The present invention relates to an accurate wind measurement device and method, and more particularly, to a device and method for accurate wind measurement onboard an aerial vehicle.
It is a common practice to utilize aerial vehicles for measurement of various environmental parameters. Typical wind measurement devices onboard aerial vehicles, particularly helicopter or multi-rotors, are affected by the vehicle's body or propulsion systems, and therefore have a limited level of accuracy. Due to the high distribution and increasing utility of low-cost small and medium size aerial vehicles (UAVs), there are evident benefits to a compact, low-weight and accurate wind measurement device, capable of being carried by these type of vehicles. One of several possible applications is the external performance monitoring of wind-turbine power production. The ability to position the accurate wind measurement device according to the invention directly in front of wind turbine rotors enables wind resource characteristics (predominantly direction and speed) detected by the measurement instrumentation mounted on the wind turbines (the logged data of which are often biased due to the positioning of the instruments behind the rotor-blades) to be compared with the data taken by an external, unbiased device, mounted on an unmanned aerial vehicle. The device's better accuracy enables corrections to the alignment of the wind turbine nacelle towards the prevailing wind direction among other corrections, thereby optimizing power production. The scale, mobility and autonomous capabilities of unmanned aerial vehicles carrying the device enable scheduled, sporadic, unmanned and on-demand, external and unbiased power production performance monitoring of wind turbines. This enables constant monitoring and immediate or post flight corrections to the wind turbine alignment, all of which capabilities are currently non-existent and very much required.
The present invention describes an accurate wind measurement device carried by an aerial vehicle.
The wind measurement is based on the photographing of an object's behavior under the force of gravity and the aerodynamic force generated by the wind. The behavior of some predefined shapes (e.g. sphere) has been widely explored, and has a broad theoretical basis. Such behavior, once calibrated against other high accuracy measurement technologies, can provide a valid and accurate measurement.
In accordance with the present invention provided herein are a device and method for accurate wind measurement, which are the subject matter of independent claims presented below.
The device deploys an object that is carried by a low cross-section string. The deployment space of the object is continuously monitored by a camera, thus enabling measurement of the string's spatial angles relative to the axis of the camera's optics. The string length, defined as a distance between the object and the camera's sensor, allows calculating the accurate location of the object relative to the camera sensor. The object location measured by the camera based on the string length, is then converted into the aerodynamic forces (e.g. drag) vector generated by the wind. The string tension is continuously measured in order to deduce the aerodynamic forces in the vertical and horizontal planes. The weighted result of the horizontal and vertical aerodynamic forces provides a well-defined wind speed spatial vector. The object can be of different aerodynamic shapes (e.g. sphere), or can be an anemometer of any known technology, to provide dual technology measurement.
In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
To fit the aerial vehicle characteristics, the length of string 10 and the parameters of the object 8 should be optimized. For example, large and powerful aerial vehicles will require a longer string 10 to minimize the aerial vehicle impact (e.g. propellers airflow, which can reduce the measurement accuracy) on the object 8 of device 2.
To monitor the power production performance of a wind turbine generator, the device 2 can be positioned directly in front of a wind turbine rotor 38, to enable comparison of the wind resource characteristics (predominantly, direction and speed) detected by the commonplace measurement instruments 40 mounted behind the wind turbine rotor 38 (
The scale and mobile potential of the device 2 in the case at hand, will enable periodic, sporadic, unmanned, on demand, external non-biased performance monitoring of wind turbines-capability, currently non-existent and very much required.
Whenever higher level of accuracy and confidence is required, dual technology measurement can be implemented based on the above-mentioned device and method. In device 2, shown in
It should be noted that features that are described with reference to one or more embodiments are described by way of example rather than by way of limitation to those embodiments. Thus, unless stated otherwise or unless particular combinations are clearly inadmissible, optional features that are described with reference to only some embodiments are assumed to be applicable to all other embodiments also.
Number | Date | Country | Kind |
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244503 | Mar 2016 | IL | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IL2017/050282 | 3/8/2017 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2017/153987 | 9/14/2017 | WO | A |
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Number | Date | Country | |
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20190094255 A1 | Mar 2019 | US |