Resilient Wheel Assembly with Slit Spokes and Four-Bar Linkage
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Solution Overview
Problem
Robotic wheel assemblies face challenges in effectively absorbing both radial and axial forces during impacts, which can lead to damage and require additional mechanisms for self-righting, while existing solutions do not adequately manage backlash between flipper and wheel structures.
Innovation Solution
A wheel structure with radially inward slits in spokes to reduce axial stiffness and absorb axial forces, combined with a flipper structure featuring a four-bar linkage for translation during impacts and an annular bushing insert for a robust, backlash-free interface with the axle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wheel structure uses solid spokes to maintain high axial stiffness, then the structural strength is improved, but the ability to absorb axial forces during side impacts deteriorates
Solution Approach 1:
The solid spoke is segmented into multiple thin spoke layers separated by slits, transforming a single rigid structure into a layered configuration that can deform independently during axial impacts while maintaining overall structural integrity
Solution Approach 2:
The axial stiffness parameter of the spokes is changed by introducing slits that reduce stiffness in the axial direction while preserving radial strength, allowing the wheel to absorb axial forces through controlled deformation
2Ease of operation
If the flipper structure is made rigid to provide rotational stiffness for lifting the robot, then the self-righting capability is improved, but the ability to absorb side-impact energy without damage deteriorates
Solution Approach 1:
The flipper structure transitions from a static rigid component to a dynamic system where the arm can translate inward during side impacts, allowing energy absorption while maintaining rotational stiffness for self-righting through controlled movement
Solution Approach 2:
The flipper arm gains an additional degree of freedom by translating in the radial direction during impacts, supplementing its primary rotational motion and enabling it to handle both impact absorption and self-righting functions
3Device complexity
If the flipper structure is directly coupled to the axle without an insert, then the device complexity is reduced, but backlash between the flipper and axle increases
Solution Approach 1:
An annular bushing insert is introduced as an intermediary component between the flipper structure and axle, providing a precision interface that eliminates backlash while maintaining rotational coupling and transmitting torque effectively
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 enhances shock absorption and self-righting capabilities of robotic vehicles by distributing radial and axial forces effectively, preventing damage and ensuring secure coupling of flipper structures to the wheel assembly.
Implementation Method 1
The spokes may be configured to absorb radial and axial forces. The at least one slit may be configured to reduce an axial stiffness of the spokes.
Implementation Method 2
The legs and attachment base comprise a four-bar linkage. The four-bar linkage may be configured to allow translation of the arm during impacts and provide rotational stiffness to the arm to lift the vehicle.
Implementation Method 3
The bushing comprises a bore with a flat surface that tapers outward from a top portion of the bushing to a bottom portion of the bushing. The flat surface may be configured to prevent backlash between the axle and the flipper structure.
Data Source
AI summary
A wheel assembly for a remote vehicle comprises a wheel structure comprising a plurality of spokes interconnecting a rim and a hub. The spokes comprise at least one slit extending therethrough radially inward from the rim to the hub. The assembly also comprises a flipper structure comprising an arm, a plurality of legs, and an attachment base. The plurality of legs and the attachment base comprise a four-bar linkage. The assembly further comprises an insert comprising a bore with a flat surface that tapers outward from a top portion to a bottom portion of the insert. The insert being configured to couple the flipper structure to the wheel structure via an axle on the remote vehicle and prevent backlash between the axle and the flipper structure. The flipper structure being configured to transmit axial forces to the wheel structure. The wheel structure being configured to absorb radial and axial forces.