Step-Climbing Link Mechanism for Mobility Support Devices
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Solution Overview
Problem
Existing mobility support devices, such as wheelchairs, face challenges in stable step climbing without impairing mobility on flat ground, often have complex mechanisms and limited user postures, particularly when encountering obstacles like sidewalk curbs.
Innovation Solution
A novel link structure based on the rocker-bogie mechanism that passively transitions the user's posture and center of gravity, utilizing elastic members and rotation joints to achieve stable and smooth step climbing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a step climbing mechanism is added to improve step climbing ability, then step climbing performance is improved, but device complexity increases
Solution Approach 1:
The patent employs a dynamic link structure with rotation joints that allow the front wheel assembly to pivot and adapt its configuration during step climbing. The first link connects the front wheel to the main body, while the second link connects the drive wheel to the rear wheel, creating a flexible mechanism that dynamically adjusts to overcome steps without requiring complex active control systems
Solution Approach 2:
The elastic member automatically stores and releases energy during the step climbing process. When the front wheel encounters a step, the elastic member deformestorage energy that assists in lifting the front wheel over the obstacle, then returns to its original state as the wheel clears the step, providing self-service without requiring additional actuators or control mechanisms
2Reliability
If a step climbing mechanism is added to improve step climbing ability, then step climbing performance is improved, but mobility on flat ground deteriorates
Solution Approach 1:
The link structure with rotation joints allows the mechanism to dynamically adapt between step climbing and flat ground modes. During flat ground movement, the links maintain a compact configuration that does not interfere with normal wheel rotation and propulsion, while during step climbing, the rotation joints enable the necessary geometric transformation to lift and clear obstacles
Solution Approach 2:
The same link structure and elastic member serve dual functions: they assist in step climbing by providing mechanical advantage and energy storage, while simultaneously maintaining a neutral, non-interfering configuration during flat ground movement, thus one component system handles both terrains effectively
3Reliability
If the user's center of gravity is used to lift front wheels for step climbing, then step climbing is achieved, but user posture is limited to sitting position
Solution Approach 1:
The link structure acts as an intermediary mechanical system that translates the user's center of gravity movement into effective step climbing action. The first and second links, connected by rotation joints, mediate between the user's body movement and the front wheel lift, allowing the mechanism to work effectively whether the user is sitting or standing by adapting to the resulting center of gravity changes
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 stable climbing of steps and grooves without compromising mobility on flat ground, applicable to various environments including urban areas and disaster sites, with a compact design suitable for standing postures.
Implementation Method 1
a first elastic member coupling the first link and the second link at a second position different from the first position
Data Source
AI summary
A mobility support device capable of stably climbing a step without impairing mobility on flat ground is provided. The mobility support device includes a front wheel, a rear wheel, a drive wheel disposed between the front wheel and the rear wheel, a first link coupled to the front wheel, a second link connecting the drive wheel and the rear wheel, a rotation joint coupling the first link and the second link at a first position, and a first elastic member coupling the first link and the second link at a second position different from the first position.