Exoskeleton Supporting Arm Weight via Counterbalancing Springs
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Solution Overview
Problem
Existing exoskeletons fail to accurately follow the natural movements of a user's arm and balance the weight of the arm effectively, often requiring user effort and lacking self-supporting capabilities.
Innovation Solution
The exoskeleton features an articulated and extendable supporting arm construction with counterbalancing springs and a tension wire mechanism to mimic natural arm movements, providing weight compensation and adjustable support, while being entirely passive to enhance user comfort and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing exoskeletons use fixed structural designs, then manufacturing is simplified, but they fail to accurately follow natural arm movements and adapt to individual arm dimensions
Solution Approach 1:
The exoskeleton arm construction is divided into multiple segments including upper arm module, forearm module, and hand module, each with independent degrees of freedom. This segmentation allows each module to move independently following natural arm kinematics while maintaining manufacturing simplicity through modular standard components
Solution Approach 2:
The exoskeleton employs dynamic structural elements including movable joints with multiple degrees of freedom, adjustable link lengths, and flexible connections that adapt to natural arm movements. The structure transitions from static to dynamic configuration to match user arm kinematics without requiring complex active control systems
2Ease of operation
If existing exoskeletons use active drives and motors, then movement capability is enhanced, but weight compensation becomes less effective and user comfort decreases
Solution Approach 1:
The exoskeleton employs passive elastic elements including springs and elastic bands arranged in antagonistic pairs that automatically balance arm weight through mechanical counterbalancing. The elastic elements store and release energy during arm movement, providing weight compensation without active motors or power sources
Solution Approach 2:
The exoskeleton system is entirely self-powered through passive elastic energy storage and release mechanisms. The elastic elements automatically adjust to user arm movements and provide continuous weight compensation without external power sources, active control systems, or user energy input
3Adaptability or versatility
If existing exoskeletons bear on user body weight for support, then structural simplicity is maintained, but they lack self-supporting capabilities and require user effort
Solution Approach 1:
The exoskeleton pre-configures elastic elements including springs and elastic bands in antagonistic arrangements that are pre-loaded to automatically counterbalance arm weight before movement begins. This preliminary elastic energy storage enables immediate self-supporting capability without requiring user activation or effort
Solution Approach 2:
The passive elastic mechanism enables the exoskeleton to automatically support and balance the user's arm weight without relying on user body weight or external power sources. The system serves itself through inherent elastic energy storage and release, eliminating the need for user effort to maintain support
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 exoskeleton effectively follows natural arm movements, balances the user's arm weight, and provides self-supporting capabilities without relying on user body weight, making it suitable for conditions like Duchenne muscular dystrophy, with improved stability and adaptability to individual arm dimensions.
Implementation Method 1
the supporting arm construction has two limbs that connect to each other with a hinge, and that on opposite sides of the hinge the limb that is farthest away from the back support connects to counterbalancing springs
Implementation Method 2
the parallelogram mechanism has guide wheels that guide a tension wire so as to provide a weight compensating upward force to the parallelogram mechanism
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Exoskeleton (1) for supporting a user's arm, comprising a supporting frame (2) that supports an up-and-down movable standard (3, 3') on which a horizontally movable arm (4, 4') is mounted, wherein on an extremity of the horizontally movable arm (4, 4') a back support (5, 5') is mounted and a supporting arm construction (6, 6') for supporting the user's arm. The horizontally movable arm (4, 4') is articulated. The supporting arm construction (6, 6') is articulated and extendable so as to tailor the arm construction (6, 6') to the users arm dimensions. Further the supporting arm construction (6, 6') has two limbs (7, 8; 7', 8') that connect to each other with a hinge (9, 9'), and that on opposite sides of the hinge (9. 9') the limb (8, 8') that is farthest away from the back support (5, 5') connects to counterbalancing springs (10, 11; 10', 11') that on their opposite sides connect to the upper limb (7, 7') and directly or indirectly to the horizontally movable arm (4, 4').