RU2165625C1 - Gear measuring accelerations - Google Patents

Abstract

FIELD: stabilization and guidance systems. SUBSTANCE: positive feedback from output of amplifier to input of moment generator through phase detector of positive feedback and voltage-to- current converter connected in series is formed in proposed gear. It has local negative feedback from output of amplifier to input of moment generator through phase detector of negative feedback, high-pass filter, voltage-to-current converter connected in series, negative integrating feedback from output of phase detector of negative feedback to input of moment generator. Gear includes integrating amplifier, comparator, single-shot synchronous oscillator, reversible binary counter, additional code-to-direct code converter, OR gate, binary amplifier, ripple filter, sign switch and synchronization circuit connected in series. Outputs of the latter are inputs of comparator and single-shot synchronous oscillator. Second output of comparator is connected to second input of reversible binary counter via single-shot synchronous oscillator. Second output of reversible binary counter is connected to second input of sign switch and second input of OR gate whose output is output of digital code of gear. Gear also incorporates reference voltage generator whose inputs are inputs of angle-data transmitter, phase detectors of positive and negative feedback. Insertion of gear with negative feedback of opposite signs provides it with stability and expanded transmission band, negative integrating feedback increases accuracy thanks to type 1 servo system and to formation of pulse coupling in it. EFFECT: improved stability and expanded transmission band and increased accuracy of gear. 2 dwg

Description

 The invention relates to measuring technique and can be used as an element in stabilization, navigation and guidance systems. It can find application in devices for measuring mechanical values of the compensation type.

 A device for measuring accelerations is known (RF patent N 2098833, class 6 G 01 P 15/13 publ. 10.12.97) containing a sensing element including two fixed electrodes and a movable plate, three amplifiers, two resistors, with the output of the first the amplifier is connected to the first resistor, and the input of the second amplifier is connected to the second resistor and is the output of the device. To increase the noise immunity when exposed to electrical noise, a reference voltage source, an electric signal generator, two transistor pairs, three resistors, two capacitors are introduced into it, which allow compensation of electrical noise due to the coverage of the amplifier with negative feedback.

 The disadvantage of this device is the low accuracy of the measurement, since the choice of the gain of the hard negative feedback is limited by the condition of stability of the system.

 The closest in technical solution is the device (described in A.S. N 742801 publ. In the bulletin of inventions N 23, 1980), containing a sensor element, an angle sensor, an integrated feedback amplifier, a torque sensor, an additional integration amplifier, an electronic key, a threshold element, and the first output of the angle sensor is connected through an integrating feedback amplifier to the torque sensor, and the second output of the angle sensor through a threshold element and an additional integrating amplifier connected to the control input onnogo key.

 The disadvantage of this device is the low accuracy of the measurement, due to the accuracy of the integrating analog amplifiers and the threshold element. In addition, the accuracy of the measurement depends on the parameters of the electronic key circuit that selects the information.

 The main error of the device is related to the finiteness of the charge time of the capacitor of the integrating amplifier. This error leads to an aperture error characteristic of a similar sampling and information processing scheme.

 The present invention solves the problem of improving the accuracy of measuring accelerations and expanding the bandwidth of the device.

 This is achieved due to the fact that two voltage converters, a current, a high-pass filter, a negative feedback phase detector, a positive feedback phase detector and a comparator connected in series, are introduced into the device containing the sensor element, an angle sensor, an amplifier, a torque sensor and an integrating amplifier. , first standby synchronous generator, reversible binary counter, additional code to direct converter, OR circuit, binary multiplier, smoothing filter and sign switch b, as well as a second standby synchronous generator, a reference voltage generator and a synchronization circuit, the outputs of which are inputs for a comparator, the first and second standby synchronous generators, while the output of the angle sensor is connected through an amplifier, respectively, to the first inputs of the phase detector of negative feedback and phase detector positive feedback, the second inputs of which, as well as the input of the angle sensor are connected to the outputs of the reference voltage generator, the output of the phase detector of positive feedback connected to the input of the first voltage-current converter, the output of which is connected to the input of the torque sensor, to which a negative feedback phase detector is also connected through a high-pass filter connected in series and a second voltage-current converter, the output of the negative feedback phase detector is connected to the input of the integrating amplifier whose output is connected to the input of the comparator, the second output of the comparator is connected to the input of the second waiting synchronous generator, the output of which is connected is connected to the second input of the reversible binary counter, and the second output of the reversible binary counter is connected to the second input of the OR circuit and the second input of the sign switch, the output of which is connected to the input of the torque sensor, the output of the OR circuit being the output of the device’s digital code.

 The introduction of local signs of different signs into the device ensures the stability of the device and the expansion of the bandwidth, and the negative integrating feedback that covers the entire device increases accuracy due to first-order astatism, as well as due to the formation of pulsed communication in the feedback circuit.

 In FIG. 1 shows a block diagram of a device; in FIG. 2 block diagram of the device.

 The proposed device contains a sensing element 1, made in the form of a pendulum, an angle sensor 2, the output of the angle sensor 2 is connected to the amplifier 3. One output of the amplifier 3 is connected to the input of the phase detector of negative feedback 4 (FDOOS), and the other output is connected to the input of the phase detector positive feedback 5 (FDOS). Additional inputs for the angle sensor 2, FDOOS 4, FDPOS 5 is the output from the reference voltage generator 6 (GON). The output of the PDOSF 5 is connected to the input of the voltage converter - current 7, and the output of the PDOS 4 is connected to the input of the high-pass filter 8, the output of which is connected to the input of the voltage - current 9. The output of the PDOS 4 is also an input for the integrating amplifier 10, the output of which is connected to the input of the comparator 11. One output of the comparator 11 is the input of the standby synchronous generator 12, and the other output 11 is connected to the input of the standby synchronous generator 13. The outputs of the standby synchronous generators 12 and 13 are inputs of a reversible binary counter 14, one output of which is an input for an additional code converter to direct 15, and the other output 14 is connected to one of the inputs of the collection circuit (OR) 16. The output of the collection circuit 16 is connected to the input of the binary multiplier 17, and at the same time is the information output of the device. The output of the binary multiplier 17 through the smoothing filter 18 is connected to the input by a sign switch 19, the second input of which is connected to one of the outputs of the reversible binary counter 14. The outputs of the synchronization circuit 20 are additional inputs for the comparator 11, and the waiting synchronous generators 12 and 13. The outputs with the converter voltage - current 7, 9 and sign switch 19 are the inputs of the torque sensor 21.

The internal contents of the FDOOS, FDOS, comparator, waiting synchronous generators, a reversible binary counter, an additional code to direct converter, a collection circuit (OR), a binary multiplier, a sign switch, a synchronization circuit are described in the book:
P. Horowitz, W. Hill. The art of circuitry. M.: Mir, t. 1-3, 1993.

 A device for measuring acceleration works as follows.

 Under the action of the acceleration W on the sensing element 1, made in the form of a pendulum, the inertial moment equal to mlW acts (I, m is the length and mass of the pendulum). Under the influence of this moment, a deviation of the sensor element 1 occurs, which is detected by the angle sensor 2, the field windings of which are connected to the output of GON 6. The signal from the angle sensor 2 after amplification by amplifier 3 is fed to the outputs FDOOS 4 and FDPOS 5. Using FDPOS 4 and GON 6 the phase of deviation of the sensitive element 1 is highlighted. At the output of FDOOS 4, the signal will always be in antiphase of the deviation of the sensitive element 1, and at the output of FDOS 5 in the phase of deviation 1.

 The signal from the output of the PDPOS 5 in the form of voltage is supplied to the input of the voltage - current 7 converter, the output signal of which is supplied in the form of current to the current winding of the torque sensor 21. The signal from the negative feedback circuit from the output of the PDOS 4 through the filter is also fed to the input of the torque sensor 21 high-pass 8 and the voltage-current converter 9. The high-pass filter 8, included in the negative feedback, which is implemented from the output of the amplifier 3 to the input of the torque sensor 21 through a series-connected FDOOS 4, filter 8 and converter Atelier voltage - current 9, is designed to eliminate the compensating effect of positive feedback, negative and stabilizes the device. (A diagram of the implementation of the filter is given in the book by G. Lam. Analog and digital filters. Calculation and design. M.: Mir, 1982, pp. 127-195). The torque sensor 21 develops a moment that will compensate for the inertial moment, and the sensing element 1 returns to its original position. The signal in the form of a voltage with FDOOS 4 is fed to the input of the integrating amplifier 10. The voltage from the output of the integrating amplifier 10 is supplied to one of the inputs of the comparator 11. In the comparator 11, the signal from the output of the amplifier 10 is compared with a signal isolated from a signal that is stable in frequency and amplitude with output of the synchronization circuit 20.

If the signal from the output of the integrating amplifier 10 is greater than the triangular voltage from the output 20, then the output of the comparator 11 will be a high logic level, if less, then the output of the comparator will have a low logic level. The signal level depends on the phase of deviation of the sensing element 1. The signals from the comparator 11, in the form of a level, are fed to the inputs of the waiting synchronous generators 12 and 13, which, using the synchronization circuit 20, give out signals in the form of a pulse at a frequency of 10 MHz, for each input signal (output 11) equal to "1". The reversible binary counter 14 counts the single pulses from the output of the standby synchronous generator 12, and subtracts the pulses coming from the output of the standby synchronous generator 13. The reverse binary counter 14 represents the positive information in the direct code, and negative in the additional code and the conversion of the additional code into the line is carried out by the converter of the additional code into the line 15. At the input of the collection circuit 16 (OR), signals are received from the reversible binary counter 14, if the sensing element 1 in the phase of GON 6 and the converter of the additional code in line 15, if the phase is 180 ^o . After the logical addition of the signals at 16, the output signal from 16 will be fed to the input of the binary multiplier 17, the output of which will be pulses, the number of which is proportional to the binary code supplied to the input of the collection circuit 16. The binary multiplier 17 converts the binary code to one. The smoothing filter 18, to the input of which pulses are received from the binary multiplier 17, not only eliminates the ripple of the input signal from 17, but also ensures the stable operation of the device, covered by feedbacks of different signs. A signal from the sign switch 19 with the sign of the sign of the reversible binary counter 14 is supplied to the current winding of the torque sensor 21. Signals from the outputs 7, 9 and 19 will be fed to the current winding 21, which will eliminate the deviation of the sensing element 1 and provide increased accuracy and increased bandwidth devices for measuring accelerations. The output of the collection circuit 16 is the output of the digital code of the device for measuring accelerations.

 The technical efficiency of the proposed device can be estimated using the transfer functions according to the structural diagram shown in FIG. 2.

где
K₀ = K_dK_УС/2ζT;
T₀ = T/2ζ
Передаточная функция по контуру местной отрицательной обратной связи запишется как:

где K₀₁ = K₀/(1+K₀K_ОСT₁);

2ζ₀T₀₁ = (T₀+T₁)/(1+K₀K_ОСT₁)
Введем обозначения T₁ = mT_ОС, где m - параметр, обеспечивающий устойчивость устройства по фазе (6 > m > 1).The following notation is used in the structural diagram:
K _d , K _us - the transmission coefficients of the angle sensor and amplifier;
T, ζ is the time constant and the attenuation coefficient of the sensor;
K _OS , K _OS1 , K _OS3 - transmission coefficients of the negative negative, positive, negative integrating circuit;
K is the integrator transfer coefficient;
T ₁ - time constant of the smoothing filter
The transfer function for the positive feedback office is written in the form:

Where
K ₀ = K _d K _US / 2ζT;
T ₀ = T / 2ζ
The transfer function along the local negative feedback loop is written as:

where K ₀₁ = K ₀ / (1 + K ₀ K _OS T ₁ );

2ζ ₀ T ₀₁ = (T ₀ + T ₁ ) / (1 + K ₀ K _OS T ₁ )
We introduce the notation T ₁ = mT _OS , where m is the parameter that ensures the phase stability of the device (6>m> 1).

Величина коэффициента затухания ζ₀ может быть обеспечена заданным значением (1+ K₀K_ОСmT₀).Then the parameters of the device when covered by feedbacks will be equal to:
T ₀₁ = T _0m2ζ0 / (1 + m) and

The value of the attenuation coefficient ζ ₀ can be provided by a given value (1+ K ₀ K _OS mT ₀ ).

Устойчивость в устройстве обеспечивается за счет m₁, который должен удовлетворять условию 6 < m₁ < 1, а увеличение частоты среза устройства ω_СР достигается за счет выбора параметра m, который может быть m << 1.We introduce the parameter m ₁ = T ₀ / T ₀₁ = (1 + m) / 2ζ ₀ .
In this case, the cutoff frequency along the negative integrating feedback loop is written as:

Stability in the device is ensured by m ₁ , which must satisfy the condition 6 <m ₁ <1, and an increase in the cutoff frequency of the device ω _{CP is} achieved by choosing the parameter m, which can be m << 1.

Предположим устройство имеет параметры:
Т=0.2 с, ζ = 2, m = 4, ζ₀ = 0,5
Тогда T₀ = 0.04 с, m₁ = 5;
ω_СР = 9,25 с^-1, K_ОС3KK₀ = 37.94 с^-2.The realized open loop gain is defined as

Suppose a device has parameters:
T = 0.2 s, ζ = 2, m = 4, ζ ₀ = 0.5
Then T ₀ = 0.04 s, m ₁ = 5;
ω _CP = 9.25 s ^-1 , K _OS3 KK ₀ = 37.94 s ^-2 .

 The cutoff frequency and gain were close to the prototype.

In the proposed device, ω _CP ≤ 9.25 s ^-1 , `
K _OS3 KK ₀ = 37.94 s ^-1
In the prototype:
ω _CP ≤ 7.52 s ^-1 ; K ₀₁ KK _OS3 ≤ 30 s ^-2 ;
Take: m = 0.1; ζ = 0.125, then
T ₀ = 0.01 MS, m ₁ = 4.4, ω _CP ≤ 473.68 s ^-1
K _OS3 KK ₀ = 62615 s
From the obtained values it follows that, compared with the prototype, the frequency increased by 62.99 times and the bandwidth increased by the same amount, the gain along an open loop increased by 2087.19 times, which ensures the stability of the device for measuring acceleration at a significant gain in the open system of the device.

 The proposed structure for constructing a device for measuring accelerations with local positive feedback, with local negative feedback, with a high-pass filter and negative integrating feedback leads to a positive effect. So the cutoff frequency increased by 62.99 times and the open-loop gain increased by 2087.19 times.

 Thus, the introduction into the device of local feedbacks of different signs and negative integrating feedback that covers the entire device increases the accuracy and extends the bandwidth.

Claims (1)

 A device for measuring accelerations, comprising a sensor, an angle sensor, an amplifier, a torque sensor and an integrating amplifier, characterized in that two voltage converters are introduced into it - a current, a high-pass filter, a phase feedback detector, a phase feedback detector, in series connected comparator, first standby synchronous generator, reversible binary counter, additional code to direct converter, OR circuit, binary multiplier, smoothing filter and a switch, as well as a second standby synchronous generator, a reference voltage generator and a synchronization circuit, the outputs of which are inputs to the comparator and the first and second standby synchronous generators, while the output of the angle sensor is connected through an amplifier, respectively, to the first inputs of the phase detector of negative feedback and phase positive feedback detector, the second inputs of which, as well as the input of the angle sensor are connected to the outputs of the reference voltage generator, the output of the positive phase detector the first feedback is connected to the input of the first voltage-current converter, the output of which is connected to the input of the torque sensor, to which is also connected a phase detector of negative feedback through a series-connected high-pass filter and a second voltage-current converter, the output of the phase detector of negative feedback is connected to the input of the integrating amplifier, the output of which is connected to the input of the comparator, the second output of the comparator is connected to the input of the second waiting synchronous generator, the output of which is connected to the second input of the reversible binary counter, and the second output of the reverse binary counter is connected to the second input of the OR circuit and the second input of the sign switch, the output of which is connected to the input of the torque sensor, the output of the OR circuit being the output of the device digital code.

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