RU2561303C1 - Linear microaccelerometer - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: linear microaccelerometer contains a base, a cover, a frame with inertial mass made from silicon, installed with a possibility of linear movement on elastic suspensions along a longitudinal axis, a position sensor of and a power supply, also two comparators, two amplifiers of current, a key, an electromagnetic power drive consisting of 2N coils placed on 2N magnetically conducting cores with concentrated poles directed towards the face sides of inertial mass are added to the device. The magnetically conducting cores are placed on opposite face sides of the frame, N from each side, and on the surface of the inertial mass around each end face the magnetic conductors closing magnetic fluxes of coils are located. Inputs of coils are connected to the key output the inputs of which through comparators are connected to the position sensor which is designed as optical, and consists of a radiator and photodetectors. The radiator is connected to the power supply, and between the radiator and the photodetectors the optical slot is located.

EFFECT: acceleration measurement accuracy improvement.

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Description

The invention relates to measuring equipment and can be used in orientation and navigation systems.

Known accelerometer (patent RU No. 2063047, IPC G01P 15/08, publ. 06/27/1996) containing an inertial mass on an elastic suspension made in the form of a rectangular plate, a position sensor and a compensation transducer comprising two magnetic systems, each of which consists of magnetic core and main permanent magnet with a pole tip.

When the object moves with acceleration in the direction of the sensitivity axis of the device, the inertial mass deviates relative to the fixed plates. The plate deflection registers and converts the position sensor into current. The compensation transducer develops a force equal to the inertial force of the plate. Moreover, the current flowing through the windings of the coils is proportional to the apparent acceleration of the object in the direction of the sensitivity axis.

A disadvantage of the known device is the low accuracy of the measurement of acceleration.

Known accelerometer (patent RU No. 2313100, IPC G01P 15/13, publ. 20.01.2007) containing an inertial mass on an elastic suspension made in the form of a quartz plate, a position sensor formed by surfaces with metal coating on both sides located on the inertial mass and facing it surfaces located in the housing, a current source and a compensation converter, consisting of two coils mounted on an inertial mass, and two permanent magnets located in the housing.

Under the action of acceleration along the axis of sensitivity, the inertial mass deviates from its average position. This deviation is detected by the position sensor, the signal from which is fed to the coils of the compensation converter. Current flowing through the coils forms a magnetic field that interacts with the magnetic field of permanent magnets. The force arising in this case compensates for the inertial force of the movable plate and returns it to its original position. The magnitude of the current flowing through the coils, judge the magnitude of the acceleration acting on the accelerometer.

A disadvantage of the known device is the low accuracy of the measurement of acceleration.

The closest in technical essence and the achieved effect is the device "ADXL50" (Doscher J. Accelerometer Design and Applications. Analog Devices. 1998), containing the base, cover, frame with an inertial mass made of silicon, mounted with the possibility of linear movement on elastic suspensions along the longitudinal axis, a position sensor, consisting of movable plates placed on an inertial mass, and fixed, rigidly fixed in the housing, a generator, a measurement circuit and a voltage source.

In the initial state, antiphase signals of a rectangular shape and the same amplitude are fed from the generator to two adjacent fixed plates. As a result, two capacitances are formed between the movable and fixed plates, which are equal in the absence of acceleration, therefore, signals of the same amplitude are transmitted to the moving plate and, therefore, the difference signal at the output is zero. With the acceleration acting on the accelerometer, the capacitance values and, consequently, the differential output signal change, and its amplitude depends on the displacement of the movable plate, and the phase is determined by the acceleration sign.

The disadvantage of this device is the low accuracy of the acceleration measurement.

The task is to create a linear microaccelerometer that measures accelerations with higher accuracy.

The technical result that provides a solution to the problem is to increase the accuracy of measuring acceleration.

The technical result is achieved in that in a linear microaccelerometer containing a base, a cover, a frame with an inertial mass made of silicon, mounted with the possibility of linear movement on elastic suspensions along the longitudinal axis, a position sensor and a voltage source, two comparators, two current amplifiers are additionally introduced , key, electromagnetic power drive, consisting of 2N coils located on 2N magnetically conductive cores with pronounced poles directed to the end faces of the inertial mass, In this case, the magnetically conductive cores are located on the opposite end sides of the frame with N on each side, and on the surface of the inertial mass in the area of each of the ends are magnetic circuits that close the magnetic fluxes of the coils, and the inputs of the coils are connected to the output of the key, the inputs of which through the comparators are connected to the position sensor which is made optical and consists of an emitter and photodetectors, while the emitter is connected to a voltage source, and between the emitter and photodetectors there is an optical slot.

The technical result is achieved due to the fact that the inertial mass oscillates along the sensitivity axis under the influence of an alternating DC signal generated in the feedback circuit of an electromagnetic power drive controlled by an optical position sensor. The presence of the input action leads to a shift in the center of oscillation and the appearance of temporary modulation of the signal. Measuring the temporal modulation of the signal improves the accuracy of the measurement of acceleration.

The set of essential features of the invention ensures the achievement of the technical result achieved by the invention, due to the fact that the base, cover, frame with inertial mass, optical position sensor, voltage source, two comparators, two current amplifiers, a key and an electromagnetic power contained in the claimed device the drive is used to more accurately measure linear acceleration.

The analysis of the prior art carried out by the applicant has established that there are no analogues characterized by sets of features identical to all the features of the claimed angular accelerometer, therefore, the claimed invention meets the condition of “novelty”.

Search results for known technical solutions in this and related fields of technology in order to identify features that match the distinctive features of the claimed invention from the prototypes showed that they do not follow explicitly from the prior art.

From the prior art determined by the applicant, the influence of the transformations provided for by the essential features of the claimed invention on the achievement of the indicated technical result has not been revealed, therefore, the claimed invention corresponds to the “inventive step”.

The invention is illustrated in figure 1, which presents a structural diagram of the sensor and introduced the following notation:

1. The basis

2. Cover

3. Frame

4. Inertial mass

5. Elastic suspensions

6. Emitter

7. The first photodetector

8. The second photodetector

9. Voltage source

10. Optical slit

11. The first coil

12. Second coil

13. The first magnetically conductive core

14. The second magnetically conductive core

15. The first magnetic circuit

16. The second magnetic circuit

17. The key

18. The first current amplifier

19. Second current amplifier

20. The first comparator

21. The second comparator

The proposed linear microaccelerometer consists of a base 1, a cover 2 and a frame 3 with an inertial mass 4 made of silicon and installed with the possibility of linear movement on elastic suspensions 5 along the longitudinal axis. The optical position sensor of the inertial mass 4 is made of emitter 6 and photodetectors 7, 8, while the emitter 6 is connected to a voltage source 9, and between the emitter 6 and photodetectors 7, 8 there is an optical gap 10. The electromagnetic power drive consists of 2N coils 11, 12 located on 2N magnetically conductive cores 13, 14 with distinct poles directed towards the end faces of the inertial mass 4, while the magnetically conductive cores 13, 14 are located on the opposite end sides of the frame 2 with N on each side and on The surface of the inertial mass 4 in the area of each of the ends are magnetic cores 15, 16. Coils 11, 12 are connected to the output of the key 17 through current amplifiers 18, 19, respectively. The inputs of the key 17 are connected through comparators 20, 21 with photodetectors 8, 9.

The emitter 6 can be performed, for example, on the basis of the commercially available Kingbright LED KR-1608NS [1].

Photodetectors 7, 8 can be made, for example, based on commercially available Kingbright KR-1608P1C photodetectors [1].

The voltage source 9 can be performed, for example, based on a commercially available microcircuit (voltage source) Mitsubishi Electric M5294 [2].

The key 17 can be performed, for example, based on a commercially available chip NJM2520V [3].

Current amplifiers 18, 19 can be performed, for example, on the basis of a commercially available microcircuit (operational amplifier) Mitsubishi Electric M5216 [2].

Comparators 20, 21 can be performed, for example, on the basis of a commercially available microcircuit (comparator) Mitsubishi Electric M51203 [2].

Linear microaccelerometer works as follows.

After turning on the power, the base 1, the cover 2 and the inertial mass 4 in the frame 3 are at rest. Key 17 is in the preset state "1". The voltage from the output of the key 17 begins to flow to the first current amplifier 18. The electric current created by it in the first coil 11 induces a magnetic field in the first magnetically conducting core 13, which, tending to close through the first magnetic circuit 15, attracts the inertial mass 4. As a result, the inertial mass 4 is displaced on elastic suspensions 5 in the direction of the first coil 11 until the optical slit 10 falls into the optical axis between the emitter 6, powered by a voltage source 9, and the first photodetector 7. At this moment, the signal with of the first photodetector 7, converted by the first comparator 20, puts the key 17 in the state "0", as a result of which the voltage from the output of the key 17 starts to flow to the second current amplifier 19, the signal from which goes to the second coil 12. The first current amplifier 18 is turned off , the signal from which ceases to flow to the first coil 11. The electric current created by the second current amplifier 19 in the second coil 12 induces a magnetic field in the second magnetically conducting core 14, which, attracting short circuit through the second magnetic circuit 16, attracts moves the inertial mass 4 in the opposite direction to the second coil 12 until the optical slit 10 falls into the optical axis between the emitter 6, powered by a voltage source 9, and the second photodetector 8. At this moment, the signal from the second photodetector 8, converted by the second comparator 21, puts the key 17 in the state "1" and the cycle is repeated again. Thus, the inertial mass 4 begins to oscillate at its own frequency, and the signal from the photodetectors 7, 8 takes the form of a meander with a duty cycle of 50%. Under the influence of external acceleration, a shift of the center of oscillation of the inertial mass 4 occurs. This shift causes a change in the duty cycle of the signal from the photodetectors 7, 8, which is proportional to the current acceleration.

Increasing the accuracy of measurements is achieved by introducing a self-oscillation mode, an optical position sensor and an electromagnetic power drive, and thereby reducing harmful moments acting on the inertial mass.

Thus, the above information proves that when implementing the claimed invention, the following conditions are met:

- the tool embodying the proposed device in its implementation is intended for use in measuring equipment, namely in accelerometers for measuring linear acceleration, for example, in inertial navigation systems;

- for the claimed invention in the form described in the independent claim, the possibility of its implementation using the means described before the filing date of the application has been confirmed;

- a tool embodying the claimed invention in its implementation, is able to provide the specified technical result.

Therefore, the claimed invention meets the condition of patentability "industrial applicability".

Information sources

1. Library of electronic components. Issue 1: Kingbright Optoelectronic Devices. - M .: DODEKA, 1999 .-- 64 p.

2. Library of electronic components. Issue 17: Analog and Digital-to-Analog Microcircuits by Mitsubishi Electric. - M: DODEKA, 2000 .-- 48 p.

3. Microcircuits for audio and radio equipment - 2. - M.: Dodeka XXI Publishing House, 2001. - 288 p.

Claims (1)

A linear microaccelerometer containing a base, a cover, a frame with an inertial mass made of silicon, mounted with the possibility of linear movement on elastic suspensions along the longitudinal axis, a position sensor and a voltage source, characterized in that two comparators, two current amplifiers, a key are additionally introduced into the device , an electromagnetic power drive, consisting of 2N coils placed on 2N magnetically conductive cores with distinct poles directed to the end faces of the inertial mass, while conductive cores are placed on opposite ends of the frame in N directions on each side, and on the surface of the inertial mass in the area of each of the ends are magnetic circuits that close the magnetic fluxes of the coils, and the coil inputs are connected to the output of the key, the inputs of which through the comparators are connected to the position sensor, which It is made optical, and consists of an emitter and photodetectors, while the emitter is connected to a voltage source, and an optical slit is located between the emitter and photodetectors.