Hip-Mounted Torque Exoskeleton for Forward Bending Support
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Solution Overview
Problem
Conventional back support devices fail to differentiate between walking and bending or sitting, leading to discomfort and hazards as they require the wearer's legs to push against the device, restricting unrestricted movement.
Innovation Solution
A trunk supporting exoskeleton with torque generators located near the hips that impose resisting torque between the trunk and thigh links only when the wearer bends forward beyond a predetermined angle, reducing muscle forces in the back and allowing unrestricted movement during other activities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a trunk support is provided to reduce the burden on the lower back, then the lower back muscle burden is reduced, but the device complexity and weight increase
Solution Approach 1:
The exoskeleton is divided into separate functional modules: thigh links that move with the wearer's thighs, a supporting trunk, and torque generators positioned at the hips. This segmentation allows each component to perform its specific function independently, reducing overall system complexity while providing effective lower back support through distributed mechanical assistance rather than a single complex support structure
Solution Approach 2:
The torque generators act as intermediary devices positioned at the hip joints, coupling the supporting trunk to the thigh links. These intermediaries generate torque to assist trunk support without requiring direct complex mechanical connections between the trunk and wearer's body, thereby reducing device complexity while maintaining support effectiveness
2Force
If continuous support force is applied to the trunk, then the trunk support effectiveness is improved, but the energy consumption increases
Solution Approach 1:
The torque generators provide support force only during specific phases of the walking cycle when the wearer bends forward beyond a predetermined angle. The system alternates between providing support torque and not providing torque, matching the periodic nature of walking. This periodic action maintains effective trunk support during needed moments while significantly reducing overall energy consumption compared to continuous force application
Solution Approach 2:
The control system monitors the wearer's trunk angle in real-time and activates the torque generators only when the trunk bends forward beyond a predetermined angle. This feedback-based control ensures support force is applied only when necessary, optimizing the balance between trunk support effectiveness and energy consumption by avoiding unnecessary force application during upright phases
3Force
If the torque generator is positioned close to the hip, then the mechanical advantage is improved, but the device complexity increases
Solution Approach 1:
The torque generators are integrated with the hip joint structure, merging the support function with the existing anatomical landmark. This positioning combines the torque generation mechanism with the natural hip rotation point, improving mechanical advantage for trunk support while minimizing additional device complexity by utilizing the hip joint as the mounting location rather than requiring separate complex transmission mechanisms
Data Source
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AI summary
A trunk supporting exoskeleton comprises: a supporting trunk; thigh links configured to move in unison with a wearer's thighs; and first and second torque generators located on both left and right halves of the wearer substantially close to the wearer's hip. The torque generators couple the supporting trunk to the thigh links, and generate torque between the thigh links and the supporting trunk. When the wearer bends forward such that a predetermined portion of the supporting trunk passes beyond a predetermined angle from vertical, a torque generator(s) imposes a resisting torque between the supporting trunk and the thigh link(s), causing the supporting trunk to impose a force against the wearer's trunk, and the thigh link(s) to impose a force onto the wearer's thigh. When the predetermined portion does not pass beyond the predetermined angle, the torque generators impose no resisting torques between said supporting trunk and respective thigh links.