Lower Limb Rehabilitation Device with Self-Aligning Articulations
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Solution Overview
Problem
Existing lower limb rehabilitation devices are limited in their ability to control movement beyond walking, as they primarily focus on hip and knee joints, leading to restricted exercise ranges and adverse forces when used with treadmills.
Innovation Solution
A device with a stationary stand, lumbar support, and pivotally connected joints for the hip, knee, and ankle, allowing movement in the sagittal plane, equipped with adjustable and self-aligning articulations, and driven by synchronized servomotors to mimic natural gait patterns without requiring contact with a foundation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only hip and knee joints are driven, then the device structure is simpler, but the range of exercises is limited to walking and full control over treading manner is not provided
Solution Approach 1:
The lower limb manipulator is segmented into multiple independent joint units (hip, knee, ankle) that can be selectively actuated. Each joint is divided into separate drive mechanisms allowing independent control, enabling diverse exercise patterns without requiring a completely complex monolithic structure.
Solution Approach 2:
The manipulator structure is designed to perform multiple functions: it can drive hip and knee joints for walking rehabilitation, add ankle joint control for balance training, and accommodate various exercise modes (walking, sitting, standing) through a single integrated device platform.
2Reliability
If feet contact the foundation/treadmill, then support is provided, but adverse forces are generated from hitting the foundation
Solution Approach 1:
The foot coupling acts as an intermediary element between the user's foot and the device foundation. It includes shock-absorbing elements and compliant mechanisms that mediate the interaction forces, reducing adverse impact forces while maintaining stable support during weight-bearing activities.
Solution Approach 2:
The device incorporates cushioning elements in the foot coupling and seat mechanisms before impact occurs. These elements are pre-positioned to absorb and dissipate impact forces during heel strike and foot contact, preventing adverse forces from being transmitted to the user's joints and the device structure.
3Reliability
If synchronized servomotors are used to drive all joints, then natural gait patterns are achieved, but energy consumption increases
Solution Approach 1:
The servomotors are controlled to operate in periodic cycles corresponding to the natural gait pattern. Each joint is actuated only during the relevant phase of the gait cycle (e.g., knee extension during push-off, ankle dorsiflexion during swing phase), reducing overall energy consumption while maintaining accurate gait reproduction.
Solution Approach 2:
The control system incorporates feedback mechanisms that monitor joint positions and user effort in real-time. The synchronized servomotors adjust their output based on feedback signals, providing assistance only when and where needed to maintain natural gait patterns, thereby optimizing energy efficiency.
Data Source
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AI summary
Device supporting the physical abilities of the lower limbs, consisting of a stand determining the user's position and parallel mobile members adjoining the lower limbs of the user, divided into segments corresponding to the parts of the lower limb and connected with articulations in a self-aligning manner characterized in that it has a lumbar belt (27), movable in the vertical plane and connected in the hip articulation (13) through arms (26) to mobile couplings (1), (2), (3) of the lower limbs, the back pusher (10) that is movable in the vertical plane and sagittal plane and connected through the lumbar belt (27) with the arms (28), and the seat (29) that is movable in the vertical plane and connected to the bracket (15), in addition the lumbar belt (27), the back pusher (10), the arms (28) and the seat (29) are mounted on the common vertical guide rails (25), whereas the arms (28) are pivotally mounted in the guide rails (25), with the ability to part sideways.