RU2253872C1 - Liquid accelerometer - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: device can be used for measuring accelerations of objects. Liquid accelerometer has channel filled with working fluid. Two hydrostatic pressure frequency converter detectors are disposed at ends of accelerometer. Frequency converter is made in form of fiber interferometer, which has coherent light source matched optically with two fiber coils and photoreceiver connected with frequency meter through amplifier. To determining sign of acceleration the special electronic circuit is introduced into accelerometer additionally.

EFFECT: optical output signal at output of accelerometer.

3 cl, 3 dwg

Description

The invention relates to measuring technique and can be used to measure acceleration.

A known liquid accelerometer for a similar purpose [1], comprising a cylinder with an electrolyte installed in the housing, in which a conductive float, a cylinder rotation drive and an electrolytic converter for linear movement of the float are located.

Closest to the proposed one is a liquid accelerometer [2], containing a channel filled with a working fluid and a frequency converter of hydrostatic pressure, two sensors of which are located at the ends of this channel, and the output of the frequency converter is connected through an amplifier to a frequency meter.

This liquid accelerometer [2] is adopted as a prototype.

In the prototype, the frequency Converter hydrostatic pressure includes two independent from each other frequency sensors, the outputs of which are connected to the computer, which includes a series-connected amplifier and frequency meter.

A disadvantage of the known liquid accelerometers [1, 2] is the lack of an optical output signal at their output.

The technical result obtained from the implementation of the invention is to obtain an optical output signal at the accelerometer output, which makes it possible to use optical communication lines as a telecommunication system for further transmission.

The stated technical result is obtained due to the fact that the known liquid accelerometer containing a channel filled with a working fluid and a frequency converter of hydrostatic pressure, two sensors of which are located at the ends of this channel, the output of the frequency converter connected through an amplifier to a frequency meter, additionally contains a sawtooth voltage source, software a command signal generator and an electronic key, and a frequency converter of hydrostatic pressure is made in the form of a source and of coherent light, two identical fiber coils and a photodetector, optically coupled to a fiber optic interferometer, the output of which is the output of a photodetector, while one of the fiber coils is wound tightly on the side surface of the piezocylinder, the electrodes of which are connected to a sawtooth voltage source, the controlled input of which connected to the output of the command signal setter, and the amplifier is connected to the frequency meter through an electronic key, the controlled input of which is connected to the output of grammnogo setpoint command signal.

In the particular case, the second fiber coil of the interferometer can also be wound on the side surface of an additional similar piezocylinder.

The liquid accelerometer may also further comprise a piston made of a material whose density exceeds the density of the working fluid located in the middle of the channel.

The invention is illustrated in the drawing. Figure 1 presents a structural diagram of an accelerometer; figure 2 - optoelectronic circuit of the device; figure 3 - frequency-time diagrams for explaining the operation of the accelerometer.

The liquid accelerometer contains a channel 1 filled with a working fluid (Fig. 1) and a hydrostatic pressure frequency converter, made in the form of a coherent light source 2 (Fig. 2), two identical fiber coils 3, 4, and a photodetector 5, which are optically matched to a fiber-optic interferometer the output of which is the output of the photodetector 5.

The fiber coil 3 is wound with an interference fit on the side surface of the piezocylinder 6, the electrodes of which are connected to a sawtooth voltage source 7.

Fiber coil 4 can be wound on a similar piezoelectric cylinder 8, the electrodes of which are not connected to a voltage source. That is, the piezocylinder 8 is essentially used as a substrate for the fiber coil 4. Both coils 3, 4 are located at the ends of the channel 1 with the working fluid.

The output of the photodetector 5 through the amplifier 9 of the photocurrent and the electronic key 10 is connected to the frequency counter 11.

The electronic key 10 and the sawtooth voltage source 7 are connected by their controlled inputs to the program controller 12 command signals.

The accelerometer may also include a piston 13 made of a material whose density exceeds the density of the working fluid. The piston 13 is located in the middle of the channel 1 with the working fluid.

In Fig. 1, a sawtooth voltage source 7 is shown connected to two electrodes of the piezoelectric cylinder 6, and in Fig. 2 to one, and for clarity of the optical design, the piezoelectric cylinder in Fig. 2 is moved outside the fiber spool 3.

Liquid accelerometer works as follows.

If there is a piston 13 in the accelerometer, the latter plays the role of an inertial mass. In the absence of a piston 13, the role of the inertial mass is played by the working fluid in the channel 1.

The impact of the acceleration W on the piston 13 (or the working fluid) leads to their displacement to the right or left, depending on the direction of action. In this case, the hydrostatic pressure near one of the coils, for example 3, increases, and about the other (4) it decreases.

This leads to the appearance of an additional phase difference at the output of the interferometer and the measurement of the Doppler frequency at the output of the photodetector 5. After amplification in the amplifier 9, the frequency of interference peaks is recorded by a frequency meter 11, which gives a signal proportional to the amplitude of the acceleration acting on the inertial mass.

To determine the sign (direction) of the acting acceleration, accelerometers are provided with blocks 7, 10, 12, as well as a piezocylinder 6.

A signal is supplied to the piezoelectric cylinder 6 from a sawtooth voltage source 7, the period of which (t ₁ + t ₂ ) (Fig. 3) is set by the command signal setter 12 (Fig. 3a).

The sawtooth voltage (Fig.3b) sets the constant frequency shift f ₀ (Fig.3c) at the interferometer output, relative to which an additional frequency shift f ₁ or f ₂ is determined, caused by the measured acceleration W.

This allows you to determine the direction of acceleration by the sign of the measured frequencies f ₁ , f ₂ relative to the frequency f ₀ . (If the frequency increased, then the acceleration is directed to the right, if it decreased, to the left.)

Due to the fact that it is difficult to obtain an ideal sawtooth voltage, the command signal generator 12 closes the electronic switch 10 at the time t _{2 of the} transition process, and the frequency meter 11 only accumulates measurement information at time periods t ₁ .

Thus, with the help of this liquid accelerometer, an optical signal is obtained at the output of the device, which can be sent along a fiber communication line several kilometers long (not shown in the drawing) to the photodetector 5 receiving location (Fig. 2).

This achieves the set technical result.

Sources of information

1. USSR author's certificate No. 1211651, cl. G 01 P 15/08, 1986.

2. Copyright certificate of the USSR No. 732750, cl. G 01 P 15/08, 1980 - prototype.

Claims (3)

1. A liquid accelerometer containing a channel filled with a working fluid and a frequency converter of hydrostatic pressure, two sensors of which are located at the ends of this channel, the output of the frequency converter being connected through an amplifier to a frequency meter, characterized in that it further comprises a sawtooth voltage source, a programmable command signal generator and an electronic key, and the frequency converter of hydrostatic pressure is made in the form of a coherent light source, two identical coils and a photodetector, optically matched to a fiber-optic interferometer, the output of which is the output of a photodetector, while one of the fiber coils is wound with an interference fit on the side surface of the piezoelectric cylinder, the electrodes of which are connected to a sawtooth voltage source, the controlled input of which is connected to the output of the command commander signals, and the amplifier is connected to the frequency meter via an electronic key, the controlled input of which is connected to the output of the command signal setter. 2. The liquid accelerometer according to claim 1, characterized in that the second fiber coil of the interferometer is also wound on the side surface of an additional similar piezocylinder. 3. The liquid accelerometer according to claim 1, characterized in that it further comprises a piston made of a material whose density exceeds the density of the working fluid located in the middle of the channel.

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