High-Strength Aluminum Cable Structure for Tethered Drone Ascent
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Solution Overview
Problem
Conventional drone cables with stranded soft copper wires are excessively heavy, limiting the drones' ability to ascend to distant locations due to increased weight and required force for movement, and suffer from poor fatigue resistance from repeated unwinding and winding.
Innovation Solution
A cable using a high-strength aluminum-based conductor with a tensile strength of 180 MPa or more, composed of 8000-series, 5000-series, or 6000-series aluminum alloys, and coated with copper, nickel, or tin, to reduce weight while maintaining or exceeding the tensile strength of soft copper conductors, and incorporating optical fibers and tension members for power supply and mooring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stranded soft copper wires are used as conductors in the composite cable, then the cable has sufficient tensile strength and good fatigue resistance, but the cable weight becomes excessively large
Solution Approach 1:
The patent changes the material parameter from copper to aluminum-based conductor, which has a specific gravity of 2.7 g/cm³ compared to copper's 8.9 g/cm³. This material substitution reduces the cable weight to approximately one-third of the copper cable weight while maintaining sufficient electrical conductivity for power supply to the mobile body.
Solution Approach 2:
The patent creates a composite cable structure combining aluminum-based conductor wires with a tension member made of aramid fibers or steel wires. This composite construction allows the aluminum conductor to provide electrical conductivity while the tension member provides the necessary mechanical strength and fatigue resistance, resolving the contradiction between weight reduction and strength maintenance.
2Weight of moving object
If the cable weight is reduced using aluminum-based conductors, then the liftable weight of the mobile body increases, but the tensile strength and fatigue resistance of the cable decrease
Solution Approach 1:
The patent employs a composite cable structure where aluminum-based conductor wires are combined with a tension member consisting of aramid fibers or steel wires. The aluminum conductor provides lightweight electrical conductivity, while the tension member compensates for the reduced mechanical strength, ensuring the cable can withstand the tensile forces and fatigue from repeated winding and unwinding operations.
Solution Approach 2:
The cable is segmented into functional components: aluminum-based conductor wires for electrical conductivity, a tension member for mechanical strength, and an outer sheath for protection. This segmentation allows each component to optimize its specific function, with the tension member specifically addressing the tensile strength requirement that would otherwise be compromised by using lightweight aluminum conductors.
3Weight of moving object
If the cable weight is reduced, then the force required for the mobile body to move decreases, but the fatigue resistance from repeated winding and unwinding becomes insufficient
Solution Approach 1:
The patent uses a composite structure combining aluminum-based conductor wires with a tension member made of aramid fibers or steel wires. The tension member is specifically designed to withstand repeated cyclic loading from winding and unwinding operations, providing the necessary fatigue resistance that pure aluminum conductors would lack, while the overall cable remains lightweight.
Solution Approach 2:
The patent adopts the composite cable structure from aerial drone applications and adapts it for underwater mobile bodies. The proven fatigue-resistant design of the tension member configuration is copied and applied to the underwater cable system, ensuring reliability in the new application environment while maintaining weight reduction benefits.
Data Source
AI summary
The purpose of the present invention is to provide a cable used to at least moor a moving body to be moored and supply power thereto, such that weight of the whole cable can be reduced. A cable according to the present invention connects a moving body to be moored to a unit assembly including a power supply unit. The cable is used to at least moor the moving body to be moored to the unit assembly and supply power from the power supply unit to the moving body to be moored. The cable includes a conductor constituted with element wires, and at least part of the element wires is a high-strength aluminum-based conductor.