Dual-Annular Tyre Assembly for Lawn Robot Traction on Uneven Ground
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Solution Overview
Problem
Prior self-propelled lawn mower robots with rigid wheels struggle to maintain adhesion and efficiency on uneven or irregular surfaces, often losing traction or overturning due to small obstacles like stones or holes.
Innovation Solution
A tyre assembly for lawn mower robots featuring an outer annular portion for traction and an inner annular portion for flexibility, allowing the tyre to deform and adapt to ground irregularities while maintaining contact, and a wheel configuration with a main wheel and auxiliary wheels for adjustable traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid wheels are used for self-propelled lawn mower robots, then structural strength and stability are improved, but adaptability to uneven surfaces and adhesion capability deteriorate
Solution Approach 1:
The wheel is divided into two separate tyres: an outer annular tyre for ground contact and an inner annular tyre for structural support and rim coupling. This segmentation allows each component to be optimized independently - the outer tyre provides flexibility and adhesion to uneven surfaces while the inner tyre maintains structural integrity and connects to the rigid rim.
Solution Approach 2:
Different parts of the wheel structure have different properties: the outer tyre is designed with flexible material and specific cross-sectional geometry to adapt to ground irregularities, while the inner tyre and rim maintain rigidity for structural support. This local differentiation of material properties and structural characteristics resolves the contradiction between overall strength and local adaptability.
2Ease of manufacture
If rigid wheels are used, then manufacturing simplicity is improved, but adhesion capability and operational reliability on irregular ground deteriorate
Solution Approach 1:
By separating the wheel into two independent tyres that can be manufactured separately and then assembled, the system achieves both manufacturing simplicity and improved adhesion. Each tyre can be produced using standard tyre manufacturing processes, and their assembly onto the rim is straightforward, maintaining ease of manufacture while the flexible outer tyre provides reliable adhesion to irregular surfaces.
3Reliability
If the tyre cross-section extends parallel to the rotation axis, then adhesion and flexibility are improved, but structural complexity increases
Solution Approach 1:
The complex adhesion requirement is resolved by segmenting the wheel into two tyres with different cross-sectional orientations. The outer tyre has its cross-section extending parallel to the rotation axis to maximize ground contact and adhesion, while the inner tyre has its cross-section extending perpendicular to the axis to simplify its structural role and connection to the rim, thereby reducing overall system complexity.
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 tyre assembly enhances the robot's ability to operate efficiently on uneven surfaces by maintaining optimal adhesion and traction, preventing loss of contact and accumulation of debris, thus improving overall performance and adaptability to varying ground conditions.
Implementation Method 1
the outer annular portion (1a) has a cross section, in a radial plane, extending mainly along a direction substantially parallel to an axis of rotation of the tyre (1)... provides the tyre with a considerable flexibility and capacity for adapting to the profile of the ground
Implementation Method 2
The inner annular portion (1b), configured for coupling the tyre to a rim, is positioned at a mid-plane of the outer annular portion (1a)
Data Source
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AI summary
Described is a tyre (1) for a self-propelled lawn mower robot comprising an outer annular portion (1a) and an inner annular portion (1b). The outer annular portion (1a) defines a tyre tread (1) and has a cross section, in a radial plane, extending mainly along a direction substantially parallel to an axis of rotation (X) of the tyre (1). The inner annular portion (1b), configured for coupling the tyre (1) to a rim (4), is positioned at a mid-plane of the outer annular portion (1a). Moreover, the inner annular section (1b) has a cross-section, in a radial plane, which extends mainly along a direction substantially perpendicular to the axis of rotation (X) of the tyre (1).