RU2226695C1 - Device for measurement of accelerations - Google Patents

Abstract

FIELD: applicable as a sensing element in the stabilization, guidance and navigation systems. SUBSTANCE: the device has a sensing element, attitude sensor, feedback-connected torque amplifier and generator, in addition, it uses three amplifier stages, two band-pass filters, two emitter followers, universal synchronous J-K flip-flop, slave synchronous oscillators, asynchronous relay R-S flip-flop, precision relay element whose information inputs from the output of the attitude sensor are series-connected to one of the inputs of the torque generator. The device also uses a crystal oscillator, whose output via a device for distribution of sync pulses is connected to the inputs of the slave synchronous oscillators, AND gates, low-digit reversible counter, first and second binary multipliers. The output of the attitude sensor is connected to one of the inputs of the first amplifier stage, and the input-to the output of the reference voltage generator, and the output from the second binary multiplier serves as the device digital output. EFFECT: provided a phase value equal to zero in carrier frequency and a phase lead in envelope frequency due to introduction of an amplifier-converter section driven into both negative feedback and intersecting positive feedbacks, which enhances the device precision and the gain factor of an open section (enhanced sensitivity of the device) and the bandwidth. 1 dwg

Description

The proposed device for measuring acceleration is intended for use as a sensitive element in stabilization, guidance and navigation systems. The invention may find application in devices for measuring mechanical values of the compensation type.

A device for measuring accelerations is known (RF patent No. 2098833 IPC ⁶ G01P 15/13, publ. 10.12.97) containing a sensor element including two fixed electrodes and a movable plate, three amplifiers, two resistors, while the output of the first 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 amplifiers with negative feedback.

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

The closest in technical solution is the device (A.S. No. 742801, IPC ⁶ G01P 15/00, B.I. No. 23, 1980) containing a sensing element, an angle sensor, an integrating feedback amplifier, a torque sensor, an additional integrating amplifier , an electronic key, a threshold element, wherein the first output of the angle sensor is connected through an integrating feedback amplifier to the moment sensor, and the second output of the angle sensor through a threshold element, an additional integrating amplifier is connected to the control input of the electronic key.

The disadvantage of this device is the low accuracy of the measurement, due to the accuracy of the integrating analog amplifiers and a 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 associated with the finiteness of the charge time of the capacitor of the integrating amplifier. This error leads to an aperture error inherent in a similar sampling and information processing scheme. The small bandwidth of the device, low speed and low gain along the open loop determine the accuracy in the steady state.

The objective of the present invention is to expand the bandwidth and increase the accuracy of the measurement.

This is achieved by the fact that a first amplifier stage, a first bandpass filter, and a second bandpass filter are introduced in a device containing a sensing element, an angle sensor, an amplifier, and a torque sensor included in the feedback, serially connected via information inputs from the output of the angle sensor to one of the inputs of the torque sensor amplifier stage, second bandpass filter, third amplifier stage, first emitter follower, universal synchronous JK-trigger, standby synchronous generators, asynchronous relay RS-trigger, precision r an oily element, the second output of the second amplifier stage being connected to the second input of the first amplifier stage. The second output of the third amplifier stage is connected to the second input of the second amplifier stage, one of the outputs of the third amplifier stage is also connected to the K-input of the universal synchronous JK trigger via an inverter and a second emitter follower, and the other output with the third input of the first amplifier stage is connected through a series-connected demodulator , the first smoothing filter of the first order and a modulator, and the second inputs of the demodulator and modulator are connected to one of the outputs of the reference voltage generator. The third inputs of the demodulator and modulator are connected to the output of the reference voltage generator through the first phase-shifting circuit. In addition, the output of the reference voltage generator is connected to the third input of the universal synchronous JK-trigger through a second phase-shifting circuit, a comparator and a pulse width former, and the second input of the torque sensor is connected to the output of the precision relay element through a second smoothing filter. S-output of an asynchronous relay RS-flip-flop through matching circuits, low-bit reversible counter, total register, digital information to direct code converter, first binary multiplier, multi-bit reverse counter connected to the input of the second binary multiplier, one of the outputs of which is connected to the second input of the multi-bit reverse counter. A quartz oscillator is introduced into the device, the output of which is connected through the clock distribution device to the inputs of the waiting synchronous generators, coincidence circuits, a low-bit reverse counter, the first and second binary multipliers, the output of the angle sensor is connected to one of the inputs of the first amplifier stage, and the input to the output of the generator reference voltage. The output from the second binary multiplier is the digital output of the device.

In the proposed device, due to the introduction of an amplifying conversion path, covered both by negative feedback and intersecting positive feedbacks, a phase value of zero is provided in the carrier frequency and phase advance in the envelope frequency, which improves the accuracy of the device and increases the coefficient open loop transmission (increasing device sensitivity) and bandwidth.

The drawing shows a functional diagram of the proposed device.

The device for measuring accelerations contains a sensing element 1, the angular position of which is fixed by the angle sensor 2. The field winding of the angle sensor 2 is connected to the output of the reference voltage generator 3. The output winding of the angle sensor 2 is connected to one of the inputs of the first amplification stage 4 of the amplification-conversion path which is connected to the input of the second amplifier stage 6 through the first band-pass filter 5. The output of the second amplifier stage 6 is connected to the input of the third amplifier stage 8 through the second bands howl filter 7. One of the outputs of the second amplifier stage 6 is connected to one of the inputs of the first amplifier stage 4, and the output of the third amplifier stage 8 is connected to one of the inputs of the stage 6. One of the outputs of the third amplifier stage 8 is connected to the input of the demodulator 9, the output of which connected to the input of the first smoothing filter of the 1st order 10, the output of the filter 10 is connected to the input of the modulator 11. The output of the serial branch, including the demodulator 9, the first smoothing filter of the 1st order 10 and the modulator 11, is connected to the corresponding the input inputs of the first amplifier stage 4. The inputs of the demodulator 9 and the modulator 11 of one branch are connected to the output of the reference voltage generator 3, and the other inputs of the demodulator 9 and modulator 11 of the other branch, negative feedback, are connected to the output of the reference voltage generator 3 through the first phase-shifting circuit 12 The output of the third amplifier stage 8 is connected to the inputs of the first emitter follower 13 and the inverter 14, the latter being connected to the input of the second emitter follower 15. The output of the generator 3 is connected to the input of the second oh phase shifting circuit 16, the output of which is connected to the input of the comparator 17, the output of which is connected to the input of the shaper of the pulse width of the carrier frequency 18. The inputs of the universal synchronous JK trigger 19 are connected to the inputs of the first and second emitter repeaters 13 and 15 and the pulse shaper 18. Outputs JK flip-flops 19 are connected to the inputs of the waiting synchronous generators (ZhSG) 20 and 21, other inputs of the ZhSG 20 and 21 are connected to the outputs of the crystal oscillator 22 through the clock distribution device 23. The outputs of the ZhSG 20 and 21 are connected s with the inputs of the asynchronous relay RS-flip-flop 24. The output of the asynchronous relay element 24 is connected to the input of the precision relay element 25, the output of which is connected to the input of the torque sensor 26 and to the second smoothing filter 27, the output of the second smoothing filter 27 is connected to the input of the torque sensor 26. The inputs of the matching circuits 28 and 29 are connected to the outputs of the clock distribution device 23 and the asynchronous relay element 24, respectively. The inputs of the low-bit reversible counter (MPC) 30 are connected to the outputs of the coincidence circuits 28 and 29 and the clock distribution device 23. The output of the final register (IR) 31 is connected to the input of the digital information converter into direct code 32, and the input of the IR 31 is connected to the output of MPC 30. The converter of digital information into direct code 32 is connected to the input of the first binary multiplier 33, the output of which is connected to the input of a multi-bit reversible binary counter 34, the other input of which is connected to the output of the second binary multiplier 35. Input w The binary binary multiplier 35 is connected to the output of the multi-bit binary counter 34.

The internal content of the blocks that implement the device for measuring acceleration are described in the books: Mayorov SA, Novikov GI The principle of organization of digital machines.-L.: Mechanical Engineering, 1974, 432 p .; Horowitz P., Hill W. Art of circuitry. - M.: Mir, t. 1-3, 1993.

The operation of the device is as follows.

The deviation of the sensor element 1 caused by the action of acceleration causes a shift in the center of self-oscillations relative to the zero position, which is detected by the angle sensor 2. The field winding of the angle sensor 2 is fed from the reference voltage generator 3. The output signal from the angle sensor 2 has a phase of 0 ° or 180 ° relative to the carrier frequency. The first amplifier stage 4, connected to the output of the angle sensor 2, contains an amplitude limiter in the local negative feedback, covering the amplifier stage, while there is no phase distortion at large signals, and after amplification, it feeds the signal from the angle sensor 2 to the first band-pass filter 5, carrier frequency transmit signal. After the first bandpass filter 5, the signal is fed to the input of the second amplifier stage 6, which has an amplitude limit in the feedback circuit, and then to the input of the second bandpass filter 7. One of the outputs of the second amplifier stage 6 is connected to the input of the first amplifier stage 4, forming a positive inverse communication. After the signal passes through the second band-pass filter 7, it enters the input of the third amplifier stage 8, covered by negative feedback on the amplitude limit, one of the outputs of which is connected to the output of the second amplifier stage 6. A direct branch, consisting of elements 4, 5, 6, 7, 8, is embraced by intersecting positive feedbacks. Negative feedback, covering 4, 5, 6, 7, 8, consists of two parallel branches and includes a series-connected demodulator 9, a first smoothing filter of the first order 10 and a modulator 11. Moreover, one branch containing 9, 11 is connected from the reference voltage generator (GON) 3, and another branch containing 9, 11 is connected from the GON 3 through the first phase-shifting circuit 12 (the circuit is 90 degrees out of phase). To the information JK inputs of the universal synchronous JK trigger 19, the signal from the third amplifier stage 8 must be supplied in antiphase. To do this, the voltage-amplified signal from 8, for one of the inputs, is inverted by the inverter 14. The first and second emitter repeaters 13 and 15 match the high output impedance 8 and 14 with the low-impedance input resistance of the information inputs of the JK-trigger 19. To determine the direction of acceleration the phases of the signals from the angle of the sensor 2 and the reference voltage generator 3 are compared on the JK-trigger 19. For this, it is necessary to apply to the synchronous input "C" a pulse of a certain duration, generated by the second phase-shifting circuit view 16, the comparator 17 and the pulse shaper 18. The second phase-shifting circuit 16 provides a phase shift of the harmonic signal of the carrier frequency by the delay time of the information signal when it passes through the circuit 4, 5, 6, 7, 8. Comparator 17 produces rectangular pulses when the harmonic is exceeded signal of a given level. The required duration is provided by the carrier frequency pulse shaper 18. If the phase of the deviation of the sensor 1 coincides with the phase of the reference voltage generator 3, then at the moment of supply of the carrier frequency pulse, the JK-trigger 19 switches to the steady state "1", otherwise - "0" . The crystal oscillator 22 produces rectangular, frequency-stabilized pulses (f = 1 MHz), providing the required rise and fall edges of the signal. The clock distribution device 23 generates strictly time-synchronized control clocks necessary for the operation of the entire device. Waiting synchronous generators 20 and 21, cocked from the JK-trigger 19, produce short (duration determined by the frequency of the clock distribution device 23) pulses, the frequency of which is determined by the switching frequency of the JK-trigger 19. Depending on the phase of the deviation of the sensitive element 1 to the asynchronous RS- trigger 24 provides a pulse either from generator 20 or from generator 21, i.e. The RS-flip-flop 24 is switched with the frequency of the JK-flip-flop 19. The output signal from the RS-flip-flop 24 cannot be directly fed to the input of the torque sensor 26 due to its instability in amplitude. To increase accuracy, this pulse is applied to a precision relay element 25, which carries out signal stabilization by level. The output signal from the relay element 25 is supplied to one of the inputs of the torque sensor 26, which will return the sensing element 1 to its original position. To increase the sensitivity, the device introduced local positive feedback from the output of the relay element 25 to the input of the torque sensor 26 through the second smoothing filter 27, which allows you to select the constant component of the input signal from the relay element 25. To one of the inputs of the matching circuits ("I" circuits) 28 and 29 signals from the outputs of the RS-flip-flop 24 are sent to other high-frequency pulses (count pulses) from the clock distribution device 23. Depending on the state of the RS-flip-flop 24, these pulses will either pass to the summing th, or to the subtracting input of a low-bit reversible counter 30. At the end of the oscillation period, information from the counter (equal to the difference between the number of "positive" and "negative" pulses) is transferred to the final register by the signal from the clock distribution device 23 (pulse to the C-input of the register) 31. The next clock on the reset input R ₀ counter 30 is reset. In this case, positive information is presented in direct code, and negative information in additional code. The most significant digit indicates the direction of the deviation of element 1. Information from the final register 31 is fed to the input of the digital information converter into direct code 32. The code from the converter 32 can be sent to the output bus of the low-bit digital computer code, as well as to the input of the first binary multiplier 33, at the output whose number of clock pulses from the distributor 23 will be proportional to the low-bit binary code. These clock pulses are fed to the summing input of a multi-bit reversible binary counter 34, the information from which is fed to the bus of a multi-bit digital code and to the input of the second binary multiplier 35. Sync pulses from the distributor 23 are received to the other input of the second binary multiplier 35, shifted in phase relative to the clock pulses arriving at the input of the multiplier 32. The number of pulses from the output of the second binary multiplier 35, proportional to the multi-digit digital code, is fed to the subtracting input of the binary multi row counter 34.

The operation of the device can be explained using the transfer functions.

The transfer function of the negative feedback of the amplifying-transforming tract can be written as

Where

- передаточная функция сглаживающего фильтра;

- transfer function of the smoothing filter;

ω ₀ is the carrier frequency;

T is the time constant.

We transform expression (1) and as a result we get:

Where

Dependence (2) allows you to determine the phase by the formula:

The device parameters are selected so that the condition is met:

Moreover, the equivalent time constant T ₀ is equal to

and is always automatically tuned to the carrier frequency.

With the obtained values of T ₀ and ξ _{0, the} phase, along the negative feedback circuit, of the amplifying-converting device is equal to:

From the analysis of (2) and (4) it follows that the negative feedback of the amplifying-transforming path stabilizes the phase at the carrier frequency and creates an advance in phase along the envelope. Creating a self-adjusting negative feedback amplifier-transform path ahead of the phase in the envelope signal leads to an expansion of the bandwidth of the entire device.

The introduction into the direct branch of three amplifiers through bandpass filters covered by intersecting positive feedbacks leads to an increase in the open-loop transmission coefficient.

Indeed, the transfer function of the first amplification path, a band-pass filter and the second amplification path, covered by positive feedback from the output of the second to the output of the first amplifier stages, has the form:

If the condition 3-QC _os = 0 is fulfilled, then the LAFCF rise of the amplifying-converting tract will be provided 30 times. By the same number of times, the AFCL of another pair of amplifying stages with a bandpass filter, covered by positive feedback, is provided. The resulting transmission coefficient, with the coverage of two pairs of amplification stages with intersecting positive feedbacks, will be increased by 900 times.

The maximum transfer coefficient of the prototype can be determined from the transfer function:

The transmission coefficient at the carrier frequency with the equality of the parameters of the band-pass filter is determined as follows:

(for two amplifiers in a straight branch).

Thus, the introduction of an amplifying-transforming path into the device, which contains amplification cascades in the direct branch, band-pass filters covered by intersecting positive feedbacks, and negative self-tuning feedback containing demodulators, smoothing filters and modulators, allows phase stabilization at the carrier frequency phase advance at the envelope frequency and increase the transfer coefficient, which determines the sensitivity, accuracy and bandwidth of the device.

Claims (1)

A device for measuring accelerations, comprising a sensor element, an angle sensor, an amplifier and a torque sensor included in feedback, characterized in that a first amplifier stage, a first strip cascade, is connected in series with information inputs from the output of the angle sensor to one of the inputs of the moment sensor filter, second amplifier stage, second bandpass filter, third amplifier stage, first emitter follower, universal synchronous JK-trigger, waiting synchronous generators, asynchronous relay R S-trigger, precision relay element, the second output of the second amplifier stage being connected to the second input of the first amplifier stage and the second output of the third amplifier stage connected to the second input of the second amplifier stage, one of the outputs of the third amplifier stage is also connected to the K-input of the universal synchronous JK-trigger through the inverter and the second emitter follower, and the other output with the third input of the first amplifier stage through series-connected demodulator, the first smooth a first-order filter and a modulator, the second inputs of the demodulator and modulator connected to one of the outputs of the reference voltage generator, and the third inputs of the demodulator and modulator connected to the output of the reference voltage generator through the first phase-shifting circuit, in addition, the output of the reference voltage generator is connected to the third input universal synchronous JK-trigger through a second phase-shifting circuit, a comparator and a pulse shaper, connected in series, and the second input of the torque sensor is connected with the output of a precision relay element through a second smoothing filter, as well as the S-output of an asynchronous RS relay trigger through matching circuits, a low-bit reversible counter, a final register, a digital information to direct code converter, a first binary multiplier, a multi-bit reversible counter connected to the input of the second binary a multiplier, one of the outputs of which is connected to the second input of a multi-bit reversible counter, in addition, a crystal oscillator is introduced into the device, the output of which is through the device on the distribution of clock pulses is connected to the inputs of the waiting synchronous generators, coincidence circuits, low-bit reversible counter, the first and second binary multiplier, also the output of the angle sensor is connected to one of the inputs of the first amplifier stage, and the input is connected to the output of the reference voltage generator and the output from the second binary multiplier is the digital output of the device.

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