RU2073872C1 - Device for measurement of horizontal wind velocity - Google Patents

Abstract

FIELD: meteorological instrument engineering. SUBSTANCE: the device for measurement of horizontal wind velocity, having a wind vane, two impellers with their angular-motion transducers wind vane angle pick-off, subtraction unit and the first addition unit, additionally uses the second addition unit, signal division unit, wind velocity modulus computer unit and correction formation unit. EFFECT: enhanced accuracy of measurement. 1 dwg

Description

 The invention relates to the field of meteorological instrumentation.

 Known devices for measuring the speed and direction of horizontal wind, consisting of two separate primary devices [1] speed meter, which is an axial pinwheel (pinwheel type propeller) or tangential pinwheel (pin type pinwheel) with a sensor of angular velocity of its rotation; direction meter, usually performed in the form of a vane sensor mounted on the vertical axis.

 These devices have two significant drawbacks, the essence of which is as follows.

где

относительная погрешность измерения скорости ветра,
γ угол скоса воздушного потока от наиболее вероятного его направления.Firstly, since the axis (plane) of the maximum sensitivity of the axial (tangential) pinwheel is oriented forward in the most probable direction of the wind (with respect to a certain basic coordinate system rigidly connected with the earth’s surface or with the body of a moving object on which the wind is measured) when airflow bevels from this direction, a methodical error in the measurement of speed occurs

Where

relative error in measuring wind speed,
γ angle of inclination of the air flow from its most probable direction.

где К, град•м²/c² коэффициент, зависящий от размеров флюгера, плотности воздуха и величины момента трения в оси вращения флюгера, приводящая к погрешности измерения флюгерным датчиком направления ветра, тем большей, как следует из формулы (2), чем меньше скорость воздушного потока.Secondly, since the moment setting the vane is proportional to the pressure head of the air flow, in the presence of friction in the axis of rotation of the vane, its dead zone (stagnation) is possible

where K, deg • m ² / s ^{2 is a} coefficient depending on the dimensions of the vane, air density and the value of the friction moment in the axis of rotation of the vane, which leads to the measurement error of the wind direction sensor, the larger, as follows from formula (2), the smaller air flow rate.

Второй из указанных выше недостатков, а именно погрешность измерения флюгерным датчиком направления ветра при малых по модулю скоростях, вызванная зоной нечувствительности (2) флюгера при трении в его оси вращения, остается и в этом известном устройстве.The device for measuring wind speed and wind direction (adopted as a prototype) known in [2] in meteorological instrumentation has a slightly better accuracy characteristic for the velocity measurement channel [2], in which the sensitive element of the speed meter (pinwheel) is rigidly connected to the moving part of the vane sensor, which ensures axis orientation maximum turntable sensitivity not in the most probable direction of the air flow, but in the actual (up to the stagnation zone) direction. Expression (1) for this device has the form

The second of the above disadvantages, namely the error in measuring the direction of the wind with a vane sensor at low modulus speeds, caused by the dead zone of the vane during friction in its axis of rotation, remains in this known device.

 The technical result of the invention is to increase the accuracy of measuring wind speed and direction at low modulus air flow rates by introducing a correction Δα, which compensates for the deadband of the vane sensor.

блок формирования поправки

на зону нечувствительности флюгера, второй блок сложения α = α_ф+Δα, где α_ф выходной сигнал флюгерного датчика, и блок определения модуля скорости ветра

где

крутизна статической характеристики (n f(v)) вертушки.This result is achieved by the fact that on the movable, wind-mounted part of the vane sensor, two turntables are installed with an angular velocity sensor n ₁ and n _{2 of} their rotation so that their axes of maximum sensitivity are symmetrically rotated from the vertical plane (vane plane) to different angles respectively + α _o and -α _o , and the first addition block (n ₁ + n ₂ ), the subtraction block (n ₁ n ₂ ), the signal division block are introduced

amendment unit

on the weather vane dead zone, the second addition unit α = α _f + Δα, where α _{f the} output signal of the vane sensor, and the unit for determining the wind speed module

Where

steepness of the static characteristic (nf (v)) of the turntable.

Из формул (7) и (8) следуют необходимость и достаточность для достижения поставленной цели предполагаемой совокупности отличительных признаков (при подстановке выражений (7) и (8) в выражения (4), (5) получаются тождества).To prove the significance of this set of distinctive features in achieving this goal, we will use the fact that the rotational speed of the spinner is proportional to the projection of the air velocity vector on the axis of maximum sensitivity, that is, known in the technique of perceiving air flow parameters
n = kvcosγ, (6)
where γ is the bevel angle of the flow. In the presence of a dead zone Da, the angular velocities n ₁ and n _{2 of} rotation of the turntables, rotated relative to the vertical plane by the angles + α _o and -α _o , will be, respectively

Formulas (7) and (8) imply the necessity and sufficiency of the proposed set of distinctive features to achieve the goal (when substituting expressions (7) and (8) into expressions (4), (5), identities are obtained).

 Based on the materials of domestic and foreign patent-technical literature, the essence of an identical or equivalent technical solution was not found. Therefore, the claimed technical solution is new.

 The drawing shows a diagram of the proposed technical solution.

 The device contains a vane sensor 1, two turntables 2 and 3 with sensors 4 and 5 of the angular velocity of their rotation, a current collector 6, a secondary converter of the vane sensor 7 (a converter of the angle of rotation of the moving part of the vane sensor into an electrical signal), a subtraction unit 8, the first addition unit 9 , a block for dividing signals 10, a block for generating corrections for the deadband of the vane 11, a second block for addition 12, a unit for determining the speed module 13.

Turntables 2, 3 are rigidly connected with the movable part of the vane sensor 1 and are installed in its front part so that their axes of maximum sensitivity are symmetrically rotated from the vertical plane (XOY plane of the vane) in different directions at angles + α _o and -α _o, respectively. The signals from sensors 4 and 5 through the current collector 6 are fed to the subtraction unit 8 and the first addition unit 9, while the signal from the sensor 4 is fed to the non-inverting input of the subtraction unit 8, and the signal from the sensor 5 is fed to the inverting input of the subtraction unit 8. Signals from blocks 8 and 9 are fed to the signal division 10, the signal from block 8 being fed to the input of the dividend, and the signal from block 9 to the input of the divider. The output of the signal division block 10 is connected to the input of the correction unit for the dead band of the weather vane 11 and to the input of the speed module determination block 13, the other input of which receives the signal from the first addition unit 9. The outputs of the correction block for the dead zone of the weather vane 11 and secondary transducer 7 the angle of rotation of the vane sensor is connected to the inputs of the second addition unit 12.

 The proposed device operates as follows.

и продольной осью OX датчика), которая тем больше, чем меньше модуль вектора скорости

потока. Наличие зоны нечувствительности приводит к тому, что вертушки 2 и 3 будут обтекаться под разными углами скоса потока, соответственно α_o-Δα и α_o+Δα. Сигналы с датчиков 4 и 5 будут пропорциональны соответственно величинам

Из выражений (7) и (8) видно, что сигналы с выходов блока вычитания 8 и первого блока сложения 9 будут зависеть как от величины зоны нечувствительности Δα, так и от величины модуля вектора скорости

, т.е.When the vane sensor 1 is blown with air flow, the sensor vane tracks the direction of flow, and a dead zone Δα (the angle between the flow velocity vector

and the longitudinal axis of the OX sensor), which is greater, the smaller the module of the velocity vector

flow. The presence of a dead zone leads to the fact that the turntables 2 and 3 will flow around at different angles of the bevel of the flow, respectively, α _o -Δα and α _o + Δα. The signals from sensors 4 and 5 will be proportional to the values

It can be seen from expressions (7) and (8) that the signals from the outputs of the subtraction unit 8 and the first addition unit 9 will depend on both the deadband Δα and the magnitude of the velocity vector module

, i.e.

На основе этого факта и основано определение зоны нечувствительности в блоке 11, алгоритм которого

вытекает из выражения (11).n ₁ -n ₂ = 2kvsinα _o sinΔα, (9)
n ₁ + n ₂ = 2kvsinα _o sinΔα, (10)
and the signal from the output of the signal division unit 10 will not depend on the velocity vector module, but will be determined only by the value of the deadband vane Δα:

Based on this fact, the definition of the dead band in block 11 is based, the algorithm of which

follows from expression (11).

Кроме того, предлагаемое устройство имеет по сравнению с упомянутыми известными устройствами лучшие динамические характеристики по каналу измерения угла за счет того, что этот угол формируется как результат сложения сигналов, проходящих через встречно-параллельное соединение, одна из ветвей которого (элементы 2, 3, 4, 5, 8, 10, 11) имеет собственную частоту, в 10-15 раз большую, чем собственная частота основного флюгерного канала (ветвь формирования α_ф).Substituting (12) into (10) and resolving the latter with respect to v, we obtain an algorithm for determining the module of the wind velocity vector module 13:

In addition, the proposed device has, in comparison with the known devices, the best dynamic characteristics along the angle measurement channel due to the fact that this angle is formed as a result of the addition of signals passing through an anti-parallel connection, one of whose branches (elements 2, 3, 4 5, 8, 10, 11) has an eigenfrequency 10-15 times greater than the eigenfrequency of the main vane channel (formation branch α _f ).

Claims (1)

A device for measuring the speed and direction of horizontal wind containing a weather vane, two turntables with angular velocity sensors for their rotation mounted on the moving part of the weather vane so that their axes of maximum sensitivity are located in a plane perpendicular to the axis of rotation of the weather vane and are symmetrically deployed from the axis of symmetry of the weather vane in different sides at the angles, respectively + α _o and -α _o , the weather vane angle sensor, the subtraction unit and the first addition unit, the inputs of which are connected to the outputs of the angular rotation speed sensors turntables, characterized in that a second addition unit, a signal division unit, a wind speed module calculation unit and a correction unit are introduced into it, while the non-inverting input of the subtraction unit is connected to the output of the angular rotation speed sensor of one turntable, and the inverting input of the subtraction unit is connected to the output of the angular rotational speed sensor of another turntable, the inputs of the dividend and divider of the signal division unit are connected respectively to the outputs of the subtraction unit and the first addition unit, the inputs of the module calculation unit with the wind speed is connected to the outputs of the signal division block and the first addition block, the input of the correction block is connected to the output of the signal division block, and the inputs of the second addition block are connected to the outputs of the correction block and to the output of the wind vane angle sensor.