RU2088487C1 - Method of measuring characteristics of transport vehicle air wake - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: method consists in measuring the characteristics of transport vehicle, characteristics of motion of flying vehicle-sounder relative to air masses and determination of characteristics of air wake. Sounding flying vehicle is placed in succession in several predetermined points after ship holding the sounding vehicle in this point and additionally measuring the parameters of flight: angle of attack and slip angle, flight speed vector, pitch angle, bank angle, heading angle, angular velocities relative to three axes, longitudinal and lateral g-loads, control surface angles of sounding flying vehicle; then direction and force of wind and motions of ship (change in trim, heeling and vertical motion of ship's center of mass) are measured, after which the following characteristics of sounding flying vehicle are measured: vertical deviations, lateral deviations and speed vector reactive to ship; measurements are conducted by means of external trajectory measurement devices on measurement platform connected with ship; platform is stabilized against motions and then differences between vector of speed of sounding vehicle relative to measurement platform and vector of speed of sounding vehicle relative to air masses are determined. EFFECT: enhanced accuracy of measurements. 1 dwg

Description

 The invention relates to the field of aviation and can be used in ship-based aircraft for measuring the characteristics of landing systems.

 A known system for measuring the satellite jet of an aircraft using a sounding aircraft.

 Conducting research using a sounding aircraft designed to fly in a vortex wake of a leading aircraft (flying in a wake and its intersection), involves the use of visualization of vortex harnesses. This is done with the help of smoke systems installed on board the leading aircraft (LA). In this case, the main difficulty is to measure the characteristics of the flow induced by the vortex wake at certain points, because under the influence of various factors the region of the satellite stream moves in space. It is necessary to move the sensors in such a way that their movement repeats the mass movement of the studied area of the wake and at the same time they are in certain predetermined positions in space. Therefore, it is necessary, either admitting errors, to conduct evaluative studies, or, complicating the processing of materials, introduce amendments.

 The method is used to determine the structure of the flow and measure the intensity of the wake from the recorded deviations of the rudders of the control aircraft, compensating for its movement in the wake. To evaluate the intensity of the vortices of the components of the flow velocity vector, the angular velocities and overloads relative to the three axes, and the deflection angles of the control surfaces are recorded on a sounding airplane. Synchronous registration of the kinematic characteristics of the flow and the movement of the aircraft, as well as the relative motion of the aircraft, is required, high accuracy of measurements and registration is required.

 According to the results of the analysis of errors in determining the characteristics of the satellite stream, it follows that they depend on the errors of the airspeed meters and the speed of movement relative to the aircraft or ship, and for standard meters at normal speeds of approach, they do not provide the necessary accuracy in determining the speeds of the satellite stream. To achieve the required accuracy characteristics of measuring the air flow parameters, it is necessary to use special sensors with a reduced error in measuring the speed of flight.

 Closest to the proposed one is a method for determining the structure of an aircraft’s wake at necessary distances behind it, while maintaining precisely the specified distances, according to which another aircraft equipped with equipment for measuring in the wake is towed behind the aircraft. The length of the tow rope is determined by the distance at which measurements are required. The sensors are mounted on a remote rod, which is introduced into the vortex wake during the experiment. This research method allows you to determine the structure of the trace at the required distance behind the aircraft and can be used to analyze its development of folding the shroud and the inviscid development of the track. In this way, a glider was towed with the hot-wire anemometer installed on it behind the Canadian De Haviland aircraft, the cable length was 18 wingspan.

 To probe the track, 3-component hot-wire anemometer sensors mounted on a remote glider rod were used.

 The disadvantage of using towed gliders for measuring the characteristics of a satellite jet behind a ship is the lack of desired accuracy results. To obtain a given accuracy in estimating the parameters of a satellite stream, it is necessary to carry out high-precision measurements using precision sensors and a long observation time at each spatial point, which the described method does not allow.

 The satellite stream behind the stern of the ship, along with the oscillatory movements of the landing site, is one of the decisive factors affecting the accuracy and safety of the aircraft landing mode. This implies the need for reliable knowledge of the real characteristics of the satellite stream and the determination of the model of this perturbation for the selection of design cases for evaluating the efficiency of landing and to predict the characteristics of the aircraft landing under calculated extreme environmental conditions.

 Airflow around the hull of the ship and deck leads to the formation of intense air disturbances in the form of bevels of the stream and vortices (air holes), which cause changes in the angle of attack of the aircraft and its airspeed. The unevenness of the vertical bevels along the wing span also leads to intense disturbances in the angle of the aircraft roll, especially before landing.

 The nature and intensity of air disturbances depend on the longitudinal balancing of the aircraft carrier, its speed, direction and intensity of wind and sea waves.

 Air disturbances behind the ship contain stationary (deterministic) disturbances, which are functions of the coordinates of the location of the aircraft relative to the ship.

They are characterized by descending and ascending air flows behind the stern of the ship, changing with a change in the location of the aircraft (bevels 4-9 ^o ).

Turbulent disturbances in the form of random functions of time depend on the speed of the air flow above the deck and the distance to the ship σ _W ≈ 0.2 ÷ 0.7 m / s.

 The vertical and horizontal slopes of the flow due to the rolling of the ship in the form of periodic functions of time depending on the oscillations of the deck (± 1.4 m / s and ± 0.6 m / s).

 Over the stern of the ship there remain swirling flow zones at large distances, and immediately after the stern the swirling flow lines up to about 150 m are directed downward, and from a distance of about 300 m and then upward. Thus, there is a downward flow failure behind the aircraft carrier, and the aircraft entering this zone tends to fall (into the pit).

 The noted points determine the need for measuring and evaluating the characteristics of the satellite air flow behind the ship in real conditions.

 The problem of determining the component velocities of a satellite stream behind a ship is solved by using aircraft such as a glider probe based on measuring the vectors of flight speed relative to the ship and airspeed.

 The purpose of the invention is the determination of the characteristics of a satellite stream behind an aircraft carrier ship.

, углы тангажа, крена, курса ν, γ, ψ, угловые скорости относительно трех осей w₂, ω_x, ω_y, продольную и боковую перегрузки (h_y, h_z), углы отклонения рулевых поверхностей δ_в, δ_э, δ_н, δ_нупс ЛА-зондировщика, измеряют направление θ_ск и силу W_ск ветра, качку корабля (дифферентную θ_к, креновую γ_к и вертикальное перемещение центра масс корабля ΔH_ск) и измеряют характеристики ЛА-зондировщика вертикальные ΔH, боковые отклонения ΔZ и вектор скорости

относительно корабля средствами внешне-траекторных измерений (ВТИ) на мерной платформе, связанной с кораблем, стабилизируя ее по качке, после чего определяют искомые разности между вектором скорости ЛА-зондировщика относительно мерной платформы

и вектором скорости ЛА-зондировщика относительно воздушных масс

.To solve this goal, a method for measuring the characteristics of the constituent velocities of a satellite stream behind an aircraft carrier ship is proposed, including measuring the characteristics of the ship, the motion characteristics of the aircraft (LA) of the probe relative to air masses, and determining the characteristics of the air satellite stream, in which the LA probe is sequentially placed in a series of predetermined points of space behind the ship, holding the LA-probe at a given point, additionally measure flight parameters — attack and slip angles (α and β), vector c orosti flight

, pitch, roll, heading angles ν, γ, ψ, angular velocities relative to the three axes w ₂ , ω _x , ω _y , longitudinal and lateral overloads (h _y , h _z ), steering surfaces deflection angles δ _в , δ _э , δ _n , δ _{nups of the} LA probe, measure the direction θ _cc and wind force W _cc , the roll of the ship (trim θ _k , roll γ _k and the vertical displacement of the ship’s center of mass ΔH _cc ) and measure the characteristics of the LA prober vertical ΔH, lateral deviations ΔZ and speed vector

relative to the ship by means of external trajectory measurements (VTI) on a measuring platform connected with the ship, stabilizing it by pitching, after which the desired differences between the velocity vector of the LA probes relative to the measuring platform are determined

and the velocity vector of the LA probe relative to air masses

.

 The drawing shows a General block diagram of a system for measuring the characteristics of the parameters of a satellite jet behind a ship, where are indicated: 1 towed probing model, aircraft (LA) -sonde; 2 power cable and data cable; 3 automatic control system (ACS); 4 - inertial system (IS); 5 system of air signals (SHS); 6 airspeed sensor pitot tube; 7 slip sensor; 8 angle of attack sensor; 9, 10, 11 gyroscopic sensors of pitch angles, roll; 15, 16 accelerometers of vertical and lateral overloads; 17 governing bodies (surfaces), including direct lifting force control (LPS); 18 electric winch control; 19 winch drive, cable and cable; 20 television information measuring system (TIIS) on a stabilized measuring platform; 21 vehicle roll sensors; 22 ship trim sensor; 23 wind sensor on the ship; 24 ship pitching sensor; 25 electric drives; 26 calculator; 27 operator control panel; 28 ship.

 The method is as follows.

 In accordance with the selected step, the air space behind the stern of the ship is divided along the X, Y, Z coordinates, forming a "cube" of points at which to measure the parameters of the satellite stream. The specified coordinates of the points are displayed on the display screen 27 facing the operator. On the same screen, the position of the LA probe 1 is observed according to the information received from the VTI - TIIS-20, stabilized by the rolling of the ship. The LA probes 1 are placed sequentially in a series of predetermined points of space behind the ship, holding it at a given point using SAU-3, by deviation of the control surfaces 17 of which they realize a predetermined flight path.

, углы тангажа, крена и курса ν, γ, ψ, угловые скорости w_z, ω_x, ω_y, продольную и боковую перегрузки (h_y, h_z), углы отклонения рулевых поверхностей (δ_в, δ_э, δ_н, δ_нупс) ЛА- зондировщика 1 и вводят в корабельный вычислитель 26.Combining the set and current coordinates of the LA probes 1, additionally measure the flight parameters, the angles of attack and slip α and β, the velocity vector

, pitch, roll and course angles ν, γ, ψ, angular velocities w _z , ω _x , ω _y , longitudinal and lateral overloads (h _y , h _z ), steering surface deviation angles (δ _in , δ _e , δ _n , δ _nups ) of the LA-probe 1 and enter into the ship computer 26.

относительно корабля средствами на мерной платформе, связанной с кораблем и стабилизированной по качке.The direction θ _cc and the wind force W _cc , the ship pitching, the differential θ _k , the roll γ _k, and the vertical displacement of the ship’s center of mass ΔH _k are measured, and the vertical sounding parameters 1 ΔH and lateral deviations ΔZ and the velocity vector are measured

relative to the ship by means on a measuring platform connected with the ship and stabilized by pitching.

и вектором скорости ЛА-зондировщика 1 относительно воздушных масс

по формуле

где

вектор скорости перемещения воздушных масс в стабилизированной посадочной системе мерной платформе в виде составляющих скоростей W_x, W_y, W_z определяется

где V_вс воздушная скорость ЛА- зондировщика 1, полученная по информации от системы воздушных сигналов (СВС).After that, using the calculator 26 determine the desired differences between the velocity vector of the LA probes 1 relative to the measuring platform

and the velocity vector of the LA probe 1 relative to air masses

according to the formula

Where

the velocity vector of the movement of air masses in a stabilized landing system measuring platform in the form of velocity components W _x , W _y , W _z is determined

where V _Sun airspeed La sounder 1 obtained according to information from air data system (SHS).

Using the obtained components of the velocity vector W _x , W _y , W _{z of the} LA probe 1, the spectral densities S (W _x / L), S (W _y / L), S (W _z / L) and RMS the values of σ _Wx , σ _Wy , σ _{Wz of the} turbulent component of the flow for various characteristics of sea waves and the direction and speed of the wind above the deck; mutual correlation functions R (τ) of turbulence and fluctuations for the parameters α, β, v _ck , ΔZ, γ _k , θ _k .

 Moreover, these statistical characteristics are obtained over the entire range of design conditions, changes in the angles of installation of the ramps, etc. including extreme cases corresponding to the maximum rolling of the ship and the installation of based squadrons on the deck according to the limiting layout at the starting positions.

приращение каждой составляющей W_x, W_y, W_z определяют разложением функций f_x, f_y, f_z в степенной ряд в окрестности параметров движения, определяющих исходную траекторию полета.The estimation of errors in the calculation of the components of wind speeds is represented as the increment of the function of many variables corresponding to the given increment of the arguments. If each of the functions f _x , f _y , f _{z is} differentiable, then for each variable

the increment of each component W _x , W _y , W _z is determined by expanding the functions f _x , f _y , f _z in a power series in the vicinity of the motion parameters that determine the initial flight path.

где X_j параметры движения ЛА, которые используют для вычисления ΔW_x, ΔW_y, ΔW_z; Δx_j -погрешности определения истинных величин этих параметров, n 7.Controls for estimating errors in calculating the velocity components of a satellite stream behind a ship are

where X _j are the aircraft motion parameters that are used to calculate ΔW _x , ΔW _y , ΔW _z ; Δx _{j -} errors in determining the true values of these parameters, n 7.

 Errors are considered independent quantities with mathematical expectations equal to zero.

Это выражение используется для назначения требований по допустимым погрешностям датчиков параметров движения ЛА и оценки точности определения скоростей спутной струи по бортовой и наземной информации о параметрах движения ЛА.Under these conditions, the standard error of the calculator of the components of the velocity of the satellite stream is determined by the formula

This expression is used to assign requirements for permissible errors in the sensors of the parameters of the aircraft motion and to evaluate the accuracy of determining the speeds of the satellite stream from the airborne and ground information about the parameters of the aircraft motion.

 Errors in measuring the parameters of the satellite stream are reduced by reducing to zero the flight speed of the LA probes 1 relative to the ship. Errors in the measurement of aircraft speed are eliminated by measuring the speed of the aircraft relative to the ship using VTI.

 The method allows for observations when measuring the parameters of the air flow at a fixed point in space relative to the ship for a long time, thereby ensuring the accuracy and stability of the characteristics of the air flow at a given point of landing.

 When using this method, the restrictions on the hydrometeorological conditions of the experiments and the dependence on geographical areas at the ship’s location are reduced, and there are no alternate coastal airfields within the reach of their aircraft.

 The ease of maintenance during the experiment makes the method economical and rational in measuring the characteristics of the satellite stream behind the ship.

 This method is implemented by a measurement system.

On board 1 of the LA-towing vehicle, the SAU-3 is connected to the sensors of the aircraft motion parameters used in the inertial system 4, which in turn is connected to the sensors of pitch angles ν 9, course j 10, roll g 11, accelerometers h _y 15, h _z 16 , and angular velocity sensors (TLS) w _z -12, ω _y -13, ω _x -14.

SVS-5 is connected to sensors of angles of attack α 8, slip b 7 and airspeed V _Sun 6, SVS-5 is connected to SAU-3; SAU-3 output is connected to controls 17.

 Ship TIIS-20 is connected to a computer 26, which is connected to the sensors of pitching 24, wind 23, trim 22, roll 27, as well as with the control panel 27 of the operator; the output of the calculator 26 is connected to the TIIS-20, the electric drives 18 of the winch 19 and the electric drive 235 ramps.

 Using the control coordinate controller, the LA probe 1, located on the remote control 27 and connected by cable to the SAU-3, place the LA-1 sequentially in a series of predetermined points of space behind the ship. To this end, control surfaces 17 are deflected using SAU-3. After combining the set and current coordinates of the LA probes 1, data is loaded into the ship computer 26 connected to the ship systems. The measurements on board the LA-1 aircraft motion parameters are synchronized with the external trajectory measurements of the flight speed and the location of the LA-1 relative to the ship.

 The operator from the control pulpit 27 through the calculator 26 also controls the range of the LA-probe 1 using the electric winch 18; with the help of an electric drive 25 changes the angles of installation of the ramps and thereby changes the structure of the satellite stream.

 LA probes 1 flying model with minimal evolving flight speeds, comparable with the speed of the ship. To evaluate the parameters of a satellite stream, a certain observation time is required at each point in space under stabilized, fixed conditions in the wind and sea waves. Only in this case is it possible to reliably estimate the random and determined components of the satellite stream.

 The rapid movement of the transition process of transferring the LA-probe 1 to another measuring point of the jet space is eliminated by the SAU-3 by means of direct control of the lifting force (LPS) 17.

 With the help of TIIS 20, which uses a Vidicon-type transmitting television tube, the coordinates of the LA probing device 1 are automatically measured along the axes that coincide with the direction of the vertical and horizontal scans. If the image of the aircraft on the screen of the television receiver remains shifted by an amount X on the horizontal axis and a value Y on the vertical, then relative to the longitudinal axis of the transmitting tube, the image will be shifted by the angles in the longitudinal tgλ X / F, horizontal by tgμ Y / F, where F is the focus lens distance. If the aircraft displacement along the X, Y axes is automatically measured, then the angular deviations of the aircraft relative to the axis of the television camera are determined. These data using the control device rotate the camera so that the image of the aircraft is continuously held in its field of view.

A necessary condition for external trajectory measurements of TIIS is DH = 0, ΔZ = 0, ΔD = 0, at which time α, β, V _ck are measured.

Claims (1)

A method for measuring the characteristics of an airborne jet behind a vehicle, mainly behind an aircraft carrier, including measuring the parameters of the vehicle, motion parameters of the sounding aircraft relative to air masses and determining the parameters of the airborne satellite, characterized in that the sounding aircraft is sequentially placed in a row preset points of space behind the ship, in which the aircraft-probe is held using an automatic control and power cable, additionally measure flight parameters, attack and slip angles (α, β), flight speed vector

pitch, roll and course angles (∂, γ, ψ), angular velocities relative to the three axes (ω _z , ω _x , ω _y ), longitudinal and lateral overloads (n _y , n _z ), steering surface deviation angles (δ _in , δ _e , δ _n ) of the sounding aircraft, measure the direction θ _ck and the force W _{c to the} wind, the ship is pitching and measure the characteristics of the vertical sounding vehicle ΔH, lateral deviations ΔZ, and the velocity vector

relative to the ship by means of external trajectory measurements on a measuring platform connected with the ship, stabilizing it along the pitching, and then determining the speed of movement in a satellite stream in the form of the difference between the velocity vector of the sounding aircraft relative to the measuring platform

and the velocity vector of the sounding aircraft relative to air masses

and from the obtained velocities of movement of the airborne satellite stream, its characteristics are calculated, namely, spectral density, rms values of the turbulent component of the flow and the scale of turbulence.