Tethered Kite Retrieval via Unstable Flight Path
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Solution Overview
Problem
The existing control methods for tethered flying elements, such as kites, are inefficient and costly, especially when dealing with large aerodynamically effective areas, as they require significant design effort to maintain stability during takeoff and landing, and are slow to respond to rapid changes in weather conditions.
Innovation Solution
A method and control device that allow the kite to be caught up by controlling its path outside the wind window, reducing the forces acting on the kite and traction cable, and using dynamic stabilization through relative wind speed generated during the hauling-in process, enabling faster and more efficient retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flying element is retrieved within the wind window using conventional control methods, then the flying element maintains stable flight position, but the retrieval process takes considerable time and requires complex control technology
Solution Approach 1:
The patent applies dynamics by transitioning the flying element from static stable flight within the wind window to dynamic unstable flight outside the wind window during retrieval. The system deliberately operates in an unstable flight regime where the flying element is moved to positions where it cannot maintain stable flight, utilizing the resulting aerodynamic forces and relative wind speeds to accelerate retrieval while maintaining controllability through the towing cable tension.
Solution Approach 2:
The patent changes the operational parameters by moving the flying element from the stable wind window region to unstable regions outside it. This involves changing the position, speed, and aerodynamic conditions from those required for stable flight to those that enable rapid retrieval. The relative wind speed generated during this parameter change is utilized to reduce forces on the towing cable while increasing retrieval speed.
2Reliability
If the aerodynamically effective area of the flying element is reduced by reefing lines, then large-scale flying elements can be controlled reliably, but considerable design effort is required to achieve uniform reduction and maintain controllable profile
Solution Approach 1:
The patent extracts the problem of managing large aerodynamic area by removing the flying element from the stable wind window operation mode during retrieval. Instead of modifying the flying element's area through complex reefing systems, the solution extracts the element to unstable flight conditions where area management becomes less critical, thereby reducing design complexity while maintaining control reliability.
3Productivity
If the flying element is retrieved at high speed, then operational efficiency increases, but the forces acting on the towing cable and flying element increase significantly
Solution Approach 1:
The patent converts the harmful effect of high forces during high-speed retrieval into a beneficial effect by operating outside the wind window. The unstable flight conditions generate relative wind speeds that create aerodynamic forces opposing the retrieval direction, effectively using the harmful aerodynamic loading to reduce the net force on the towing cable while maintaining high retrieval speed.
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
This approach significantly reduces the forces and speed required for hauling in the kite, allowing for quicker and more efficient operation, even in adverse weather conditions, while minimizing stress on the system components.
Implementation Method 1
a flying element which is aerodynamically effective and generates an aerodynamic force when exposed to wind
Implementation Method 2
the retrieval process on the flying element generates a relative wind speed with respect to the holding point, which can be advantageously used to dynamically stabilize the flight condition of the flying element outside the wind window
Data Source
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AI summary
The invention relates to a method for controlling a tethered flying element (30), in particular a kite, which is connected to a retaining point (20, 22) by means of at least one tension rope (21). In particular, the invention relates to a pull-in procedure for such a flying element. A method according to the invention comprises the following steps: controlling the kite at the edge (41) of a wind window (40), inside of which the flying element assumes a stable flying position while a tensile force is applied to the tension rope when a wind having a specified wind direction and wind intensity is incident on the flying element and outside of which the flying element cannot assume a stable flying position; pulling the at least tension rope in; moving the flying element into a position outside of the wind window while the tension rope is being pulled in; and pulling the flying element in along a flight path (50) that lies at least partially outside of the wind window (40).