Wearable Assisted-Walking Device Knee Energy Storage
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Solution Overview
Problem
Current wearable assisted-walking devices are complex, costly, and require high synchronization, with passive devices failing to effectively utilize muscle energy for assistance due to limited energy storage, leading to inadequate support during walking.
Innovation Solution
A passive wearable assisted-walking device that stores energy during knee extension at peak K4 and releases it during ankle push-off at peak A2, using a kinematic storage mechanism with a ratchet and pawl locking system to ensure energy is only released at the appropriate phase of the walking stride, without overloading joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If passive wearable assisted-walking devices are designed to store and release muscle-generated energy, then the device can assist walking without motors or batteries, but the energy storage capacity is very small and thus the device makes a limited contribution to assisting walking
Solution Approach 1:
The patent transfers energy storage from the traditional ankle-foot level to the knee level, utilizing the knee joint's motion space and mechanical advantage. The spring mechanism is positioned at the knee to capture energy during knee extension (peak K4) and release it during ankle push-off (peak A2), effectively using a different spatial dimension in the leg to overcome the limited storage capacity at the ankle-foot level.
Solution Approach 2:
The patent introduces a cable as an intermediary element that connects the knee joint motion to the ankle-foot orthosis. The cable transmits the force generated by knee extension to the ankle push-off mechanism, enabling energy transfer across different joints and amplifying the contribution to walking assistance.
2Ease of operation
If motorized actuators are used to simulate muscles and control motion, then the device can provide active assistance, but the device complexity, costs, and synchronization requirements increase significantly
Solution Approach 1:
The device is designed to be self-regulating by utilizing the user's own muscle-generated energy to power the assistance mechanism. The spring automatically stores energy during knee extension and releases it during ankle push-off without requiring external control systems, motors, or batteries, thereby eliminating the complexity associated with motorized actuators while maintaining ease of use.
3Use of energy by moving object
If energy is stored during knee extension at peak K4 and released during ankle push-off at peak A2, then the device maximizes muscle-generated energy utilization, but the energy must be stored and released at different phases requiring precise timing control
Solution Approach 1:
The device operates on the periodic nature of the walking gait cycle, with the spring mechanism automatically storing energy during the stance phase (knee extension at peak K4) and releasing it during the push-off phase (ankle push-off at peak A2). This periodic operation eliminates the need for complex real-time control synchronization, as the energy transfer is inherently timed by the user's own walking rhythm.
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 device effectively assists walking by maximizing the use of muscle-generated energy, reducing metabolic cost, and providing support without the need for motors or batteries, resulting in a lightweight, easy-to-use, and cost-effective solution.
Implementation Method 1
a spring that is adapted to store energy when it is pulled in a first direction and adapted to release the stored energy when it is allowed to move in a second direction opposite to the first direction
Implementation Method 2
a ratchet and pawl locking system to ensure energy is only released at the appropriate phase of the walking stride
Data Source
AI summary
Provided is a wearable assisted-walking device including one lower attachment body to the foot defining a lower anchoring point at the heel of the foot of a leg of the user; an upper attachment body to an upper part of the leg proximal from the knee defining an upper ventral anchoring point and an upper dorsal anchoring point arranged on the opposite side of the coronal plane of the user; and an intermediate attachment body defining a first intermediate anchoring point, a second intermediate anchoring point and a third intermediate anchoring point, each anchoring point movable respect and connected by cables to the leg; the intermediate attachment body being adapted to store the energy by a relative motion between the anchoring points and then use it for assist walking.