RU2263283C1 - Method and device for complex testing of flying micro-vehicle provided with platform-free inertial navigation system - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: method and device can be used for measuring aerodynamic characteristics of inertial navigation systems. Rigidity of suspension of integral platform-free inertial navigation system is calibrated. Signals of the system are used for determining dynamic characteristics of flying micro-vehicle and its engines. Free end of portable flexible suspension is disconnected from motionless base, the end is fastened to transportation vehicle, speed of linear motion of transportation vehicle is specified in environment and aerodynamic characteristics of flying micro-vehicle are determined depending on speed of linear motion.

EFFECT: widened functional capabilities.

8 cl, 5 dwg

Description

The present invention relates to measuring equipment, in particular to test benches for determining the dynamic and aerodynamic characteristics of aircraft micro-devices controlled by inertial navigation systems.

Known methods for determining aerodynamic characteristics, for example, drag, when the model of an aircraft is installed in a wind tunnel by means of a strain gauge, the air velocity is set and the drag force is measured using strain gauges, and it is not possible to determine the moment of inertia of the apparatus, in addition to the force and drag coefficient, damping coefficients and engine time constant (see Mikeladze V.G., Titov V.M. Basic geometric and aerodynamic characteristics of aircraft and missiles. Handbook. M., 1982).

On the other hand, the methods and stands on which the attached moments of inertia and damping coefficients are determined by the amplitude and natural vibration frequency of products suspended on elastic suspensions, using strain gauges as vibration amplitude meters, do not allow measurements of drag coefficient and transition time engines. Such a complex problem arises in connection with the use of a motion control automaton in an aircraft microcircuit, the coefficients of the regulators of which determining the stability of the apparatus’s movement depend on the values of inertia moments, damping and drag coefficients, and engine time constant.

A common drawback of the above systems is the need to use special measuring tools, in particular strain gauges or other dynamometric transducers, which introduce their own errors into the test results, which depend, inter alia, on the environmental characteristics.

Known methods for testing gyro-inertial systems, including reproducing the output signals of the angular motion of the gyro-inertial system using a three-stage dynamic stand according to a given model of the aircraft’s motion, generating output parameters of the translational motion of the gyro-inertial system (6B1.623.005 RE I-21, MIEA, 1984, p.102- 112).

The disadvantage of these methods is that the gyroinertial system does not give parameters about the translational motion of the aircraft, it does not have the errors caused by it, and, of course, in this case it is impossible to control their accuracy.

The closest technical solution is a method of testing gyro-inertial systems, which includes reproducing the output signals of the angular motion of the gyro-inertial system using a three-stage dynamic stand according to a given model of the aircraft’s movement, comparing the real parameters determined by the gyro-inertial system and the ideal or calibration parameters of the same name, the results of which evaluate the functioning and dynamic characteristics of the aircraft (see RF patent No. 1768980, class G 01 C 2 5/00, 1990).

The disadvantage of this method and its implementing device is that they do not allow measurements of drag coefficient and transient time of an aircraft engine containing a motion control automaton, the regulator coefficients of which, determining the stability of the apparatus’s movement, depend on the moment of inertia, damping coefficients and drag, engine time constant. In addition, the use of various mathematical models of the aircraft’s behavior significantly and often unjustifiably complicates the process of processing measurement information.

The technical result of the invention is to create a method and expand the functionality of the device that implements it by providing the ability to measure a wide range of additional, qualitatively excellent parameters, while ensuring the reliability of the reproduction of operating conditions during testing and simplifying the processing of measurement information about the state of the test aircraft.

The specified technical result is achieved by the fact that in the test method of an aircraft with an integrated strapdown inertial navigation system (IBINS), including the calibration of measuring instruments for complex tests of the aircraft and the subsequent determination of its dynamic characteristics using the indicated measuring means, to achieve the above result, the aircraft is first the microapparatus (LMA), which includes IBINS, is rigidly fixed at one end of the portable elastic the suspension, the free end of which is fixed on a fixed base, calibrate the rigidity of the specified suspension with LMA mounted on it according to IBINS signals and determine the dynamic characteristics of the LMA and its engines, then disconnect the free end of the portable elastic suspension from the fixed base, fix it on the vehicle, set the speed of the rectilinear movement of the vehicle in the surrounding air environment and determine the aerodynamic characteristics of the LMA depending on the speed of straight frost movement.

In addition, the stiffness calibration of the portable suspension with the LMA mounted on it can be performed by rejecting it by a predetermined amount in a given direction relative to the fixed base, and the corresponding IBINS signals can be stored in a mobile personal computer (IPC).

In addition, the dynamic characteristics of the LMA are determined by its moments of inertia and damping coefficients, for which the LMA is fixed at the end of the portable elastic suspension with orientation in the given direction of its navigation axis, the suspension from the LMA is rejected in the direction orthogonal to this axis by a predetermined value and release it, and the IBINS signals corresponding to the oscillations of the LMA are processed in the IPC and the moment of inertia and the damping coefficient of the LMA relative to this axis are determined from them, after which they are indicated in this paragraph Actions are performed for another navigational axis.

In addition, as a dynamic characteristic of each LMA engine, the time constant of this engine relative to a given navigational axis is determined, for which an engine located outside a vertical plane passing through a given navigational axis is turned on at full power, the transitional stabilization time of the LMA under the influence of the stiffness of the portable elastic suspension, which is controlled by signals IBINS processed in the IPC, and determine the time constant of this engine.

In addition, the drag coefficient of the LMA in the direction of its navigational axis is determined as the aerodynamic characteristic, for which, at a given vehicle speed in the air, the angle of deviation of the LMA is fixed by the IBINS signals processed in the IPC, and the drag coefficient C _{x is} determined from the expression

where γ is the deviation angle of the portable elastic suspension,

S is the cross-sectional area of the LMA,

ρ is the density of air,

V is the vehicle speed,

- число Рейнольдса,

is the Reynolds number,

D is the maximum size of the LMA,

ν is the viscosity of air.

To achieve the above technical result in the device for complex testing of an aircraft micro-device (LMA) with an integrated strapdown inertial navigation system (IBINS), which contains a fixed table with a mounting unit for the test LMA and elements for specifying the test load and a processing information processing system, the mounting unit for the tested LMA consists of from a base having a surface for basing on a fixed table and a vehicle and mounting elements in the form of holes along mounting screws and magnets pressed into the base tangentially to the base surface, and crosses for mounting the test LMA connected to the base with an elastic beam, and the test load task elements are made in the form of at least one rack rigidly mounted on a fixed table with a steering wheel and thrust through it with a load at one end and an element of communication with the LMA at the other, while a removable pin is installed on the steering wheel, and an emphasis for this pin is mounted on the rack.

In addition, the measuring information processing system is made in the form of an IBINS LMA radio interface and a mobile personal computer (MPC) containing a radio interface for communication with an IBINS radio interface.

Figure 1 presents a General view of the device for complex testing (stand).

Figure 2 presents a top view of a portable elastic suspension LMA.

Figure 3 presents a side view of a portable elastic suspension LMA.

Figure 4 presents the structural diagram of IBINS and processing systems for measuring information.

Figure 5 shows the mounting scheme of a portable elastic suspension LMA on a vehicle.

The list of used items in the description of inventions.

1. LMA

2. Portable elastic suspension

3. Table

4. Cross

5. The elastic beam

6. The basis

7. Holes

8. Magnets

9. Fixing screws

10. Stud

11. Stand

12. Nut

13. IBINS

14. The block of sensing elements

15. The microprocessor of the strapdown inertial block

16. The BINS microprocessor

17. Radio interface 1

18. The engine control board PUD

19-22 D1-D4 engines

23. Mobile personal computer

24. IPC Radio Interface

25. Racks

26. Guide wheel

27. thrust

28. Cargo

29. Pin

30. Emphasis

31. Car.

The proposed device for determining the moments of inertia, damping and drag coefficients, traction characteristics and time constants of the engines of the aircraft micro-device contains the test aircraft micro-device 1, which by means of a portable elastic suspension 2 is mounted on a table 3. A portable elastic suspension 2 consists of a cross 4, which is rigidly connected by means of an elastic beam 5 with a base 6 of a portable elastic suspension 2. At the base 6, holes 7 are made and magnets 8 are pressed in. Holes 7 and m Agnitals 8 are used to mount the suspension 2. If the table 3 is steel, then magnets 8 are used for fastening, in other cases 2 are attached with screws 9. The aircraft micro-camera is attached with pins 10, posts 11 and nuts 12 to the cross 4.

Aircraft microapparatus 1 includes an integrated strapdown inertial system 13, which includes a block of sensitive elements (BEC) 14 (3 gyroscopes and 3 accelerometers), a microprocessor of a strapdown inertial block (BIB) 15, a microprocessor of a strapdown inertial navigation system (BINS 16) , the radio interface 17, the engine control board 18 and the engines 19-22.

The stand includes a mobile personal computer (MPC) 23 with a radio interface 24. On a table 3, a rack 25 with a guide wheel 26 is rigidly mounted. One of the control engines 20 is connected to the load 28 via a traction 27.

The method of determining the moments of inertia, damping coefficients, drag coefficients and traction characteristics of the engines and the operation of the stand to determine these characteristics is as follows.

Before starting the measurements, the stiffness of the elastic beam 5 is measured. For this, the load 28 is attached to the rod 27. As a result, a moment of gravity equal to

M _z = m · g · l,

where m is the mass of the load, g is the acceleration of gravity, l is the shoulder.

Under the influence of this moment, the beam deviates by a certain angle γ. At the same time, a signal proportional to the angular velocity of the LMA relative to the Z axis will appear along the Z axis with the BChE, which will be transmitted to the BIB 15 microprocessor, where it will be integrated. The value of the calculated angle through the BINS 16 microprocessor and the radio interface 17 will go to the IPC 23 radio interface.

The stiffness of the elastic beam will be determined by the expression

Processing of the measurement results is as follows:

, где i=1-N - число измерений.

where i = 1-N is the number of measurements.

In this case, the error in processing the measurement results will be

After calibrating the stiffness of the elastic beam, they begin to determine the moments of inertia and damping coefficients. To do this, disconnect the load 28 from the rod, insert the pin 29 into the guide wheel 26 and manually pull the rod 27 until the pin 29 abuts against the stop 30 and release the rod. The LMA deviates by a fixed angle γ and it starts to oscillate relative to the Z axis. A signal proportional to the angular velocity of the apparatus oscillations around the Z axis will appear from the gyroscope along the Z axis of the IBINS. This information will be sent to the IPC 24 air interface and recorded in the file in the same way as during calibration. IPC drain 24. Moreover, the movement of the apparatus can be described by the equation

where γ is the angle of rotation of the apparatus along the Z axis;

J _z is the moment of inertia along the Z axis;

To _d - damping coefficient;

Ku - stiffness of the portable suspension.

Equation (2) can be reduced to the form

In the operator record, equation (3) takes the following form:

where T is the period of free oscillations (in the absence of attenuation);

ξ is the attenuation parameter lying in the range 0 <ξ <1;

- символ производной.

- derivative symbol.

According to equations 3 and 4, we obtain

- могут быть определены: частота λ и период затухающих колебаний Т₀, амплитуды колебаний при времени t=t₁ и t=t₁+T₀ соответственно, а также коэффициент затухания переходного процесса

, используя соотношениеTaking data from the gyroscope, according to the graph of the change in time of the angular velocity

- can be determined: the frequency λ and the period of damped oscillations T ₀ , the oscillation amplitudes at time t = t ₁ and t = t ₁ + T _0, respectively, as well as the damping coefficient of the transient

using the ratio

The period of free oscillations T, the damping parameter - ξ and the frequency of the damped oscillations are related by the relation

Using relations (7), (8) and (9), the following parameters are determined: Т, ξ and, accordingly, the required moment of inertia and the damping coefficient of the LMA relative to the Z axis using the equations

J _z = Ku · T ² -m · l ² ,

To _d = 2 · ξ · Ku · T.

Carrying out multiple measurements and calculations of J _z and K _d , we can get their average values, as well as average statistical errors in determining J _z and K _d .

The moment of inertia and the damping coefficient along the X axis are determined similarly.

Consider the definition of time constants of engines. For this, one of the engines, not lying in the vertical plane of the LMA mount, is turned on at full power. LMA, being at rest, will begin to turn around the X axis and stabilize under the action of the stiffness of a portable elastic suspension. Time constant

where τ _dv is the time constant of the engine;

T _{pereh.protsessa} - the transition process stabilization device. The average statistical value, as well as the average statistical error in determining τ _{dv, is} found as follows:

After determining the moments of inertia, the damping coefficients of the LMA and the time constants of the engines, the drag coefficient is measured. For this, the LMA 1 together with the portable elastic suspension 2 is disconnected from the table 3 and mounted on the roof of the car with magnets 8, and a mobile personal computer 23 with the radio interface MPK 24 is installed inside the car. A straight section of the road is selected. The car moves at a given constant speed. According to the SINS, the angle γ and the vehicle speed are recorded. In this case, the drag coefficient of the LMA is calculated from the expression

where γ is the deviation angle of the portable elastic suspension,

S is the cross-sectional area of the LMA,

ρ is the density of air,

V is the vehicle speed,

- число Рейнольдса,

is the Reynolds number,

D is the maximum transverse size of the LMA,

ν is the viscosity of air.

By changing the speed of the car, we obtain the dependence of the drag coefficient of the LMA on the Reynolds number under the conditions of the tests, as close as possible to the real ones.

Thus, the present invention provides a technical result, which consists in expanding the functionality of the method of complex testing of LMA containing IBINS and implementing its device by providing the ability to measure a wide range of additional, qualitatively excellent parameters, while ensuring the reliability of the reproduction of operating conditions during testing and simplifying the processing of measurement information about the state of the test LMA.

Claims (7)

1. A method for complex testing of an aircraft micro-device (LMA) with an integrated strapdown inertial navigation system (IBINS), comprising calibrating measuring instruments for complex tests of LMA and then determining the dynamic characteristics of LMA using the indicated measuring means, characterized in that the LMA first includes IBINS composition, is rigidly fixed at one end of a portable elastic suspension, the free end of which is fixed on a fixed base, calibrated rigidly The indicated suspension with the LMA mounted on it according to IBINS signals and determine the dynamic characteristics of the LMA and its engines, then disconnect the free end of the portable elastic suspension from the fixed base, fix it on the vehicle, set the speed of the rectilinear movement of the vehicle in the surrounding air and determine the aerodynamic LMA characteristics depending on the speed of rectilinear motion. 2. The method according to claim 1, characterized in that the stiffness of the portable suspension with the LMA mounted on it is calibrated by deflecting it by a predetermined amount in a given direction relative to the fixed base, and the corresponding IBINS signals are stored in a mobile personal computer (IPC). 3. The method according to claim 2, characterized in that as the dynamic characteristics of the LMA determine its moments of inertia and damping coefficients, for which the LMA is fixed at the end of a portable elastic suspension with orientation in a given direction of its navigation axis, the suspension from the LMA is rejected in the direction orthogonal to this axis by a predetermined value and release it, and IBINS signals corresponding to the oscillations of the LMA are processed in the IPC and the moment of inertia and the damping coefficient of the LMA relative to this axis are determined from them, after which specified in this paragraph to produce other actions navigation axis. 4. The method according to claim 3, characterized in that as the dynamic characteristic of each LMA engine, the time constant of this engine relative to a given navigation axis is determined, for which an engine located outside a vertical plane passing through a given navigation axis is turned on at full power, fixed the time of the transition process of stabilization of the LMA under the action of the stiffness of a portable elastic suspension, which is controlled by the IBINS signals processed in the IPC, and the time constant of this is determined from it engine. 5. The method according to claim 2, characterized in that the drag coefficient of the LMA in the direction of its navigation axis is determined as the aerodynamic characteristic, for which, at a given vehicle speed in the air, the angle of deviation of the LMA is fixed by the IBINS signals processed in the IPC, and determine the drag coefficient. 6. A device for complex testing of an aircraft micro-device (LMA) with an integrated strapdown inertial navigation system (IBINS), comprising a fixed table with a fastening unit for the tested LMA and elements for specifying the test load and a processing information processing system, characterized in that the fastening unit for the tested NMA consists of a base having a surface for basing on a fixed table and a vehicle and mounting elements in the form of holes for mounting screws, and magnets, piled into the base tangentially to the base surface, and crosses for installing the test LMA, connected with the base by an elastic beam, and the elements of the test load are made in the form of at least one rack rigidly fixed to a fixed table with a guide wheel and a thrust thrown over it with a load at one end and a communication element with the LMA at the other, with a removable pin mounted on the steering wheel, and an emphasis for this pin on the rack. 7. The device according to claim 6, characterized in that the measurement information processing system is made in the form of an IBINS LMA radio interface and a mobile personal computer (IPC) containing a radio interface for communication with an IBINS radio interface.

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