Trunk-Supporting Exoskeleton With Angle-Triggered Hip Torque
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Solution Overview
Problem
Conventional back support devices fail to differentiate between walking and bending or sitting, leading to discomfort and potential hazards as the wearer's legs must push against the device during these activities, preventing unrestricted movement.
Innovation Solution
A trunk supporting exoskeleton with torque generators that generate torque between the thigh links and the supporting trunk, imposing a resisting torque only when the wearer bends forward beyond a predetermined angle, thus reducing muscle forces in the back during lumbar flexion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive spring resistance is used to create torque between torso and legs, then back injury probability is reduced, but wearer comfort during walking and sitting deteriorates due to unnecessary resistance
Solution Approach 1:
The exoskeleton employs a dynamic control system that actively adjusts torque generation based on real-time detection of wearer posture and motion state. The controller distinguishes between bending motions (where support is needed) and walking/sitting motions (where resistance should be minimized), enabling the device to adapt its mechanical assistance dynamically rather than providing constant passive resistance.
Solution Approach 2:
The system changes the torque parameter dynamically based on detected motion type. During bending activities, the torque generator activates to provide supporting moment; during walking or sitting, the torque is reduced or eliminated. This parameter modulation resolves the contradiction by providing back support only when physiologically necessary.
2Force
If constant resisting torque is applied during bending, then muscle forces in lower back are reduced, but movement freedom during normal activities is restricted
Solution Approach 1:
The exoskeleton incorporates sensors that continuously monitor wearer posture, trunk angle, and motion state, feeding this information to the controller. Based on this feedback, the controller determines whether the wearer is bending or performing normal activities like walking or sitting, and adjusts torque generation accordingly. This feedback loop enables the system to provide force reduction only when bending is detected, preserving movement freedom during other activities.
Solution Approach 2:
The torque generation is made dynamic rather than static. The system transitions between different operational states (active support during bending, minimal resistance during normal activities) based on real-time conditions, allowing the exoskeleton to adapt its mechanical properties to match the wearer's instantaneous needs.
3Stability of the object's composition
If passive back support devices provide resistance during bending, then trunk stability is improved, but unrestricted movement during walking and sitting is prevented
Solution Approach 1:
The controller uses feedback from motion sensors to detect whether the wearer is engaged in bending or normal mobility activities. When bending is detected, the system activates torque generation to enhance trunk stability; when walking or sitting is detected, the resistance is minimized or deactivated, allowing unrestricted movement. This conditional stability provision resolves the contradiction between support and mobility.
Solution Approach 2:
The control function is segmented into different operational modes: bending mode (where stability support is activated) and normal activity mode (where movement freedom is prioritized). This functional segmentation allows the device to optimize performance for each specific activity type independently, providing stability when needed and freedom when appropriate.
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 comfortable walking and sitting by minimizing muscle forces in the lower back during bending, allowing unrestricted movement without unnecessary resistance during normal activities.
Implementation Method 1
two 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 respective thigh links and are configured to generate torque between the thigh links and the supporting trunk
Implementation Method 2
when the wearer bends forward in the sagittal plane such that a predetermined portion of the supporting trunk passes beyond a predetermined angle from the vertical gravity line, at least one of the first or second torque generators imposes a resisting torque
Data Source
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.