RU1838804C - Vertical gravity gradiometer - Google Patents

Abstract

Usage: measuring technique, in particular for measuring the vertical gradient of gravity. SUBSTANCE: cargoes are placed in separate blocks of cases, a device is provided for changing the places of blocks in height in the form of a bar mounted by a pin and a support in the stand, the displacement sensor of one of the loads through an amplifier is connected to the provided additional force sensor of another load equipped with a displacement sensor, an amplifier and a sensor strength. Both weights are equipped with consoles, the free end of which is suspended on an elastic member. 1 ill.

Description

The invention relates to a measurement technique for measuring a vertical acceleration gradient of gravity.

An object of the invention is to improve the accuracy of vertical gradient measurements.

The drawing shows a schematic diagram of a gravitational vertical gradiometer.

Its sensitive system contains two blocks with loads, buildings 1, 2 of which have a device for changing the places of blocks in height, in which buildings 1, 2 of the first and second blocks with trunnions 3.4 with supports in the form of a hem 5, 6 (supports can be slipped ) are mounted in a vertical rod 7, connected by means of a pin 8 and a support 9 with a stand 10. The blocks and the rod 7 are locked in a vertical position by means of arresters not shown in the drawing. By turning the rod 7 through 180 °, the blocks are altered in height.

In cases 1. 2 of the first and second blocks placed loads in the form of permanent magnets 11, 12 and 13, 14, magnetic cores 15, 16 and 17, 18 and pole pieces 19, 20 and 21, 22. The load of the first block (in the case) equipped with an electric spring in the form of a displacement sensor 23, an amplifier 24 and a force sensor in the form of a magnetoelectric transducer, consisting of permanent magnets 11, 12, magnetic cores 15, 16, pole pieces 19, 20 and coil 25 in the frame 26 mounted in the housing 1 on racks 27, 28.

The displacement sensor 23 through the amplifier 24 is connected to the coil 29 of the additional load force sensor of the second block, consisting of permanent magnets 13, 14, magnetic cores 17,18, pole pieces 21, 22 and coil 29 in the frame 30, mounted in the housing 2 on the racks 31, 32. Coils 25 and 29 are connected in this case.

WITH

00

with

00

2

with

tea in parallel, namely, sequentially.

The load of the second block (in housing 2) is equipped with an additional electric spring in the form of a displacement sensor 33, an amplifier 34 and a force sensor in the form of a coil 35 in the frame 30, permanent magnets 13.14, magnetic cores 17, 18 and pole pieces 21, 22. The output from the amplifier 34, i.e. the input of the coil 35 is connected to a counting-decisive (block 36, the output of which is WM.

The loads of both blocks are equipped with horizontal consoles 37, 38 whose free ends are suspended on elastic elements in the form of elastic plates 39, 40.

Electrical springs (i.e., compensating feedbacks) may include integrating links.

The device for changing the places of blocks in height may have another design, for example, transferring blocks manually from one platform of one height to another platform, etc.

In the operating position, the axis of sensitivity of the gradiometer is located in the direction of gravity.

The proposed gradiometer determines the measured value in two measurement steps and operates as follows.

The first beat.

The block in the housing 1 is located at the top, the block in the housing 2 is located at the bottom.

The gravity of the upper load is balanced by the electric spring force sensor and the force of the elastic element 39:

mig Fgcn + C1X11

(1)

The gravity of the lower load is balanced by an additional force sensor (coil 29 with a magnetic system), a force sensor of an additional electric spring (coil 35 with a magnetic system) and elastic elements 40:

m2 (g + WzzH) Fgc21 + Fgc21 + C2X21, (3)

where ma is the mass of the lower load,

Wzz - vertical gradient

H is the distance between the centers of mass

cargo

Fgc2i - force of an additional force sensor (coil 29 with a magnetic system) at

the first measure

Fgc21 KgnlKglKgc2Xl1 nFgc11, (4) n Kgc2 / Kgc1. (5) .

FgcSi - force of the force sensor of the additional electric spring (coil 35 with a magnetic system) at the first measurement step,

C2 is the stiffness of the elastic element 40, reduced to the axis of sensitivity of the gradiometer,

X21 is the displacement of the mass rri2 during the first measurement step.

From (1), (3), taking into account (2), (4), (5), we have:

.Fgc3i (t.2 - nrm) g + maWzzH - ncixn - C2X21

(b)

The value of the Rdcz is supplied in the form of the input current of the coil 35 to the computing unit 36, because the value of Fgc3 is equal to

where mi is the mass of the upper load,

g is the acceleration of gravity at the center of gravity of the upper load,

RDSP is the force of the force sensor of the electric spring at the first measurement step,

Fgc11 Kgm Kg | Kgc1X11

(2)

Kgnt is the slope coefficient of the static characteristic of the displacement sensor 23,

Kgi is the gain of the amplifier unit 24.

Kgd is the slope coefficient of the static characteristic of the force sensor (coil 25 with a magnetic system).

C1 is the stiffness of the elastic element 39, reduced to the axis of sensitivity of the gradiometer,

xii is the mass transfer of the PC at the first measurement step.

40

Fgc3 Vz1z,

(10)

where Bz is the magnetic induction in the gap between the pole piece 21, 22 and the magnetic wire 17, 18,

h is the length of the wire of the coil 35, i is the current flowing in the coil 35. The second cycle.

The blocks are interchanged in height; We have:

mi (g + WZ2H) Fgcn + cixi2, (7)

GP29 n (Fgc12 + Fgc32 + C2X22), (8)

Fgc32 (m2- nmi) g - nmiWzzH + ncixi2-C2X22,

(9)

where Fgci2 is the force of the electric spring force sensor during the second measurement step,

X12 is the displacement of mass mi at the second measurement step,

Fgc32 - force of the force sensor of an additional electric spring (coil 35 with a magnetic system) during the second measurement step,

X22 is the displacement of the mass rri2 at the second measurement step.

The value of FgC32 is supplied as input current of the coil 35 to the counting decisive block 36.

From (6) and (9) we have:

Fgc31 - FgC32 (PG12 + nrTt2) WzzH - PS1 (xc + + X12) -C2 (X21-X22) (11)

We see that the methodological error from g, unlike the prototype, is absent.

In the presence of integrating links in the circuit of electric springs xc, xi2, x2i, x22 tend to zero and the second and third terms on the right in (11) will be absent and WZz will be determined from (11}.

Wz

 Fgc31 Fgc32

(rri2 + nmi) H

FROM (6), (9) WE SEE THAT Fgc31, Fgc32 AND Fgc31

- Fgc32 are comparable and according to (5) the relative measurement error is determined by the formula

 P - t + b + chz, 03)

W;

gg

A (FgC31 Fgc32) | Fgc31 Fgc32

A (PG12 + PGP2),

---- -----. J

-I - V V 111 tЈ.

 ma + nmi)

. Nam, -rlzipj-1 (14)

(fifteen)

(sixteen)

where t is the relative measurement error Wzz,

- with

b

1

10

fifteen

twenty

25

thirty

35

40

45

rj i is the relative measurement error Fgc2,

C 2. 7 h relative aging error ma + nmi and H,

(Three measurement ranges W «- 4000 Oe and m} 1 J / 2, in order we have rj of the same order and, therefore,

.43.

For the prototype, with a measurement accuracy of 5 Oe, Dt / m, D1 / 1 and other parameters must be maintained with a relative error, i.e. Requirements for the design parameters of the proposed device, which determine the accuracy of its measurement, are many orders of magnitude lower than for the design parameters of the prototype.

Thus, in comparison with the prototype, the accuracy of the proposed gravitational vertical gradiometer is achievable several orders of magnitude higher.

Claims (1)

The claims Gravity vertical gradiometer, containing a sensitive system of two loads located at different heights located in the housing, a transducer and a recording system, characterized in that, in order to increase the measurement accuracy, each load is equipped with horizontal consoles, the free end of each of which - hung on an elastic element, with each load placed in a separate housing, which by means of pins with supports mounted on a vertical rod, the converter is made in the form of two systems, each one of which is supplied with a load, each system including a displacement sensor, an amplifier and a power sensor. Moreover, the first load displacement sensor is connected to the second load force sensor through the first load amplifier, the output of the second load amplifier is connected to a recording system made in the form of a counting decision block. I AM .