Tracked Mobility Device With Segmented Drive And Dynamic Contact Control
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Solution Overview
Problem
Personal mobility devices face challenges with friction and terrain adaptability, as wheeled vehicles sink in soft ground and struggle with uneven terrain, while tracked vehicles require significant power and can damage floors and have large turning radii.
Innovation Solution
A tracked mobility device with a pair of track drives comprising a powered center drive wheel, front and rear rollers, and a flexible track, where the center drive wheel is significantly larger than the rollers, and a rear wheel assembly with three wheels on a common axle, allowing for efficient traction and reduced ground contact on hard surfaces while increasing contact area on soft or uneven surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tracked vehicle uses a long and wide footprint track, then it can traverse soft and uneven terrain effectively, but it requires significant power to overcome friction resistance and can cause damage to carpets or floors
Solution Approach 1:
The track drive system is segmented into multiple independent rollers (front roller, center roller, rear roller) that can independently adjust their contact with the ground. This segmentation allows the track to adapt to different terrains by selectively engaging or disengaging rollers, reducing the overall friction resistance and power consumption while maintaining terrain adaptability.
Solution Approach 2:
The track drive system employs dynamic adjustment capabilities where rollers can tilt upward or downward relative to the body, and the multi-directional wheel can be lowered to raise part of the track drive ground contact areas from the ground. This dynamic adjustment optimizes the ground contact area based on terrain conditions, reducing friction and power consumption on hard surfaces while maintaining adaptability on soft terrain.
2Adaptability or versatility
If a tracked vehicle uses a long and wide footprint track, then it can traverse soft and uneven terrain effectively, but it can cause significant damage to carpets or floors when used indoors
Solution Approach 1:
The system dynamically adjusts the ground contact area of the track drive by lowering the multi-directional wheel to raise at least part of the track drive ground contact areas from the ground. This reduces the contact area with indoor floors, preventing damage while maintaining the ability to engage the full track surface when needed for soft terrain traversal.
Solution Approach 2:
The track drive system applies different contact characteristics to different parts of the track. By selectively raising or lowering specific rollers and the multi-directional wheel, the system creates localized variations in ground contact, allowing gentle contact with indoor floors while maintaining sufficient contact for off-road capability.
3Reliability
If a tracked vehicle uses a conventional track design, then it provides good traction on soft ground, but it has a larger turning radius compared to wheeled vehicles
Solution Approach 1:
The track drive system is divided into independent segmented rollers that can be controlled individually or in groups. This segmentation enables differential movement of track sections, allowing the vehicle to achieve zero-turning-radius capability by rotating one end of the track in the opposite direction, similar to wheeled vehicles, while maintaining the traction benefits of tracked design.
Solution Approach 2:
The independent rollers are capable of dynamic adjustment in their rotation and position, allowing the track to adapt its configuration during turning maneuvers. This dynamic control enables the track to bend sharply or even cross over itself, achieving tight turning radii while maintaining continuous ground contact for reliable traction.
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 achieves improved drivability on both indoor and outdoor surfaces with reduced friction and damage, maintaining superior off-road capability and efficient traction without sinking into soft terrain.
Implementation Method 1
The tracks are in contact with a larger surface area than would generally be the case with wheels, and thus exert a lower force per unit area on the ground being traversed
Data Source
AI summary
A tracked mobility device includes: a) a frame supporting a seat; b) a pair of track drives connected to the frame, with each track drive including a powered center drive wheel, a front roller, a rear roller, and a flexible track, with the center drive wheel having a diameter that is at least 50% greater than the diameter of either the front roller or the rear roller, and c) a rear wheel assembly connected to the frame, with the rear wheel assembly having three wheels sharing a common axle, with the diameter of the center rear wheel being at least 10% larger than the diameter of the two outer rear wheels; d) a source of power to power said center drive wheels; and e) a controller effective for controlling the speed and direction of rotation of each of the track drives.