CN113452351A - Filtering method of magnetic speed sensor suitable for single-tooth flywheel - Google Patents
Filtering method of magnetic speed sensor suitable for single-tooth flywheel Download PDFInfo
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
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- H03H21/0012—Digital adaptive filters
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- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
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Abstract
The invention relates to the technical field of filtering, and discloses a filtering method of a magnetic speed sensor suitable for a single-tooth flywheelth，For voltage amplitude smaller than threshold voltage VthThe digital signal is filtered, so that the waveform of the filtered signal can be matched with the position of an actual single tooth close to the magnetic rotating speed sensor, namely the rising edge of the waveform of the signal corresponds to the position of the single tooth boundary close to the magnetic rotating speed sensor, and the falling edge of the waveform of the signal corresponds to the position of the single tooth boundary away from the magnetic rotating speed sensor, so that the accurate positioning of the position and the accurate calculation of the rotating speed of the single-tooth flywheel are realized.
Description
Technical Field
The invention relates to the technical field of filtering, in particular to a filtering method of a magnetic speed sensor suitable for a single-tooth flywheel.
Background
The rotation speed sensor is a device capable of converting angular displacement into an electrical signal, and can be divided into a laser type rotation speed sensor, a capacitance type rotation speed sensor and a magnetoelectric type rotation speed sensor according to a working principle. The magnetoelectric rotation speed sensor converts an input motion speed into an induced potential in a coil to be output by utilizing an electromagnetic induction principle. The sensor directly converts the mechanical energy of a measured object into an electric signal to be output, does not need an external power supply during working, and is a typical passive sensor. The sensor has the advantages of high output power, non-contact measurement, good anti-interference performance, simple matched circuit, stable performance and the like, and is widely applied to various industrial controls.
In industrial control, in order to obtain various magnetic conductive materials such as: such as the rotation speed of the gear, the impeller, the disc with holes (or slots, screws) and the position of the mechanical object, it is common to mark the position of the object to be measured, for example, by adding one tooth on the rotating flywheel, as shown in fig. 8. When the flywheel rotates to drive the teeth to pass through the magnetoelectric revolution speed sensor, the magnetoelectric revolution speed sensor can generate a pulse, and the width of the generated pulse is much larger than that of the actual teeth due to the magnetic field, so that the positioning error is caused. In some industrial controls, it is important to be able to accurately locate the speed and position of a moving object. For example, in the control of an engine, the position of the piston is correlated to injection and ignition timing. If the position is inaccurate, the engine can be flamed out and even the cylinder can be exploded.
Disclosure of Invention
In view of the defects of the background art, the invention provides a filtering method of a magnetic speed sensor suitable for a single-tooth flywheel, which ensures that the width proportion of the high-level width of a filtered signal in a signal period is matched with the proportion of the circumference of a single tooth in the circumference of the flywheel, and reduces the positioning error.
In order to solve the technical problems, the invention provides the following technical scheme: a filtering method of a magnetic speed sensor suitable for a single-tooth flywheel comprises the following steps:
s1: converting an analog signal output by a magnetic rotating speed sensor into a digital signal, wherein the digital signal is a pulse signal, inputting the digital signal into a digital processing module, and the digital processing module inputs the digital signal when the voltage amplitude of the digital signal is greater than a threshold voltage VthA first level signal is output, and when the voltage amplitude of the digital signal is lower than the threshold voltage VthOutputting a second level signal;
s2: after receiving the digital signal, the digital processing module firstly obtains the maximum voltage value E of the digital signal in the current period, and then compares the maximum voltage value E with a proportionality coefficient
Multiplying and finally multiplying the threshold voltage VthIs updated to
E, the proportionality coefficient
The ratio of the voltage value of the output signal of the magnetic rotation speed sensor at the boundary of the single tooth to the maximum voltage value of the output signal when the single tooth passes through the magnetic rotation speed sensor is obtained.
In one embodiment, the first level signal is a high level signal and the second level signal is a low level signal.
In one embodiment, step S2 includes step S20, which is as follows:
s20: the digital processing module acquires a maximum voltage value E1 of the digital signal in a first period of the digital signal and then compares the maximum voltage value E1 with a scaling coefficient
Multiplying and multiplying by a threshold voltage VthIs updated to
E1。
In one embodiment, step S2 further includes step S21, which is as follows:
s21: the digital processing module looks for the upward zero crossing point of the voltage of the digital signal and the maximum voltage value E2 in the second period of the digital signal, calculates the distance d2 between the upward zero crossing point of the voltage and the maximum voltage value, and then combines the maximum voltage value E2 with the proportionality coefficient
Multiplying and multiplying by a threshold voltage VthIs updated to
E2, the voltage zero-crossing point is the starting point of the digital signal with the voltage amplitude larger than 0V.
In certain embodiments, step S2 further includes the steps of:
s22: in the nth period of the received digital signal, n is an integer and is greater than 2, searching for an upward zero crossing point of the voltage in the nth period, and calculating the period length Tn-1 of the nth-1 period;
s23: the digital processing module is based on a formula
Solve out
Wherein
Designing the ratio of the perimeter of the single tooth to the perimeter of the flywheel;
s24: the digital processing module is based on a formula
Updating the scaling factor
According to the formula
Updating
，
Is a ratio of a maximum voltage value in an n-1 th period of the digital signal to a maximum voltage value in an n-2 th period of the digital signal;
s25: the digital processing module is based on a formula
Updating the threshold voltage Vth；
S26: the digital processing module searches the maximum voltage value En of the digital signal in the nth period, calculates the distance dn between the upward zero crossing point of the voltage in the nth period and the maximum voltage value En, and then updates the threshold voltage
。
In one embodiment, the digital processing module finds the voltage zero-crossing point of the current cycle as follows: the digital processing module samples an input digital signal, and takes a first sampling point of the digital signal with the voltage greater than 0V as a voltage upward zero crossing point of a current period.
In certain embodiments, the
Is 1.
In one embodiment, in step S2, the process of the digital processing module finding the maximum voltage value E of the current cycle is as follows: the digital processing module samples the input digital signal, compares the voltage of the currently sampled digital signal with the voltage of the digital signal sampled last time, and if the voltage of the currently sampled digital signal is smaller than the voltage of the digital signal sampled last time, the voltage of the digital signal sampled last time is used as the maximum voltage value of the most current period, and then the searching for the maximum voltage value of the current period is finished.
In one embodiment, the analog signal output by the magnetic rotation speed sensor in step S1 is input to a differential amplifier, and the output signal of the differential amplifier is input to a digital-to-analog converter, and the digital-to-analog converter outputs the digital signal.
Compared with the prior art, the invention has the beneficial effects that:
1: in the filtering method of the invention, the threshold voltage V in the digital processing module is adjusted according to the ratio of the perimeter of the single tooth to the perimeter of the flywheel and the maximum voltage value of the digital signal in the current periodthFor voltage amplitude smaller than threshold voltage VthThe digital signal is filtered, so that the waveform of the filtered signal can be matched with the position of an actual single tooth close to the magnetic rotating speed sensor, namely the rising edge of the waveform of the signal corresponds to the position of the single tooth boundary close to the magnetic rotating speed sensor, and the falling edge of the waveform of the signal corresponds to the position of the single tooth boundary away from the magnetic rotating speed sensor. Particularly, the falling edge of the waveform of the signal, namely the position of the single tooth away from the magnetic rotating speed sensor, is irrelevant to the rotating speed of the flywheel.
2: when a digital signal received by the digital processing module is in an nth period, the maximum voltage value En of the nth period is predicted according to the proportional relation between the maximum voltage value En-1 of the nth-1 period and the maximum voltage value En-2 of the nth-2 period, and the threshold voltage V of the digital processing module in the nth period is adjusted according to the predicted maximum voltage value En of the nth periodthSo as to ensure the threshold voltage V of the nth periodthCan be changed according to the change of the maximum voltage value En-1 of the (n-1) th period and the maximum voltage value En-2 of the (n-2) th period, and the threshold voltage V of the (n) th period is obtained immediately when the maximum voltage value En of the digital signal in the (n) th period is obtainedthIs updated to
To ensure that the filtered signal is at the nthThe position of the falling edge in the cycle matches the position where the single tooth is away from the magnetic tachometer sensor.
Drawings
FIG. 1 is a schematic diagram of a conventional filter circuit;
FIG. 2 is a schematic diagram of the adaptive hysteresis circuit of FIG. 1;
FIG. 3 is a schematic diagram of the input and output relationships of the logic block of FIG. 2;
FIG. 4 is a schematic diagram illustrating the filtering effect of the adaptive hysteresis circuit of FIG. 2 on the output signal of the magnetic tachometer sensor;
FIG. 5 is a schematic diagram of a filter circuit for implementing the present invention;
FIG. 6 is a waveform of an output signal of the magnetic rotation speed sensor when a single tooth passes the magnetic rotation speed sensor;
FIG. 7 is a graph illustrating the effect of filtering the output signal of a magnetic tachometer sensor using the present invention;
fig. 8 is a schematic structural view of a flywheel with a single tooth added.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.
As shown in fig. 1, the filtering unit in fig. 1 includes an adaptive hysteresis circuit and an adaptive time filtering circuit, and mainly filters an output signal of the magnetic speed sensor when a flywheel of 11, 23, 31, 63 or 128 teeth passes by the magnetic speed sensor.
Referring to fig. 2, the adaptive hysteresis circuit of the filter unit includes a fully differential amplifier, a peak detection circuit and an AD conversion circuit, a logic block, a hysteresis square circuit and a time filter circuit, wherein a detection signal outputted from the magnetic rotation speed sensor, i.e., VRS voltage, is first inputted to the fully differential amplifier, an output signal of the fully differential amplifier is then respectively inputted to the peak detection circuit, the hysteresis square circuit and the time filter circuit, an output signal of the peak detection circuit is then inputted to the AD conversion circuit, an output signal of the AD conversion circuit, i.e., a quantized peak voltage, is then inputted to the logic block, the logic block inputs a corresponding hysteresis output voltage to the hysteresis square circuit and the time filter circuit according to a magnitude of the quantized peak voltage, wherein an input-output relationship of the logic block refers to fig. 2, the hysteresis square circuit and the time filter circuit filter an output signal of the fully differential amplifier according to the inputted hysteresis output voltage, the schematic diagram of the filtering effect can be seen in fig. 4. As can be seen from fig. 4, although the adaptive hysteresis circuit performs filtering based on the maximum voltage value of the detection signal, the signal output from the adaptive hysteresis circuit is still deviated from the actual signal regardless of the ratio of the circumference of the single tooth to the circumference of the flywheel.
In addition, the filtering time of the current adaptive time filter circuit depends on the duration Tn of the previous cycle of the detection signal, and the current filtering time is about 1/32 × Tn, so that very short peaks can be filtered through the filtering time. However, since the single-tooth flywheel only generates one pulse when rotating for one circle, the magnetic speed sensor can be in a constant level state for a long time in one period, and if an adaptive time filter with the filtering time of 1/32T is used, most or all of the pulse can be filtered out, so that the single-tooth flywheel cannot be positioned or the speed of the flywheel can not be acquired.
In addition, the peak value of the voltage for dynamically adjusting the hysteresis dependence in the structure in fig. 1 and the relevant parameters of the 1/32T filter are both dependent on the past period, not the current period.
The output characteristics of a single tooth on the flywheel passing through the magnetic speed sensor are now analyzed:
when a single tooth on the flywheel passes through the magnetic speed sensor, the change of the magnetic flux in the magnetic speed sensor along with time is as follows:
(ii) a The magnetic flux when the single tooth boundary passes through the magnetic speed sensor is fixed as follows:
the magnetic flux does not change with the speed of the rotating speed, and is only designed to generate a fixed included angle in the system
The values are related.
When a single tooth passes through the magnetic speed sensor, the voltage generated by the magnetic speed sensor changes with time as follows:
when the single-tooth boundary passes through the magnetic rotation speed sensor, the voltage generated by the magnetic rotation speed sensor is as follows:
the point voltage is at the maximum voltage
The proportion of (A):
the ratio is therefore a fixed value, independent of the rotational speed, according to which the invention is designed.
In this embodiment, to simplify the filtering step, the formula of the change of the output voltage of the magnetic rotation speed sensor with time is obtained by coordinate translation
。
A filtering method of a magnetic speed sensor suitable for a single-tooth flywheel comprises the following steps:
s1: converting analog signals output by the magnetic speed sensor into digital signals, inputting the digital signals into a digital processing module, and enabling the digital processing module to output digital signals when the voltage amplitude of the digital signals is larger than a threshold voltage VthTime-out first level signal, and when the voltage amplitude of the digital signal is lower than the threshold voltage VthOutputting a second level signal;
s2: after receiving the digital signal, the digital processing module firstly obtainsTaking the maximum voltage value E of the digital signal in the current period, and then combining the maximum voltage value E with a proportionality coefficient
Multiplying and finally multiplying the threshold voltage VthIs updated to
E, coefficient of proportionality
The ratio of the voltage value of the output signal of the magnetic rotation speed sensor at the boundary of the single tooth to the maximum voltage value of the output signal when the single tooth passes through the magnetic rotation speed sensor is adopted.
As shown in fig. 5, in this embodiment, the analog signal output by the magnetic speed sensor in step S1 is input to the differential amplifier, the output signal of the differential amplifier is input to the digital-to-analog converter, and the digital-to-analog converter outputs a digital signal. In addition, the signal processing flow of the structure of the filter circuit in fig. 4 is unidirectional, during actual operation, each module of the filter circuit in fig. 4 only needs to process the input signal and then output the signal, there is no coupling between the modules, and there is a ring structure between each module of the adaptive hysteresis circuit in fig. 2, and each module in the adaptive hysteresis circuit in operation needs to process the input signal and also needs to consider the coupling between each module, which is not beneficial to design.
In addition, the signal Vdiff output by the sensor in fig. 8 may be a positive voltage or a negative voltage, and when the signal Vdiff is the positive voltage, the P-terminal voltage in fig. 4 is greater than the N-terminal voltage, and when the signal Vdiff is the negative voltage, the P-terminal voltage is less than the N-terminal voltage. In this embodiment, the P-terminal voltage is greater than the N-terminal voltage.
In this example, the proportionality coefficient
Is initially of
，
Can be determined according to the design parameters of the single tooth and the flywheel.
In this embodiment, the first level signal is a high level signal, and the second level signal is a low level signal. It should be noted that the position location and the rotation speed calculation of the flywheel are calculated according to the proportion of the high level of the output filtering signal in one period, and in one embodiment, the filtering signal can be processed by a voltage conversion circuit, the filtering signal of the high level is converted into a low level signal, and the filtering signal of the low level is converted into a high level signal, so that the position and the rotation speed of the flywheel can be calculated according to the proportion of the low level signal in the processed signal in one period.
Since the digital signal is a pulse signal, specifically, in this embodiment, the processing of the first pulse by the digital processing module refers to step S20, and step S20 is as follows:
s20: when the digital processing module receives the first pulse in the first period of the digital signal, the digital processing module obtains the maximum voltage value E1 of the digital signal, and then the maximum voltage value E1 and the proportionality coefficient are compared
Multiplying and multiplying by a threshold voltage VthIs updated to
E1。
In this embodiment, the threshold voltage VthMay be determined based on the output voltage of the magnetic speed sensor when the single tooth is bordered on the magnetic speed sensor.
In this embodiment, the digital processing module refers to step S21 for processing the second pulse, and step S21 is as follows:
s21: the digital processing module looks for the upward zero crossing point and the maximum voltage value E2 of the voltage of the digital signal in the second period of the digital signal and calculates the voltageUpward crossing the distance d2 between the zero point and the maximum voltage value, and then multiplying the maximum voltage value E2 by the scaling factor
Multiplying and multiplying by a threshold voltage VthIs updated to
E2, the voltage zero crossing point is the starting point of the digital signal with the voltage amplitude larger than 0V.
As can be seen from steps S20 and S21, the digital processing module will obtain the maximum voltage value of the current pulse when receiving the first pulse and the second pulse, and then adjust the threshold voltage V according to the maximum voltage valuethAnd further ensuring that the position of the single tooth on the flywheel away from the magnetic speed sensor just corresponds to the position of the falling edge of the filtered signal.
In this embodiment, the processing procedure of the nth pulse by the digital processing module is as follows:
s22: in the nth period of the received digital signal, n is an integer and is greater than 2, searching for an upward zero crossing point of the voltage in the nth period, and calculating the period length Tn-1 of the nth-1 period;
s23: the digital processing module is based on a formula
Solve out
Wherein
Designing the ratio of the perimeter of the single tooth to the perimeter of the flywheel;
s24: the digital processing module is based on a formula
Updating the scaling factor
According to the formula
Updating
，
Is a ratio of a maximum voltage value in an n-1 th period of the digital signal to a maximum voltage value in an n-2 th period of the digital signal;
s25: the digital processing module is based on a formula
Updating the threshold voltage Vth；
S26: the digital processing module searches the maximum voltage value En of the digital signal in the nth period, calculates the distance dn between the upward zero crossing point of the voltage in the nth period and the maximum voltage value En, and then updates the threshold voltage
。
The formula in step S23 is explained as follows: when each period of the digital signal is different from the others and is the same, because
For designing the ratio of the circumference of the single tooth to the circumference of the flywheel to be fixed and known, the proportion of the signal output by the magnetic speed sensor to the whole period when the single tooth passes through the magnetic speed sensor is theoretically combined
Similarly, the variable x is defined as the point corresponding to the boundary of the single tooth when the flywheel rotates and the magnetic speed is sensed, and the distance dn-1 between the maximum voltage point in the n-1 th period and the upward zero crossing point of the voltage is obtained, and the (dn-1-x) × 2 is used to obtain the magnetic speed sensing passing point of the single tooth on the flywheelTime of sensor, ratio of time to cycle time and sum
As such.
After x is obtained, the point corresponding to the single tooth passing through the magnetic speed sensor in the (n-1) th period is obtained, and then the proportionality coefficient is recalculated according to the formula in the step S24 according to x
. Thereby ensuring the proportionality coefficient in the current cycle
The adjustment can be carried out according to the digital signal in the last period, and the positioning error of the flywheel is further reduced.
In addition, when the digital processing module receives the digital signal in the nth period, if the maximum voltage value En-1 of the digital signal in the nth-1 period is different from the maximum voltage value En-2 of the digital signal in the nth-2 period, and there is a deviation, if this deviation is not adjusted in the nth period, the position of the high-low level position of the filtered signal in the nth period will also be mismatched with the position of the single tooth passing through the magnetic rotation speed sensor in one rotation of the flywheel, resulting in a positioning error. Therefore, step S24 is to redefine the scaling factor
Also introduces variables
，
Is the ratio of the maximum voltage value of the digital signal in the (n-1) th period to the maximum voltage value of the digital signal in the (n-2) th period, and is obtained by substituting the variation of the ratio of the maximum voltage value in the (n-1) th period to the maximum voltage value of the digital signal in the (n-2) th period into the variation of the maximum voltage value in the nth periodTherefore, the positioning error can be reduced.
In this embodiment, the process of the digital processing module finding the upward zero crossing point of the voltage in the current period is as follows: the digital processing module samples an input digital signal, and takes a first sampling point of the digital signal with the voltage greater than 0V as a voltage upward zero crossing point of a current period.
In this embodiment, in step S2, the process of the digital processing module finding the maximum voltage value E of the current cycle is as follows: the digital processing module samples the input digital signal, compares the voltage of the currently sampled digital signal with the voltage of the last sampled digital signal, if the voltage of the currently sampled digital signal is less than the voltage of the last sampled digital signal, the voltage of the last sampled digital signal is taken as the maximum voltage value of the most current period, and then the searching for the maximum voltage value of the current period is finished
In this example, variables
Is 1.
Further, as can be seen from step S26, in the nth period of the digital signal, when the maximum voltage value En in the nth period is not obtained, the threshold voltage V used in the digital processing module is obtainedthIs the threshold voltage V updated in step S25thImmediately updating the threshold voltage when the maximum voltage En of the digital signal in the nth period is obtained
And further ensuring that the position of the single tooth on the flywheel away from the magnetic speed sensor just corresponds to the position of the falling edge of the filtered signal.
Fig. 7 is a graph showing effects of the present invention after filtering the waveform of fig. 6, which is an output signal of the magnetic speed sensor, in which a sine wave in fig. 7 is a waveform of the output signal of the magnetic speed sensor when a single tooth on a flywheel passes through the magnetic speed sensor, and a high-level square wave in fig. 7 is a waveform of the signal output from the magnetic induction sensor after filtering according to the present invention.
In conclusion, the invention has the following beneficial effects when used in time:
1: in the filtering method of the invention, the threshold voltage V in the digital processing module is adjusted according to the ratio of the perimeter of the single tooth to the perimeter of the flywheel and the maximum voltage value of the digital signal in the current periodthFor voltage amplitude smaller than threshold voltage VthThe digital signal is filtered, so that the waveform of the filtered signal can be matched with the position of an actual single tooth close to the magnetic rotating speed sensor, namely the rising edge of the waveform of the signal corresponds to the position of the single tooth boundary close to the magnetic rotating speed sensor, and the falling edge of the waveform of the signal corresponds to the position of the single tooth boundary away from the magnetic rotating speed sensor. Particularly, the falling edge of the waveform of the signal, namely the position of the single tooth away from the magnetic rotating speed sensor, is irrelevant to the rotating speed of the flywheel.
2: when a digital signal received by the digital processing module is in an nth period, the maximum voltage value En of the nth period is predicted according to the proportional relation between the maximum voltage value En-1 of the nth-1 period and the maximum voltage value En-2 of the nth-2 period, and the threshold voltage V of the digital processing module in the nth period is adjusted according to the predicted maximum voltage value En of the nth periodthSo as to ensure the threshold voltage V of the nth periodthCan be changed according to the change of the maximum voltage value En-1 in the (n-1) th period and the maximum voltage value En-2 in the (n-2) th period, and the threshold voltage V of the (n) th period is immediately obtained when the maximum voltage value En of the digital signal in the (n) th period is obtainedthIs updated to
And thus ensures that the position of the falling edge of the filtered signal in the nth cycle matches the position of the single tooth away from the magnetic speed sensor.
In light of the foregoing, it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (9)
1. A filtering method applicable to a magnetic speed sensor of a single-tooth flywheel is characterized by comprising the following steps: the method comprises the following steps:
s1: converting an analog signal output by a magnetic rotating speed sensor into a digital signal, wherein the digital signal is a pulse signal, inputting the digital signal into a digital processing module, and the digital processing module inputs the digital signal when the voltage amplitude of the digital signal is greater than a threshold voltage VthA first level signal is output, and when the voltage amplitude of the digital signal is lower than the threshold voltage VthOutputting a second level signal;
s2: after receiving the digital signal, the digital processing module firstly obtains the maximum voltage value E of the digital signal in the current period, and then compares the maximum voltage value E with a proportionality coefficient
Multiplying and finally multiplying the threshold voltage VthIs updated to
E, the proportionality coefficient
The ratio of the voltage value of the output signal of the magnetic rotation speed sensor at the boundary of the single tooth to the maximum voltage value of the output signal when the single tooth passes through the magnetic rotation speed sensor is obtained.
2. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 1, characterized in that: the first level signal is a high level signal, and the second level signal is a low level signal.
3. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 1, characterized in that: step S2 includes step S20, which is specifically as follows:
s20: the digital processing module acquires a maximum voltage value E1 of the digital signal in a first period of the digital signal and then compares the maximum voltage value E1 with a scaling coefficient
Multiplying and multiplying by a threshold voltage VthIs updated to
E1。
4. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 3, characterized in that: step S2 further includes step S21, which is as follows:
s21: the digital processing module looks for the upward zero crossing point of the voltage of the digital signal and the maximum voltage value E2 in the second period of the digital signal, calculates the distance d2 between the upward zero crossing point of the voltage and the maximum voltage value, and then combines the maximum voltage value E2 with the proportionality coefficient
Multiplying and multiplying by a threshold voltage VthIs updated to
E2, the voltage zero-crossing point is the starting point of the digital signal with the voltage amplitude larger than 0V.
5. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 4, characterized in that: step S2 further includes the steps of:
s22: in the nth period of the received digital signal, n is an integer and is greater than 2, searching for an upward zero crossing point of the voltage in the nth period, and calculating the period length Tn-1 of the nth-1 period;
s23: the digital processing module is based on a formula
Solve out
Wherein
Designing the ratio of the perimeter of the single tooth to the perimeter of the flywheel;
s24: the digital processing module is based on a formula
Updating the scaling factor
According to the formula
Updating
，
Is the ratio of the maximum voltage value of the digital signal in the (n-1) th period to the maximum voltage value of the (n-2) th period of the digital signal;
s25: the digital processing module is based on a formula
Updating the threshold voltage Vth；
S26: the digital processing module searches the maximum voltage value En of the digital signal in the nth period, calculates the distance dn between the upward zero crossing point of the voltage in the nth period and the maximum voltage value En, and then updates the threshold voltage
。
6. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 4, characterized in that: the process of the digital processing module for finding the upward zero-crossing point of the voltage of the current period is as follows: the digital processing module samples an input digital signal, and takes a first sampling point of the digital signal with the voltage greater than 0V as a voltage upward zero crossing point of a current period.
7. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 4, characterized in that: the above-mentioned
Is 1.
8. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 1, characterized in that: in step S2, the process of the digital processing module finding the maximum voltage value E of the current cycle is as follows: the digital processing module samples the input digital signal, compares the voltage of the currently sampled digital signal with the voltage of the digital signal sampled last time, and if the voltage of the currently sampled digital signal is smaller than the voltage of the digital signal sampled last time, the voltage of the digital signal sampled last time is used as the maximum voltage value of the most current period, and then the searching for the maximum voltage value of the current period is finished.
9. The filtering method of the magnetic speed sensor for the single-tooth flywheel according to claim 1, characterized in that: in step S1, the analog signal output by the magnetic speed sensor is input to the differential amplifier, and the output signal of the differential amplifier is input to the digital-to-analog converter, which outputs the digital signal.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5583800A (en) * | 1992-06-19 | 1996-12-10 | Toyota Jidosha Kabushiki Kaisha | Vehicle speed sensor utilizing relationship between vehicle wheel speed and doppler-effect speed |
| US20140375282A1 (en) * | 2013-06-21 | 2014-12-25 | Denso Corporation | Rotating electric machine for vehicles |
| CN107121564A (en) * | 2016-02-24 | 2017-09-01 | 英飞凌科技股份有限公司 | It is used to provide output using variable switch threshold value |
| CN112383309A (en) * | 2020-11-13 | 2021-02-19 | 广东澳鸿科技有限公司 | Analog-to-digital conversion circuit of magnetoelectric revolution speed sensor |
-
2021
- 2021-09-01 CN CN202111017591.XA patent/CN113452351B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5583800A (en) * | 1992-06-19 | 1996-12-10 | Toyota Jidosha Kabushiki Kaisha | Vehicle speed sensor utilizing relationship between vehicle wheel speed and doppler-effect speed |
| US20140375282A1 (en) * | 2013-06-21 | 2014-12-25 | Denso Corporation | Rotating electric machine for vehicles |
| CN107121564A (en) * | 2016-02-24 | 2017-09-01 | 英飞凌科技股份有限公司 | It is used to provide output using variable switch threshold value |
| CN112383309A (en) * | 2020-11-13 | 2021-02-19 | 广东澳鸿科技有限公司 | Analog-to-digital conversion circuit of magnetoelectric revolution speed sensor |
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