Prosthetic Hand With Selective Cable Stopping for Independent Fingers
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Solution Overview
Problem
Existing underactuated prosthetic hands lack the ability to independently actuate multiple fingers, limiting their functionality to a single grasp type and requiring complex, bulky structures.
Innovation Solution
A prosthetic hand with a single actuator system that includes a stopping mechanism using a cam-type mechanism and a brushless DC motor to control the movement of fingers independently, allowing selective locking or stopping of finger movements, enabling differentiated three-finger actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single actuator system is used to actuate multiple fingers, then device complexity and weight are reduced, but the ability to independently actuate each finger is limited
Solution Approach 1:
The patent divides the finger actuation system into independent controllable segments by introducing stopping mechanisms for each finger. Each finger can be independently stopped or released from the cable-driven actuation, allowing selective independent actuation while maintaining the simplicity of a single cable-driven actuator system.
Solution Approach 2:
The stopping mechanisms are designed to be dynamically controllable, allowing the system to switch between different actuation modes. The fingers can be selectively locked or unlocked during the actuation cycle, enabling independent finger movement when needed while maintaining coordinated movement when the stopping mechanisms are engaged.
2Adaptability or versatility
If stopping mechanisms are added to enable independent finger actuation, then adaptability is improved, but device complexity increases
Solution Approach 1:
The stopping mechanisms are designed as separate, extractable components that can be independently added to or removed from each finger assembly. This modular approach allows the stopping functionality to be added without redesigning the entire actuator system, minimizing the increase in overall device complexity.
Solution Approach 2:
The stopping mechanisms act as intermediary elements between the cable-driven actuator and the finger joints. They provide a simple mechanical interface that can engage or disengage the cable force from individual fingers without requiring complex control systems or multiple actuators.
3Adaptability or versatility
If multiple actuators are used for each degree of freedom, then independent finger actuation is achieved, but weight and bulk increase
Solution Approach 1:
The patent merges the actuation of multiple fingers into a single cable-driven system. By using one actuator to control a cable that can selectively actuate multiple fingers through the stopping mechanisms, the weight of multiple separate actuators is replaced by the weight of a single actuator and lightweight stopping mechanisms.
Solution Approach 2:
Instead of using multiple physical actuators, the system uses a single actuator whose effect is copied or distributed to multiple fingers through the cable transmission system. The stopping mechanisms allow this single actuation source to be selectively applied to different fingers, achieving independent actuation without the weight penalty of multiple actuators.
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 independent actuation of multiple fingers with reduced energy consumption, enhancing grasping and manipulation capabilities while maintaining a compact and lightweight design, replicating complex hand movements with a single actuator.
Implementation Method 1
a cam-type mechanism and a brushless DC motor to control the movement of fingers independently, allowing selective locking or stopping of finger movements
Implementation Method 2
a brushless DC motor to control the movement of fingers independently
Data Source
Figure 1~2
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AI summary
The invention relates to a Hannes-type hand prosthesis (1), wherein the fingers (3, 3a, 3b, 3 c) provided with phalanges (31, 32) are controlled in flexion and extension by a system of sliding cables (5, 5a, 5b) and pulleys (64, 65). A stopping device (100, 101, 103, 104, 105) acts upon a slider (62) supporting the pulleys (64, 65) for selectively stopping the movements of the fingers (3, 3a, 3b, 3c), so that, when the user commands the actuation of some of them, the other fingers will remain locked in the flexed or extended position, and vice versa.