SU1464110A1 - Device for measuring linear acceleration - Google Patents

Abstract

The invention relates to accelerometers built in an open circuit with self-oscillating transducers of deformation on surface-acoustic waves (SAW). The aim of the invention is to increase the sensitivity by introducing additional transducers to the surfactant. In the presence of measurable acceleration, directed perpendicular to the plane of the dual console beam 1, a sensitive elastic element with inertial masses 2 and 3 at the ends of the consoles, the operating modes of the automatic deformation transducers, which are differentially connected via buffer amplifiers 4 and 5 to the recorder 6, change. deformation contains parallel to the main 7, 10 and internal additional 8, 9 pairs of anti-aging transducers (IDT) surfactants connected respectively T., by amplifiers 13 and 12. The multiplicity of wavelengths. Acoustic synchronism of all pairs of IDTs provides common-mode addition of signals at receiving IDTs 7.8. These pairs of IDTs are located. wives are symmetrical to the IDP, placed on the other side of the two-console beam. The total signal from each strain transducer is amplified due to the response of the internal oscillator circuit of the oscillator, including TF1 8.9 and amplifier 12. 2 Il. § (L

Description

20

The external and internal 15 L, n-A2 first and second surfactants of the autogeneration circuits of the first and second surfactants that have the same wavelength, L, are the amplitudes of the alternating electric voltage (the frequency of which uniquely corresponds to the wavelength A of the first and the second surfactant) on the signal electrode systems of IDT 8 and 7 directly proportional to the amplitude of the resulting surfactant, the value of which is equal to the vector sum of the first and second surfactants,

In addition, if the wavelength, the acoustic synchronism of identical IDT 8 and 9 differs from the wavelength

The external and internal autogeneration contours in-phase are added to each other at receiving IDT 8 and 7, therefore, the autogeneration mode of the first SAW deformation converter is provided with the lowest values of the gain factors K and K; 2 amplifiers 12 and 13,

The second self-generating surfactant deformation transducer is completely identical to the first self-generating surfactant deformation transducer and contains transducer 15-18, located on the wide face 19 of the elastic element LL of acoustic synchro- micals-. About that 1, and two identical amplifier 20

tsehnyh VSh 7 and 10, namely T (, F L. or tF1, then the wavelength L of the resulting surfactant interacting with the receiving IDT 8 and 7 is equal to the shortest of the lengths

and 21.

The internal circuit of the autogeneration of the second surfactant of the strain converter consists of the amplifier 20 and the line

waves H, or / d, acoustic synchro “consists of unm 17„ 16 kos- 2. „35 delayed SAW between BSP 1 / and ID,

some have the same design and are placed symmetrically to each other

since the surfactant with the -L wavelength can simultaneously exist in the external and internal contour of autogeneration, if its length L is equal to the smallest

published L, or 1, acoustic 40 of the elastic element 1, and distance - synchronism of pairs BSP U, o or /,.iu. -. .

with respect to the transverse plane of symmetry of the biplane axle

L (between the centers of IDT 16 and 17 is chosen to be, where K is the center of the short-term instability of the output frequency f of the first autogenerator SAW deformation converter, and hence the highest, other things being equal, resolution of the measured value of linear accelerations is provided if external and internal self-excitation circuits, each separately, operate in an uncooled mode. For this, the gain value K of the amplifier .12 the internal contour is selected by about 10% less and in which the self-oscillation would have occurred on the inner loop circuit HPS 8, amplifier 9 IDT 12, SAW delay line 9 from the IDT to IDT 8 "greatness

  L, p - A2 first and second surfactant

The external and internal autogeneration contours in-phase are added to each other at receiving IDT 8 and 7, therefore, the autogeneration mode of the first SAW deformation converter is provided with the lowest values of the gain factors K and K; 2 amplifiers 12 and 13,

The second self-generating surfactant deformation converter is completely identical to the first self-generating surfactant deformation converter and contains IDTs 15-18, located on the wide face 19 of the elastic element 1, and two identical amplifiers 20

and 21.

elastic element 1, and the distance -. .

with respect to the transverse plane of symmetry of the biplane axle

elastic element 1, and the distance - -. .

L (between the centers of the IDP 16 and 17 is chosen to be equal, where K is an integer, and L is the length of the SAW of the acoustic synchronism of a pair of WCP 16 and 17,

The outer loop of the autogeneration of the second SAW deformation converter consists of the amplifier 21 and the SAW delay line between the IDTs 15 and 18, which have the same designs and are placed. symmetrically to each other with respect to the transverse plane of the symmetry of the elastic element 1 (Fig, 1), the scattering L between the centers of high-school high school 15 and 18 is chosen equal to Lj, N-A, where N is an integer and a is the length of the surfactant of acoustic synchronism at IDT 15 and 18. The magnitude of the gain Kj of the amplifier 20 of the internal circuit of the autogeneration of the second surfactant transforms

514

The deformation voltage is approximately 107, a smaller value, at which the internal circuit along the Vish 16 circuit, the amplifier 20, the IDT 17, the SAW 17 delayed line and the HS 16, and the gain factor K external amplifier the contour is chosen such as to provide the missing gain along the external contour for the occurrence of the self-excitation regime of the two-circuit second self-oscillator surfactant of the deformation converter.

Due to their complete identity with each other in the absence of linear accelerations, the output frequencies f, and f, respectively, of the first and second autogenous surfactants of the deforming transducers are equal. Their values are determined by the spatial period of the BSP 7-Yun 15-V 10 and 15-18 electrode systems, the propagation velocity of the surfactant in the material of the elastic element 1, which simultaneously plays the role of the acoustic circuit, and the distance values L, and L. between the centers of internal combustion engines of external and internal circuits of autogeneration of the first and second surfactants of strain transducers

Buffer amplifiers 4 and 3 are used to provide isolation between the outputs of the first and second self-oscillating SAW of the strain transducers and the corresponding inputs of the recording device 6.

The device for measuring linear accelerations works as follows.

With the appearance of measurable accelerations, due to the inertial properties of masses 2 and 3, mutually opposite deformations of wide faces 11 and 19 of elastic element 1 occur, which leads to mutually opposite changes in output frequencies f, + uf and f ,, + 4-uf of the first and the second self-oscillating surfactant strain transducers.

Iq

t5 20 25 Q

35

40

45

ten

directly proportional to the magnitude of the measured accelerations.

In the presence of angular accelerations, the wide faces 11 and 19 of the elastic element 1 experience the same magnitude and sign of deformation, as a result of which the output frequencies f and f of the first and second self-oscillating SAW transducers of the deformation change by the same amount, i.e. f, ± tAf and f., and therefore do not change the readings of the recording device 6.

Claims (1)

Invention Formula A device for measuring linear accelerations containing a resilient, sensitive element fixed in the housing. a dual-console beam with inertial masses at the ends and two self-oscillating converters of the deformation of a pair, the interdigital transducers of the surface acoustic waves of which are located on opposite cavities of the beam, which, in order to increase the sensitivity, to each of the self-oscillating converters of the deformation An additional pair of interdigital transducers is introduced, located parallel to the transducers of the main pair, and an amplifier connecting the interdigital pins. e converters of an additional pair, the distance between the centers of the transducers in the main pair and the additional multiples of the integer number of acoustic synchronism wavelengths of these pairs, and the acoustic synchronism wavelengths of the main pairs are multiple to each other, with all the interdigital transducers fixed on one side of the dual console beams are arranged symmetrically with interdirectional transducers placed on the other side of the beam about FIG. 2