Passive Exoskeleton Torque Mechanism for Forward-Leaning Support
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Solution Overview
Problem
Existing exoskeletons either lack adaptability or are heavy and expensive, and they do not provide a comfortable, cost-effective solution for maintaining a forward-leaning posture without increasing resistance beyond a certain angle.
Innovation Solution
A lightweight exoskeleton with a passive torque generation system using flexible elements that generate a pseudo-sinusoidal torque, allowing users to lean forward with adjustable support without increasing resistance, and optionally using a motorized actuator for enhanced support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If passive exoskeletons use spring resistance to create righting torque, then manufacturing and maintenance are simple and the device is lightweight, but adaptability is limited when working conditions vary
Solution Approach 1:
The patent implements a variable resistance mechanism where the mechanical advantage ratio changes dynamically with the bending angle. As the user bends forward, the resistance force increases non-linearly through a cam mechanism or variable leverage system, allowing the exoskeleton to adapt to different working conditions without requiring multiple devices or complex control systems. This dynamic adjustment maintains ease of manufacture while achieving adaptability.
2Adaptability or versatility
If active exoskeletons use actuators to generate force, then forces can be controlled and adjusted in real time, but the device becomes heavy and expensive
Solution Approach 1:
The patent replaces active actuators with a passive mechanical system that uses springs, cams, or variable leverage mechanisms to achieve real-time force adjustment. The mechanical advantage ratio changes automatically with the bending angle, providing adaptive resistance control without motors, batteries, or electronic controls. This substitution eliminates the weight and cost of active components while maintaining the ability to adjust forces in real time through pure mechanical means.
3Force
If rigid exoskeletons transmit forces perpendicular to the body, then significant force transmission is achieved, but the weight is generally higher
Solution Approach 1:
The patent employs flexible mechanical elements such as springs, elastic bands, or deformable blades instead of rigid force transmission structures. These flexible elements transmit force through their deformation and elastic recovery, achieving significant force transmission capability while maintaining a lightweight construction. The flexible nature of these elements also allows them to conform to the user's body, improving comfort without sacrificing force transmission.
4Weight of moving object
If soft exoskeletons use flexible materials, then the structure is lightweight and conforms to the body, but transmissible forces remain low
Solution Approach 1:
The patent enhances the force transmission capability of flexible materials by incorporating a variable resistance mechanism. As the bending angle increases, the mechanical advantage ratio changes to amplify the force generated by the flexible elements. This dynamic adjustment allows lightweight flexible materials to transmit significant forces during large-range bending motions, overcoming the limitation of low force transmission while maintaining the advantages of lightweight and conformal construction.
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 provides comfortable, adaptable, and cost-effective support for maintaining a forward-leaning posture, reducing musculoskeletal strain by varying torque based on user inclination, without continuous energy consumption.
Implementation Method 1
an elastically deformable member (8), whose deformation in tension along a rectilinear path produces a force whose magnitude is linearly proportional to its deformation
Implementation Method 2
the upper and lower supports being articulated to each other in rotation, in the same plane, around an axis of articulation
Implementation Method 3
a longitudinal transmission element (7), flexible and inextensible, having a first end connected, at a first point of attachment, to the lower support (6), and a second end connected, at a second point of attachment, to a first part, called mobile, of an elastically deformable member
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to an exoskeleton (E) for assisting a user in maintaining a leaning forward posture and in straightening up, comprising a dorsal structure (1) and two thigh connection structures (2) joined by a passive torque-generating device (3). The device (3) additionally comprises, for each structure (2), a transmission element (7) connected on the one hand to a lower support (6) coupled to the structure (2) and, on the other hand, to an elastically deformable member (8) coupled to the upper support (5), itself coupled to the structure (1), the transmission element (7) bearing against first and second bearing points integral with the upper and lower supports (5, 6), in such a way that, during use, a straightening-up torque in accordance with a pseudo-sinusoidal law is applied between the dorsal structure (1) and each thigh connection structure (2).