Variable Compliance Wheel Torque Measurement
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Solution Overview
Problem
Non-pneumatic tires face challenges in adjusting radial stiffness during operation and measuring torque on the wheel axis, especially in environments where pneumatic tires are impractical, such as on planets with thin atmospheres or rough terrain, due to the complexity and bulk of existing torque measurement systems.
Innovation Solution
A non-pneumatic wheel design incorporating a leaf spring element with adjustable radial stiffness via counter-rotation of hub disks and a simple torque sensor integrated into the drive train, utilizing a slip ring for power and a motorized mechanism to regulate stiffness and measure torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a non-pneumatic wheel uses a complex torque sensor combined with continuous rotation electrical connection (slip ring) to measure torque, then torque measurement capability is achieved, but device complexity and mass increase substantially
Solution Approach 1:
The patent combines the torque sensor functionality directly into the drive train mechanism, specifically integrating it with the differential assembly. This merging eliminates the need for separate torque sensors and slip rings, reducing device complexity while maintaining torque measurement capability through the existing mechanical components of the drive train
Solution Approach 2:
The drive train components are designed to serve multiple functions: power transmission, differential motion, and torque measurement. By making the torque measurement system part of the existing drive train structure rather than a separate addition, the system achieves multi-functionality that reduces overall device complexity
2Adaptability or versatility
If a non-pneumatic wheel uses elastic spokes for shock absorption, then comfort and terrain adaptability are improved, but durability decreases due to puncturing and material degradation
Solution Approach 1:
The patent employs composite material construction for the wheel components, combining materials with different properties to achieve both shock absorption and durability. The composite structure allows the wheel to maintain elastic deformation capabilities while resisting puncturing and degradation that would affect pure elastic materials
Solution Approach 2:
The wheel is divided into modular components including the rim, spokes, and hub that can independently deform and absorb shocks. This segmentation allows each component to be optimized for specific functions while maintaining overall structural integrity and durability
3Reliability
If a non-pneumatic wheel uses rigid metallic structure for durability, then reliability is improved, but shock absorption capability deteriorates
Solution Approach 1:
The patent applies different material properties to different parts of the wheel structure. Rigid metallic materials are used in components requiring strength and durability (such as the hub and rim structure), while more compliant materials are used in components requiring shock absorption (such as the spokes and connecting elements). This local differentiation of material quality allows the wheel to simultaneously achieve durability and shock absorption capability
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 solution allows for adjustable radial stiffness and accurate torque measurement, enhancing durability and safety for unmanned vehicles on rough terrain or planetary surfaces by varying wheel flexibility and monitoring torque in real-time.
Implementation Method 1
a leaf spring element (3, 4) mounted on each one of a plurality of holes of their periphery
Implementation Method 2
The relative angle between the two hubs can be modified by a motor (21)
Data Source
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AI summary
A non-pneumatic wheel is provided including a tubular member forming two split hubs (1, 2) attachable to an axle. Said two split hubs (1,2) are able to counter-rotate relative to each other. Said non-pneumatic wheel further comprises a number of interconnected and freely rotating between each- other caterpillar-like tiles (5) forming the outer periphery of the wheel, which are in contact with the ground during wheel operation. A plurality of connecting leaf springs (3, 4) mounted between the said tubular member and the outer tiles (5) in a circular circumferential direction and configured to connect the tubular member and the tile (5) bodies to each other. E ach leaf spring element (3, 4) is formed in a way to present a main curvature and a tail, in a way that the main curvature bends by the exertion of radial forces on the tiles of the wheel periphery and the tail deforms due to its contact with the adjacent spring and the counter-rotation of the two split hubs. The leaf springs (3, 4) mounted on the same tile (5), are mounted at relatively distant locations on the counter rotating split hubs (1, 2). The effect of counter rotation of the split hubs (1, 2) generates the development of forces in the leaf springs (3, 4) that initially rotate around their fixing rods, but then enter in contact through their tails, resulting to the generation of radial outwards forces exerted on the tiles (5), thus producing finally the increase of stiffness of the wheel.