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, causing discomfort and potential hazards due to the wearer's legs pushing 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, 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 system dynamically adjusts the engagement of torque generators based on detected movement type. During walking and sitting, the torque generators remain disengaged allowing free movement. During forward bending, the torque generators engage to provide support torque. This dynamic switching resolves the contradiction by making the system adaptive to different operational states rather than maintaining constant resistance.
Solution Approach 2:
The system incorporates sensors that detect the wearer's movement state (walking, sitting, or forward bending) and use this feedback to control the engagement of torque generators. When forward bending is detected, the feedback signal activates the torque generators to provide support. This feedback mechanism ensures the system provides assistance only when needed, eliminating unnecessary resistance during normal activities while maintaining back support during hazardous movements.
2Force
If torque generators engage continuously to support the trunk, then muscle forces in the back are reduced, but movement freedom deteriorates during normal activities like walking and sitting
Solution Approach 1:
The torque generators are designed to dynamically engage and disengage based on real-time detection of forward bending movement. During normal activities like walking and sitting where no forward bending occurs, the torque generators remain disengaged, allowing full movement freedom. When forward bending beyond a threshold angle is detected, the torque generators engage to reduce back muscle forces. This dynamic operation mode resolves the contradiction between force support and movement freedom.
3Reliability
If the exoskeleton provides resistance during forward bending, then back support is improved, but device complexity increases due to differentiation mechanisms
Solution Approach 1:
The exoskeleton system uses the wearer's own movement characteristics (the physical act of forward bending beyond a certain angle) to automatically trigger torque generator engagement. The system differentiates between activities by detecting whether the trunk movement exceeds the predetermined angle threshold, eliminating the need for complex external control mechanisms. This self-service approach resolves the contradiction by using simple geometric detection rather than complex differentiation systems.
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, sitting, and other movements without unnecessary resistance, effectively reducing muscle forces in the lower back by providing support only when needed.
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 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 between the supporting trunk and at least one of the thigh links. This causes the supporting trunk to impose a force against the wearer's trunk
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.