SU754322A1 - Null velocity sensor - Google Patents

Description

The invention relates to automation and computing and can be used in automatic control systems where accurate measurement of linear or angular speeds is required.

Known devices containing tachogenerators, counters and delay unit [1].

A disadvantage of the known devices is the increased sensitivity to destabilizing factors: interference in the sensor circuit, significant fluctuations of the pulse frequency interval in the zero speed zone 15 due to climatic and mechanical influences on the device, the speed of which is measured. Under the influence of these factors there are deformations signal 20 zero speed, which causes failures in the control system.

Of the known devices, the closest technical solution to the invention is a device containing a pulse generator, a valve block, a pulse counter, a frequency sensor, a delay unit, a driver and a synchronization unit [2]. thirty

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A disadvantage of the known device lies in the fact that the more accurately the moment of reaching zero speed is determined, the more likely it is to miss due to interference and disturbances affecting the frequency sensor circuit.

The purpose of the invention is to increase reliability.

This goal is achieved in that a device containing a series-connected pulse generator, a valve block and a pulse counter, are connected in series to a frequency sensor and an output unit, the output of which is connected to a pulse counter set to the initial state, as well as sequentially connected a synchronization unit, the second input of which is connected to the output of the frequency flow sensor, the first output of the synchronization unit is connected to the second input of the valve block, and the first output is tchika pulses connected to the input of the signal generator, the trigger administered sequentially connected element ►chogovhodovoy

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matches, an inverter and a matching element, the second input of which is connected to the output of the frequency tachometer, and the third input of the matching element is connected to the trigger output, the first input of which is connected to the output of the multi-input matching element, and the second trigger input is connected to the second output of the synchronization unit, all The η inputs of the multilink coincidence element are connected to all the outputs of the pulses counter bits, except for the first one.

The drawing shows a diagram of the device.

The device contains a pulse counter 1, a valveing unit 2, a pulse generator 3, a signal shaper 4, a multi-input coincidence element 5, an inverter 6, a trigger 7, a synchronization unit 8, a frequency sensor 9, a coincidence element 10 and a delay unit 11.

The device works as follows.

From the generator 3 to the input of the valve block the pulses of the filling of the counter 1 arrive. The allowing level of the signal to the second input of the valve circuit is given by the synchronization circuit. The moment of his arrival is determined by the control system and corresponds to the beginning of the search for zero speed, for example, the transition to braking the device, the speed of which is measured. Up to this point, or at the moment the permissive level is supplied to the valve block 2, the second output of the synchronization block 8 receives a reset signal to the trigger 7 and sets a low level at its output. The reset of the counter 1 occurs from each pulse of the frequency tachometer 9 after forming a signal at the output of the delay block 11. The number of filling pulses received in the interval between the reset pulses is counted by counter 1,

In this case, the longer the interval between the indicated pulses, the higher the discharge of the counter, which will be established in one state. If the time interval is such that the high-order bit K is set to one, then with such a code in the counter driver 4 generates a Zero speed signal and the desired goal will be achieved.

At the same time, prior to installation in the unit state of the discharge K, there is a moment when all the lower bits from K-1 to 1 will be in the same state. Thus, always until the zero speed is generated, a signal will be generated at the output of the multi-input coincidence element 5 set to single state

trigger 7. The greater the number of low-order bits connected to the inputs of the multi-input coincidence element 5, the smaller the difference between the speed at which the trigger 7 is set to one state and the zero speed. The magnitude of the difference is chosen in each particular case based on the nature of the speed change so that after the trigger 7 is set to one, the speed always passes through the zero value. From the moment when the trigger 7 is installed and until the zero speed signal is inserted, the intervals between the pulses of the frequency tachometer will always be sufficient to form a code in the counter that ensures the co-ordination of high levels of the input of the multi-input element 5 at the moment of arrival of the next impulse 6 at the input element 10 matches. For this reason, the pulse received from the frequency tachometer will not generate a reverse signal at the output of element 10.

• If the zero speed signal is generated and entered at the synchronization unit 8, the signal at its output will reset trigger 7 (at the reset input), which will prohibit the formation of a false reverse signal at the time of arrival of the next pulse from the frequency sensor 9, regardless of the level of signals at the other two inputs element 10 matches.

If the K-1, ...,] bits are not connected without a pass from K-1 to] to the inputs of the coincidence element 5 (suppose the K-1 and K-3 bits of the counter are connected), then at the time of the matching of the coincidence element 10 Frequency Tachometer 9 impulse may be installed K-1 and K-2 discharges, which corresponds to a time interval greater than that at which K-1 and K-3 discharges are established, but the output of inverter 6 will be high due to low level the signal received from the output of the K-3 discharge, and at the output of the coincidence element 10 a false signal will be generated reverse. For the same reason, the pass between the high bit K connected to the driver 4 and the high bit (K-1) connected to the AND 5 scheme by the multi-input coincidence element 5 is not allowed. This feature determines the inseparable functional relationship between signal generation ’of the reverse and zero speed and eliminates the possibility of separating the scheme of signal generation of the reverse as an independent device, separate from the sensor of the nuping speed.

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If, after installation at the output of the trigger 7 of the unit level, the zero speed signal was not formed, and the speed value after passing the zero value increases (reverse occurs), then the setting 5

the counter to its original state will be

to grow more and more often, and when the next pulse arrives at the input of element 10, the coincidence at the input connected to inverter 6 will be high and, due to the coincidence of high levels at all inputs of element 10, a reverse signal will be generated at its output. To state the counter during the survey element 10 ¹³

the coincidence of the frequency tachometer mipulses was unchanged, these pulses through the synchronization unit 8 prohibit the passage of signals from the generator 3 to the input of the counter 1. 2®

The technical advantage of the proposed zero speed sensor is to increase the reliability of the sensor. Zero-speed signal generation in systems with 25

active braking (due to the counter-moment applied to the device, the speed of which is measured) is adjusted according to the intensity of braking set in the particular device, 30 which determines the time intervals between the frequency pulses of the tachometer. Moreover, the higher the required accuracy of the zero-speed signal generation relative to the moment of the real zero speed, the more accurate the sensor setting should be (the value of the discharge connected to the zero-speed driver is selected correctly). At the same time, the system becomes very sensitive to the influence of destabilizing factors that constantly occur in the system (interference, change in supply voltages, climatic conditions, mechanical influences). Under the influence of these factors in such a sensitive system there are cases of non-generation of the signal of zero speed, which in most cases

leads to serious consequences in the system. Accounting for the reverse signal allows you to increase the reliability of the system in which the zero speed sensor is used, since the reverse signal almost duplicates the zero speed signal and is formed immediately after the zero speed search zone.

Claims (1)

Claim A zero-speed sensor containing a series-connected pulse generator, a valve block and a pulse counter, a frequency switch connected in series, and a delay unit, the output of which is connected to a pulse counter for resetting it, as well as a serially connected signal conditioner and synchronization unit, the second input of which connected to the output of the frequency tachometer, the first output of the synchronization unit is connected to the second input of the valve block, and the first output of the pulse counter connected to the input of the signal conditioner, characterized in that, in order to increase reliability, a trigger is inserted in it, a multi-input coincidence element connected in series, an inverter and a coincidence element whose second input is connected; to the output of the frequency tachometer, and the third input of the coincidence element is connected to the output trigger, the first input of which is connected to the output of the multiple coincidence element, and the second input of the trigger is connected to the second output of the synchronization unit, with all ή inputs of the multi-input element coinciding I connected to all the outputs of the pulse counter bits, except the first.