swiveling axis relative to the chassis and towards each other by means of a drive. The aim of the invention is to provide a hand prosthesis which has a simple control mechanism, works reliably and can be produced at low cost. For this purpose, the force transmission devices (10) on a common drive (6) are coupled to the finger prostheses (3, 4, 5) in such a manner that starting from a rest position and depending on the direction of rotation of the drive (6) at least two finger prostheses (3, 4, 5) go through different angles of adjustment relative to the chassis (2).