RU2039989C1 - Shaft speed of rotation electro-mechanical sensor - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: three NOT gates, four-input AND gate and six flip-flops are introduced into the device. As a result false pulses are excluded at boundaries of areas of operation of induction detectors. EFFECT: higher truth of measurements. 3 dwg

Description

 The invention relates to measuring technique, is intended to convert the angular velocity of the shaft into pulse repetition rates, determine the direction of rotation of the shaft and can be used to measure linear speed and determine the direction of movement (back and forth) of moving ground wheeled or tracked objects.

 Known electromechanical speed sensor used in serial navigation equipment [1] containing a modulation disk, induction sensors located with the overlapping of the zones of operation, a generator whose output is connected to the primary windings of the induction sensors, the secondary windings of which are connected respectively to the inputs of the detectors, the outputs of which are connected respectively with inputs of rectangular pulse shapers.

 The principle of operation of the known device is based on the fact that it generates two identical sequences of rectangular pulses, shifted relative to each other in phase in one direction or another, depending on the direction of rotation of the disk. In this case, the shift does not exceed the pulse duration and is usually equal to its half. The pulse repetition rate is proportional to the speed of rotation of the disk.

 A disadvantage of the known device is the low reliability associated with the presence of interference at the fronts of the output pulses caused by both parasitic mechanical vibrations of the disk due to vibration of the sensor installation object and electrical noise at the fronts of the envelopes at the inputs of the rectangular pulse shapers. Interference is especially likely at low speeds when the envelope fronts are extended over time.

 The aim of the invention is to increase the reliability of the electromechanical speed sensor by eliminating false pulses at the boundaries of the zones of operation of induction sensors.

 The goal is achieved by the fact that three elements NOT, six triggers, element 4I are additionally introduced into the electromechanical speed sensor, and the output of one square-wave driver is connected to the first element NOT, with inverse R inputs and direct D inputs of the first and second triggers and direct D - the input of the third trigger, the direct dynamic C-input of which is connected to the output of the second element NOT, the input of which is connected to the output of the element 4I and the direct dynamic C-input of the fourth trigger, the direct D-output of which is connected to the output ohm of another generator of rectangular pulses, direct dynamic C-inputs of the first and fifth triggers and the input of the third element NOT, the output of which is connected to direct dynamic C-inputs of the second and sixth triggers, the output of the first element is NOT connected to inverse R inputs and direct D inputs fifth and sixth triggers, and the inverse outputs of the first, second, fifth, sixth triggers are connected to the inputs of element 4I.

 Figure 1 presents a functional diagram of an electromechanical speed sensor.

 The sensor contains a modulation disk 1, induction sensors 2, 3, located with the overlapping of the zones of operation, a generator 4, the output of which is connected to the primary windings of the induction sensors 2, 3, the secondary windings of which are connected respectively to the inputs of the detectors 5, 6, the outputs of which are connected respectively the inputs of the shapers of 7.8 rectangular pulses, the output of the shaper of 7 rectangular pulses is connected to the input of the element NOT 9, with inverse R-inputs and direct D-inputs of the triggers 10, 11 and a direct D-input of the trigger 12, the output of which is the first output of the electromechanical speed sensor, and the direct dynamic C-input is connected to the output of the element HE 13, the input of which is connected to the output of the element 4I 14 and to the direct dynamic C-input of the trigger 15, the output of which is the second output of the electromechanical speed sensor, and the direct D - the input is connected to the output of the shaper 8 of the rectangular pulses, direct dynamic C-inputs of the triggers 10, 16 and the input of the element HE 17, the output of which is connected to the direct dynamic C-inputs of the triggers 11, 18, the output of the element 9 is connected with inverse R inputs and direct D inputs of triggers 16, 18, and the inverse outputs of triggers 10, 11, 16, 18 are connected to the inputs of element 4I.

 Electromechanical speed sensor works as follows.

The high-frequency alternating current voltage is supplied from the generator 4 to the primary windings of the induction sensors 2, 3 and is transformed into their secondary windings. The magnetic flux enveloping the core of the induction sensor depends on the angular position of the modulation disk 1 having a periodic structure (for example, in the form of teeth evenly spaced around the periphery of the disk). When the modulation disk rotates, the magnetic flux of the induction sensor changes, causing a change in the amplitude of the voltage on the secondary winding of the sensor. The envelope amplitude is extracted in the detectors 5, 6, and is supplied to the inputs of the shapers 7, 8 of rectangular pulses, which can be used as threshold devices such as Schmitt trigger or comparators. The pulse frequency at the output of the shapers 7, 8 depends on the rotation speed of the modulation disk 1, and the phase shift on the direction of its rotation. The number of pulses is proportional to the path traveled by the sensor installation object. Optimal for the proposed technical solution is the option when the pulse sequences taken from the outputs of the shapers 7, 8 of rectangular pulses have a meander shape and are shifted relative to each other by an amount equal to half the pulse duration, i.e. at 90 ^about . This is achieved by choosing the dimensions of the active and passive zones of the modulation disk 1 (for example, the width of the teeth and the distance between the teeth) and the relative angular position of the induction sensors.

 Figure 2 and 3 presents a diagram of the work of newly introduced elements in various directions of the disk 1.

In the first case (figure 2), phase a _{1 is} ahead of phase a ₂ , in the second (figure 3) vice versa.

,

представляют собой инверсию диаграмм а₁, а₂.At the fronts of phases a ₁ , a ₂ , interference is shown. Charts

,

represent the inverse of the diagrams a ₁ and ₂ .

Triggers 10, 11, 16, 18 generate signals that control triggers 12, 15 (see diagrams b ₁ , b ₂ , b ₃ , b ₄ ). Two of the four triggers generate control signals unconditionally (see b ₁ , b _{4 of} FIG. 2; b ₂ , b _{3 of} FIG. 3), and two triggers in the presence of interference (see b ₂ , b _{3 of} FIG. 2; b ₁ , b _{4 of} Fig. 3). The results of the addition of control signals are presented on the diagram e. Noises on it are already absent. To control the trigger 12, the signal of the diagram e is used, to control the trigger 15, this signal is inverted (diagram ) Triggers 12, 15 are switched only on the leading edges of the signals arriving at their C-inputs. Since these fronts occur in the middle of a pulse or a pause of the initial phases a ₁ , a ₂ , i.e. to the part of the triggering zone of the induction sensors (in angular or temporal terms), the information of which is the most reliable, the information at the outputs of the triggers 12, 15 will be the most reliable. The output signals A ₁ , A ₂ have the same phase relationships as a ₁ and a ₂ .

 At zero speed (when the object is parked), the presence of disk vibrations within the zone of reliable operation (without interference) of the induction sensor (for example, 2) will not cause interference, like in the prototype, in this phase. In contrast to the prototype, false pulses in another phase, caused by crossing the response boundary of its induction sensor 3, will be absent, since in this case the potential is stored at the C-input of the corresponding trigger 15 and the previous information is stored at the output of the trigger 15, respectively.

Claims (1)

 ELECTROMECHANICAL SHAFT ROTATION SPEED SENSOR containing a modulation disk, two induction sensors, located with overlapping response zones by disk elements, a generator connected to the primary windings of the induction sensors, the secondary windings of which are connected through the detectors to square-wave formers, characterized in that, in order to increase reliability by eliminating false pulses at the boundaries of the zones of operation of induction sensors, three elements are entered into it, a four-input element And and triggers, and the output of the first pulse former is connected to the inverse R inputs of the first and second triggers, with the D inputs of the first, second, and third triggers and through the first element NOT with inverse R inputs and the D inputs of the fourth and fifth triggers, the output of the second the pulse shaper is connected to the direct C-inputs of the first and fourth triggers, the D-input of the sixth trigger and through the second element NOT to the direct C-inputs of the second and fifth triggers, the inverse outputs of the first, second, fourth and fifth triggers are connected to the inputs of element And, the output of which is connected to the direct C-input of the sixth trigger and through the third element NOT to the direct C-input of the third trigger, while the outputs of the third and sixth triggers are the sensor outputs.

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