RU2803452C1 - Three-component angular velocity meter - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: measuring the motion parameters of an object, used in strapdown inertial navigation systems. The three-component angular velocity sensor contains three angular velocity sensors with torque sensors in feedback with mutually perpendicular measuring axes and axes of proper rotation, three three-input adders, six inverting amplifiers, the first inputs of the three-input adders are connected to the outputs of the respective angular velocity sensors, while three meters of angular oscillations of rotors are additionally introduced.

EFFECT: increase in the accuracy of measuring motion parameters with a three-component angular velocity sensor.

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Description

Two-degree gyroscopes are known that measure the angular velocity of an object, containing a gyroscope unit and electrical feedback [1, p.8]. In this case, the gyro unit is made [1, p. 31] in the form of a synchronous hysteresis motor (SHM) with gas-dynamic supports. Like all synchronous machines, the SGD rotor has low-frequency oscillations relative to the stator magnetic field, which are measured by non-contact methods [1, pp. 134-137], [2].

The disadvantage of two-degree gyroscopes is the lack of compensation for errors due to the influence of the angular acceleration of the object. Differentiation of the measured angular velocity to obtain angular acceleration and further compensation of the resulting drift causes an increase in high-frequency measurement noise. Methods for correcting errors caused by the influence of angular accelerations according to the readings of the angular acceleration sensor unit are complex and expensive.

A three-component angular velocity meter [3] is known, containing first, second and third angular velocity sensors with mutually perpendicular axes, first, second and third three-input adders, first, second and third, fourth, fifth and sixth inverting amplifiers. In this case, the first input of the first, second and third three-input adder is connected to the output of the first, second and third angular velocity sensor. The inputs of the first and second inverting amplifiers are connected to the output of the first angular velocity sensor, the outputs of the third and fourth inverting amplifiers are connected to the output of the second angular velocity sensor, the outputs of the fifth and sixth inverting amplifiers are connected to the output of the third angular velocity sensor. The second and third inputs of the first three-input adder are connected to the output of the third and fifth inverting amplifiers, the second and third inputs of the second three-input adder are connected to the output of the first and sixth inverting amplifiers, the second and third inputs of the third three-input adder are connected to the output of the second and fourth inverting amplifiers. The gain of each of the inverting amplifiers depends on the degree of influence of the angular velocity measured by the angular velocity sensor, the output of which is connected to the first input of the three-input adder, the other input of which is connected to the output of the inverting amplifier.

The device compensates for errors caused by the influence of cross angular velocities. The gain of each of the inverting amplifiers depends on the degree of influence of the angular velocity, measured by the angular velocity sensor, the output of which is connected to the input of the inverting amplifier, on the angular velocity sensor, the output of which is connected to the first input of the three-input adder, the other input of which is connected to the output of the inverting amplifier .

The disadvantage of two-degree gyroscopes is the lack of compensation for errors due to the influence of the angular acceleration of the object.

The closest in technical essence from among the known technical solutions is a three-component angular velocity meter [4], containing the first, second and third angular velocity sensors with mutually perpendicular measuring axes, first, second and third three-input adders, first, second, third, fourth, fifth and a sixth inverting amplifier, wherein the first input of the first three-input adder is connected to the output of the first angular velocity sensor, the first input of the second three-input adder is connected to the output of the second angular velocity sensor, the first input of the third three-input adder is connected to the output of the third angular velocity sensor, the inputs of the first and second inverting amplifiers are connected to the output of the first angular velocity sensor, the inputs of the third and fourth inverting amplifiers are connected to the output of the second angular velocity sensor, the inputs of the fifth and sixth inverting amplifiers are connected to the output of the third angular velocity sensor, the second and third inputs of the first three-input adder are connected to the output of the third and fifth inverting amplifiers, the second and third inputs of the second three-input adder are connected to the output of the first and sixth inverting amplifiers, the second and third inputs of the third three-input adder are connected to the output of the second and fourth inverting amplifiers.

The device compensates for errors caused by the influence of the angular velocity of the base on the initial positions of the axes of their own rotation of gyroscopic angular velocity sensors. Errors due to the influence of angular accelerations of the object are not compensated.

The objective of the claimed invention is to increase the accuracy of measuring motion parameters with a three-component angular velocity sensor by compensating for errors caused by the angular acceleration of the object.

The task is achieved by the fact that a three-component angular velocity meter containing three angular velocity sensors with feedback torque sensors, with mutually perpendicular measuring axes and axes of their own rotation, three three-input adders, six inverting amplifiers, and the first inputs of the three-input adders are connected to the outputs of the corresponding angular velocity sensors, three rotor angular swing meters are introduced, the outputs of the first of which are connected through the first inverting amplifier to the second input of the first three-input adder, and through the fifth inverting amplifier with the third input of the second three-input adder, the outputs of the second rotor swing meter are connected through the second inverting amplifier with the second input of the second three-input adder, and through the sixth inverting amplifier with the third input of the three-input adder, the output of the third rotor swing meter is connected through the third inverting amplifier with the second input of the three-input adder, and through the fourth inverting amplifier is connected with the third input of the first three-input adder. The coefficients of inverting amplifiers have the form:

and the adjusted current of the torque sensors has the form:

where i _j (s), I _O , I _S, I _SP , k, m, $$\chi$$ , $$\gamma$$ - uncorrected current of the torque sensor, moments of inertia of the angular velocity meter relative to the output axis, the axis of its own rotation of the rotor and the rotor in the casing, respectively, damping coefficients of the angular velocity sensor and its rotor, respectively, the angle of non-orthogonality of the axis of its own rotation and the swing angle of the rotor. The orientation of the axes of the angular velocity meter corresponds to:

where X,Y,Z are the measuring axes of a three-component angular velocity meter; $$x_j$$ _, $$y_j$$ , $$z_j$$ - axes of trihedrons associated with angular velocity meters: sensitivity axis, output axis and axis of own rotation, respectively, (j=1, 2, 3).

When the connection of the first inputs of the three-input adders with the corresponding angular velocity meters is open, the outputs of the three-input adders are connected to additional windings of the torque sensors corresponding to the angular velocity meters.

In Fig.1. shows a three-component angular velocity sensor with measuring axes X, Y, Z, in which the output signals are generated in an open circuit. Signals corrected from the influence of the object’s angular acceleration can be sent to the object’s on-board computer.

In Fig.2. shows a three-component angular velocity sensor with measuring axes X, Y, Z, in which the output signals are generated using closed feedback connections. Corrective electrical signals are sent to additional windings of torque sensors of each angular velocity sensor.

In Fig.1 and Fig.2. shown: 1, 2, 3 - the first, second and third angular velocity sensors, the measuring axes of which x ₁ , x ₂ , x ₃ , as well as the axes of their own rotation z ₁ , z ₂ , z ₃ are mutually perpendicular and directed along the measuring axes of the three-component angular velocity sensor; 4,5,6 - first, second and third rotor swing meter; 7, 8, 9, 10, 11, 12 - first, second, third, fourth, fifth and sixth inverting amplifiers; 13, 14, 15 - first, second and third three-input adders.

The outputs of the first rotor angular swing meter 4 are connected through the first inverting amplifier 7 to the second input of the first three-input adder 13, and through the fifth inverting amplifier 11 - with the third input of the second three-input adder 14, the outputs of the second rotor swing meter 5 are connected through the second inverting amplifier 8 with the second input of the second three-input adder 14, and through the sixth inverting amplifier 12 with the third input of the three-input adder 15, the output of the third rotor swing meter 6 is connected through the third inverting amplifier 9 with the second input of the three-input adder 15, and through the fourth inverting amplifier 10 is connected with the third input of the first three-input adder 13.

In Fig.1. the first inputs of the three-input adders are connected to the outputs of the corresponding angular velocity sensors. In Fig.2. this connection is absent, and the outputs of the three-input adders are connected to the additional winding of the torque sensor, the corresponding angular velocity sensors.

Let us give a theoretical justification for this technical solution.

For the following axis orientation:

where X,Y,Z are the measuring axes of a three-component angular velocity meter; $$x_j$$ _, $$y_j$$ , $$z_j$$ - axes of trihedrons associated with angular velocity meters: sensitivity axis, output axis and axis of own rotation, respectively, (j=1, 2, 3).

We write the equations of motion of a three-component angular velocity meter in the form:

where I _O , I _S, $$I_{spi}$$ ,n,k,H, $$W_{EP}(s)$$ - moments of inertia of the angular velocity meter relative to the output axis, the axis of its own rotation of the rotor and the rotor in the casing, respectively, the damping coefficient, the slope of the torque sensor, the kinetic moment and the transfer function of the electric spring of the angular velocity meter of the object, respectively; $$\chi ,\beta$$ - the angle of non-orthogonality of the axes and the angle of precession of the gyroscope.

$$w$$ , $$\dot{w}$$ ,i - components of the angular velocity and angular acceleration of the object along the corresponding axes, as well as the torque sensor current, respectively;

_ISP , $$\lambda$$ ,m, $$M_{TO}$$ - polar moment of inertia of the rotor, damping coefficient, specific synchronizing moment, friction moment in the main supports, respectively; $$\gamma$$ - instability of the angular position of the rotor (rotor swing) in a coordinate system rotating at synchronous speed.

The components of the angular acceleration vector of the object are projected onto the output axes of the angular velocity sensor and, in the presence of non-orthogonality of the axes $$\chi$$ , - on the axis of its own rotation.

Gas-dynamic supports have a low friction moment ( $$M_{TO}$$ $$\prec$$ 10 ^-3 cNcm), for

therefore, the moment of friction in the supports can be neglected, and the swing angle of the rotor is proportional to the acceleration on the axis of its own rotation:

Where

The axis of rotation of the rotor of each angular velocity meter is directed along one of the axes of the object trihedron: z ₁ along Z, z _{2 along} X, z ₃ along Y.

At the outputs of the three-input adders in Fig.1. Corrected signals from angular velocity meters are generated without errors caused by the influence of the angular acceleration of the object:

Where

If you break the connection of the first inputs of the three-input adders with the angular velocity meters, and the outputs of the three-input adders are connected to additional windings of the torque sensors of the corresponding angular velocity meters, as shown in Fig. 2, then compensation for the noted errors will not be in the on-board computer, but in the angular velocity meters themselves .

The gain of each of the integrating amplifiers is set in accordance with algorithm (8).

Let's give an example. Let the parameters of all angular velocity sensors be identical to each other, the components of the angular acceleration vector are [5,6]: I _O = 1 cNcms ² : I _S =0.1 cNcms ² , I _SP =0.02 cNcms ² ; m =10 cN/rad; k=10 ⁴ cH/A; $$\chi$$ =0.1 rad; $$\gamma$$ = 0.15 rad. Angular acceleration of an object $$\dot{w}$$ =75 rad/s ² . Then the error of the angular velocity sensor current from the influence of angular acceleration (the second term on the right side of equation (2) from the influence of angular acceleration will be equal to: (I _O $$\dot{w}$$ / k )=7.5 mA, the swing angle (3) measured during this time is equal to 0.15 rad or 9 angular degrees, and the corrective current into the additional winding of the torque sensor: the second term on the right side of equation (8) will be equal to: ( 1*10*0.15)/(10 ⁴ *0.02)=7.5 *10 ^-3 A= 7.5 mA. Because the non-orthogonality of the axes is small $$\chi$$ =0.1 rad, then the second current addition to the torque sensor winding (the third term on the right side of equation (8) will be 0.75 mA.

List of sources used.

1. Hydromotors. Edited by Orlov I.N.-M. Mechanical engineering. - 1983. S 8, 31, 134-137.

2. A.s. No. 1337677. A device for determining the torque on the shaft of a synchronous gyromotor. B.I. No. 34. 1987.

3. Application for invention No. 2004133601. Three-component angular velocity meter. Publ. 04/10/2006.

4. Patent for IZ No. 2273858. Three-component angular velocity meter. Publ. 04/27/2006.

5. Klimov D.M., Kharlamov S.A. Dynamics of a gyroscope in a gimbal. -M.Science.-1978.

6. Ruleva L. B. Application of the method of observing devices for gyroscopic meters // Physico-chemical kinetics in gas dynamics. 2010. T. 9. http://chemphys.edu.ru/issues/2010-9/articles/153/.

Claims (10)

1. A three-component angular velocity sensor, containing three angular velocity sensors with torque sensors in feedback with mutually perpendicular measuring axes and axes of their own rotation, three three-input adders, six inverting amplifiers, and the first inputs of the three-input adders are connected to the outputs of the corresponding angular velocity sensors, different in that three rotor angular swing meters are introduced, the outputs of the first of which are connected through the first inverting amplifier to the second input of the first three-input adder, and through the fifth inverting amplifier with the third input of the second three-input adder, the outputs of the second rotor swing meter are connected through the second inverting amplifier with the second input of the second three-input adder, and through the sixth inverting amplifier with the third input of the third three-input adder, the output of the third rotor swing meter is connected through the third inverting amplifier with the second input of the third three-input adder, and through the fourth inverting amplifier is connected with the third input of the first three-input adder , while the coefficients of the inverting amplifiers have the form: $$l_j=\frac{I_{Oj}}{k_j}$$ ; $${\mu }_j=\frac{m_{{}_j}}{I_{spj}}$$ ; $$r_j=\frac{I_{sj}}{k_j}$$ , (j=1, 2, 3), and the adjusted current of the torque sensors has the form: $$i_{1c\mathrm{To}ORR}(s)=i_1(s)-l_1{\mu }_3{\gamma }_3(s)-r_1{\mu }_1{\chi }_1{\gamma }_1(s)$$ , $$i_{2c\mathrm{To}ORR}(s)=i_2(s)-l_2{\mu }_1{\gamma }_1(s)-r_2{\mu }_2{\chi }_2{\gamma }_2(s)$$ , $$i_{3c\mathrm{To}ORR}(s)=i_3(s)-l_3{\mu }_1{\gamma }_2(s)-r_3{\mu }_3{\chi }_3{\gamma }_3(s)$$ , where i _j (s), I _O , I _S , I _SP , k, m, $$\chi$$ , $$\gamma$$ - uncorrected current of the torque sensor, moments of inertia of the angular velocity meter relative to the output axis, the axis of rotation of the rotor and the rotor in the casing, respectively, damping coefficients of the angular velocity sensor and its rotor, respectively, the angle of non-orthogonality of the axis of its own rotation and the swing angle of the rotor, the initial orientation of the angular meter axes speed corresponds to: $$\left[\begin{array}{c}X\\ Y\\ Z\end{array}\right]=\left[\begin{array}{c}{x}_1\\ y_1\\ z_1\end{array}\right]=\left[\begin{array}{c}{z}_2\\ x_2\\ y_2\end{array}\right]=\left[\begin{array}{c}{y}_3\\ z_3\\ x_3\end{array}\right]$$ , where X, Y, Z are the measuring axes of a three-component angular velocity meter; $$x_j$$ , $$y_j$$ , $$z_j$$ - axes of trihedrons associated with angular velocity meters: sensitivity axis, output axis and axis of own rotation, respectively, (j=1, 2, 3). 2. The three-component angular velocity sensor according to claim 1, characterized in that when the first inputs of the three-input adders are open-loop with the corresponding angular velocity meters, the outputs of the three-input adders are connected to additional windings of the torque sensors corresponding to the angular velocity meters.