Aero-engine rotating speed measuring device

Abstract

The embodiment of the invention discloses an aero-engine rotating speed measuring device which is characterized by comprising a tachogenerator module, a hardware conditioning module, a high-speed A / D conversion module, a data picking and buffering module, a digital signal processing module, a rotating speed measuring module, a power supply module, an operation control module and a communication module which are connected in sequence. The tachogenerator module converts an acquired engine rotating speed signal into a sine-wave-like alternating-current voltage signal of which the frequency and the amplitude are positively correlated with the rotating speed. The hardware conditioning module is used for conditioning the sine-like signal with a relatively wide amplitude range into a signal meeting the amplitude range requirement of the high-speed A / D conversion module; the high-speed A / D conversion module performs high-speed sampling on the conditioned sinusoidal-like signal and converts the conditioned sinusoidal-like signal into a digital signal; the data picking and buffering module is used for picking and buffering the digital signals subjected to A / D conversion; the digital signal processing module is used for converting the digital signal into a digital square wave signal; the rotating speed measuring module is used for monitoring the frequency of the digital square wave signal and calculating the rotating speed of the engine through the frequency; and the communication module is used for uploading the engine rotating speed measurement result to the flight control computer. The technical scheme of the invention solves the problem.

Description

Technical Field

[0001] The present invention relates to, but is not limited to, the technical field of aircraft engine control, and in particular to an aircraft engine speed measuring device. Background Art

[0002] The speed is one of the key target quantities for aircraft engine control. The speed measurement is the feedback for the closed-loop control of the engine. The existing aircraft engine speed measurement adopts a multi-redundancy design, with a tachometer generator as the speed sensor. The tachometer generator outputs a quasi-sinusoidal AC signal whose frequency and amplitude are positively correlated with the speed. When the engine digital electronic controller monitors the tachometer generator signal, it forms a digital square wave signal through signal limiting, amplification, sine to square wave conversion, square wave signal conditioning, and electrical isolation. The digital square wave signal is further conditioned and subjected to software frequency measurement.

[0003] The existing speed measurement methods are highly complex, costly, and have a high failure rate, which is not conducive to the reliability and cost control of aircraft engine control systems. Summary of the invention

[0004] Purpose of the present invention: In order to solve the above-mentioned technical problems, an embodiment of the present invention provides an aircraft engine speed measuring device to solve the problems that the existing measurement method has high complexity, high cost, and high failure rate, which is not conducive to the reliability and cost control of the aircraft engine control system.

[0005] The technical solution of the present invention: The embodiment of the present invention provides an aircraft engine speed measurement device, comprising: a speed measurement generator module, a hardware conditioning module, a high-speed A / D conversion module, a data pickup and buffer module, a digital signal processing module, a speed measurement module, a power supply module, an operation control module and a communication module connected in sequence;

[0006] The power supply module is respectively connected to the hardware conditioning module, the high-speed A / D conversion module, the operation control module and the communication module, and is used to provide secondary power supply to each module connected thereto;

[0007] The operation control module is respectively connected to the high-speed A / D conversion module, the data pickup and buffer, the digital signal processing module, the speed measurement module and the communication module; the communication module is also respectively connected to the output end of the flight control computer and the speed measurement module;

[0008] The speed measuring generator module is used to convert the collected engine speed signal into a quasi-sine wave AC voltage signal whose frequency and amplitude are positively correlated with the speed, and transmit the quasi-sine wave AC voltage signal to the hardware conditioning module;

[0009] The operation control module is the carrier for the operation of the digital signal processing module, the speed measurement module, the communication software, and the high-speed A / D conversion module drive control software;

[0010] The hardware conditioning module is used to condition the quasi-sinusoidal signal with a wide amplitude range into a signal that meets the amplitude range requirements of the high-speed A / D conversion module;

[0011] A high-speed A / D conversion module is used to perform high-speed sampling on the conditioned quasi-sine signal and convert it into a digital signal;

[0012] A data pickup and buffer module is used to pick up and buffer the digital signal after A / D conversion;

[0013] A digital signal processing module, used for converting a digital signal into a digital square wave signal;

[0014] The speed measurement module is used to monitor the frequency of the digital square wave signal and calculate the engine speed through the frequency;

[0015] Communication module, used to upload engine speed measurement results to the flight control computer.

[0016] Optionally, in the aircraft engine speed measuring device as described above, the tachometer generator module is installed on the engine, and the engine accessory casing drives the tachometer generator module to rotate synchronously to form an engine speed signal, which is converted and output as a quasi-sine wave AC voltage signal. The voltage amplitude and frequency of this type of sinusoidal wave AC voltage signal are positively correlated with the engine speed, and the maximum peak value of the output voltage is 10V.

[0017] Optionally, in the above-mentioned aircraft engine speed measurement device, the hardware conditioning module includes: a signal limiting unit and a signal biasing unit connected in series;

[0018] The signal limiting unit is composed of two diodes connected in parallel on the signal input line, one of which is forward-conducting and the other is reverse-conducting, respectively used to limit the positive half-cycle signal and the negative half-cycle signal of the quasi-sine wave AC voltage signal;

[0019] The signal bias unit is configured as an adder consisting of a bias voltage generator and an operational amplifier; wherein the bias voltage generator is used to generate a reference bias voltage with an amplitude of 1 / 2VCC, and two resistors with equal resistance values ​​are connected in series to divide the power supply voltage VCC, and the voltage 1 / 2VCC after the resistor division is impedance matched by an emitter follower, 1 / 2VCC is input to the non-inverting end of the emitter follower, the inverting end of the emitter follower is connected to the output end, the output end of the emitter follower is connected to the non-inverting input end of the operational amplifier, and the quasi-sine wave AC voltage signal after limiting is transmitted to the inverting end of the operational amplifier, and the quasi-sine wave AC voltage signal is conditioned into a DC voltage signal with a bias voltage of 1 / 2VCC through the operational amplifier.

[0020] Optionally, in the above-mentioned aircraft engine speed measurement device, the maximum sampling rate of the high-speed A / D conversion module is not less than 100KHz, and the trigger signal of the A / D conversion module is driven by the PWM signal output by the operation control module;

[0021] The operation control module outputs a PWM signal with a frequency of 100KHz and a duty cycle of 50% to drive the start of the high-speed A / D conversion module and convert the DC voltage signal into a speed digital signal; the speed digital signal converted by the high-speed A / D conversion module supports the direct reading function of the DMA controller.

[0022] Optionally, in the above-mentioned aircraft engine speed measuring device,

[0023] The data pickup and buffer module is used to batch pick up and cache the speed digital signal output by the A / D conversion module. The speed digital signal formed by the A / D conversion module is output to the DMA controller in the data pickup and buffer module, and the DMA controller caches the data.

[0024] The DMA controller is used to send a DMA controller buffer full interrupt signal to the operation control module after its buffer is full of data, instructing the operation control module to send a data processing request to the digital signal processing module to transfer the data stored in the buffer of the DMA controller to the digital signal processing module for signal processing.

[0025] Optionally, in the above-mentioned aircraft engine speed measurement device, the digital signal processing module includes: a sinc3 filter, a hysteresis comparator, and a waveform corrector connected in series in sequence;

[0026] The sinc3 filter is used to suppress the high-frequency disturbance in the speed digital signal. The sinc3 filter receives the speed digital signal output by the data pickup and buffer module, and caches the speed digital signal after filtering by the sinc3 filter into a post-filtering buffer, and the length and width of the post-filtering buffer are the same as those of the buffer in the DMA controller;

[0027] The hysteresis comparator is used to convert the filtered speed digital signal into a digital square wave signal; the signal conversion method is: sequentially calculating the first-order differential of the filtered speed digital signal in the filtered buffer, and determining the signal change trend of the filtered digital signal according to the differential result; according to the signal change trend and the preset comparison threshold lower limit or comparison threshold upper limit, converting the filtered speed digital signal into a square wave digital signal;

[0028] The waveform corrector is used to suppress the high-frequency disturbance component in the compared square wave digital signal, and the suppression method is: firstly set a rectangular window with a data length of 35; secondly, perform windowing and interception on the square wave digital signal with the rectangular window of 35 data length, and buffer the intercepted data into another buffer; thirdly, analyze the continuous length of 0 and 1 in the intercepted data in the rectangular window of 35 data length, take a sliding window of 10 data lengths in the rectangular window of 35 data length, perform sliding windowing on the data in the rectangular window of 35 data length, if the data in the sliding window has a data jump of 0-1-0, then all the data in the sliding window will be corrected to 0, and if the data in the sliding window has a data jump of 1-0-1, then all the data in the sliding window will be corrected to 1.

[0029] Optionally, in the above-mentioned aircraft engine speed measurement device, the speed measurement module comprises: a signal generating unit and a speed measurement unit connected in series, and an output port of the signal generating unit is connected to an input port of the speed measurement unit;

[0030] The signal generating unit is used to convert the 0 and 1 square wave digital signals formed after being processed by the waveform corrector into hardware signals, and output them to the capture channel of the speed measurement unit; when the signal generating unit is running, the square wave digital signals in the buffer of the waveform corrector are sampled in sequence with a period of 10us, and if the sampling result is 0, the output port corresponding to the signal generating unit is set to a low level, and if the sampling result is 1, the output port corresponding to the signal generating unit is set to a high level;

[0031] The speed measurement unit is used to collect the hardware signal output by the signal generation unit, and determine the speed of the engine according to the frequency and period of the hardware signal.

[0032] Optionally, in the above-mentioned aircraft engine speed measurement device, the speed measurement unit includes: a high-precision counter, an edge capturer, a timer, a register, and a rising edge counter;

[0033] There are two ways to calculate the frequency of hardware signals:

[0034] Mode 1, the high-precision counter runs at a period of 10ns and counts from 0 to 2 32 Incremental, after overflow, it becomes 0; the edge capturer is used to identify the rising edge of the hardware signal input to the speed measurement unit. If the rising edge arrives, an interrupt is generated. In the interrupt service program, the software assigns the value of the high-precision counter to the register. According to the value in the register and the step size of the high-precision counter, the time between two rising edges, that is, the signal period, is calculated; after the signal period calculation is completed, the value of the high-precision counter is assigned to 0, and the signal frequency 1 is calculated according to the signal period;

[0035] Mode 2: The timing time of the timer is 0.2s. The number of occurrences of the rising edge within 0.2s is counted with a period of 0.2s. The rising edge counter is accumulated in each interrupt. After the 0.2s timing time is up, the signal frequency 2 is calculated based on the count value of the rising edge counter and the 0.2s time period. After the calculation is completed, the rising edge counter is cleared;

[0036] If the hardware signal frequency is lower than 100 Hz, the engine speed is calculated using hardware frequency 1. If the hardware signal frequency is higher than 100 Hz, the engine speed is calculated using hardware frequency 2.

[0037] Optionally, in the aircraft engine speed measurement device as described above, the communication module receives a speed reporting instruction issued by a flight control computer, and uploads the engine speed to the flight control computer in real time according to a preset period.

[0038] Beneficial effects of the invention: An embodiment of the invention provides an aircraft engine speed measurement device, comprising: a speed measurement generator module, a hardware conditioning module, a high-speed A / D conversion module, a data pickup and buffer module, a digital signal processing module, a speed measurement module, and a power supply module, an operation control module and a communication module connected in sequence; wherein the power supply module is respectively connected to the hardware conditioning module, the high-speed A / D conversion module, the operation control module and the communication module, for providing secondary power supply to each module connected thereto; the operation control module is respectively connected to the high-speed A / D conversion module, the data pickup and buffer, the digital signal processing module, the speed measurement module and the communication module; the communication module is also respectively connected to the output ends of the flight control computer and the speed measurement module. The aircraft engine speed measurement device provided by the embodiment of the invention is mainly used in aircraft engine control systems, and has the following beneficial effects:

[0039] 1) Reduce the hardware complexity of the aircraft engine speed measurement device by increasing the software complexity;

[0040] 2) Based on the reduction of hardware complexity of aircraft engine speed measurement devices, the risk of hardware being affected by electromagnetic interference is reduced, thereby improving the electromagnetic compatibility and reliability of aircraft engine speed measurement;

[0041] 3) Based on the reduction of hardware complexity of aircraft engine speed measurement devices, that is, the corresponding reduction of hardware circuits, it is beneficial to reduce the size, weight and cost of the speed measurement device, and it is more beneficial to improve the power-to-weight ratio of the measurement device.

[0042] 4) Lay the foundation for improving the reliability and power density of aircraft engine control systems.

[0043] To sum up, the aircraft engine speed measuring device provided by the embodiment of the present invention has low hardware complexity and high algorithm complexity, and exchanges algorithm complexity for hardware complexity, and the total cost, reliability, electromagnetic compatibility, and volume-weight performance of the aircraft engine speed measuring device are more optimized, thereby improving the operating safety of the numerical control system and the aircraft engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0045] Figure 1 A schematic diagram of the overall structure of an aircraft engine speed measuring device provided by an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the structure of a hardware conditioning module in an aircraft engine speed measurement device provided by a few embodiments of the present invention;

[0047] Figure 3 for Figure 2 A schematic diagram of the limiting effect and biasing effect of the signal limiting unit in the hardware conditioning module provided by the illustrated embodiment;

[0048] Figure 4 The figure is a schematic diagram of the working principle of the waveform corrector in the digital signal processing module in the embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0050] The present invention provides the following specific embodiments which can be combined with each other. The same or similar concepts or processes may not be described in detail in some embodiments.

[0051] Figure 1 The overall structural diagram of the aircraft engine speed measuring device provided by the embodiment of the present invention. The aircraft engine speed measuring device provided by the embodiment of the present invention comprises: a speed measuring generator module, a hardware conditioning module, a high-speed A / D conversion module, a data pickup and buffer module, a digital signal processing module, a speed measuring module, a power supply module, an operation control module and a communication module connected in sequence.

[0052] like Figure 1 In the structure of the aircraft engine speed measuring device shown, the power supply module is respectively connected to the hardware conditioning module, the high-speed A / D conversion module, the operation control module and the communication module, and is used to provide secondary power supply to each module connected thereto. The operation control module is respectively connected to the high-speed A / D conversion module, the data pickup and buffer, the digital signal processing module, the speed measurement module and the communication module; the communication module is also respectively connected to the output end of the flight control computer and the speed measurement module.

[0053] The functions of the above modules in the embodiment of the present invention are described as follows:

[0054] The speed measuring generator module is used to convert the collected engine speed signal into a quasi-sinusoidal AC voltage signal whose frequency and amplitude are positively correlated with the speed, and transmit the quasi-sinusoidal AC voltage signal to the hardware conditioning module.

[0055] The operation control module serves as a carrier for the operation of the digital signal processing module, the speed measurement module, the communication software, and the high-speed A / D conversion module driving the control software.

[0056] The hardware conditioning module is used to condition a quasi-sinusoidal signal with a wide amplitude range into a signal that meets the amplitude range requirements of the high-speed A / D conversion module.

[0057] The high-speed A / D conversion module is used to perform high-speed sampling on the conditioned quasi-sine signal and convert it into a digital signal.

[0058] The data pickup and buffer module is used to pick up and buffer the digital signal after A / D conversion.

[0059] The digital signal processing module is used to convert the digital signal into a digital square wave signal.

[0060] The speed measurement module is used to monitor the frequency of the digital square wave signal with high reliability and further calculate the engine speed through the frequency.

[0061] Communication module, used to upload engine speed measurement results to the flight control computer.

[0062] The tachometer generator module in the embodiment of the present invention is installed on the engine, and the engine accessory casing drives the tachometer generator module to rotate synchronously to form an engine speed signal, which is converted and output as a quasi-sine wave AC voltage signal. The voltage amplitude and frequency of this type of sinusoidal wave AC voltage signal are positively correlated with the engine speed, and the maximum peak value of the output voltage is 10V.

[0063] In one implementation of the embodiment of the present invention, the hardware conditioning module includes: a signal limiting unit and a signal biasing unit connected in series; Figure 2 , which is a schematic diagram of the structure of a hardware conditioning module in an aircraft engine speed measurement device provided by a few embodiments of the present invention.

[0064] In this implementation, the signal limiting unit is composed of two diodes connected in parallel on the signal input line, one of which is forward-conducting and the other is reverse-conducting, respectively used to limit the positive half-cycle signal and the negative half-cycle signal of the sine-wave AC voltage signal.

[0065] In a specific embodiment, the function of the signal limiting unit is to limit the input quasi-sine wave AC voltage signal to a peak value of 0.7V. When the peak value of the sinusoidal signal is greater than 0.7V, the part greater than 0.7V is limited to 0.7V, and when the peak value is less than -0.7V, the part less than -0.7V is limited to -0.7V; when the peak value of the sinusoidal signal is less than 0.7V, the signal limiting unit has no effect on the sinusoidal signal.

[0066] In this implementation, the signal bias unit is an adder composed of a bias voltage generator and an operational amplifier. The bias voltage generator is used to generate a reference bias voltage with an amplitude of 1 / 2VCC. It is composed of two high-precision resistors with good temperature drift characteristics and equal resistance values ​​that are connected in series to divide the power supply voltage VCC. The voltage 1 / 2VCC after the resistor division is impedance matched by an emitter follower. 1 / 2VCC is input to the in-phase end of the emitter follower, the inverting end of the emitter follower is connected to the output end, and the output end of the emitter follower is connected to the in-phase input end of the operational amplifier. The quasi-sine wave AC voltage signal after limiting is transmitted to the inverting end of the operational amplifier, and the quasi-sine wave AC voltage signal is conditioned into a DC voltage signal with a bias voltage of 1 / 2VCC through the operational amplifier. Figure 3 for Figure 2 The illustrated embodiment provides a schematic diagram of the limiting effect and biasing effect of the signal limiting unit in the hardware conditioning module.

[0067] In one implementation of an embodiment of the present invention, the maximum sampling rate of the high-speed A / D conversion module is not less than 100KHz, and the trigger signal of the high-speed A / D conversion module is driven by the PWM signal output by the operation control module; the operation control module outputs a PWM signal with a frequency of 100KHz and a duty cycle of 50% to drive the start of the high-speed A / D conversion module and convert the DC voltage signal into a speed digital signal; the speed digital signal converted by the high-speed A / D conversion module supports the direct reading function of the DMA controller.

[0068] In one implementation of an embodiment of the present invention, the data pickup and buffer module is used to batch pick up and cache the speed digital signal output by the A / D conversion module. The speed digital signal formed by the A / D conversion module is output to the DMA controller in the data pickup and buffer module, and the DMA controller performs data cache.

[0069] In this implementation, for example, the buffer length of the DMA controller is configured to be 65536 and the width to be 16 bits. When the buffer reaches 65536 stored data, a DMA controller buffer full interrupt signal is sent to the operation control module, instructing the operation control module to send a data processing request to the digital signal processing module to transfer the data stored in the DMA controller buffer to the digital signal processing module for signal processing.

[0070] Correspondingly, the digital signal processing module in this implementation includes: a sinc3 filter, a hysteresis comparator, and a waveform corrector connected in series in sequence.

[0071] In this implementation, the sinc3 filter is used to suppress the high-frequency disturbance in the speed digital signal. The sinc3 filter receives the speed digital signal output by the data pickup and buffer module, and caches the speed digital signal after filtering by the sinc3 filter into a post-filtering buffer with a width of 16 bits and a length of 65536.

[0072] In the specific implementation, the implementation method of the sinc3 filter is as follows: the speed digital signal is first substituted as z into 1 / (1-z -1 ) is integrated, and the result is substituted as z into (1+z -4 ) is differentiated and multiplied by the gain to obtain the final output filtered speed digital signal.

[0073] The hysteresis comparator in this implementation is used to convert the filtered speed digital signal into a digital square wave signal. The signal conversion principle is as follows: first, set the comparison threshold lower limit and the comparison threshold upper limit, the lower limit is set to (1 / 2VCC-0.1)V, and the upper limit is set to (1 / 2VCC+0.1)V; then, calculate the first-order differential of the speed digital signal in the filtered buffer in turn, and determine the signal change trend of the filtered speed digital signal according to the differential result, the slope greater than 0 indicates that the signal is in an increasing section, and less than 0 indicates that the signal is in a decreasing section; again, the filtered speed digital signal is converted into a square wave digital signal by combining the signal change trend with the comparison threshold lower limit or the comparison threshold upper limit; specifically, if the filtered digital signal is in an increasing section and lower than the upper limit, the comparison result is 0, and higher than the upper limit is 1; if the filtered digital signal is in a decreasing section, it is 1 when it is higher than the lower limit, and 0 when it is lower than the lower limit; finally, the hysteresis comparator outputs the conversion result, that is, the output is equal to the length of the filtered buffer and only contains square wave signals with comparison results of 0 and 1.

[0074] The waveform corrector in this implementation is used to suppress the high-frequency disturbance component in the compared square wave digital signal. Figure 4 As shown, it is a schematic diagram of the working principle of the waveform corrector in the digital signal processing module in an embodiment of the present invention, and its suppression principle is: first, a rectangular window with a data length of 35 is set; secondly, the square wave digital signal is windowed and intercepted with the rectangular window of 35 data length, and the intercepted data is buffered in another buffer; thirdly, the continuous length of 0 and 1 in the intercepted data in the rectangular window of 35 data length is analyzed, and a sliding window of 10 data lengths is taken in the rectangular window of 35 data length, and the data in the rectangular window of 35 data length is slidingly windowed. If a data jump of 0-1-0 occurs in the data in the sliding window, all the data in the sliding window is corrected to 0, and if a data jump of 1-0-1 occurs in the data in the sliding window, all the data in the sliding window is corrected to 1.

[0075] In an implementation of the embodiment of the present invention, the rotation speed measurement module includes: a signal generating unit and a rotation speed measurement unit connected in series, and an output port of the signal generating unit is connected to an input port of the rotation speed measurement unit.

[0076] The signal generating unit in this implementation is used to convert the 0 and 1 square wave digital signals formed after being processed by the waveform corrector into hardware signals, and output them to the capture channel of the speed measurement unit; when the signal generating unit is running, it samples the square wave digital signals in the buffer of the waveform corrector in sequence with a period of 10us. If the sampling result is 0, the output port corresponding to the signal generating unit is set to a low level; if the sampling result is 1, the output port corresponding to the signal generating unit is set to a high level.

[0077] The speed measurement unit in this implementation is used to collect the hardware signal output by the signal generation unit, and determine the speed of the engine according to the frequency and period of the hardware signal.

[0078] In the specific implementation, the speed measurement unit includes a high-precision counter, an edge capturer, a timer, a register, and a rising edge counter. The high-precision counter runs at a cycle of 10ns and counts from 0 to 2. 32 Incremental, and become 0 after overflow; the edge capturer is used to identify the rising edge of the hardware signal input to the speed measurement unit. If the rising edge arrives, an interrupt is generated. In the interrupt service program, the software assigns the value of the high-precision counter to the register. According to the value in the register and the step size of the high-precision counter, the time between two rising edges, that is, the signal period, is calculated. After the signal period is calculated, the value of the high-precision counter is assigned to 0, laying the foundation for the next time statistics, and calculating the signal frequency 1 according to the signal period; the timing time of the timer is 0.2s, and the number of occurrences of the rising edge within 0.2s is counted with a period of 0.2s. The rising edge counter accumulates in each interrupt. After the 0.2s timing time is up, the signal frequency 2 is calculated according to the count value of the rising edge counter and the 0.2s time period. After the calculation is completed, the rising edge counter is cleared to prepare for the next technology.

[0079] If the signal frequency is lower than 100 Hz, signal frequency 1 is used to calculate the engine speed. If the signal frequency is higher than 100 Hz, signal frequency 2 is used to calculate the engine speed.

[0080] In one implementation of the embodiment of the present invention, the communication module receives the speed reporting instruction issued by the flight control computer, and uploads the engine speed to the flight control computer in real time according to a certain period.

[0081] The aircraft engine speed measuring device provided by the embodiment of the present invention comprises: a speed measuring generator module, a hardware conditioning module, a high-speed A / D conversion module, a data pickup and buffer module, a digital signal processing module, a speed measurement module, and a power supply module, an operation control module and a communication module connected in sequence; wherein the power supply module is respectively connected to the hardware conditioning module, the high-speed A / D conversion module, the operation control module and the communication module, and is used to provide secondary power supply to each module connected thereto; the operation control module is respectively connected to the high-speed A / D conversion module, the data pickup and buffer, the digital signal processing module, the speed measurement module and the communication module; the communication module is also respectively connected to the output end of the flight control computer and the speed measurement module. The aircraft engine speed measuring device provided by the embodiment of the present invention is mainly used in aircraft engine control systems, and has the following beneficial effects:

[0082] 1) Reduce the hardware complexity of the aircraft engine speed measurement device by increasing the software complexity;

[0083] 2) Based on the reduction of hardware complexity of aircraft engine speed measurement devices, the risk of hardware being affected by electromagnetic interference is reduced, thereby improving the electromagnetic compatibility and reliability of aircraft engine speed measurement;

[0084] 3) Based on the reduction of hardware complexity of aircraft engine speed measurement devices, that is, the corresponding reduction of hardware circuits, it is beneficial to reduce the size, weight and cost of the speed measurement device, and it is more beneficial to improve the power-to-weight ratio of the measurement device.

[0085] 4) Lay the foundation for improving the reliability and power density of aircraft engine control systems.

[0086] To sum up, the aircraft engine speed measuring device provided by the embodiment of the present invention has low hardware complexity and high algorithm complexity, and exchanges algorithm complexity for hardware complexity, and the total cost, reliability, electromagnetic compatibility, and volume-weight performance of the aircraft engine speed measuring device are more optimized, thereby improving the operating safety of the numerical control system and the aircraft engine.

[0087] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. An aircraft engine speed measuring device, characterized in that: include: The speed measuring generator module, hardware conditioning module, high-speed A / D conversion module, data pickup and buffer module, digital signal processing module, speed measuring module, power supply module, operation control module and communication module are connected in sequence; The power supply module is respectively connected to the hardware conditioning module, the high-speed A / D conversion module, the operation control module and the communication module, and is used to provide secondary power supply to each module connected thereto; The operation control module is respectively connected to the high-speed A / D conversion module, the data pickup and buffer, the digital signal processing module, the speed measurement module and the communication module; the communication module is also respectively connected to the output end of the flight control computer and the speed measurement module; The speed measuring generator module is used to convert the collected engine speed signal into a quasi-sine wave AC voltage signal whose frequency and amplitude are positively correlated with the speed, and transmit the quasi-sine wave AC voltage signal to the hardware conditioning module; The operation control module is the carrier for the operation of the digital signal processing module, the speed measurement module, the communication software, and the high-speed A / D conversion module drive control software; The hardware conditioning module is used to condition the quasi-sinusoidal signal with a wide amplitude range into a signal that meets the amplitude range requirements of the high-speed A / D conversion module; A high-speed A / D conversion module is used to perform high-speed sampling on the conditioned quasi-sine signal and convert it into a digital signal; A data pickup and buffer module is used to pick up and buffer the digital signal after A / D conversion; A digital signal processing module, used for converting a digital signal into a digital square wave signal; The speed measurement module is used to monitor the frequency of the digital square wave signal and calculate the engine speed through the frequency; Communication module, used to upload engine speed measurement results to the flight control computer.

2. The aircraft engine speed measuring device according to claim 1, characterized in that: The tachometer generator module is installed on the engine, and the engine accessory case drives the tachometer generator module to rotate synchronously to form an engine speed signal, which is converted and output as a quasi-sine wave AC voltage signal. The voltage amplitude and frequency of this type of sinusoidal wave AC voltage signal are positively correlated with the engine speed, and the maximum peak value of the output voltage is 10V.

3. The aircraft engine speed measuring device according to claim 1, characterized in that: The hardware conditioning module comprises: a signal limiting unit and a signal biasing unit connected in series; The signal limiting unit is composed of two diodes connected in parallel on the signal input line, one of which is forward-conducting and the other is reverse-conducting, respectively used to limit the positive half-cycle signal and the negative half-cycle signal of the quasi-sine wave AC voltage signal; The signal bias unit is configured as an adder consisting of a bias voltage generator and an operational amplifier; wherein the bias voltage generator is used to generate a reference bias voltage with an amplitude of 1 / 2VCC, and two resistors with equal resistance values ​​are connected in series to divide the power supply voltage VCC, and the voltage 1 / 2VCC after the resistor division is impedance matched by an emitter follower, 1 / 2VCC is input to the non-inverting end of the emitter follower, the inverting end of the emitter follower is connected to the output end, the output end of the emitter follower is connected to the non-inverting input end of the operational amplifier, and the quasi-sine wave AC voltage signal after limiting is transmitted to the inverting end of the operational amplifier, and the quasi-sine wave AC voltage signal is conditioned into a DC voltage signal with a bias voltage of 1 / 2VCC through the operational amplifier.

4. The aircraft engine speed measuring device according to claim 1, characterized in that: The maximum sampling rate of the high-speed A / D conversion module is not less than 100KHz, and the trigger signal of the A / D conversion module is driven by the PWM signal output by the operation control module; The operation control module outputs a PWM signal with a frequency of 100KHz and a duty cycle of 50% to drive the start of the high-speed A / D conversion module and convert the DC voltage signal into a speed digital signal; the speed digital signal converted by the high-speed A / D conversion module supports the direct reading function of the DMA controller.

5. The aircraft engine speed measuring device according to claim 1, characterized in that: The data pickup and buffer module is used to batch pick up and cache the speed digital signal output by the A / D conversion module. The speed digital signal formed by the A / D conversion module is output to the DMA controller in the data pickup and buffer module, and the DMA controller caches the data. The DMA controller is used to send a DMA controller buffer full interrupt signal to the operation control module after its buffer is full of data, instructing the operation control module to send a data processing request to the digital signal processing module to transfer the data stored in the buffer of the DMA controller to the digital signal processing module for signal processing.

6. The aircraft engine speed measuring device according to claim 5, characterized in that: The digital signal processing module includes: a sinc3 filter, a hysteresis comparator, and a waveform corrector connected in series in sequence; The sinc3 filter is used to suppress the high-frequency disturbance in the speed digital signal. The sinc3 filter receives the speed digital signal output by the data pickup and buffer module, and caches the speed digital signal after filtering by the sinc3 filter into a post-filtering buffer, and the length and width of the post-filtering buffer are the same as those of the buffer in the DMA controller; The hysteresis comparator is used to convert the filtered speed digital signal into a digital square wave signal; the signal conversion method is: sequentially calculating the first-order differential of the filtered speed digital signal in the filtered buffer, and determining the signal change trend of the filtered digital signal according to the differential result; according to the signal change trend and the preset comparison threshold lower limit or comparison threshold upper limit, converting the filtered speed digital signal into a square wave digital signal; The waveform corrector is used to suppress the high-frequency disturbance component in the compared square wave digital signal, and the suppression method is: firstly set a rectangular window with a data length of 35; secondly, perform windowing and interception on the square wave digital signal with the rectangular window of 35 data length, and buffer the intercepted data into another buffer; thirdly, analyze the continuous length of 0 and 1 in the intercepted data in the rectangular window of 35 data length, take a sliding window of 10 data lengths in the rectangular window of 35 data length, perform sliding windowing on the data in the rectangular window of 35 data length, if the data in the sliding window has a data jump of 0-1-0, then all the data in the sliding window will be corrected to 0, and if the data in the sliding window has a data jump of 1-0-1, then all the data in the sliding window will be corrected to 1.

7. The aircraft engine speed measuring device according to claim 1, characterized in that: The rotation speed measurement module comprises: a signal generating unit and a rotation speed measurement unit connected in series, wherein an output port of the signal generating unit is connected to an input port of the rotation speed measurement unit; The signal generating unit is used to convert the 0 and 1 square wave digital signals formed after being processed by the waveform corrector into hardware signals, and output them to the capture channel of the speed measurement unit; when the signal generating unit is running, the square wave digital signals in the buffer of the waveform corrector are sampled in sequence with a period of 10us, and if the sampling result is 0, the output port corresponding to the signal generating unit is set to a low level, and if the sampling result is 1, the output port corresponding to the signal generating unit is set to a high level; The speed measurement unit is used to collect the hardware signal output by the signal generation unit, and determine the speed of the engine according to the frequency and period of the hardware signal.

8. The aircraft engine speed measuring device according to claim 7, characterized in that: The rotation speed measurement unit includes: a high-precision counter, an edge capturer, a timer, a register, and a rising edge counter; There are two ways to calculate the frequency of hardware signals: Mode 1, the high-precision counter runs at a period of 10ns and counts from 0 to 2 32 Incremental, after overflow, it becomes 0; the edge capturer is used to identify the rising edge of the hardware signal input to the speed measurement unit. If the rising edge arrives, an interrupt is generated. In the interrupt service program, the software assigns the value of the high-precision counter to the register. According to the value in the register and the step size of the high-precision counter, the time between two rising edges, that is, the signal period, is calculated; after the signal period calculation is completed, the value of the high-precision counter is assigned to 0, and the signal frequency 1 is calculated according to the signal period; Mode 2: The timing time of the timer is 0.2s. The number of occurrences of the rising edge within 0.2s is counted with a period of 0.2s. The rising edge counter is accumulated in each interrupt. After the 0.2s timing time is up, the signal frequency 2 is calculated based on the count value of the rising edge counter and the 0.2s time period. After the calculation is completed, the rising edge counter is cleared; If the hardware signal frequency is lower than 100 Hz, the engine speed is calculated using hardware frequency 1. If the hardware signal frequency is higher than 100 Hz, the engine speed is calculated using hardware frequency 2.

9. The aircraft engine speed measuring device according to any one of claims 1 to 8, characterized in that: The communication module receives the speed reporting instruction issued by the flight control computer, and uploads the engine speed to the flight control computer in real time according to a preset period.

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