Design method of aircraft ground speed detection system

Abstract

The invention provides a design method of an aircraft ground speed detection system. The design method comprises the following steps: step 1, determining the maximum ground speed of an aircraft in a ground taxiing process; 2, determining the highest rotating speed of a front airplane wheel corresponding to the maximum ground speed in the ground sliding process of the airplane; 3, determining the detection speed range of a speed sensor according to the highest rotating speed of the front airplane wheel; 4, determining a ground speed detection range in the ground taxiing process of the aircraft; 5, determining a ground speed detection signal frequency range in the ground taxiing process of the aircraft; and 6, outputting a ground speed detection signal in the ground sliding process of the aircraft. The real-time ground speed of the aircraft can be obtained, the detection precision can be ensured without calibration, and the system is convenient to use and maintain.

Description

Technical Field

[0001] This invention relates to a design method for an aircraft ground speed detection system. Background Technology

[0002] Aircraft ground speed is the horizontal velocity of an aircraft relative to the ground, typically categorized into inertial navigation (INS) ground speed and GPS ground speed. INS ground speed is determined by the aircraft's inertial navigation system (INS) through internal gyroscopes and accelerometers, measuring the aircraft's motion and performing integration and coordinate transformation. GPS ground speed is provided by GPS satellites. INS ground speed offers advantages in autonomy and interference resistance, but requires periodic calibration to ensure long-term accuracy. Current methods for detecting aircraft ground speed result in an average speed, which can only approximate the true speed, making it difficult to obtain real-time ground speed data. Furthermore, the accuracy of INS ground speed depends entirely on calibration.

[0003] Currently, real-time vehicle speed measurement uses GPS technology or vehicle wheel speed sensors, which are actually detection methods that approximate real-time speed with average speed, but cannot obtain the real-time speed of the vehicle. To accurately measure vehicle speed, Doppler speed sensors are used, which can accurately measure vehicle speed and output pulse signals with a frequency proportional to the measured speed. Summary of the Invention

[0004] In view of this, the present invention provides a design method for an aircraft ground speed detection system to achieve accurate and reliable detection of the real-time ground speed of an aircraft during ground taxiing.

[0005] This invention provides the following technical solution: a design method for an aircraft ground speed detection system, comprising the following steps: Step 1, determining the maximum ground speed during aircraft taxiing; Step 2, determining the maximum rotational speed of the nose wheel corresponding to the maximum ground speed during aircraft taxiing; Step 3, determining the speed range detected by the speed sensor based on the maximum rotational speed of the nose wheel; Step 4, determining the ground speed detection range during aircraft taxiing; Step 5, determining the frequency range of the ground speed detection signal during aircraft taxiing; Step 6, outputting the ground speed detection signal during aircraft taxiing.

[0006] Compared with the prior art, the beneficial effects achieved by at least one of the above-mentioned technical solutions adopted in this invention include at least the following: during the aircraft's ground taxiing process, the aircraft's nose wheel drives the speed sensor to rotate at high speed, enabling the speed sensor to accurately and reliably detect the real-time ground speed of the aircraft during ground taxiing. This ground speed detection system can obtain the aircraft's real-time ground speed, ensuring detection accuracy without calibration, and the system is convenient to use and maintain. Attached Figure Description

[0007] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0008] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0009] Figure 2 This is a schematic diagram of the excitation detection circuit in an embodiment of the present invention; Figure 3 This is the output waveform and fluctuation error diagram of the speed sensor in an embodiment of the present invention. Detailed Implementation

[0010] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0011] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0012] This invention transforms the centrifugal sensor, originally mounted on the aircraft's nose wheel bracket, into a speed sensor capable of real-time detection of the wheel's rotational speed. The wheel speed sensor operates based on the principle of electromagnetic induction. A gear at the front of the speed sensor connects to a transmission gear on the aircraft's nose wheel bracket, driving the speed sensor rotor to rotate at high speed. During aircraft taxiing on the ground, relative motion occurs between the teeth on the speed sensor rotor and the teeth on the gear ring. When teeth are aligned, magnetic resistance is minimal, and the magnetic flux is maximum; when teeth are aligned with slots, magnetic resistance is maximum, and the magnetic flux is minimum. This change in magnetic resistance causes a change in magnetic flux in the magnetic circuit, which in turn generates an alternating induced voltage signal in the working coil. The speed sensor rotor and gear ring each have 12 teeth, so that one rotation of the speed sensor rotor outputs a 12Hz, approximately sinusoidal voltage signal with an amplitude of not less than 1V.

[0013] The wheel speed sensor is mounted on the bracket of the nose wheel. The speed sensor gear is connected and meshed with the shift fork inside the nose wheel bracket. The 14-tooth pinion of the transmission device reliably meshes with the 98-tooth gear of the wheel assembly, driving the speed sensor to rotate and output an approximately sinusoidal voltage signal. The transmission ratio is 1:7. During the aircraft's taxiing, the speed sensor rotates 7 times for every one rotation of the nose wheel.

[0014] During ground taxiing, the aircraft's nose wheel drives a speed sensor to rotate at high speed, enabling the sensor to accurately and reliably detect the aircraft's real-time ground speed. This ground speed detection system can obtain the aircraft's real-time ground speed without calibration, ensuring accuracy, and is easy to use and maintain.

[0015] Example 1 like Figure 1 As shown, this embodiment of the invention provides a design method for an aircraft ground speed detection system, including the following steps: Step 1: Determine the maximum ground speed of the aircraft during its taxiing process. During taxiing, the aircraft's maximum ground speed is determined based on the maximum speed achievable by the nose wheel. The maximum ground speed is the maximum speed that the speed sensor can detect on the nose wheel.

[0016] The following five parameters are related to the speed of an aircraft's nose wheel: maximum takeoff speed, maximum landing speed, tire inflation pressure, tire size, and average tire compression under normal takeoff load.

[0017] In this embodiment, the maximum takeoff speed is 360 km / h, the maximum landing speed is 280 km / h, the tire inflation pressure is (950±40) kPa, the tire size is 680×260 (mm), and the average tire compression under normal takeoff load is 30 (mm). In this embodiment, the maximum ground speed that can be accurately detected during aircraft taxiing is determined to be 360 ​​km / h.

[0018] Step 2: Determine the maximum speed of the nose wheel corresponding to the maximum ground speed during the aircraft's ground taxiing process; The maximum rotational speed of the nose wheel is calculated based on the maximum ground speed, tire outer diameter, and average tire compression under normal takeoff load. The specific calculation formula is as follows: (1) Front wheel speed, in revolutions per second (rpm), maximum front wheel speed nDmax; Ground speed of an aircraft, measured in km / h, is the maximum ground speed Vmax during taxiing. : Outer diameter of the front wheel tire, in meters; Average tire compression under design load, in meters (m). : Take it as 3.14.

[0019] In this embodiment, the maximum ground speed of the aircraft during ground taxiing is 360 km / h, the outer diameter of the nose wheel tire is 0.68m, and the average tire compression under normal takeoff load is 30mm. The maximum rotational speed nDmax of the nose wheel is determined by formula (1), and in this embodiment, nDmax = 51.366 rpm.

[0020] Step 3: Determine the speed range detected by the speed sensor; Based on the meshing relationship between the small gear in the internal transmission device of the front wheel and the large gear in the wheel assembly, the relationship between the front wheel speed and the rotation of the speed sensor shaft is first determined, and then converted into the speed range detected by the speed sensor. The relationship between the front wheel speed and the rotation of the speed sensor shaft is specifically determined by formula (2): nS=nD×ZD / Zd(2) nS: The rotational speed of the speed sensor shaft corresponding to nD, in revolutions per second (rpm). The maximum rotational speed of the speed sensor shaft is nSmax. ZD: Number of teeth on the large gear in the internal gear assembly of the front wheel, in teeth; Zd: Number of teeth on the pinion gear in the internal transmission device of the front wheel, in teeth.

[0021] In this embodiment, the maximum ground speed corresponding to the maximum ground speed during aircraft taxiing is 51.366 rpm; the number of teeth on the large gear of the internal wheel assembly of the front wheel is 98; and the number of teeth on the small gear of the internal transmission device of the front wheel is 14. Based on formula (2), nSmax = 359.562 rpm, that is, the maximum speed is 21573.72 rpm.

[0022] Since the speed sensor is an electromagnetic induction principle speed sensor, the speed sensor itself has a minimum detection speed. The speed sensor in this embodiment can detect a minimum rotational speed of 200 rpm, that is, a minimum rotational speed of 3.333 rpm.

[0023] The speed range of the speed sensor is determined to be 200 rpm to 21573.72 rpm, which is equivalent to a rotational speed range of 3.333 rpm to 359.562 rpm.

[0024] Step 4: Determine the ground speed detection range during aircraft taxiing. Determining the rotational speed range of the speed sensor determines the range for real-time ground speed detection during aircraft taxiing. During taxiing, the speed sensor reliably detects the rotational speed of the nose wheel and outputs an approximately sinusoidal voltage signal proportional to the nose wheel's rotational speed. The frequency of this signal is the aircraft's ground speed.

[0025] The wheel speed corresponding to the minimum rotational speed of the speed sensor is determined by formula (2), and the ground speed of the aircraft corresponding to the minimum rotational speed of the speed sensor is determined by formula (1).

[0026] In this embodiment, the minimum rotational speed of the speed sensor corresponds to a nose wheel rotation speed of 0.476 rpm, which corresponds to an aircraft ground speed of 3.336 km / h. Therefore, the aircraft ground speed detection range during taxiing is determined to be 3.336 km / h to 360 km / h. Based on engineering requirements, the aircraft ground speed during taxiing is determined to be 4 km / h to 360 km / h.

[0027] Step 5: Determine the frequency range of the ground speed detection signal during aircraft taxiing. The gear at the front end of the speed sensor is connected to the transmission gear on the aircraft's nose wheel bracket, driving the speed sensor rotor to rotate at high speed. When the aircraft taxis on the ground, relative motion occurs between the teeth on the speed sensor rotor and the teeth on the gear ring. The change in magnetic resistance between the speed sensor rotor and the gear ring causes the magnetic flux through the working coil in the magnetic circuit to alternate, generating an alternating induced electromotive force. The speed sensor rotor and gear ring each have 12 teeth. When the speed sensor rotor rotates once, the working coil in the sensor outputs an approximately sinusoidal voltage signal with an amplitude of not less than 1V at 12Hz. The ground speed signal frequency during the aircraft's taxiing is proportional to the rotational speed of the aircraft's nose wheel. The relationship between the ground speed signal frequency and the aircraft speed during the aircraft's taxiing is determined by formula (3): fS=K×nS(3) fS: Frequency of the speed sensor output signal, in Hz; K: Number of teeth inside the speed sensor, in units of teeth.

[0028] In this embodiment, the minimum ground speed during aircraft taxiing corresponds to the lowest rotational speed of the sensor shaft of 3.333 rpm, and the maximum ground speed corresponds to the highest rotational speed of the nose wheel of 359.562 rpm. The K value in the speed sensor is 12.

[0029] The minimum ground speed signal frequency of the aircraft, calculated using formula (3), is 39.996 Hz, and is determined to be 40 Hz. The maximum ground speed signal frequency of the aircraft, calculated using formula (3), is 4314.744 Hz, and is determined to be 4315 Hz. During ground taxiing, when the aircraft's ground speed is between 3.336 km / h and 360 km / h, the output detection signal frequency is determined to be between 40 Hz and 4315 Hz. Based on engineering requirements, during ground taxiing, when the aircraft's ground speed is between 4 km / h and 360 km / h, the output detection signal frequency is determined to be between 48 Hz and 4315 Hz.

[0030] Step 6: Determine the ground speed detection signal output circuit during aircraft taxiing. The speed sensor is mounted on the aircraft's nose wheel to sense its speed, accurately detecting the aircraft's ground speed in real time during taxiing. The speed sensor outputs an approximately sinusoidal voltage signal, the frequency of which is proportional to the aircraft's ground speed, providing data for the aircraft's use.

[0031] The main technical parameters of the speed sensor selected in this embodiment are as follows: a) Input speed range: (0~22000) r / min b) Rotation direction: clockwise or counterclockwise c) Output waveform: Sine wave (approximate) d) Output peak-to-peak value with load: VP-P greater than or equal to 1V e) Excitation current: (5±1) mA f) Fluctuation error: less than or equal to 15% See the speed sensor performance detection circuit. Figure 2 The schematic diagram of the excitation detection circuit and the output waveform of the speed sensor are shown below. Figure 3 The speed sensor output waveform and fluctuation error. During aircraft taxiing on the ground, when the aircraft's ground speed ranges from 4 km / h to 360 km / h, the aircraft ground speed testing system can accurately measure the aircraft speed signal frequency from 48 Hz to 4315 Hz, providing the data for aircraft use.

[0032] Example 2: A modified implementation based on multi-sensor fusion This embodiment, based on Embodiment 1, introduces multi-sensor data fusion to improve the accuracy and reliability of ground speed detection.

[0033] Step 1: Determine the maximum ground speed In addition to the front wheel speed sensor, ground speed data is also obtained by combining the airborne GPS module. The maximum ground speed measured by GPS is weighted and fused with the front wheel sensor data, and the value with higher confidence is taken as the maximum ground speed.

[0034] Step 2: Determine the maximum speed of the front wheel. When calculating the maximum speed of the front wheel, considering the tire wear factor λ (0.95~1.0) and correcting the tire compression δ, the formula is adjusted as follows: ; Ground speed of an aircraft, measured in km / h, is the maximum ground speed Vmax during taxiing. : Outer diameter of the front wheel tire, in meters; Average tire compression under design load, in meters (m). : Take it as 3.14 Step 3: Determine the detection range of the speed sensor Dual redundant speed sensors are used, with the detection range being the union of the two sensors, and fault switching logic is set.

[0035] Step 4: Determine the ground speed detection range By fusing front wheel sensor and GPS data through Kalman filtering, the upper and lower limits of ground speed detection are dynamically corrected.

[0036] Step 5: Determine the frequency range of the ground speed detection signal Adding a digital signal processor (DSP) to perform frequency domain analysis on the sensor output eliminates interference frequency components, and the effective frequency range is adaptively adjusted according to the signal-to-noise ratio.

[0037] Step Six: Signal Output The output circuit integrates a CAN bus interface to transmit ground speed data and health status information to the flight control system in real time.

[0038] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical solutions, and technical solutions in this invention can be freely combined and used.

Claims

1. A design method for an aircraft ground speed detection system, characterized in that, Includes the following steps: Step 1: Determine the maximum ground speed of the aircraft during its taxiing process. Step 2: Determine the maximum speed of the nose wheel corresponding to the maximum ground speed during the aircraft's ground taxiing process; Step 3: Determine the speed range detected by the speed sensor based on the maximum rotational speed of the front wheel; Step 4: Determine the ground speed detection range during aircraft taxiing. Step 5: Determine the frequency range of the ground speed detection signal during the aircraft's ground taxiing process; Step 6: Output the ground speed detection signal during the aircraft's ground taxiing process.

2. The design method for an aircraft ground speed detection system according to claim 1, characterized in that, Step one specifically involves detecting the maximum speed of the front wheel using a speed sensor and using it as the maximum ground speed.

3. The design method for an aircraft ground speed detection system according to claim 2, characterized in that, The maximum speed of the nose wheel includes the maximum takeoff speed and the maximum landing speed, and the larger of the maximum takeoff speed and the maximum landing speed is taken as the maximum ground speed.

4. The design method for an aircraft ground speed detection system according to claim 3, characterized in that, Step two specifically involves determining the maximum speed of the nose wheel based on the maximum ground speed detectable during aircraft taxiing, tire outer diameter, and average tire compression under normal takeoff load.

5. The design method for an aircraft ground speed detection system according to claim 4, characterized in that, Step three specifically involves: The maximum speed of the speed sensor is determined based on the meshing relationship between the pinion of the internal transmission device of the front wheel and the large gear of the wheel assembly, as well as the maximum speed of the front wheel. The maximum speed of the speed sensor is then taken as the highest value of its detection range. The minimum rotational speed of the speed sensor is used as the lowest value of its detection range to obtain the detection range of the speed sensor.

6. The design method for an aircraft ground speed detection system according to claim 5, characterized in that, Step four specifically involves: The wheel speed corresponding to the minimum rotational speed of the speed sensor is determined by using the minimum rotational speed of the speed sensor and according to step three. Based on the wheel speed corresponding to the minimum rotational speed of the speed sensor and step two, determine the aircraft ground speed corresponding to the minimum rotational speed of the speed sensor.

7. The design method for an aircraft ground speed detection system according to claim 6, characterized in that, Step five specifically involves: The speed sensor's rotor rotates one revolution and outputs a voltage signal of a set amplitude. Determine the relationship between the ground speed signal frequency and the rotational speed of the aircraft's nose wheel during ground taxiing.

8. The design method for an aircraft ground speed detection system according to claim 7, characterized in that, Step six specifically involves: Based on the voltage signal and the ground speed signal frequency during aircraft taxiing, the ground speed detection signal output circuit during aircraft taxiing is determined, and the output waveform and fluctuation error of the speed sensor are output.

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