Walking Assist Device One-Way Damper Fall Impact Mitigation
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Solution Overview
Problem
Existing walking assist devices face challenges in safely managing user falls, as actively driving the actuator can cause undesirable movements, while shutting off the actuator's power can lead to impact upon falling due to sudden loss of body weight support.
Innovation Solution
A walking assist device equipped with an upper leg link, lower leg link, actuator, and one-way damper, where the controller controls the actuator to follow a predetermined knee angle pattern and engages/disengages the one-way damper to allow free rotation in the straightening direction while resisting rotation in the bending direction, mitigating impact by allowing slow lowering of the user's body in case of actuator power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator is actively driven to correct abnormal walking attitude, then the user's walking posture is improved, but the risk of causing undesirable effects to the user increases due to active movement of the lower leg link
Solution Approach 1:
The patent extracts the active driving function from the actuator during abnormal conditions and replaces it with passive gravitational assistance. When an abnormality is detected, the controller shuts off actuator power and engages the one-way damper, allowing the lower leg link to rotate passively under gravity rather than being actively driven, thus eliminating the risk of undesirable active movements while maintaining posture correction capability
Solution Approach 2:
The patent prepares safety measures in advance by equipping the system with a one-way damper that can be engaged before a fall occurs. When abnormality is detected, the damper is activated to control the rotation of the lower leg link, providing gradual gravitational assistance that cushions the impact of potential falls rather than allowing sudden uncontrolled movements
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 reduces the impact of falls by ensuring the lower leg link rotates slowly in the bending direction when the actuator power is lost, maintaining user safety without actively driving the link, thus addressing the risks associated with both active movement and power loss.
Implementation Method 1
a one-way damper configured to generate a resisting force against rotation of the lower leg link in a knee bending direction
Data Source
AI summary
A walking assist device having a safety mechanism that mitigates an impact upon falling is provided. A walking assist device has an upper and lower leg links, a motor, and a controller. The controller controls the motor to apply torque to the lower leg link. The walking assist device also has a one-way damper which generates a resisting force against rotation of the lower leg link in the knee bending direction, and does not generate a resisting force against rotation of the lower leg link in the knee straightening direction. The controller engages the one-way damper while controlling the motor to apply torque to the lower leg link in the knee straightening direction, and disengages the one-way damper while controlling the motor to apply torque to the lower leg link in the knee bending direction.