Adjustable Dolly Drawbar for Coupling Load and Drag Control
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Solution Overview
Problem
Existing self-powered dolly vehicles lack the ability to dynamically adjust vertical coupling loads and extend/retract drawbars to optimize vehicle performance and safety under varying conditions, limiting their full potential in enhancing fuel efficiency and maneuverability.
Innovation Solution
An adjustable drawbar mechanism with a control unit that adjusts the vertical coupling load and extends/retracts based on sensors and predefined targets, optimizing load distribution and reducing air drag, while providing a mechanical retraction feature for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drawbar is extended to improve vehicle handling and maneuverability in tight spaces, then the swept area increases and handling improves, but air drag increases at high speeds
Solution Approach 1:
The drawbar is designed to be dynamically adjustable between extended and retracted positions. The control system automatically extends the drawbar at low speeds to improve handling and maneuverability, and retracts it at high speeds to reduce air drag. This dynamic adaptation resolves the contradiction by optimizing the drawbar position according to operating conditions.
2Force
If the vertical coupling load is increased to provide increased traction for improved startability, then traction improves, but vehicle handling deteriorates when the load is not optimally balanced
Solution Approach 1:
The control system dynamically adjusts the vertical coupling load by actuating the drawbar to change its angle and position. This parameter change allows optimization of the load distribution between traction and handling requirements. The system can increase vertical load to improve startability when needed, while maintaining optimal handling characteristics during steady-state operation.
3Reliability
If a mechanical retraction arrangement is added to provide safety in case of power failure, then reliability improves, but device complexity increases
Solution Approach 1:
The mechanical retraction arrangement is designed as a self-activating safety mechanism that automatically engages upon power failure or system malfunction. The arrangement uses spring-loaded or gravity-based mechanisms that require no external power or control input, thereby providing reliable safety functionality while minimizing the complexity of control systems required.
4Loss of energy
If the drawbar is retracted to reduce air drag at high speeds, then fuel efficiency improves, but vehicle handling and maneuverability deteriorate
Solution Approach 1:
The control system implements periodic or conditional adjustment of the drawbar position based on operating conditions. During high-speed cruising, the drawbar is retracted to reduce air drag and improve fuel efficiency. When maneuvering or navigating tight spaces, the system automatically extends the drawbar to restore handling and maneuverability capabilities. This conditional periodic adjustment resolves the contradiction between fuel efficiency and maneuverability.
Data Source
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Figure 7A~7B
AI summary
A drawbar arrangement for a dolly vehicle, the drawbar arrangement comprising a control unit and an adjustable drawbar attached to the dolly vehicle, the adjustable drawbar comprising a front coupling element arranged to be adjusted vertically with respect to a ground plane by the control unit, wherein the control unit is arranged to determine a vertical coupling load associated with the front coupling element, and wherein the control unit is arranged to set a desired vertical coupling load associated with the front coupling element by vertically adjusting the front coupling element when coupled to a towing vehicle unit.