Multimodal Hinge Joint Torque Control for Natural Prosthetic Motion
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Solution Overview
Problem
Existing prostheses and orthoses with hinge joint systems struggle to accurately replicate the complex cyclic sequence of limb movements, leading to discomfort and instability, especially in varied operational conditions such as walking on slopes or with different speeds.
Innovation Solution
A hinge joint system comprising a first member, a second member, a passive elastic element, and a torque controlling mechanism, which allows for three modes of operation to adapt to different conditions, enhancing the comfort and reliability of the prosthesis or orthosis, and enabling a more natural motion in humanoid or animal-inspired robots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a complex mechanism is used to accurately transition between different phases of cyclic sequence, then the comfort and naturalness of prosthesis/orthosis is improved, but the weight of the mechanism increases
Solution Approach 1:
The mechanism is divided into multiple independent components: a first elastic element for energy storage, a second elastic element for torque control, a clutch mechanism with multiple modes, and a damping element. Each component performs a specific function, allowing the system to achieve complex cyclic motion control without requiring a single heavy complex mechanism.
Solution Approach 2:
The clutch mechanism provides dynamic switching between multiple operational modes (first mode, second mode, third mode) that allow the system to adapt to different phases of the cyclic sequence. This dynamic adaptability enables accurate transition control while maintaining lighter weight through selective engagement of mechanical elements rather than continuous complex actuation.
2Weight of moving object
If a simplified hinge joint system is used, then the weight of the mechanism is reduced, but the ability to accurately reproduce joint motion and maintain balance is compromised
Solution Approach 1:
The first elastic element is pre-configured to store energy during specific phases of the cyclic sequence (e.g., during stance phase in walking), and the second elastic element is pre-set to provide appropriate torque control. This preliminary energy storage and torque preparation enables accurate reproduction of joint motion dynamics without requiring heavy real-time actuation systems.
Solution Approach 2:
The combination of elastic elements and damping elements creates a passive feedback mechanism that automatically adjusts torque and energy storage based on the phase of motion. The system responds to mechanical conditions (load, velocity, position) through the inherent properties of the elastic and damping elements, maintaining balance and motion accuracy without complex active control systems.
3Adaptability or versatility
If a hinge joint system with multiple modes of operation is implemented, then the adaptability to different operational conditions is improved, but the device complexity increases
Solution Approach 1:
The clutch mechanism serves multiple functions: it engages/disengages the first elastic element, controls the second elastic element, and provides damping through the damping element. This multi-functionality allows the system to adapt to different operational conditions (level walking, slopes, different speeds) without requiring separate mechanisms for each condition, thereby managing complexity while maintaining versatility.
4Ease of operation
If energy storage and release mechanisms are added to reproduce double pendulum motion, then the naturalness of limb movement is improved, but the manufacturing complexity increases
Solution Approach 1:
The elastic elements and damping element are configured to automatically perform energy storage, energy release, and damping functions based on the mechanical conditions of motion. The system serves itself by utilizing the inherent properties of these components rather than requiring external control systems or complex manufacturing assemblies, thereby achieving natural double pendulum-like motion with manageable manufacturing complexity.
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
The proposed hinge joint system improves the comfort and adaptability of prostheses and orthoses by accurately controlling the motion through various modes of operation, effectively mimicking human joint movements, and ensuring stability across different operational conditions.
Implementation Method 1
The passive elastic element is configured for storing energy when a load is applied to it. The load applied to it may be the result of an applied torsion, elongation, tension, and/or pressure
Implementation Method 2
The torque controlling mechanism is configured for controlling a torque around the first axis in at least three modes of operations: a first mode wherein load is not transmitted, a second mode wherein load is transmitted in one working direction and not transmitted in the other working direction, and a third mode wherein load is transmitted in both working directions
Data Source
AI summary
A prosthesis or orthosis comprising a c system comprising: a first member (100); a second member (200) pivotally coupled to the first member around a first axis; a passive elastic element (210) fixed to the second member and acting on the rotation around the first axis; a torque controlling mechanism (300) mounted between the first member and the passive elastic element. The torque controlling mechanism is configured for controlling a torque around the first axis in three modes of operations: a first mode wherein load is not transmitted between the first member and the passive elastic element in both working directions of the passive clastic element; a second mode wherein load is transmitted between the first member and the passive elastic element in one working direction and not transmitted in the other; a third mode wherein load is transmitted between the first member and the passive elastic element in both working directions.