RU2087864C1 - Analytical gyrocompass - Google Patents

Abstract

FIELD: high-accuracy independent and corrected inertial systems of round and sea navigation, mobile facilities of geological prospecting and mapping. SUBSTANCE: on platform of three-axes gyrostabilizer there are installed two accelerometers, three gyrounits and two amplifiers and gyrounit with wide-range code angle pickup is mounted is mounted. Before start of operation platform is levelled and stabilized in inertial space relative to vertical axis. System of levelling is transferred to storage mode with the help of control unit and two switches at specified time moment and precession angles are fed intro computer where azimuth of platform is determined roughly with the use of constants of unit. By instruction from control unit switch connected circuit of gyroscope setting composed of adder, comparison element, digital-to-analog converter and amplifier to pickup of moment of gyrounit and gyroscope is set into required position. Computer calibrates key parameters of system and makes azimuth of platform more precise. EFFECT: improved operational accuracy. 1 dwg

Description

 The invention relates to the field of gyroscopic systems and can be used to determine the azimuth, for example, in high-precision systems for various purposes.

Known system analytical gyrocompassing platform [1]
The prototype of the invention is a platform analytical exhibition system [2]
This system contains a platform with two accelerometers and four gyro blocks located on it, and the outputs of the first and second accelerometers are connected to the inputs of the moment sensors of the first and second gyro blocks through the first and second correction amplifiers. The moment sensor of the third gyro block through the third correction amplifier and the switch is connected, depending on the operating mode, to the output of the second accelerometer, or to a stabilized current source. The output of the angle sensor of the fourth gyro block through a feedback amplifier is connected to a torque sensor, it is also connected via an analog-to-digital converter and a register for storing feedback current values to the calculation unit. The control unit, at the input of which the output from the control system is connected, is connected by its outputs to the switch, the computation unit, and the storage register of feedback current values. The first and second accelerometers, correction amplifiers, and gyro blocks form two channels for leveling the platform. The third gyro block with a third correction amplifier, a switch and a stabilized current source control the platform relative to the vertical axis.

 The disadvantages of the prototype are as follows. For the computing unit to work, you must first know the basic parameters of the device, which are part of the coefficients of the system of algebraic equations. The feedback current and its derivative are used as working information, for the measurement of which it is necessary to know the feedback parameters with great accuracy. During measurements, the leveling system may be disturbed by external factors, and then the desired exhibition parameters, the platform non-horizontal angles can vary significantly and introduce errors into the computational algorithm. And finally, the exhibition algorithm does not take into account the drift of the platform during the measurement.

 The technical result of using the invention is to eliminate these disadvantages to improve the accuracy of determining the azimuth of the platform.

 This result is achieved by the fact that in a device containing a platform with two accelerometers and four gyro blocks installed on it, as well as two correction amplifiers, a control unit, a calculation unit, a constant memory constant, an amplifier, and the outputs of the first and second correction amplifiers are connected respectively to inputs of the moment sensors of the first and second gyro blocks, and the first output of the computing unit is connected to the first output of the control unit, the input of which is connected to the bus of the device enable signal a, an adder, a comparison element, a digital-to-analog converter, three switches are additionally introduced, while the outputs of the first and second accelerometers are respectively through the first and second switches, the controlled inputs of which are connected to the second output of the control unit, connected to the outputs of the first and second correction amplifiers, the sensor output the angle of the fourth gyro block through a block of calculations, an adder, a comparison element, the second input of which is directly connected to the output of the angle sensor of the fourth gyro block, digital-to-analog conversion the caller, amplifier, and a third switch, the control input of which is connected to the third output of the control unit, is connected to the input of the moment sensor of the fourth gyro block, and the first and second outputs of the constant storage constant device are connected respectively to the second input of the adder and the third input of the calculation unit, the second output of which is connected to the output bus of the device.

In the analytical gyrocompass according to the invention, the fourth gyro block uses a wide-range encoder of the gyroscope angle, which allows you to record information about the precession angles in the range of 0 ^o 360 ^o , which makes it possible to set the gyroscope in any position relative to the platform. In addition, the gyroscope exhibit chain was introduced into this gyrocompass in the optimal position relative to the platform (adder, comparison element, digital-to-analog converter, third switch), which reduces the effect of instability of the device parameters on the accuracy of determining the platform azimuth. The introduction of the first and second switches, which translate the platform leveling system into storage mode, eliminates the influence of linear accelerations that act on the accelerometers of the leveling system, which also leads to a decrease in errors in the azimuth estimation.

 The invention is illustrated in figure 1. The analytical gyrocompass contains platform 1 with accelerometers 2 and 3 installed on it and gyro blocks 4, 5, 6, 7, while the outputs of the first 2 and second 3 accelerometers are connected through the first 8 and second 9 switches to the inputs of the first 10 and second 11 correction amplifiers, the outputs of which are connected respectively to the inputs of the moment sensors of the first 4 and second 5 gyroblocks. The second output of the control unit 12 is connected to the control inputs of the switches 8 and 9, the first input of which is connected to the first input of the computing unit 13, and the third output is connected to the control input of the third switch 14. The input of the control unit is connected to the control signal bus. The output of the angle sensor of the fourth gyro block 7 through the computing unit 13, the adder 15, the comparison element 16, the second input of which is directly connected to the output of the angle sensor of the fourth gyro block, a digital-to-analog converter 17, amplifier 18, and the third switch 14 are connected to the input of the moment sensor of the fourth gyro block. The constant storage device of the constants 19 is connected by its first output to the second input of the adder, and the second output to the third input of the computing unit 13, the second output of which is connected to the output terminal of the device.

Each two-stage gyro block 4, 5, 6, 7 includes an angle sensor and a torque sensor, and the fourth gyro block 7 uses a wide-range code angle sensor 20. Computation block 13 is a specialized computer that can be implemented on microprocessors. The control unit 12 may be implemented, for example, by a shift register with parallel input and output. The switches 8, 9, 14 can be implemented, for example, on a relay. The adder 15, the comparison element 16 can be performed on standard elements. The amplifier 18 serves to amplify the current supplied to the windings of the moment sensor of the fourth gyro block 7, for which a standard amplifier can be used. The wide-range angle encoder 20 is a precision sensor with a resolution of at least 0.1 arcs and a rotor angle of rotation of the rotor relative to the stator 360 ^o . The digital-to-analog converter 17 converts a digital signal into an analog one and must have a 32-bit grid. Permanent storage device must have a memory capacity of at least 56 kbytes.

где I момент инерции гироскопа,
f коэффициент демпфирования,
H кинетический момент,
ω_в, ω_г проекции угловой скорости вращения Земли,
А₀ начальный азимут платформы,
ω_ГБ скорость собственного ухода измерительного гироблока,
δ^*, γ^* статические ошибки системы горизонтирования,
b угол прецессии гироскопа,
a угол поворота платформы относительно Земли,

ω_др скорость дрейфа платформы относительно вертикальной оси.The principle of operation of the analytical gyrocompass is as follows. The current azimuth of the platform is determined by continuously processing information about the precession angle of the gyroscope of the fourth gyro block 7, taken from a wide-range angle sensor 20. The algorithm for determining the azimuth of the platform is based on the full dynamic model of the gyroscope:

where I is the moment of inertia of the gyroscope,
f damping factor
H kinetic moment,
ω _in , ω _g projection of the angular velocity of rotation of the Earth,
And _{0 is the} initial azimuth of the platform,
ω _GB self-care speed of the measuring gyro block,
δ ^* , γ ^* static errors of the leveling system,
b angle of precession of the gyroscope,
a the angle of rotation of the platform relative to the Earth,

ω _dr the drift velocity of the platform relative to the vertical axis.

A feature of the proposed device is that the platform is "free in azimuth" vertically relative to the Earth, therefore, the vertical component ω _{In the} angular velocity of the Earth with an unmounted platform does not affect the determination of azimuth. The influence of the drift of the platform ω _dr relative to the vertical axis and the inertial term in formula (1) is also small.

где: β_o=β(t_o) начальное значение угла прецессии гироскопа,
a, b, F коэффициенты, вычисляемые в соответствии с приближенно известными значениями параметров:

где: I^*, H^*, f^*, ω $\genfrac{}{}{0ex}{}{\text{*}}{\text{ГБ}}$ , ω $\genfrac{}{}{0ex}{}{\text{*}}{\text{др}}$ предварительно известные значения параметров.The current azimuth is determined in two stages. First, based on the approximately known parameters of the meter, a preliminary assessment of the initial azimuth is made according to the formula, which can be obtained by solving equations (1):

where: β _o = β (t _o ) the initial value of the angle of precession of the gyroscope,
a, b, F coefficients calculated in accordance with approximately known parameter values:

where: I ^* , H ^* , f ^* , ω $\genfrac{}{}{0ex}{}{\text{*}}{\text{GB}}$ , ω $\genfrac{}{}{0ex}{}{\text{*}}{\text{dr}}$ previously known parameter values.

A significant feature of the proposed system is the ability to set the gyroscope in an optimal position relative to the platform, which allows to reduce the influence of instability of the meter parameters on the accuracy of determining the azimuth:
β $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ = A $\genfrac{}{}{0ex}{}{\text{*}}{\text{o}}$ -q $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ (4)
where: q $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ a parameter pre-calculated for the inventive device and characterizing the position of the kinematic moment of the gyroscope of the fourth gyro block.

Then, the deviations of the true values of the main parameters f, ω _dr , ω _GB and azimuth A ₀ from their approximate values are estimated by solving a system of algebraic equations obtained from (1):
a _i1 ΔA _o + a _i2 Δf + a _i3 Δω _dr + a _i4 Δω _GB = C _i , i = 1,2,3,4 (5)
where: ΔA _o , Δf, Δω _dr , Δω _GB deviations of the initial azimuth, damping coefficient, drift of the platform and gyro block, and _{ij are the} coefficients of the system (5).

По формулам Крамера

где: D, Δ₁, Δ₂ известные определители Крамера:

Окончательно искомый текущий азимут платформы вычисляется следующим образом:

где: Т_изм время измерения:
T_изм=t₇-t₀ (10)
Работа аналитического гирокомпаса заключается в следующем. Перед началом работы система горизонтирования платформы функционирует обычным образом - акселерометры 2, 3 через замкнутые первый и второй переключатели 8, 9 подключены к усилителям 10,1 коррекции, которые выдают сигнал на датчики момента первого и второго гироблоков. Система стабилизации платформы в инерциальном пространстве относительно вертикальной оси работает непрерывно (на фиг. 1 показан только третий гироблок чувствительный элемент системы стабилизации). Измерительная часть аналитического гирокомпаса включена - информация об угле прецессии β(t)) измерительного гироскопа постоянно подается в блок вычислений. Третьим переключателем отключен вход датчика момента четвертого измерительного гироблока 7 от усилителя, т.е. гироскоп находится в произвольном относительно платформы положении.

According to Cramer's formulas

where: D, Δ ₁ , Δ ₂ known Cramer determinants:

Finally, the desired current platform azimuth is calculated as follows:

where: T _meas. measurement time:
T _meas = t ₇ -t ₀ (10)
The work of the analytical gyrocompass is as follows. Before starting work, the platform leveling system functions in the usual way - accelerometers 2, 3 are connected to the correction amplifiers 10,1 through the closed first and second switches 8, 9, which provide a signal to the moment sensors of the first and second gyro blocks. The platform stabilization system in inertial space relative to the vertical axis works continuously (in Fig. 1 only the third gyro block is a sensitive element of the stabilization system). The measuring part of the analytical gyrocompass is turned on - information about the precession angle β (t)) of the measuring gyroscope is constantly supplied to the calculation unit. The third switch disconnects the moment sensor input of the fourth measuring gyro block 7 from the amplifier, i.e. the gyroscope is in an arbitrary position relative to the platform.

В блоке вычислений далее постоянно обрабатывается информация о текущем угле β(t) и по команде К(t₁), которая подается в блок вычислений, предварительно определяется азимут

в соответствии с алгоритмом (по формулам (2), (3)). По вычисленному значению A $\genfrac{}{}{0ex}{}{\text{*}}{\text{o}}$ и известному значению q $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ вычисляется (по формуле (4)) оптимальный угол β $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ на который нужно развернуть гироскоп относительно платформы для точного определения азимута. По команде К(t₂) третий переключатель подключает усилитель к входу датчика момента измерительного гироблока 7. После выставки гироскопа на β $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ по команде К(t₃) третий переключатель отключает датчик момента от усилителя и начинается этап точного определения азимута платформы. Вычисляются коэффициенты а_ij по формуле (6) для моментов времени t_i (i=3, 4, 5, 6, 7). После набора соответствующей информации блок вычислений 13 по соответствующему алгоритму (по формулам (5) (8)) производит калибровку основных параметров измерителя. По формулам (9) и (10) вычисляется текущий азимут платформы А(t). По команде К(t₇) работа аналитического гирокомпаса заканчивается и на выходную шину выдается информация о текущем азимуте платформы

на момент подачи команды К(t₇).The moment of operation of the analytical gyrocompass is determined by the supply of a control signal to the input of the control unit. By this command, the control unit generates a command K (t ₀ ), by which the first and second switches put the correction amplifiers into storage mode, turning off the accelerometers. By the same command, the initial value of the gyro precession angle is stored in the calculation block

In the block of calculations, information on the current angle β (t) is then constantly processed, and by the command K (t ₁ ), which is supplied to the block of calculations, the azimuth is preliminarily determined

in accordance with the algorithm (according to formulas (2), (3)). According to the calculated value of A $\genfrac{}{}{0ex}{}{\text{*}}{\text{o}}$ and the known value of q $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ the optimal angle β is calculated (by formula (4)) $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ on which you need to deploy the gyroscope relative to the platform to accurately determine the azimuth. At the command K (t ₂ ), the third switch connects the amplifier to the input of the moment sensor of the measuring gyroblock 7. After the gyro is set to β $\genfrac{}{}{0ex}{}{\text{opt}}{\text{o}}$ by the command K (t ₃ ), the third switch disconnects the torque sensor from the amplifier and the stage of accurately determining the azimuth of the platform begins. The coefficients a _{ij are} calculated by the formula (6) for time moments t _i (i = 3, 4, 5, 6, 7). After collecting the relevant information, the calculation unit 13 according to the corresponding algorithm (according to formulas (5) (8)) calibrates the main parameters of the meter. By formulas (9) and (10), the current azimuth of platform A (t) is calculated. By the command K (t ₇ ), the work of the analytical gyrocompass ends and information on the current azimuth of the platform is output to the output bus

at the time of the submission of the command K (t ₇ ).

Claims (1)

 An analytical gyrocompass containing a platform with two accelerometers and four gyro blocks installed on it, as well as two correction amplifiers, a control unit, a calculation unit, a constant storage device of constants, an amplifier, the outputs of the first and second correction amplifiers being connected respectively to the inputs of the moment sensors of the first and second gyro block, and the first input of the computing unit is connected to the first output of the control unit, the input of which is connected to the input bus of the device, characterized in that a ummator, a comparison element, a digital-to-analog converter, three switches, and the fourth gyro block is equipped with a wide-range angle encoder, while the outputs of the first and second accelerometers are connected through the first and second switches, the controlled inputs of which are connected to the second output of the control unit, and the inputs of the first and second correction amplifiers, the output of the angle sensor of the fourth gyro block through the calculation unit, the adder, a comparison element, the second input of which is directly connected to the output of the angle sensor a gyro block, a digital-to-analog converter, an amplifier, and a third switch, the control input of which is connected to the third output of the control unit, connected to the input of the moment sensor of the fourth gyro block, and the first and second outputs of the constant storage constant device are connected respectively to the second input of the adder and the third input of the calculation unit, the second output of which is connected to the output bus of the gyrocompass.