A three-parameter measurement method for turboprop based on priority and multi-tooth threshold pairing

Abstract

The present invention relates to a three-parameter measurement method for turboprop based on priority and multi-tooth threshold pairing, belonging to the field of aero-turboprop engine control. The method disclosed by the present invention is as follows: install and adjust a tone wheel (4), a magnetic induction probe (5) and a signal processing module (6), the tone wheel (4) is coupled to the propeller, and the magnetic induction probe (5) can generate signals in response to the passing of a plurality of regular teeth, a first marker tooth (2) and a second marker tooth (3) on the tone wheel (4); set a fixed-frequency trigger source on the signal processing module (6) and connect it to the input capture terminal in hardware, so that obtaining the current measurement moment event is upgraded to a background high-priority interrupt event; use the multi-tooth threshold sequence pairing method to identify specific delays, phase angle reference moments and expected delays from the signals, and calculate the pitch angle, phase angle and rotational speed of the propeller respectively. The present invention improves the accuracy of the acquisition moment by using the real-time performance of the background interrupt, solves the problem of the phase angle measurement dead zone and multi-parameter coupling interference, and improves the measurement accuracy and real-time performance.

Description

Technical Field

[0001] The present invention relates to a method for measuring three parameters of a turboprop based on priority and multi-tooth threshold pairing, and belongs to the field of aero-turboprop engine control. Background Art

[0002] An important task in the multi-engine matching control of turboprop aircraft is the same-step noise reduction control of the propellers. For this purpose, it is necessary to accurately and real-time obtain the engine speed, the pitch angle and the phase angle of the propeller.

[0003] Currently, for the measurement of the pitch angle, phase angle and speed of a turboprop engine, most are separate and independent sensors. For example, in the patent with the patent number US2018050586A1, a tone wheel structure with single helical teeth and multiple pairs of symmetric eight-shaped marks was successively proposed, and the ratio (Ts - Tm) / (Ts + Tm) of the mark space was used to calculate the pitch angle. However, it only solves the problem of pitch angle measurement and does not involve the problem of mutual interference in the measurement of pitch angle, phase angle and speed; the patent with the publication number CN110655030A discloses a method of adding a single-mark helical tooth to a tone wheel with equally spaced conventional teeth to calibrate the reference position of the phase angle. The single helical tooth technical means is not suitable for phase angle measurement because the position of the marked tooth of the single helical tooth will change with the change of the pitch, while the flat teeth cannot measure the pitch angle. It solves the problems of inaccuracy of the same-step phasing technology based on missing teeth and the need for accessory equipment. When solving the phase angle measurement problem, a single-threshold recognition algorithm is used, and the phase angle dead zone problem derived after adding pitch measurement is not considered. For the acquisition of the current moment, generally, the overflow interrupt of the timer is used for triggering acquisition. Since this event is carried out in the foreground main program, it is easily occupied by the background interrupt service program, resulting in poor real-time performance of itself. Moreover, both CN110655030A and US2018050586A1 only stay at the theoretical stage of artificially setting accurately for the accuracy of obtaining the measurement moment, and do not mention the problem of how to obtain the current measurement moment with high precision when actually applied to an embedded system, that is, there is still a certain gap in the technology of high-precision current moment acquisition.

[0004] In summary, there is currently no method to improve the accuracy of obtaining the current measurement moment, and the problems of non-interference between the pitch angle, phase angle and speed and the real-time measurement of the 0 - 360° dead-zone-free phase angle are solved during its development process. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for measuring three parameters of a turboprop based on priority and multi-tooth threshold pairing, aiming to realize the problems of non-interference between the pitch, phase angle and speed and the real-time measurement of the 0 - 360° dead-zone-free phase angle only by using a magneto-electric sensor with a tone wheel, and to be able to obtain the counting time of the current measurement moment with high precision, so as to carry out high-precision measurement.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A three-parameter measurement method for turboprop based on priority and multi-tooth threshold pairing, comprising the following steps:

[0008] Step 1: Install and adjust the tone wheel, magnetic induction probe and signal processing module. The tone wheel is coupled to the propeller. During the operation of the turboprop engine, the tone wheel rotates and moves axially together with the propeller pitch change system. The magnetic induction probe is fixed to the stationary part of the engine, installed without contact with the tone wheel, and can generate signals in response to the passing of a plurality of regular teeth, a first marking tooth and a second marking tooth on the tone wheel. The first marking tooth and the second marking tooth are symmetric "eight"-shaped marking helical teeth. The signal processing module is connected to the magnetic induction probe by a circuit;

[0009] Step 2: The signal processing module processes the signals generated by the magnetic induction probe, conditions them into a plurality of square wave signals, the square wave signals are connected to the input capture channel, and the arrival time of each tooth is obtained. Define the expected delay as the time interval between two adjacent regular teeth. Define the pulses associated with the first marking tooth and the second marking tooth as the first specific pulse and the second specific pulse, and the specific delay as the time interval between the first specific pulse and the second specific pulse. Select the first regular tooth adjacent to the second marking tooth as the phase angle reference time, and thereby determine the current measurement time and the phase angle size of the phase angle reference position relative to the magnetic induction probe;

[0010] Step 3: Use a method for obtaining the current measurement time based on a high-priority interrupt event in the background to upgrade the current measurement time acquisition event in the foreground to a high-priority interrupt event in the background, thereby improving the measurement accuracy and real-time performance;

[0011] Step 4: Use the multi-tooth threshold sequence pairing method to identify the specific delay, phase angle reference time and expected delay in real time from a plurality of pulse signals, and calculate the pitch, phase angle and rotational speed of the propeller respectively.

[0012] The three-parameter measurement method for turboprop based on priority and multi-tooth threshold pairing, characterized in that upgrading the current measurement time acquisition event in the foreground to a high-priority interrupt event in the background is a method for obtaining the current measurement time based on a high-priority interrupt event in the background. The core idea is to use hardware means to upgrade the foreground event to a background interrupt event to improve the acquisition accuracy of the current measurement time. The foreground is also called the task level. The real-time performance of this system in processing is worse than what is actually achieved. The background is also called the interrupt level. For key operations with high real-time requirements such as obtaining the current measurement time, it needs to be ensured by the interrupt service program and has the following structural characteristics:

[0013] An interrupt event based on high priority in the background within the signal processing module, including three high-priority trigger events of multi-channel input capture defined within the same timer, namely the current measurement interrupt, the input capture interrupt, and the overflow interrupt. Among them, the external input interfaces of the current measurement interrupt and the input capture interrupt are the first input capture channel and the second input capture channel respectively, and the overflow interrupt is triggered by the internal timer. The current measurement interrupt uses an equi-frequency square wave PWM output with an adjustable period as the trigger source, and connects the hardware interface of the trigger source output to the first input capture channel, so that the current measurement interrupt is triggered in the form of an input capture interrupt to obtain the current measurement moment with high precision. The frequency of the adjustable-period equi-frequency square wave needs to meet the frequency and hardware requirements of the Shannon sampling theorem, that is, the sampling frequency cannot be lower than 2 times the frequency of the phase angle change from 0 to 360 degrees, and cannot be too high to avoid getting stuck in the hardware. The second input capture channel is connected to the magnetic induction probe to capture the edge moment of the square wave signal with high precision. The overflow interrupt is used to extend the counting time length of the timer. When the number of overflows exceeds a predetermined value, the task level set in the foreground will temporarily close the input capture interrupt, and perform an overall minimization of all stored moment values, that is, subtract the same size value as a whole instead of clearing all to zero, and then open the interrupt, avoiding the influence of other interrupt events on this event, and avoiding the problem of needing to reassign and store the data storage unit after clearing all to zero.

[0014] The described method for measuring three parameters of a turboprop based on priority and multi-tooth threshold pairing is characterized in that, as a better option of the present invention, the method for obtaining the current measurement moment in step 3 obtains the current phase angle in the foreground and converts it to the phase angle of the specified sampling point according to the actual system time, that is, corrects the current measurement value to the sampling moment. The method is to measure and count the system time from the start to the end of the foreground loop, and correct the phase angle calculation triggered by the fixed-frequency interrupt of the timer during measurement.

[0015] The described method for measuring three parameters of a turboprop based on priority and multi-tooth threshold pairing is characterized in that the multi-tooth threshold sequence pairing method includes a multi-tooth threshold comparison logic and a pairing logic. The multi-tooth threshold comparison logic includes comparison operations of greater than, less than, and equal to. The pairing logic refers to the pairing of the latest sequence from the low bit to the high bit to identify the sequence that meets the multi-tooth threshold comparison logic. The real-time requirement of the sequence is to update the value at the arrival moment of each tooth;

[0016] Since when the middle position between the first marker tooth and the second marker tooth is used as the phase angle reference position, only the middle moment will be recognized when the second marker tooth crosses, that is, there will be a small phase angle dead zone. Therefore, taking the first regular tooth after the second marker tooth as the phase reference tooth as an example, the tone wheel has k teeth, and the marker tooth bevel angle is The signal processing module needs to store k + 4 square-wave edge time units and the current measurement time. Compared with storing k data units, it avoids the dead zone of phase angle measurement from 0 to 4 * 360 / k°, t i represents the rising edge time of the first flag tooth, t i+1 represents the rising edge time of the second flag tooth, t i+2 represents the rising edge time of the phase reference, t t represents the current measurement time, t k+4 represents the next rising edge time that has not arrived yet, and has the following logical steps:

[0017] Step 41: When t k+4 arrives, that is, the input capture interrupt is triggered, and the current time t t = t k+4 , the stored k + 4 square-wave edge time units are changed in value from low to high to ensure that the stored data is the data of the latest time, that is, to ensure real-time performance. The specific loop code can be for(n = 1; n <= k + 4; n++) t n-1 = t n ;

[0018] Step 42: At the same time as the value change, use the period measurement method to calculate the expected delay t = (t k+3 - t3) / (k - 1). In the stored data units t0, t1, t2,..., t i-1 …, t k+1 , t k+2 , t k+3 , quickly identify the pairing sequence composed of t i-1 , t i , t i+1 , t i+2 . The specific method is to pair step by step from low to high. The pairing rule is multi-tooth threshold pairing comparison. The interval between the first flag tooth and the adjacent regular tooth, and the interval between the second flag tooth and the adjacent regular tooth are both less than the interval between two normal adjacent regular teeth, that is, (t i - t i - 1) < e·t and (t i+2 - t i+1 ) < e·t. If the requirements are met, the pairing will end, and the rising edge time t i+2 of the phase reference will be updated, as well as the time interval t i+1 - t i between the first flag tooth and the second flag tooth. When the next rising edge arrives, return to Step 41; between t k+4 and t k+3 , when the current measurement interrupt is triggered, obtain t t and the latest flag tooth i and perform calculations of three parameters: pitch Phase angle a = 360·(t t - t i+2 ) / (t k+3 ) - t3), rotational speed N P = 60 / (t k+3 ) - t3).

[0019] As a more optimal multi - tooth threshold comparison logic of the present invention, a comparison operation of sum - equality in magnitude is adopted. The time interval between the first flag tooth (2) and the adjacent regular tooth is less than the time interval between two adjacent regular teeth, and the time intervals between the left and right adjacent regular teeth of the two flag teeth are equal to two expected delays, that is, (t i - t i-1 ) < e·t and e·2·t <= (t i+2 - t i - 1) <= (2 - e)·2·t.

[0020] Compared with the prior art, the advantages of the present invention are as follows: A method for obtaining the current measurement moment based on a background high - priority interrupt event is proposed. The core idea is to upgrade the foreground event to a background interrupt event by means of hardware to improve the acquisition accuracy of the current measurement moment. The experimental results show that the measurement accuracy is improved by about 4 times. A method of multi - tooth threshold sequence pairing is proposed to update the flag tooth and the phase reference position in real - time, realizing the real - time measurement of the pitch angle, phase angle and rotational speed without mutual interference, with high precision and no dead zone in the 0 - 360° phase angle range. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The three - dimensional structure diagram of the application carrier of the present invention and the parameter measurement mechanism.

[0022] Figure 2 The front - back - stage system schematic diagram of the present invention based on a background high - priority interrupt event.

[0023] Figure 3 The phase - angle measurement accuracy comparison diagram of the present invention for foreground - triggered measurement and background - interrupt measurement at 600 rpm.

[0024] Figure 4 The logic diagram of the multi - tooth threshold sequence pairing method of the present invention.

[0025] In the figure: 1 - regular tooth, 2 - first flag tooth, 3 - second flag tooth, 4 - cylinder, 5 - through - hole, 6 - tone wheel, 5 - magnetic induction probe, 6 - signal processing module. DETAILED DESCRIPTION OF THE INVENTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Please refer to Figure 1 , in an embodiment of the present invention, a three-parameter measurement method for a turboprop based on priority and multi-tooth threshold pairing includes the following steps:

[0028] Step 1: Install and adjust the tone wheel 4, the magnetic induction probe 5, and the signal processing module 6. The tone wheel 4 is coupled to the propeller. The tone wheel 4 rotates and moves axially together with the propeller pitch change system during the operation of the turboprop engine. The magnetic induction probe 5 is fixed to the stationary part of the engine, installed without contact with the tone wheel 4, and can generate signals in response to the passing of a plurality of regular teeth 1, a first marker tooth 2, and a second marker tooth 3 on the tone wheel 4. The first marker tooth 2 and the second marker tooth 3 are symmetric "eight"-shaped marker helical teeth. The signal processing module 6 is connected to the magnetic induction probe 5 by a circuit.

[0029] Step 2: The signal processing module 6 processes the signals generated by the magnetic induction probe 5, conditions them into a plurality of square wave signals, the square wave signals are connected to the input capture channel, and the arrival time of each tooth is obtained. Define the expected delay as the time interval between two adjacent regular teeth 1. Define the pulses associated with the first marker tooth 2 and the second marker tooth 3 as the first specific pulse and the second specific pulse, and the specific delay as the time interval between the first specific pulse and the second specific pulse. Select the first regular tooth 1 adjacent to the second marker tooth 3 as the phase angle reference moment, and thereby determine the current measurement moment and the phase angle magnitude of the phase angle reference position relative to the magnetic induction probe 5.

[0030] Step 3: Use a method for obtaining the current measurement moment based on a high-priority background interrupt event to upgrade the current measurement moment acquisition event in the foreground to a high-priority background interrupt event, thereby improving the measurement accuracy and real-time performance.

[0031] Step 4: Use the multi-tooth threshold sequence pairing method to identify the specific delay, the phase angle reference moment, and the expected delay in real time from a plurality of pulse signals, and calculate the pitch, phase angle, and rotational speed of the propeller respectively.

[0032] Please refer to Figure 2 and Figure 3, in the embodiment of the present invention, the described method for measuring three parameters of a turboprop based on priority and multi-tooth threshold pairing is characterized in that upgrading the current measurement moment acquisition event in the foreground to a high-priority background interrupt event is a method for acquiring the current measurement moment based on a high-priority background interrupt event. The core idea is to use hardware means to upgrade the foreground event to a background interrupt event to improve the acquisition accuracy of the current measurement moment. The foreground is also called the task level. The real-time performance of this system in processing is worse than what can be actually achieved. The background is also called the interrupt level. For critical operations with high real-time requirements such as acquiring the current measurement moment, it needs to be ensured by the interrupt service program and has the following structural characteristics:

[0033] A high-priority interrupt event based on the background in the signal processing module 6, including three high-priority trigger events of multi-channel input capture defined in the same timer, namely the current measurement interrupt, the input capture interrupt, and the overflow interrupt. Among them, the external input interfaces of the current measurement interrupt and the input capture interrupt are the first input capture channel and the second input capture channel respectively. The overflow interrupt is triggered by the internal timer. The current measurement interrupt uses an equi-frequency square wave PWM output with an adjustable period as the trigger source, and the hardware interface of the trigger source output is connected to the first input capture channel, so that the current measurement interrupt is triggered in the form of an input capture interrupt to obtain a high-precision current measurement moment. The frequency of the adjustable-period equi-frequency square wave needs to meet the frequency and hardware requirements of the Shannon sampling theorem, that is, the sampling frequency cannot be lower than 2 times the phase angle change frequency from 0 to 360 degrees and cannot be too high to avoid getting stuck in the hardware. The second input capture channel is connected to the magnetic induction probe 5 to accurately capture the edge moment of the square wave signal. The overflow interrupt is used to extend the counting time length of the timer. When the overflow count exceeds a predetermined value, it is set that the task level in the foreground will temporarily close the input capture interrupt and perform overall minimization on all stored moment values, that is, subtract the same size value as a whole instead of clearing all to zero, and then open the interrupt, avoiding the influence of other interrupt events on this event and the problem of needing to reassign and store data in the data storage unit after clearing all to zero;

[0034] The front-end and back-end system designs for specific implementation are as follows: The front-end system is an infinite loop that will cyclically execute three events: "sending the measurement data of the previous moment", "normalizing all rising-edge moments by subtracting the same number to make them smaller", and "processing the measurement data". In the back-end interrupt events, there are mainly PWM output interrupt and input capture interrupt. The PWM output interrupt generates a square wave signal with a fixed period, which is used as the trigger source for the current measurement instruction. The period of this square wave signal is set at about 10 ms and is connected to the input capture interface through a physical interface. The connection method can be external connection or internal connection. The input capture interrupt captures the square wave edge signal of the magnetoelectric sensor and the square wave signal generated by the PWM output for the current measurement instruction. In order to extend the counting time length, the input capture interrupt also has an overflow interrupt. The front-end events will be interrupted by the back-end interrupt events to execute the back-end interrupt events. After the back-end interrupt events are executed, they will return to the infinite loop of the front-end;

[0035] Please refer to Figure 3 , in the embodiment of the present invention, upgrading the front-end event of obtaining the current measurement moment to a back-end interrupt event. At a rotational speed of 600 rpm, the measurement accuracy triggered by the front-end event is ±4°, and the measurement accuracy triggered by the back-end interrupt event is ±1°. The accuracy is improved by about 4 times, which is sufficient to prove the effectiveness of the method for obtaining the current measurement moment based on the high-priority interrupt event in the back-end.

[0036] As a more optimal option of the present invention, for the method for measuring three parameters of a turboprop based on priority and multi-tooth threshold pairing, it is characterized in that for the method for obtaining the current measurement moment described in step 3, the current phase angle is obtained in the front-end and converted to the phase angle at the specified sampling point according to the actual system time, that is, the current measurement value is corrected to the sampling moment. The method is to count the system time from the start to the end of the front-end loop and correct the phase angle calculation triggered by the fixed-frequency interrupt of the timer.

[0037] Please refer to Figure 4 , in the embodiment of the present invention, for the method for measuring three parameters of a turboprop based on priority and multi-tooth threshold pairing, it is characterized in that the multi-tooth threshold sequence pairing method includes a multi-tooth threshold comparison logic and a pairing logic. The multi-tooth threshold comparison logic includes comparison operations of greater than, less than, and equal to. The pairing logic refers to the pairing of the latest sequence from the low bit to the high bit in order to identify the sequence that meets the multi-tooth threshold comparison logic. The real-time requirement of the sequence is to update the value at the arrival moment of each tooth;

[0038] Since when the middle position between the first flag tooth 2 and the second flag tooth 3 is used as the phase angle reference position, only the middle moment will be recognized when the second flag tooth 3 crosses, that is, there will be a small phase angle dead zone. Therefore, taking the first normal tooth after the second flag tooth 3 as the phase reference tooth as an example, the tone wheel has k teeth, and the flag tooth bevel angle is The signal processing module 6 needs to store k + 4 square wave edge time units and the current measurement time. Compared with storing k data units, it avoids the dead zone of phase angle measurement from 0 to 4 * 360 / k °, t i represents the rising edge time of the first flag tooth 2, t i+1 represents the rising edge time of the second flag tooth 3, t i+2 represents the rising edge time of the phase reference, t t represents the current measurement time, t k+4 represents the next rising edge time that has not arrived yet, and has the following logical steps:

[0039] Step 41: When t k+4 arrives, that is, the input capture interrupt is triggered, and the current time t t = t k+4 , the k + 4 stored square wave edge times are changed in value from the lowest bit to the highest bit to ensure that the stored data is the data of the latest time, that is, to ensure real-time performance. The specific loop code can be for(n = 1; n <= k + 4; n++) t n-1 = t n ;

[0040] Step 42: At the same time as the value change, use the period measurement method to calculate the expected delay t = (t k+3 - t3) / (k - 1). In the stored data units t0, t1, t2,..., t i-1 …, t k+1 , t k+2 , t k+3 , quickly identify the pairing sequence composed of t i-1 , t i , t i+1 , t i+2 . The specific method is to pair step by step from the lowest bit to the highest bit. The pairing rule is multi-tooth threshold pairing comparison. The interval between the first flag tooth 2 and the adjacent regular tooth, and the interval between the second flag tooth 3 and the adjacent regular tooth are both less than the interval between two normal adjacent regular teeth, that is, (t i - t i-1 ) < e · t and (t i+2 - t i+1 ) < e · t. If the requirements are met, the pairing will end, and the rising edge time t i+2 of the phase reference will be updated, as well as the time interval t i+1 - t i between the first flag tooth 2 and the second flag tooth 3. When the next rising edge arrives, return to Step 41; between t k+4 and t k+3 , when the current measurement interrupt is triggered, obtain t t and the latest flag tooth i and perform the calculation of three parameters: pitch Phase angle α = 360·(t t - t i+2 ) / (t k+3 - t3), rotational speed N P = 60 / (t k+3 - t3).

[0041] As a more preferable multi - tooth threshold comparison logic of the present invention, a comparison operation of sum - of - magnitude equality is adopted. The time interval between the first marked tooth 2 and the adjacent normal tooth is less than the time interval between two adjacent normal teeth, and the time intervals between the left and right adjacent normal teeth of the two marked teeth are equal to two expected delays, that is, (t i - t i-1 ) < e·t and e·2·t <= (t i+2 - t i-1 ) <= (2 - e)·2·t.

[0042] The present invention is not limited to the above - mentioned embodiments. Based on the technical solutions disclosed in the present invention, those skilled in the art can make some simple modifications, equivalent changes and modifications to some of the technical features without creative labor, and all of them fall within the scope of the technical solutions of the present invention.

Claims

1. A three-parameter measurement method for turboprop based on priority and multi-tooth threshold pairing, comprising the following steps: Step 1: Install and adjust the tone wheel (4), magnetic induction probe (5) and signal processing module (6). The tone wheel (4) is coupled to the propeller. During the operation of the turboprop engine, the tone wheel (4) rotates and moves axially together with the propeller pitch change system. The magnetic induction probe (5) is fixed to the stationary part of the engine, installed without contact with the tone wheel (4), and can generate signals in response to the passing of a plurality of regular teeth (1), a first marker tooth (2) and a second marker tooth (3) on the tone wheel (4). The first marker tooth (2) and the second marker tooth (3) are symmetric "eight"-shaped marked helical teeth. The signal processing module (6) is connected to the magnetic induction probe (5) by wires; Step 2: The signal processing module (6) processes the signals generated by the magnetic induction probe (5), conditions them into square wave signals, the square wave signals are connected to the input capture channel, and the arrival times of each tooth are obtained. Define the expected delay as the time interval between two adjacent regular teeth (1). Define the pulses associated with the first marker tooth (2) and the second marker tooth (3) as the first specific pulse and the second specific pulse, and the specific delay as the time interval between the first and second specific pulses. Select the first regular tooth (1) adjacent to the second marker tooth (3) as the phase angle reference moment, and thereby determine the phase angle size of the current measurement moment relative to the magnetic induction probe (5); Step 3: Use a method for obtaining the current measurement moment based on high-priority background interrupt events to upgrade the current measurement moment acquisition event in the foreground to a high-priority background interrupt event, thereby improving the measurement accuracy and real-time performance; Step 4: Use the multi-tooth threshold sequence pairing method to identify the specific delay, phase angle reference moment and expected delay in real time from multiple pulse signals, and calculate the pitch, phase angle and rotational speed of the propeller respectively, specifically including: Step 41: When t k+4 arrives, that is, the input capture interrupt is triggered, and the current time t t = t k+4 , the stored k + 4 square wave edge times are changed in value starting from the lowest bit to the highest bit; Step 42: After the value is changed, the expected delay t is calculated using the cycle measurement method. k+3 -t3) / (k-1), in the stored data units t0, t1, t2, ..., t i-1 …、t k+1 ,t k+2 ,t k+3 Quickly identify the i-1 ,,t i ,t i+1 ,t i+2 The specific method is to gradually pair from low to high positions. The pairing rule is a multi-tooth threshold sequence pairing method. The comparison operation of size is adopted. The time interval between the first marker tooth (2) and the adjacent regular tooth, and the time interval between the second marker tooth (3) and the adjacent regular tooth are both smaller than the time interval between two adjacent regular teeth, that is, (t i -t i-1 )<e·t and (t i+2 -t i+1 )<e·t, if the requirement is met, the pairing will be terminated and the phase reference rising edge time t will be updated. i+2 time, and the time interval t between the first marker tooth (2) and the second marker tooth (3) i+1 -t i , when the next rising edge arrives, return to step 41; at t k+4 and t k+3 When the current measurement interrupt is triggered, get t t and the latest marker gear i and calculate three parameters: pitch Phase angle a=360·(t t -t i+2 ) / (t k+3 -t3), speed N P =60 / (t k+3 -t3); Among them, the tone wheel has k teeth, and the marked tooth bevel angle is The signal processing module (6) stores k + 4 square wave edge time units and the current measurement time, t i Represents the rising edge time of the first marked tooth (2), t i+1 Represents the rising edge time of the second marked tooth (3), t i+2 Represents the rising edge time of the phase reference, t t Represents the current measurement time, t k+4 Represents the next rising edge time that has not yet arrived.

2. The three-parameter measurement method of a turboprop based on priority and multi-tooth threshold pairing according to claim 1, characterized in that The upgrading of the current measurement moment acquisition event in the foreground to a high-priority background interrupt event is a method for obtaining the current measurement moment based on high-priority background interrupt events. The core idea is to use hardware means to upgrade the foreground event to a background interrupt event to improve the acquisition accuracy of the current measurement moment. The foreground is also called the task level. The real-time performance of this system in processing is worse than what is actually achieved. The background is also called the interrupt level. For key operations with high real-time requirements such as obtaining the current measurement moment, it needs to be guaranteed by the interrupt service program and has the following structural characteristics: An interrupt event based on high priority in the background within the signal processing module (6), including three high-priority trigger events of multi-channel input capture defined in the same timer, namely the current measurement interrupt, the input capture interrupt, and the overflow interrupt. For the current measurement interrupt, an isofrequency square wave PWM output with an adjustable period is used as the trigger source, and the hardware interface of the trigger source output is connected to the input capture channel, so that the current measurement interrupt is triggered in the form of an input capture interrupt to obtain the current measurement moment with high precision. The frequency of the isofrequency square wave with an adjustable period needs to meet the frequency and hardware requirements of the Shannon sampling theorem, that is, the sampling frequency cannot be lower than 2 times the frequency of the phase angle change from 0 to 360 degrees, nor can it be too high to avoid getting stuck in hardware. The magnetic induction probe (5) is also connected to the input capture to capture the edge moment of the square wave signal with high precision. The overflow interrupt is used to extend the counting time length of the timer. When the number of overflows exceeds a predetermined value, the task level set in the foreground will temporarily close the input capture interrupt, subtract the same value from all stored moment values as a whole, and then open the interrupt.

3. A three-parameter measurement method for turboprop based on priority and multi-tooth threshold pairing as claimed in claim 1, characterized in that, For the method of obtaining the current measurement moment described in step 3, the current phase angle is obtained in the foreground and converted to the phase angle of the specified sampling point according to the actual system time, that is, the current measurement value is corrected to the sampling moment. The method is to count the system time from the start to the end of the foreground loop and correct the phase angle calculation in the measurement triggered by the fixed-frequency interrupt of the timer.

4. A three-parameter measurement method for turboprop based on priority and multi-tooth threshold pairing as claimed in claim 1, characterized in that The multi-tooth threshold sequence pairing method includes multi-tooth threshold comparison logic and pairing logic. The multi-tooth threshold comparison logic includes comparison operations of greater than, less than, and equal to. The pairing logic refers to the pairing of the latest sequence from the low bit to the high bit to identify the sequence that meets the multi-tooth threshold comparison logic. The real-time requirement of the sequence is to update the value at the arrival moment of each tooth.

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