RU2308039C1 - Device for measuring accelerations - Google Patents

Abstract

FIELD: measuring technique.

SUBSTANCE: device comprises sensing member, pickup of angle and pickup of moment with electronic switch that are connected to the negative feedback, two negative feedbacks provided with preliminary and selective amplifiers, comparators, converters of signal level, logical units, synchronous generators, main and auxiliary reverse binary counters, adder, binary multiplier, and control circuit.

EFFECT: enhanced reliability.

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Description

The invention relates to measuring equipment and can be used as an element in stabilization and navigation systems. It can 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 sensing element including two fixed electrodes and a movable plate, three amplifiers, two resistors, while the output of the first amplifier 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 gain, with hard negative feedback, is limited by the condition of stability of the system.

The closest in technical solution is the device (described in IPC ⁶ A.S. No. 742801, published in the bulletin of inventions No. 23, 1980), containing a sensor element, an angle sensor, an integrated feedback amplifier, a torque sensor, an additional integrating amplifier, an electronic key, a threshold element, a feedback amplifier to the torque sensor, and the second output of the angle sensor through a threshold element and 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 the threshold element. In addition, the accuracy depends on the parameters of the electronic key 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 error inherent in a similar scheme of sampling and processing information.

The present invention is to expand the bandwidth of the device and improve the accuracy of the measurement.

This is achieved due to the fact that two negative feedbacks are introduced into the device containing the sensor element, the angle sensor and the moment sensor with an electronic key included in the negative feedback: one from the output of the angle sensor to the input of the torque sensor through series-connected information inputs preliminary and selective amplifiers, the first comparator, the first signal level converter, a pair of matching circuits (I), the first pair of waiting synchronous generators (JSG), a couple of circuits EXCLUSIVE OR (logical e addition modulo “2”), the main reversible binary counter, binary multiplier and electronic key, the second negative feedback is introduced from the output of the selective amplifier to the inputs of a pair of EXCLUSIVE OR circuits through an adder, an amplitude detector, and a high-pass filter connected in series with the information inputs, a second comparator, a second signal level converter, a second pair of waiting synchronous generators. In addition, the additional inputs of the pair of coincidence circuits And and the adder are connected to the output of the reference voltage generator (GON), and the additional inputs of the first and second pairs of ZhSG control circuits are connected to the output of the auxiliary frequency generator through the auxiliary frequency generation circuit. The auxiliary input of the binary multiplier is connected to the output of the auxiliary reversible binary counter, in the reverse circuit of which a control circuit is introduced. In addition, the second input of the electronic key is connected to the output of the current generator. The output of the main reversible binary counter is a digital output of the device for measuring accelerations.

The introduction of two negative feedbacks into the device, containing preliminary and selective amplifiers, comparators, signal level converters, logic elements, waiting for synchronous generators, primary and secondary reversible binary counters, an adder, a binary multiplier, and a control circuit, made it possible to create a device with an extended bandwidth, t .to. there are no restrictions on the digits of the digital code, and with astatism on deviation due to the introduction of a binary multiplier into negative feedback.

Figure 1 shows the functional diagram of the device, figure 2 is a structural diagram of the device, figure 3 is a transient in an analog model of a device for measuring acceleration.

The proposed device contains a sensing element 1, the deviation of which captures the angle sensor 2, the output of the angle sensor 2 is connected to the input of the pre-amplifier 3, the output of which is connected to the input of the selective amplifier 4. One of the outputs of the selective amplifier 4 is connected to the input of the first comparator 5, the output of which is connected with the input of the first signal level converter 6. The first and second outputs of the first signal level converter 6 are connected to the inputs of a pair of matching logic circuits 7 and 8. The additional inputs of the circuits match Adenia And 7 and 8 are connected to one of the outputs of the reference voltage generator (GON) 9. The outputs of circuits And 7 and 8 are connected to the inputs of the first pair of waiting synchronous generators (ZhSG) 10 and 11. The outputs of the ZhSG 10 and 11 are connected to the inputs of a pair of circuits EXCLUSIVE OR 12 and 13. One of the outputs of the GON 9 is connected to the first input of the adder 14, the second input of the adder 14 is connected to the output of the selective amplifier 4. The output of the adder 14 through the amplitude detector 15, the high-pass filter 16, the second comparator 17, connected to the information inputs second level converter I signal 18 is connected to the inputs of the second pair of ZhSG 19 and 20, the outputs of which are connected to the second inputs of the circuit EXCLUSIVE OR 12 and 13. The outputs of the circuit EXCLUSIVE OR 12 and 13 are connected respectively to the summing and subtracting inputs of the main reversible binary counter 21. The output of the binary counter 21 connected to one of the inputs of the binary multiplier 22. The other input of the binary multiplier 22 is connected to the output of the auxiliary reversible binary counter 23. The output of the auxiliary reversible binary counter 23 through the control circuit 24 is connected to the input of the auxiliary reversible binary counter 23. The output of the binary multiplier 22 is connected via an electronic key 25 to the input of the torque sensor 26. One of the inputs of the electronic key 25 is connected to the output of the current generator 27. Additional inputs of the first and second pairs of ZhSG 10, 11, 19, 20, control circuits 24 are connected to the output of the auxiliary frequency generator 28 through the auxiliary frequency generation circuit 29. The output of the main binary counter 21 is the digital output of the device for measuring accelerations.

The internal contents of preliminary and selective amplifiers, a comparator, waiting synchronous generators, a reversible binary counter, an additional code converter into a direct one, a binary multiplier, an adder, an amplitude detector, a high-pass filter, a signal level converter, control circuits, and auxiliary frequency generation are described in the book: П 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 sensitive element 1, made in the form of a pendulum, the inertial moment equal to mlW acts (l, m is the reduced length and mass of the pendulum). Under the influence of this moment, the sensor 1 deviates, which is detected by the angle sensor 2, the field windings of which are connected to the output of GON 9. The signal from the angle sensor 2 after amplification by the pre-amplifier 3 is fed to the input of the selective amplifier 4, which selects the signal at the carrier frequency f ₁ (GON), which is then fed to the input of the first comparator 5. The signal from the first comparator 5 in the form of voltage ± U ₄ from the amplifier 4 is fed to the input of the first signal level converter 6, in which a signal is generated al in the form of voltage from 0 to ± 2.5 (V), i.e. the necessary voltage level for the operation of coincidence circuits And 7 and 8. Match circuits 7 and 8 perform the operation of logical multiplication of signals from the output of the GON 9 and from the output of the first signal level converter 6, and the matching circuits of And 7 and 8 are activated at the carrier frequency GON-9 and depending on the phase of deviation 1. The first pair of ZhSG 10 and 11 is “cocked” by a logic level signal from circuits I 7 and 8 and the signals from outputs 10 and 11 are limited, reset by signal f ₂ from the auxiliary frequency generation circuit 29 (at the output from 10 or 11 signal right angle n form). The output signals from the reference voltage generator 9 and from the output of the selective amplifier 4 are fed to the input of the adder 14 and are summed. The signal, shifted in level depending on the phase of deviation of the sensing element 1, from the output of the adder 14 is fed to the input of the amplitude detector 15, in which the signal at the carrier frequency is converted into a DC signal. The high-pass filter 16, included at the output of the amplitude detector 15, provides a given transient in the device. The signal from the output of the high-pass filter 16 is fed to the input of the second comparator 17, which is triggered by the sign of the amplitude detector 15, at the output of the second comparator 17, we have a signal in the form of a level that is fed to the input of the second signal level converter 18 and in which the output signal is converted from 18 to the level signal necessary for operation of the second pair of ZhSG 19 and 20. The outputs of the first pair of ZhSG 10 and 11 are connected to the inputs of the circuits EXCLUSIVE OR 12 and 13. Other inputs of the circuits 12 and 13 are connected to the outputs of the second pair of ZhSG 19 and 20. As a result logical If the signal is added by circuits 12 and 13, depending on the phase of deviation 1, we will have a logical “0” or a logical “1”. The output pulses from 12 or 13 will be fed either to the summing input of the main reversible binary counter 21, or to the subtracting input 21. Information equal to the difference between the "positive" and "negative" pulses from 21 is written to the binary multiplier 22 by pulse from the auxiliary reverse binary counter 23, in the reverse circuit of which a control circuit 25 (count pulses) is introduced. The pulse generation of the count by the control circuit 25 is carried out by the auxiliary frequency generating circuit 29 in accordance with the frequency of the auxiliary frequency generator 28 connected to the input of the circuit 29. The pulses from the binary multiplier 22 are supplied to one of the inputs of the electronic key 25 in accordance with the deviation sign of the sensitive element 1. Another the input of the electronic key 25 is connected to the current generator 27. The signal in the form of pulse width modulation (PWM) from the output of the electronic key 25 is fed to the input of the torque sensor 26, which ivaet moment, modulo and sign of compensating for the angular deviation 1. The output of the acceleration measuring device is a digital code output from the main reversible binary counter 21.

The introduction of two negative feedbacks into the device, containing amplifiers, comparators, signal level converters, an adder, multiplication and addition logic circuits, a binary multiplier, primary and auxiliary reversible binary counters, and a control circuit, allows you to create a device for measuring accelerations with first-order astatism and extended bandwidth. Moreover, one connection provides stability and a given quality of the transition process, and the other negative feedback provides the issuance of information in a digital code.

The analog model of the device for measuring accelerations (Fig. 2) was modeled on a computer with the parameters: T = 0.2 s, T ₁ = 0.2 s, T ₂ = 0.02 s, K ₁ = 0.9, K ₂ = 1, K ₃ = 100 at the width of the ambiguity zone of the threshold elements included in the feedback equal to 0.5, and the simulation results are presented in figure 3. From the analysis of the transient process it follows that the device is stable (stability provides a high-pass filter) and at the output of the model we have a signal in the form of pulse-width modulation with a frequency depending on the parameters of threshold elements (comparators).

Claims (1)

A device for measuring accelerations containing a sensor, an angle sensor and a torque sensor with an electronic key included in the negative feedback, characterized in that two negative feedbacks are inserted into it, one from the output of the angle sensor to the input of the torque sensor through series-connected information pre and selective amplifiers, the first comparator, the first signal level converter, a pair of matching circuits (I), the first pair of waiting synchronous generators (JSG), a couple of circuits MORE OR (logical addition modulo "2"), the main reversing binary counter, binary multiplier and electronic key, the second negative feedback is input from the output of the selective amplifier to the inputs of a pair of circuits EXCLUSIVE OR through an adder, an amplitude detector, a filter connected in series with the information inputs high frequencies, the second comparator, the second signal level converter, the second pair of FSWs, in addition, the additional inputs of the pair of matching circuits And and the adder are connected to the output of the reference voltage generator (GON), and additional inputs of the first and second pairs of FSWs, control circuits are connected to the output of the auxiliary frequency generator through the auxiliary frequency generation circuit, an additional input of the binary multiplier is connected to the output of the auxiliary reversible binary counter, into the reverse circuit of which the control circuit is inserted, the second input the electronic key is connected to the output of the current generator and the output of the main reversible binary counter is a digital output of the device for measuring accelerations.

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