SU1244597A1 - Accelerometer - Google Patents

Abstract

The invention relates to the measurement of motion parameters. The purpose of the invention is to increase the measurement accuracy of acceleration by reducing the effect of capillary forces. In the cavity of the cylindrical rotor 1, a common cylindrical element 12 is installed along its axis with electrodes 13, 14, comprising common electrodes of a position sensor containing insulating I cylinders 6.7. Differential 8-11 and common 13, 14 electrodes of the position sensor are made in the form of alternating plate-sectors of not wettable and wettable materials by the area around the area. The plates of all electrodes from the same material are equal in area and are located opposite each other. In the presence of acceleration, the shape of the free surface of the chemical liquid 5 changes, and the deformation of the surface of the liquid at the points of contact with the surfaces of the electrode sectors will have an alternating character relative to the level corresponding to the absence of capillary forces. The information parameters are determined by the measurement system. 9 il. (L / 2 L 1 S 4 4 SP with J

Description

The invention relates to the measurement of motion parameters, in particular to linear accelerometers with a liquid inertial element.

The aim of the invention is to improve the measurement accuracy of acceleration by reducing the effect of capillary forces.

On .fig.1. Presented constructive scheme of the proposed accelerometer; in Fig.2 a cut of A-L in Fig.1; on fig.Z - B-B in Figure 1; on php.4, the position of the free surface of the liquid in the presence of the radial components jj and jy of the linear acceleration vector; FIG. 3 shows the arrangement of sectors in the plates of the sensor for positioning a liquid; Fig. 6 is a view of the free surface of the liquid at the place of its contact with the plates of the sensor of the position of the liquid in the absence of the above composition, or acceleration; 7 - 8 the shape of the free surface of the liquid between the sector No. 1 of the plates and the sectors of the ends of the common output element, made respectively of a material wetted and not wetted by a binder; figure 9 - structural diagram of the accelerometer measuring system.

The accelerometer (Figures 1-3) contains a cavity rotor 1 with a cavity, a drive 2 of constant speed, a support 3 and 4 of the rotor, a dielectric fluid 5, "insulating cylinders 6 and 7 of the sensor of the liquid, differential electrode) 8-11 liquid position sensor, common 1C1Lindric1 1 element 12 with electrodes 13 and 14, which are common electrodes of the position sensor, transformers 15-17 of the measuring system, generators 18-19, amplifier 20, ring electrode 21, demodulators 22-25, two phase generator 26.

Insulating cylinders 6 and 7 are installed in the ends of the rotor 1 and have differential electrodes, for example, 8 and 9 (figure 2). In the cylindrical element 12, axial bores 12 and 122 are filled (FIG. 3), which serve for the flow of liquid and leveled

D 1vleniya in the cavity of the rotor 1. The ring-55 rhenium j with projections j, j i and j on

The howling electrode 21 is installed in the rotor case 1 and is electrically isolated from no. -Electrodes 8-11 and common coordinates eolei leads to a change in the shape of the free surface of the dielectric fluid 5. The presence of

The electrodes 13 and 14 of the cylindrical element 12 are made in the form of sectors, with one half of these sectors made of material wetted by liquid 5, and the other from material not wetted by liquid 5. These sectors in each electrode are alternating and electrically interconnected.

A two-phase generator 26 is mounted on a common shaft with a rotor 1 (Fig. 1). One output of a two-phase generator 26 (Fig. 9) is connected to the second input of the demodulator 23, the second output from the VTO5 eye of the demodulator 24, the first inputs of these demodulators tori connected to the output of the demodulator 22, the first input of which is connected to the output of the amplifier 20, the ring electrode 21

0 and the first input of the demodulator 25. The second input of the demodulator 22 is connected to. the output of the generator 19 and with the beginning of the primary winding of the transformer 15. The second input of the demodulator 25 is connected

5 with the output of the generator 18 and with the beginnings of the primary windings of transformers 16 and 17, the ends of these windings are connected to the end of the primary winding of the transformer 15, with an average output

0, the secondary winding of this transformer and with the accelerometer case. The beginning of the secondary winding of the transformer 15 and its end are connected respectively to the middle leads of the secondary windings of transformers 16 and 17, the beginning of the secondary windings of which are connected respectively to the plates 8 and 9, and the ends of these windings to the plates 10 and L. The common electrodes of the cylindrical element 12 are electrically connected to the input of the amplifier 20.

five

0

The accelerometer works as follows.

The rotor 1 is driven in a uniform rotation by the drive 2. At the same time, under the action of centrifugal forces, the dielectric fluid 5 concentrates to the peripheral Part of the rotor cavity 1. The presence of channels in the common output element 12 contributes to a faster flow of the dielectric fluid 5.

The presence of the linear acceleration vector of coordinates leads to a change in the shape of the free surface of the dielectric fluid 5. The presence of the radial acceleration components jj and jj leads to the displacement of the free surface of the dielectric fluid 5 in the corresponding radial direction by the values of Dx and Dy, respectively, which are proportional to the values of these projections (Fig. ). The presence of the linear acceleration vector jj jj causes the deformation of the free surface of the dielectric fluid 5 symmetrically with respect to the axis of the rotor 1, and the action of i capillary forces leads to an additional deformation of the free surface of the dielectric fluid 5 at its contact with the electrodes 8-11 and 13 and 14.

Due to the fact that the sectors 8 /, and 8 of the electrode 8 are arranged side by side and alternate, the deformation of the free surface of the liquid 5 on the surfaces of these sectors will be of alternating character with respect to the level of Go (Fig.6), which corresponds to the absence of capillary forces . The shape of the free surface of the liquid 5 between the electrodes and 13 and 14 will have the form shown in Fig.7 and 8.

Measurement of information parameters, i.e. values and lu carried out using a measuring system (Fig, 9). At the same time, electrodes 8-11 and 13 and 14 form four capacitors, the first of which consists of electrodes 8 and 13, the second and 13, the third and a quarter, respectively, electrodes 10 and 14, 11 and 14. These capacitors, as well as transformers 16 and 17 form two bridge circuits. To separate information signals that carry information about the components jjj., Jy, and j, the transformer 15 is powered at a frequency f, and the transformers 16 and 17 are fed at a frequency fj 19 and 18. In this case, the electrical signal is removed from the common electrode of the cylindrical element 12 and through the amplifier 20 is fed to the outputs of demodulators 22 and 25, the second inputs of which are fed to the signal of the reference frequency f and f, respectively

244597

but. To improve the stability of the gain factor of amplifier 20, a capacitive feedback channel is used by providing the output signal of this

5 amplifier through the ring electrode 21 to the common element 12.

The signal taken from the output of demodulator 25 will be proportional to the axial component ja of the linear acceleration vector, and to isolate the radial components j and jy, a secondary demodulation with a reference frequency equal to the frequency of rotation of the rotor 1 is necessary. To this end, the frequency signals,

J5 equal to the frequency of rotation of the rotor 1, from the output of the two-phase generator 26 (the signals are shifted in phase by 90) are fed to the second inputs of the demodule -. tori 23 and 24. Pa first entrances of these

The 20 demodulators receive a signal from the output of the demodulator 22. In this case, the output signals of demodulators 23 and 24 will be proportional to the component JX and jy, respectively.

25

Claims (1)

Invention Formula 35 An accelerometer containing a drive of constant rotational speed, a cylindrical hollow rotor, partially filled with a dielectric fluid and having a central part of the cavity. a cylindrical element with a common, and at the rotor ends, cylindrical elements with differential electrodes of a fluid position sensor are connected to a measurement circuit, characterized in that, in order to improve the accuracy of acceleration measurements by reducing the effect of capillary forces, the common and differential electrodes of the sensor the positions of the liquid are made in the form of alternating along the circumference of the plate sectors of the material not wetted and wetted by the liquid, all of the plates of each electrode being electrically connected together and, a plate of electrodes made from the same material, are equal in size and opposite to each other. 40 45 50 LA in-in at (riz.2 fpiif.3 сride 4Si (9jlOr, // j  V , South (rig 5 8, In { L 5c 8 (9-Jt) t-ar .ЛЗ / Лс (pus. 6 (rig. 7 8 (9-ff) y g „-l l3ffJ Editor Y. Sereda Compiled by K.Lukomsky Tehred L.Oleynik Proofreader S.Shekmar 3910/48 Circulation 778 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4