UA21726U - Compensation accelerometer - Google Patents

Abstract

Compensation accelerometer has split body with one basic installation surface, with placed in it movable plate of sensitive element installed on springy suspension, with upper and lower magnetic systems, each of those consists of magnetic conductor, permanent magnet and pole tip. Magnetic systems together with two movable coils connected in sequence, placed on movable plate of sensitive element and with placed inside gaps of magnetic systems between surfaces of respective magnetic conductors and pole tips form torque indicator. Two movable toroid excitation coils connected differentially and placed on permanent magnets of systems, magnetic systems themselves and movable coils of torque indicator form angle indicator. Connected in sequence pre-amplifier, de-modulator, correction link, power amplifier form servo-amplifier forming together with high-frequency generator, coils of torque indicator and angle indicator contour of negative back coupling of accelerometer, and output filter. Split body is equipped with safety case. In accelerometer split body consists of upper and lower bodies that are rigidly connected to each other and have placed coaxially through openings with possibility to place there magnetic conductors. Sensitive element is made metallic, its movable plate is with one end connected to the base by means of springy suspension. Sensitive element is placed between the upper and the lower body and is rigidly fixed with base on the edge of the lower body.

Description

Description of the invention

This useful model belongs to the field of instrumentation, in particular - to compensating pendulum 2 linear accelerometers with an elastic suspension of a sensitive element. A set of such accelerometers, mounted orthogonally, can be used to measure acceleration in each direction for the purpose of locating, for example, a vehicle.

Known accelerometers (US patent Mob 4498342, class CO0O1R15/13 "Ipiedgaiiy zviyysop asseiigoteiyeg my zygez-pee geraiIapsipd", 12.02.1985; US patent Mob073490, class 50O1R15/00 "Begmo assayIegotegseg", 13.016, 2000 containing a removable housing, a pendulum inertial mass (hereinafter referred to as IM), connected by means of an elastic suspension to a ring mounting frame installed in the housing, an angle sensor, a torque sensor with moving coils and an electrical part.

Disadvantages of the accelerometer design, described in the US patent Mo44983421, include: 1) the implementation of the angle sensor using the bridge circuit of tensor resistors leads to a very large temperature drift of the zero signal of the accelerometer. Since the pendulum inertial mass of the device has elements of an elastic suspension, the indicated zero drift of the signal causes a significant error of the compensating type accelerometer, the value of which is proportional to the stiffness of the suspension; 2) there is no system for adjusting the zero signal of the sensor of the angular displacement of the MI;

C) the performance of a sensitive element made of silicon deteriorates the resistance of the accelerometer to shock and vibration loads, especially when it is turned off.

The closest in terms of technical essence to the claimed useful model is the accelerometer described in the above-mentioned US patent Mob6073490).

The accelerometer of the compensation type includes a removable housing and an IM connected by means of an elastic suspension with an adjustable frame installed in the housing. Both halves of the removable housing are made in the form of 22 rectangular bars with a cylindrical hole and a cup-shaped magnetic circle, which has a gap between the pole-o tips. A cup-shaped magnetic circle has a central core consisting of a permanent magnet and a pole tip. Both bars of the removable body are made of silicon single crystal, which has the same orientation of the silicon single crystal axes as the IM plate.

On the permanent magnets of the central cores of the cup-shaped magnetic circles, the toroidal coils ee, the angle sensor, are differentially switched on. The left and right halves of the detachable body of the accelerometer are connected to each other with the help of elastic elements (springs).

This accelerometer works as a conventional compensating type device. When the base of the device moves with - acceleration directed along the sensitivity axis of the BA device, the IM is deflected under the action of the moment of inertia "-- the acceleration that is measured. The angle sensor converts the MI deflection angle into an electrical signal. The preamplifier, demodulator, correction circuit and power amplifier connected in series 325 form the accelerometer servo amplifier and produce the current flowing through the coils of the torque sensor, which is necessary to balance the moment of inertia. The output of the power amplifier is connected in series with a filter whose output voltage is the output signal of the accelerometer. "

Distinctive features of this accelerometer are its design and the principle of operation of the angle sensor. In the moving coil Z 70 of the moment sensor, along with the feedback current, an alternating current is supplied from the high-frequency generator, connected to the input of the power amplifier. This current creates an alternating magnetic flux that passes through

From" toroidal coils of the angle sensor, located on the central cores of the magnetic circles of the torque sensor. These magnetic fluxes passing through the toroidal coils of the angle sensor change in magnitude when the position of the IM relative to the accelerometer body changes due to the fact that the displacement of the IM changes the flux coupling of the magnetic flux between the moving coils and the magnet wire. In the coils of the angle sensor, alternating voltages are induced, the amplitude of which depends on the relative position of the moving coils of the torque sensor and the coils of the angle sensor, that is, on the position of the IM accelerometer relative to its housing. The differentially coupled coils of the angle sensor create a high-frequency variable output signal. Its amplitude is proportional to the angle of deviation of the MI, while the phase depends on the direction of the deviation of the MI. ka 20 Thus, in an accelerometer, the moving coils of the torque sensor act as the primary windings of the angle sensor, both the output coils of the angle sensor and the torque sensor coils use a common magnetic circuit. This simplifies the design of the mechanical part of the accelerometer.

The disadvantages of the accelerometer, which is the closest in terms of technical solution to the proposed useful model and chosen as the closest analogue, include: 29 1) IM, its elastic suspension and the guide frame for attachment to the body are made of single crystal silicon, while the magnetic coils of the accelerometer are made of metallic ones, the coefficients of thermal expansion of which differ from the coefficients of thermal expansion of silicon. This leads to a temperature drift of the zero signal of the accelerometer, to reduce which it is necessary to select in a certain combination the materials from which the design elements of the accelerometer are made, which have different coefficients of thermal expansion; 60 2) the presence of elements made of silicon in the accelerometer reduces, as noted above, its resistance to vibration and shock loads, especially when it is turned off. This requires, when installing the accelerometer at the object, the use of additional means to reduce the impact of the above actions;

C) the design of the device has means for electrical adjustment of the output zero signal of the angle sensor.

However, this leads to the complication of the electrical part of the device, since the adjustment is carried out by closing the sections of additional toroidal coils located on the central cores (magnets) of the magnetic circles; 4) in the design of the device | see Fig. 4 of the US patent Mob073490| mechanical adjustment of the output zero signal of the angle sensor is possible. Adjustment is carried out by changing the position of the ferromagnetic core relative to the coils of the angle sensor. However, at the same time, the permanent magnets in the magnetic circuit are external, and the metal magnetic wire in which the core moves is internal. This leads to the influence of external magnetic fields on the magnets, which distort the magnetic fluxes in the magnetic systems, which reduces the accuracy of the acceleration measurement; 5) the design of the device has one basic setting surface, perpendicular to its axis of sensitivity ZA. When measuring two or three projections of the object's acceleration vector with accelerometers installed on it, the presence of one basic mounting surface complicates the process of installing the accelerometer and requires the use of additional devices for its installation; 6) the use in the design of the accelerometer of the moving coils of the moment sensor as the excitation coils of the angle sensor reduces the value of the voltage at the output of the power amplifier, which goes to balance the moment /5 of the inertia, by the magnitude of the amplitude of the high-frequency voltage of the excitation of the angle sensor.

The useful model is based on the task of improving the compensating accelerometer by simplifying its design, increasing the accuracy of acceleration measurement when using a different (compared to the closest analogue) scheme of mechanical adjustment of the output zero signal of the angle sensor, using a different electrical scheme, simplifying the process of installing the device on the object when introducing an additional basic mounting surface of the accelerometer, increasing its resistance to vibration and shock loads.

The task is solved in such a way that in the compensation accelerometer, which contains a removable housing with one basic mounting surface, with a moving plate of a sensitive element located in it, mounted on an elastic suspension, upper and lower magnetic systems, each of which consists of a magnet wire, a permanent magnet and pole tip, and the magnetic systems in combination with two moving coils connected in series, located on the moving plate of the sensitive element and o, placed inside the gaps of the magnetic systems between the surfaces of the corresponding magnetic wires and pole tips, form a moment sensor, two stationary toroidal excitation coils, included differentially and placed on the permanent magnets of the magnetic systems, the magnetic systems themselves and the moving coils of the Gezo torque sensor form the angle sensor, and the preamplifier, demodulator, correction link, power amplifier connected in series form the servo amplifier, which together with the high-frequency generator, with the coils of the moment sensor and the angle sensor, the negative feedback circuit of the accelerometer, and the output y-filter, and the detachable case is equipped with a protective cover, the new thing is that the detachable case in the accelerometer consists of an upper and a lower case, which is rigidly are interconnected and have coaxially located through holes with the possibility of placing magnetic wires in them, the sensitive element is made of metal, the movable plate of which is connected to the base by means of an elastic suspension at one end, while the sensitive element is located between the upper and lower housings and rigidly fixed by the base on the end of the lower housing, in addition, the fixed toroidal coils of the excitation of the angle sensor are connected to a high-frequency generator to supply them with an alternating high-frequency voltage, the output of the power amplifier through the "inductance" coil is connected to the input of the pre-amplifier and to the coils of the sensor moment, the other end of which 7-3) c is connected with connected in parallel by a resistor and a capacitor, which are connected to the output filter, and through . the openings of the upper and lower housings and the outer surfaces of the magnetic conductors are made, to an extreme extent, threaded and with the possibility of mechanical adjustment of the zero signal of the angle sensor by moving the magnetic systems relative to the upper and lower housings, and the upper and lower housings have side threaded holes for fixing the magnetic conductors in the housings with the help of locking screws, and for installation on the object

The GI accelerometer is equipped with an additional base mounting surface, made, like the first base mounting surface, on the lower case and perpendicular to it. - The proposed compensatory accelerometer allows to improve its operational and durability characteristics and to increase the efficiency of its work when installed on an object - for example, on a vehicle. o Design of the claimed accelerometer and the principle of mechanical adjustment of the zero signal of the angle sensor

Ф are explained by the following drawings: the cross-section of the accelerometer, drawn along the axis of sensitivity ЗА and the axis of the pendulum RA, that is, its main view, shown in Fig. 1; view B in Fig. 1 (without elements pos. 1, 12, 14, 16, 18, 21) is shown in Fig. 2; section E-E in Fig. 2 of the accelerometer is presented in Fig. 3; c in Fig. 4 shows the design of the sensitive element; section F-F in Fig. 4 is presented in Fig. 5; Fig. 1 shows the view G in Fig. 1 of the accelerometer, which shows the basic mounting surface A of the accelerometer; Fig. 7 shows view D in Fig. 1 of the accelerometer, showing the basic mounting surface B of the accelerometer; Fig. 8 shows the functional electrical circuit of the accelerometer; Fig. 9 shows the structural diagram of the accelerometer, illustrating the mechanical adjustment of the zero signal 65 of the angle sensor; 10a and 106 show a kinematic diagram explaining the principle of mechanical adjustment of the zero signal of the angle sensor.

The accelerometer (Fig. 1-5) consists of upper 1 and lower 2 housings, rigidly connected to each other, having coaxially located threaded holes 3, 4, thus representing a detachable housing, inside which a sensitive element is placed between these housings, which consists of an IM formed by a moving plate 5 and two torque sensor coils 6 and 7 installed on it, a fixed base 8 and an elastic suspension 9 of the plate 5 to the base 8. The base 8 is rigidly fixed to the lower body, for example, with the help of a screw 10 and a spring washer 11.

A differential angle sensor and a torque sensor are located inside the detachable housing, and these 7/0 sensors use the same magnetic systems. Magnetic systems include magnetic lines 12 and 13, permanent magnets 14 and 15, pole tips 16 and 17, while the said magnetic lines are connected, respectively, to the upper 1 and lower 2 cases by means of threaded connections C and 4. On magnets 14 and 15 placed toroidal excitation coils 18 and 19 of the angle sensor.

The moving coils b and 7 are placed inside the gaps of the magnetic systems between the surfaces of the corresponding /5 magnetic conductors 12, 13 and the pole tips 16, 17, while the moving coils 6 and 7 of the torque sensor are also the output coils of the angle sensor.

The magnetic systems can move relative to the housings 1 and 2 along the ZA axis along the threads Z and 4 and are fixed to the housings with locking screws 20 (Fig. 2, Z).

The lower housing 2 has two mutually perpendicular base mounting surfaces A and B for mounting the 2o accelerometer on the object (for example, with the help of screws screwed into threaded holes in the surfaces A and

B), (Fig. b, 7).

The design of the accelerometer is covered by an external protective cover 21.

The functional electrical diagram of the accelerometer is shown in Fig.8. It consists of a signal amplifier of the angle sensor 22, a demodulator 23, a correction circuit 24, a power amplifier 25, a high-frequency generator 26, permanent magnets 14 and 15, moving coils of the moment sensor 6 and 7, toroidal coils of excitation of the angle sensor 18 and 19, and an inductance coil 27 , resistor 28, capacitor 29 and filter 30, Oor is the output voltage t of the accelerometer.

The accelerometer works like this.

In the absence of measured acceleration of the object on which the accelerometer is installed, directed "o z along the axis A, and the zero signal of the angle sensor has been set, the output signal of the accelerometer in the form of a direct current voltage Oor is absent. Under the action of the measured acceleration a along the axis ZA IM of the pendulum s sensitive element under the action of the moment of inertia M;i-tia (t - the mass of the IM, I - the distance from the axis of the suspension NA to the M center of mass of the IM) is deflected on the elastic suspension 9 relative to the accelerometer body . With a positive acceleration, the IM moves to the lower case 2, and with a negative acceleration - to the upper case 1. --

Accordingly, the movable coils 6 and 7 are also moved with the IM relative to the stationary toroidal coils 18 and 19. c

The stationary toroidal excitation coils 18 and 19 are powered by alternating high-frequency voltage from the reference generator 26 (Fig. 86). At the same time, variable magnetic fluxes of constant amplitude and frequency arise in magnetic systems. When moving the coils 6 and 7 together with the IM, their flux coupling with the magnetic fluxes mentioned above changes. At the same time, alternating voltages are induced in coils 6 and 7, and the current directions in coils 18 and 19 are such that these voltages are subtracted. The voltage obtained as a result of the subtraction enters the input of the previous amplifier 22. At the same time, the amplitude of this voltage is proportional to the value of the displacement of the IM, and the phase of this voltage depends on the direction of movement. The reference voltage from the generator is supplied to the second input of the demodulator 23;" 26. A constant voltage is formed at the output of the demodulator, the value of which is proportional to the value of the deviation of the IM, and the sign corresponds to the direction of the deviation of the IM. Next, this voltage passes through the correction circuit 24 and the power amplifier 25, the output voltage of which in the form of a feedback signal is fed through the coil of inductance 27 to the moving coils 6 and 7. Flowing through the coils 6 and 7, the feedback current Ior interacts with by the fields of permanent magnets 14 and 15 of the moment sensor and creates a feedback moment (Ampere's moment of force) - Me, the balancing moment of inertia force M; of the measured acceleration and returning the MI to the neutral -I position. Flowing through the resistor 28, the feedback current creates a voltage Oor-Iork (K - the resistance of the resistor 5or 28), which is the output signal of the accelerometer. The setting of the zero signal of the angle sensor is explained in Fig. 9, 10a and 106. Fig. 9 shows the sensitive element

Ф 31, angle sensor 32, source of stable voltage 33, correction link with power amplifier 34, moment sensor Z5, adders Z6, 37 and 38.

The angle sensor 32 measures the angle, which with the help of the adder 37 is represented on the diagram as the sum of two angles: - the angle p of the deviation of the IM from the neutral position, where neutral means the position at which the net effect of the moments of all forces applied to the IM is zero ; - the angle AD of the angle sensor adjustment error, which is the angle between the neutral position of the IM and the position of the IM, at which the voltage at the output of the angle sensor 32 is zero. в The adjustment error of the angle sensor 32 leads to the appearance of a zero offset of the output signal of the accelerometer, which is shown in the diagram in the form of a feedback current Ior flowing through the coils of the torque sensor 35. To reduce this zero offset, an electrical circuit for compensation of the error of the angle sensor adjustment is usually used . In Fig. 9, it is an adder 38 installed at the output of the angle sensor 32 and an adjustable source of stable constant voltage Or 33. The signal from the output of the adder 38 is fed to the correction link with the power amplifier 65 34, to which the moment sensor 35 is connected. For this structural scheme, taking into account that the link 34 in the accelerometers contains an integrator, for a static state, when the equivalent moments of all external forces applied to the IM are equal to zero, the following expression is valid for the displacement of the zero of the accelerometer Di: where s is the angular stiffness of the IM suspension, K/ is the transmission coefficient of the moment sensor 35, Ko is the transmission coefficient /o of the angle sensor.

During adjustment by changing the voltage, the ODs tend to fulfill the condition I sheroz (

ШЕ сай В и я, where " indicates that the values of these quantities are determined at the time of completion of the setup.

However, during the operation of the accelerometer due to a change in temperature (relative to the temperature at which the setting was carried out), all components of expression (1) will change their value, and a shift of zero will appear - З вхо Е | The same vk (3) gave me tp yary relltsi tya Ba TNK kAlee V

Rules and response coefficients 2 de oV, p4; odu - temperature coefficients, respectively, the error angle of the angle sensor 32, the transmission coefficient of the angle sensor 32, voltage Or.

As can be seen from expression (3), the displacement of the zero of the output signal of the Lee accelerometer! as a result of the change in temperature, it is directly proportional to the angle of error of the adjustment of the Ar angle sensor. Reducing this angle using the proposed mechanical adjustment of the angle sensor 32 allows to increase the accuracy of the accelerometer. high school

Fig. 104, 106, which explains the principle of mechanical adjustment of the zero signal of the angle sensor, shows the accelerometer 39 and the horizontal base 40, on which the zero signal of the angle sensor of the accelerometer is adjusted. Setting the zero signal of the angle sensor is carried out as follows. Base 40 is displayed. at - : «- in the horizon, while the gravitational acceleration vector 9 will be perpendicular to the surface E of the base 40.

The accelerometer is installed on the surface E in the position | (Fig. 10a) and II (Fig. 106) with the orientation of the ZA and RA axes of the accelerometer shown in these figures. At the same time, the measuring axis 5A must be parallel to the plane E of the base 40, and the axis of the pendulum RA is directed in the position | along the vector of gravitational acceleration 9 down, and in position II - opposite the vector of gravitational acceleration 9 up. However, the accelerometer always has an error of the base plane y (the angle of non-perpendicularity of the measuring axis ZA of the accelerometer to its base setting surface A). At the same time, the output signals of the accelerometer are in positions | and II have the following form: - хз оч зеде шк в (4) izhe N A zak zi : sho ko ЯВ ; INC KU de Chau - displacement of the zero of the output signal of the accelerometer, caused by the displacement of the zero signal of the -I angle sensor, K - the conversion factor of the accelerometer, 9 - the amount of gravitational acceleration.

From the expression (4), it follows that there is) tyu, la sva (5) with Ya zrnnia still EE; Academy of Sciences etc

The purpose of the mechanical adjustment of the zero signal of the angle sensor is to fulfill the condition c Mo-o, (6) which, as follows from (5), will be achieved at 60 t s, ee, av Mate yar

The adjustment of the angle sensor consists in a step-by-step approach to the fulfillment of condition (7) by moving along the b5 threads 3, 4 of the magnetic conductors 12, 13 relative to the upper and lower housings 1, 2 and monitoring the echo fossaye voltages

I live

Varva in positions I and II after changing the position of each of the magnetic conductors 12 or 13.

After completing the zero signal adjustment of the kuga sensor, the magnetic wires 12, 13 are fixed by the locking screws 20 in the housings 1, 2.

Claims (5)

The formula of the invention 1. A compensating accelerometer containing a removable housing with one base mounting surface, with a moving plate of a sensitive element located in it, mounted on an elastic suspension, upper and lower magnetic systems, each of which consists of a magnetic conductor, a permanent magnet, and a pole tip, and the magnetic system in combination with two moving coils, connected in series, 75 located on the moving plate of the sensitive element and placed inside the gaps of the magnetic systems between the surfaces of the corresponding magnetic conductors and pole tips, form a torque sensor, two stationary toroidal excitation coils, included differentially and placed on permanent magnets of magnetic systems, the magnetic systems themselves and the moving coils of the moment sensor form the angle sensor, and the preamplifier, demodulator, correction link, power amplifier connected in series form the servo amplifier, which together with the high-frequency generator, coils of the torque sensor creates ent and the angle sensor, the circuit of the negative feedback of the accelerometer, and the output filter, and the removable housing is equipped with a protective casing, which differs in that the detachable housing in the accelerometer consists of upper and lower housings that are rigidly connected to each other and have coaxially located through holes with the possibility of placing magnetic wires in them, the sensitive element is made of metal, the movable plate of which is connected to its base at one end by means of an elastic suspension, while the sensitive element is located between the upper and lower Z housings and is rigidly fixed by the base on the end of the lower housing . 2. Compensation accelerometer according to claim 1, which is characterized by the fact that the fixed toroidal coils of the angle sensor excitation are connected to a high-frequency generator to supply them with an alternating high-frequency voltage, the output of the power amplifier through the inductor is connected to the input of the pre-amplifier and to (Ce) coils of the moment sensor, the other end of which is connected to a parallel-connected resistor and a capacitor, which are connected to the output filter. 3. Compensatory accelerometer according to claim 1, which is characterized by the fact that the through holes of the upper and lower housings and the outer surfaces of the magnetic conductors are made at least slotted with the possibility of mechanical adjustment - the zero signal of the angle sensor by moving the magnetic systems relative to the upper and lower housings. 4. Compensatory accelerometer according to claim 3, which differs in that the upper and lower housings of the SM have side threaded holes for fixing the magnetic wires in the housings with the help of locking screws. 5. The compensating accelerometer according to claim 1, which is characterized by the fact that to install it on the object, it is equipped with an additional base mounting surface, made, like the first base mounting surface, on the lower case and perpendicular to it. - . and? ime) - -and ime) 4) 60 b5