Helicopter rotor laser common taper measuring system

Abstract

The invention discloses a laser common taper measurement system for a helicopter rotor, relates to the technical field of precision measurement, and aims to solve the problems that at least ten pulse signals need to be introduced to participate in calculation of time intervals and blade waving taper parameters in an existing laser measurement method, an indirect measurement method is adopted, and the measurement uncertainty reaches 0.5 mm. According to the method, the laser distance measuring sensor and the timestamp concept are utilized, the height and the cutting time of the rotor blade are directly measured through a non-contact measurement method of blade cutting laser beams, only two signals are needed to participate in calculation, and the uncertainty of measurement of the flapping and shimmy characteristic parameters of the rotor blade is not larger than 0.1 mm.

Description

Technical Field

[0001] The invention relates to the technical field of precision measurement, in particular to a helicopter rotor laser common taper measurement system. Background Art

[0002] The common taper refers to the degree of deviation of the two conical parts of the helicopter rotor in the height direction. In the helicopter rotor system, the common taper is an important parameter, which affects the balance and flight stability of the rotor.

[0003] The common taper measurement is crucial to ensure the safety and efficiency of helicopter flight, because it directly affects the aerodynamic performance and mechanical stability of the rotor. There have been many methods for rotor common taper measurement in its development history, such as: benchmark method, stroboscope method, infrared technology method, general trajectory equipment method, panoramic vision method, high-speed CCD imaging method and laser measurement method. At present, the high-speed CCD imaging method and laser measurement method are mainly used in practice in my country. Among them, the laser measurement method has higher accuracy and shorter delay than other methods. However, the previous laser measurement method is limited by the backwardness of sensor technology and computer processing capabilities, as well as the complexity of algorithms and structures, and is no longer suitable for the application of contemporary helicopter rotor common taper measurement.

[0004] The existing laser measurement method originated from the French technology in the 1980s and 1990s. It requires the introduction of at least 10 pulse signals to participate in the calculation of the time interval and blade flapping taper parameters. It is an indirect measurement method with a measurement uncertainty of 0.5mm. Summary of the invention

[0005] The purpose of the present invention is to provide a helicopter rotor laser common taper measurement system to address the problem that the existing laser measurement method requires the introduction of at least 10 pulse signals to participate in the calculation of the time interval and the blade flapping taper parameters, which is an indirect measurement method with a measurement uncertainty of up to 0.5 mm.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A helicopter rotor laser common taper measurement system, the system comprising a laser ranging subsystem and a data processing subsystem;

[0008] The laser distance measurement subsystem includes a laser displacement sensor, a laser sensor and a reflector;

[0009] The laser displacement sensor is a self-reflective laser sensor;

[0010] The laser sensor is a regression reflection type laser sensor, and the reflector is used to reflect the laser emitted by the laser sensor;

[0011] The data processing subsystem specifically performs the following steps:

[0012] Step 1: When the blade cuts the light beam emitted by the laser displacement sensor, the height value of each cut is recorded, and the height difference of the blade is obtained based on the height value recorded each time;

[0013] Step 2: When a blade cuts the beam emitted by the laser sensor, the timestamps of the two consecutive times are recorded as T A1 and T A1 ' and timestamps the time when the remaining blades cut the beam from the laser sensor;

[0014] Step 3: The average time T taken for the blade to rotate 360° / n is expressed as:

[0015] T=(T A1 '-T A1 ) / n

[0016] The blade swing angle difference ΔΦ at 360° / n is expressed as:

[0017] ΔΦ=360° / n(1-Tn / T)

[0018] Where n is the total number of blades, and Tn is the difference between the timestamps of the current blade and the previous blade.

[0019] Further, the laser ranging subsystem includes a first laser displacement sensor, a second laser displacement sensor, a first laser sensor, a second laser sensor, a first reflector and a second reflector;

[0020] The first laser displacement sensor and the second laser displacement sensor are self-reflective laser sensors;

[0021] The first laser sensor and the second laser sensor are regression reflection type laser sensors, the first reflector is used to reflect the laser emitted by the first laser sensor, and the second reflector is used to reflect the laser emitted by the second laser sensor;

[0022] The first laser displacement sensor, the second laser displacement sensor, the first laser sensor and the second laser sensor are cross-arranged, the distance between the first laser displacement sensor, the first laser sensor and the first reflector is the same as the distance between the second laser displacement sensor, the second laser sensor and the second reflector, and the first reflector and the second reflector are on the same reference plane.

[0023] Furthermore, the system also includes a signal processing subsystem, and the signal processing subsystem uses a signal amplifier to amplify the signals of the laser displacement sensor and the laser sensor.

[0024] Furthermore, the system also includes a network interface module for sending the signal amplified by the signal amplifier to the data processing subsystem, and the network interface module and the data processing subsystem are connected via an EtherCAT communication cable.

[0025] Furthermore, the data processing subsystem includes a C6930 industrial computer, an EK1100 EtherCAT network coupler and an EL1252 digital input module. The EK1100 EtherCAT network coupler and the EL1252 digital input module constitute an EtherCAT network substation. The EtherCAT network substation is used to receive digital signals from the signal amplifier and send them to the C6930 industrial computer via EtherCAT communication.

[0026] Furthermore, the laser displacement sensor is an IL2000 CMOS laser displacement sensor.

[0027] Furthermore, the laser sensor is a LV-NH62 digital laser sensor.

[0028] Furthermore, the system also includes a signal processing subsystem, which includes an IL1500 signal amplifier and a LV-N11P signal amplifier. The IL1500 signal amplifier is used to amplify the signal of the IL2000 CMOS laser displacement sensor, and the LV-N11P signal amplifier is used to amplify the signal of the LV-NH62 digital laser sensor.

[0029] Furthermore, the angle θ formed by the laser sensor and the rotor shaft is greater than 0.9°.

[0030] The beneficial effects of the present invention are:

[0031] This application utilizes laser ranging sensors and timestamp concepts to directly measure the rotor blade height and cutting time through a non-contact measurement method of the blade cutting laser beam. This application only requires two signals to participate in the calculation, so that the measurement uncertainty of the rotor blade flapping and swing characteristic parameters is no more than 0.1mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the system structure diagram of this application;

[0033] Figure 2 This is a system configuration diagram of this application;

[0034] Figure 3 This is a schematic diagram of the system connection structure of this application;

[0035] Figure 4 A light diagram of the laser sensor for this application;

[0036] Figure 5 This is a pulse timing diagram of the three rotor blades of this application rotating one circle;

[0037] Figure 6 This is a schematic diagram of the spatial position relationship between the laser sensor and the rotor shaft in this application. DETAILED DESCRIPTION

[0038] It should be particularly noted that, in the absence of conflict, the various embodiments disclosed in this application can be combined with each other.

[0039] Specific implementation method 1: A helicopter rotor laser common taper measurement system described in this implementation method includes a laser ranging subsystem and a data processing subsystem;

[0040] The laser distance measurement subsystem includes a laser displacement sensor, a laser sensor and a reflector;

[0041] The laser displacement sensor is a self-reflective laser sensor;

[0042] The laser sensor is a regression reflection type laser sensor, and the reflector is used to reflect the laser emitted by the laser sensor;

[0043] The helicopter rotor blades are driven by the hub to rotate in the laser ranging subsystem, cutting the laser light;

[0044] The data processing subsystem specifically performs the following steps:

[0045] Step 1: When the blade cuts the light beam emitted by the laser displacement sensor, the height value of each cut is recorded, and the height difference of the blade is obtained based on the height value recorded each time;

[0046] Step 2: When a blade cuts the beam emitted by the laser sensor, the timestamps of the two consecutive times are recorded as T A1 and T A1 ' and timestamps the time when the remaining blades cut the beam from the laser sensor;

[0047] Step 3: The average time T taken for the blade to rotate 360° / n is expressed as:

[0048] T=(T A1 '-T A1 ) / n

[0049] The blade swing angle difference ΔΦ at 360° / n is expressed as:

[0050] ΔΦ=360° / n(1-Tn / T)

[0051] Where n is the total number of blades, and Tn is the difference between the timestamps of the current blade and the previous blade.

[0052] Specific implementation method 2: This implementation method is a further description of specific implementation method 1. The difference between this implementation method and specific implementation method 1 is that the laser ranging subsystem includes a first laser displacement sensor, a second laser displacement sensor, a first laser sensor, a second laser sensor, a first reflector and a second reflector;

[0053] The first laser displacement sensor and the second laser displacement sensor are self-reflective laser sensors;

[0054] The first laser sensor and the second laser sensor are regression reflection type laser sensors, the first reflector is used to reflect the laser emitted by the first laser sensor, and the second reflector is used to reflect the laser emitted by the second laser sensor;

[0055] The first laser displacement sensor, the second laser displacement sensor, the first laser sensor and the second laser sensor are cross-arranged, the distance between the first laser displacement sensor, the first laser sensor and the first reflector is the same as the distance between the second laser displacement sensor, the second laser sensor and the second reflector, and the first reflector and the second reflector are on the same reference plane.

[0056] Specific implementation method three: This implementation method is a further explanation of specific implementation method one. The difference between this implementation method and specific implementation method one is that the system also includes a signal processing subsystem, and the signal processing subsystem uses a signal amplifier to amplify the signals of the laser displacement sensor and the laser sensor.

[0057] Specific implementation method four: This implementation method is a further explanation of specific implementation method three. The difference between this implementation method and specific implementation method three is that the system also includes a network interface module for sending the signal amplified by the signal amplifier to the data processing subsystem, and the network interface module and the data processing subsystem are connected via an EtherCAT communication cable.

[0058] Specific implementation method five: This implementation method is a further explanation of specific implementation method four. The difference between this implementation method and specific implementation method four is that the data processing subsystem includes a C6930 industrial computer, an EK1100 EtherCAT network coupler and an EL1252 digital input module. The EK1100 EtherCAT network coupler and the EL1252 digital input module constitute an EtherCAT network substation, and the EtherCAT network substation is used to receive digital signals from the signal amplifier and send them to the C6930 industrial computer via EtherCAT communication.

[0059] Specific implementation example 6: This implementation example is a further description of the specific implementation example 1. The difference between this implementation example and the specific implementation example 1 is that the laser displacement sensor is an IL2000 CMOS laser displacement sensor.

[0060] Specific implementation method seven: This implementation method is a further description of specific implementation method six. The difference between this implementation method and specific implementation method six is ​​that the laser sensor is a LV-NH62 digital laser sensor.

[0061] Specific implementation eight: This implementation is a further explanation of specific implementation seven. The difference between this implementation and specific implementation seven is that the system also includes a signal processing subsystem, and the signal processing subsystem includes an IL1500 signal amplifier and a LV-N11P signal amplifier. The IL1500 signal amplifier is used to amplify the signal of the IL2000 CMOS laser displacement sensor, and the LV-N11P signal amplifier is used to amplify the signal of the LV-NH62 digital laser sensor.

[0062] Specific implementation method 9: This implementation method is a further description of specific implementation method 8. The difference between this implementation method and specific implementation method 8 is that the angle θ formed by the laser sensor and the rotor shaft is greater than 0.9°.

[0063] Example:

[0064] like Figure 1 As shown, the system described in the present application includes a laser ranging subsystem 1, a signal processing subsystem 4, a network interface module 5 and a data processing subsystem 6. The rotor blades 2 are driven by the hub 3 to rotate in the laser ranging subsystem 1 and cut the laser light.

[0065] like Figure 2 and 3As shown, the laser ranging subsystem consists of two pairs of IL2000 CMOS laser displacement sensors 1.1 and 1.2, two pairs of LV-NH62 digital laser sensors 1.3 and 1.4, reflectors 1.5 and 1.6, helicopter rotor blades 2 and hub 3. Among them, the IL2000 CMOS laser displacement sensor and the LV-NH62 digital laser sensor are used in pairs, sensors 1.1 and 1.3 and reflector 1.5 are one group, and sensors 1.2 and 1.4 and reflector 1.6 are one group. The two combinations are redundant backups for each other, and the measurement data can be mutually verified. When the rotor blades rotate and cut the LV-NH62 sensor light column, the sensor outputs a digital signal to mark the blade sequence for the IL2000 laser displacement sensor. When cutting the IL2000 laser displacement sensor light column, the sensor can directly measure the blade height and output the height value to the IL1500 signal amplifier. The IL2000 CMOS laser displacement sensor is a self-reflective laser sensor and does not require a reflector. The LV-NH62 digital laser sensor is a retro-reflective laser sensor and needs to be used with a reflector.

[0066] The signal processing subsystem includes two IL1500 signal amplifiers 4.1 and 4.2, and two LV-N11P signal amplifiers 4.3 and 4.4. One end of the IL1500 signal amplifier 4.1 is connected to the IL2000 CMOS laser displacement sensor 1.1 through a data line, and one end of 4.2 is connected to 1.2 to read the measured value. The IL1500 signal amplifier can set parameters such as measurement distance and sampling period, can output analog quantities, and can also support multiple communication protocols. The sampling period can be as fast as 0.33ms, and the repeatability is 0.1mm; the LV-N11P signal amplifier 4.3 is connected to the LV-NH62 digital laser sensor 1.3 through a data line, and 4.4 is connected to 1.4 to read the digital signal. The LV-N11P signal amplifier outputs digital signals and transmits them directly to the digital input module 6.3 of the data processing system through a signal cable. The response time can be as fast as 80μs, and the output can be selected to be valid at the rising edge or the falling edge of the sensing light.

[0067] The network interface module includes DL-EC1A communication modules 5.1 and 5.2. DL-EC1A communication module 5.1 is connected to the other end of IL1500 signal amplifier 4.1 through a data line, and communication module 5.2 is connected to the other end of signal amplifier 4.2. Two DL-EC1A communication modules and the data processing system are connected through an EtherCAT communication cable to complete data exchange. DL-EC1A communication module supports EtherCAT bus communication with a transmission rate of 100Mbps. EtherCAT was initiated and developed by BECKHOFF and is a real-time fieldbus system based on Ethernet.

[0068] like Figure 1 , Figure 2 and Figure 3 As shown, the data processing subsystem includes C6930 industrial computer 6.1, EK1100 EtherCAT network coupler 6.2 and EL1252 digital input module 6.3. The EL1252 module is a 2-channel digital input module that can generate time stamps for digital signals. The digital signal edge trigger time stamp resolution is 1ns, and the time stamp accuracy within the module is 10ns. The EL1252 digital input module and the EK1100 network coupler are assembled together to form an EtherCAT network substation, which is used to receive digital signals from LV-N11P signal amplifiers 4.3 and 4.4 and transmit them to C6930 industrial computer 6.1 through EtherCAT communication. The EK1100 EtherCAT network coupler 6.2 is connected to the DL-EC1A EtherCAT communication module 5.2 through the EtherCAT communication cable, and transmits the measured values ​​from the IL1500 signal amplifiers 4.1 and 4.2 to the C6930 industrial computer 6.1 through EtherCAT communication. The C6930 industrial computer is the control core for implementing the measurement algorithm of this application. The algorithm program and control logic are implemented in the TWINCAT programming software in the C6930 computer, and finally displayed, stored or printed in the host computer program written by C# software.

[0069] like Figure 4 As shown in the figure, the IL2000 laser displacement sensor can directly measure the blade height, with a measurement range of 1000 to 3500 mm. When using the IL2000 sensor to measure displacement, the reference datum plane must be set first. The measurement value of the IL2000 sensor to the reference datum plane is 0. When the blade rotates between the IL2000 sensor and the reference datum plane to cut the light, the measured height value is a positive value. The light of the laser sensor in the figure is marked as light A, B, C, and D from right to left. The horizontal dotted line in the figure represents the different heights of the cutting light when the blade rotates, and the horizontal solid line represents the reference datum plane for the laser sensor to measure the distance.

[0070] When blade 1 cuts beam B, the measured height is recorded as h B1 , which are then denoted as h B2 ,h B3 …. Similarly, when the blades cut the beam D in sequence, the measured height is recorded as h D1 、h D2 ,h D3 ….

[0071] Therefore, the height difference between the blades is:

[0072] Δh12=h B2 -hB1 =h D2 -h D1

[0073] Δh13=h B3 -h B1 =h D3 -h D1

[0074] Δh23=h B3 -h B2 =h D3 -h D2

[0075] For the swing angle parameters of the rotor blades, if there are three blades, the pulse timing diagram of the laser sensor beam cut by the blades when rotating is as follows: Figure 5 As shown:

[0076] The timestamps of the two consecutive times when blade 1 cuts beam A are recorded as T A1 and T A1 ', the timestamps when blades 2 and 3 cut beam A are recorded as T A2 and T A3 .

[0077] The average time T taken for a blade to rotate 120° is 120 have:

[0078] T 120 =(T A1 '-T A1 ) / 3

[0079] The swing angle differences of the three rotor blades at 120° are:

[0080] ΔΦ1=120(1-T1 / T 120 )

[0081] ΔΦ2=120(1-T2 / T 120 )

[0082] ΔΦ3=120(1-T3 / T 120 )

[0083] in,

[0084] T1=T A2 -T A1

[0085] T2=T A3 -T A2

[0086] T3=T A1 '-T A3

[0087] Similarly, the timestamp can also be marked by cutting the light beam C with a blade, and the algorithm is the same as above.

[0088] The rotation speed of the rotor blade is no more than 450 rpm, the timestamp resolution is 1 nanosecond, the input delay in the acquisition module is 10 nanoseconds, and the fastest sampling times of the IL2000 laser displacement sensor and LV-NH62 digital laser sensor are 0.33ms and 80μs respectively, that is, the sampling frequencies are 3.03kHz and 12.5kHz respectively.

[0089] The relationship between the linear velocity, angular velocity and rotational speed during the rotation of the rotor blade is calculated as follows:

[0090] v=ωR=2πn×R. Where:

[0091] v: Linear speed

[0092] ω: angular velocity (rad / s)

[0093] n: speed (r / s)

[0094] R: Radius

[0095] If the maximum rotor speed is 450rpm, the angular velocity is 15π / s, and the time required to rotate through the angle θ is:

[0096] tθ=θ / 15π(s)

[0097] So the frequency of edge triggering the two laser sensors is:

[0098] fθ=15π / θ(Hz)

[0099] The sampling frequency of the sensor should be greater than fθ, so the angle θ formed by the installation position of the laser sensor and the rotor axis determines the sampling frequency of the measurement signal. Therefore:

[0100] fθ<3030Hz, that is, 15π / θ<3030, so θ>0.005π, that is, θ>0.9°.

[0101] like Figure 6 As shown, it is obvious that an angle greater than 0.9° is easily achievable. Therefore, the present application has a simpler installation structure.

[0102] This application reduces the number of laser sensors used and adopts a redundant design, which makes the structure simpler and the installation and debugging more convenient. Figure 1As shown, the system consists of CMOS laser displacement sensor IL2000 (1.1, 1.2) and digital laser sensor LV-NH62 (1.3, 1.4). Among them, 1.1 and 1.3 are a group, 1.2 and 1.4 are a group, each group can complete the measurement output independently, and can perform data verification and redundant backup for each other.

[0103] This application introduces the concept of timestamp. The timestamp comes from the synchronized clock of a computer or other timing device. The specific reference point is based on international standardized time. It is a time mark (digital value) that represents a specific moment, and the measurement unit can be accurate to nanoseconds. It is widely used to record the time when an event occurs, maintain time consistency, compare time, sort data, and prevent tampering. In this application, the timestamp generated when the rotor blade cuts the two laser sensors can be used to obtain the time interval when the blade passes the two sensors. Therefore, the use of timestamps does not require the introduction of synchronous control signals, which simplifies the control logic and algorithms.

[0104] In summary, the present invention utilizes advanced sensors and data processing technology to simplify, changes indirect measurement into direct measurement, simplifies the algorithm and structure while ensuring the accuracy and safety and reliability of the measurement, and the measurement uncertainty is no more than 0.1 mm.

[0105] It should be noted that the specific implementation is only an explanation and description of the technical solution of the present invention, and cannot be used to limit the scope of protection of the rights. Any partial changes made according to the claims and description of the present invention should still fall within the scope of protection of the present invention.

Claims

1. A helicopter rotor laser common taper measurement system, characterized in that The system includes a laser ranging subsystem and a data processing subsystem; The laser distance measurement subsystem includes a laser displacement sensor, a laser sensor and a reflector; The laser displacement sensor is a self-reflective laser sensor; The laser sensor is a regression reflection type laser sensor, and the reflector is used to reflect the laser emitted by the laser sensor; The data processing subsystem specifically performs the following steps: Step 1: When the blade cuts the light beam emitted by the laser displacement sensor, the height value of each cut is recorded, and the height difference of the blade is obtained based on the height value recorded each time; Step 2: When a blade cuts the beam emitted by the laser sensor, the timestamps of the two consecutive times are recorded as T A1 and T A1 ' and timestamps the time when the remaining blades cut the beam from the laser sensor; Step 3: The average time T taken for the blade to rotate 360° / n is expressed as: T=(T A1 ’-T A1 ) / n The blade swing angle difference ΔΦ at 360° / n is expressed as: ΔΦ=360° / n(1-Tn / T) Where n is the total number of blades, and Tn is the difference between the timestamps of the current blade and the previous blade.

2. A helicopter rotor laser common taper measurement system according to claim 1, characterized in that The laser ranging subsystem includes a first laser displacement sensor, a second laser displacement sensor, a first laser sensor, a second laser sensor, a first reflector and a second reflector; The first laser displacement sensor and the second laser displacement sensor are self-reflective laser sensors; The first laser sensor and the second laser sensor are regression reflection type laser sensors, the first reflector is used to reflect the laser emitted by the first laser sensor, and the second reflector is used to reflect the laser emitted by the second laser sensor; The first laser displacement sensor, the second laser displacement sensor, the first laser sensor and the second laser sensor are cross-arranged, the distance between the first laser displacement sensor, the first laser sensor and the first reflector is the same as the distance between the second laser displacement sensor, the second laser sensor and the second reflector, and the first reflector and the second reflector are on the same reference plane.

3. A helicopter rotor laser common taper measurement system according to claim 1, characterized in that The system also includes a signal processing subsystem, which uses a signal amplifier to amplify the signals of the laser displacement sensor and the laser sensor.

4. A helicopter rotor laser common taper measurement system according to claim 3, characterized in that The system also includes a network interface module for sending the signal amplified by the signal amplifier to the data processing subsystem, and the network interface module is connected to the data processing subsystem via an EtherCAT communication cable.

5. A helicopter rotor laser common taper measurement system according to claim 4, characterized in that The data processing subsystem includes a C6930 industrial computer, an EK1100 EtherCAT network coupler and an EL1252 digital input module. The EK1100 EtherCAT network coupler and the EL1252 digital input module constitute an EtherCAT network substation. The EtherCAT network substation is used to receive digital signals from a signal amplifier and send them to the C6930 industrial computer via EtherCAT communication.

6. The helicopter rotor laser common taper measurement system according to claim 1, characterized in that The laser displacement sensor is an IL2000 CMOS laser displacement sensor.

7. A helicopter rotor laser common taper measurement system according to claim 6, characterized in that The laser sensor is a LV-NH62 digital laser sensor.

8. A helicopter rotor laser common taper measurement system according to claim 7, characterized in that The system also includes a signal processing subsystem, which includes an IL1500 signal amplifier and a LV-N11P signal amplifier. The IL1500 signal amplifier is used to amplify the signal of the IL2000 CMOS laser displacement sensor, and the LV-N11P signal amplifier is used to amplify the signal of the LV-NH62 digital laser sensor.

9. The helicopter rotor laser common taper measurement system according to claim 1, characterized in that The angle θ formed by the laser sensor and the rotor shaft is greater than 0.9°.

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