Cart Robot Wheel-Axle Control for Stair Navigation
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Solution Overview
Problem
Conventional cart robots are unable to navigate stairs, limiting their functionality and versatility.
Innovation Solution
A cart robot equipped with a travel cart body, multiple axles and wheels, and a control device that adjusts the extension and rotation of these components to enable navigation over both flat surfaces and stairs, using a combination of lock units and driving units to manage wheel contact and axle extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional cart robot design is used, then the structure is simple, but the robot cannot navigate stairs
Solution Approach 1:
The wheel assembly is segmented into multiple independent wheels (first wheel, second wheel, third wheel, fourth wheel) arranged at different positions. Each wheel can be independently controlled to contact or separate from the ground, allowing the robot to adapt to various terrain conditions including stairs while maintaining manageable structural complexity
Solution Approach 2:
The patent employs dynamic adjustment of wheel contact status through lifting mechanisms. The wheels can transition between contacting and separating from the ground based on terrain requirements, enabling the robot to navigate stairs by selectively engaging wheels at different heights, thus improving adaptability without permanently increasing structural complexity
2Adaptability or versatility
If multiple wheels are used to navigate stairs, then navigation capability is improved, but the number of components increases
Solution Approach 1:
Each wheel assembly is designed with multi-functionality, serving both as a propulsion element and a terrain adaptation element. The same set of wheels used for normal movement on flat surfaces is also utilized for stair navigation by adjusting their contact status, eliminating the need for separate specialized components and reducing the overall quantity of parts required
3Adaptability or versatility
If wheels are lifted to navigate stairs, then stair navigation is enabled, but control complexity increases
Solution Approach 1:
The control system is designed to preliminarily identify stair conditions using sensors before navigation. Once stairs are detected, the control device pre-configures the wheel lifting sequence and propulsion sequence, allowing the robot to execute the predetermined plan without real-time complex decision-making, thus enabling stair navigation while keeping control system complexity manageable
Data Source
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AI summary
A cart robot according to an embodiment includes a travel cart body; a first axle that is arranged on the travel cart body; multiple second axles that extend in a diameter direction of the first axle from a distal end portion of the first axle, and that can extend and retract in the diameter direction; a wheel that is arranged at a distal end portion of the respective second axles; a first driving unit that rotates the second axles in a circumference direction of the first axle; a second driving unit that rotates the wheel with respect to the second axle; a third driving unit that extends and retracts the second axle in the diameter direction; a first lock unit that can restrict rotation of the second axle in the circumference direction; a second lock unit that can restrict rotation of the wheel; and a control device that controls extension and retraction of the second axle, restriction by the first lock unit, and restriction by the second lock unit.