Helicopter tail rotor speed control method, device, equipment and medium

Abstract

The present invention belongs to the field of helicopter control technology and specifically discloses a method, device, equipment, and medium for controlling the tail rotor speed of a helicopter. The method comprises obtaining the position information of the helicopter; determining the operating phase of the helicopter based on the position information, wherein the operating phase includes a ground startup phase and an airborne phase; and regulating the tail rotor speed according to the operating phase. Specifically, when the operating phase is the ground startup phase, the tail rotor speed is closed-loop controlled so that the tail rotor speed during the stable operation of the helicopter is within a first preset range; and when the operating phase is the airborne phase, the tail rotor speed is within a second preset range. The present invention solves the problems of helicopter spinning on the ground and excessive tail boom vibration levels.

Description

Technical Field

[0001] The present invention belongs to the technical field of helicopter control, and in particular relates to a method, device, equipment and medium for controlling the rotational speed of a helicopter tail rotor. Background Art

[0002] With the accelerating development of intelligent and unmanned technologies, electric unmanned helicopters are demonstrating tremendous potential in a wide range of fields. Traditional fuel-powered helicopters suffer from high fuel consumption, high noise levels, and high maintenance costs. Electric unmanned helicopters, with their environmentally friendly, efficient, and low-cost advantages, are poised to become a key direction for future aviation development. In particular, the market is urgently demanding efficient, flexible, and low-cost unmanned aerial vehicles in sectors such as logistics, agriculture, and emergency response.

[0003] However, traditional helicopter tail rotor control methods use mechanical transmission combined with variable collective pitch control, but this control method relies on a complex mechanical structure. Prior art has proposed a tail rotor control solution that uses a direct motor drive. This adjusts the tail rotor speed to control the thrust and thereby balance the helicopter's main rotor torque. However, this new solution also brings new problems. The main rotor and tail rotor are controlled independently. During ground startup, the torque generated by the rotation of the main rotor and tail rotor does not match, often causing the helicopter to spin in place on the ground. In addition, when the tail rotor is in yaw control, due to the wide speed adjustment range, the tail boom vibrates significantly during the speed adjustment process, which can also affect the helicopter's flight state. Summary of the Invention

[0004] The object of the present invention is to provide a method, device, equipment and medium for controlling the speed of a helicopter tail rotor, so as to solve the problems of helicopter spinning on the ground and excessive vibration level of the tail boom.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] According to one aspect of the present invention, a method for controlling the speed of a helicopter tail rotor is provided, comprising the following steps:

[0007] Get the location information of the helicopter;

[0008] Determine the operation phase of the helicopter according to the position information, the operation phase includes the ground start phase and the air flight phase;

[0009] The tail rotor speed is regulated according to the operation stage; when the operation stage is the ground start-up stage, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids a first preset range; when the operation stage is the air flight stage, the tail rotor speed is avoided within a second preset range.

[0010] The first preset range is the preset range in which the tail rotor and the tail boom resonate during the ground startup phase; the second preset range is the preset range in which the tail rotor and the tail boom resonate during the air flight phase.

[0011] "When the helicopter is stable" means that the main rotor speed and tail rotor speed reach the preset idle or ground operation value, and the fluctuation range is within the allowable threshold. Generally, the allowable threshold is ± (3~5)%.

[0012] The main rotor and tail rotor of the helicopter are independently controlled. The above technical solution can prevent the helicopter from spinning in place during the ground startup phase due to the mismatch between the torque generated by the rotation of the main rotor and the tail rotor. It can effectively reduce the vibration level of the helicopter's tail boom during the flight phase, reduce the displacement of the tail boom end, and improve structural stability.

[0013] According to one embodiment of the present invention, when the operation phase is the ground start phase, the step of performing closed-loop control on the tail rotor speed so that the tail rotor speed when the helicopter is stable avoids a first preset range includes:

[0014] Get the current main rotor speed and tail rotor speed;

[0015] According to the current main rotor speed and tail rotor speed, the adjustment amount of the tail rotor speed is obtained based on the linear relationship between the tail rotor speed and the main rotor speed;

[0016] The tail rotor speed is adjusted according to the adjustment amount of the tail rotor speed so that the tail rotor speed when the helicopter is stable avoids the first preset range.

[0017] Furthermore, the linear relationship between the tail rotor speed and the main rotor speed is as follows:

[0018] ;

[0019] Where, k 1 is the correlation coefficient, Oh t is the tail rotor speed; Oh m Main rotor speed.

[0020] Among them, the correlation coefficient k The initial value of 1 can be calculated according to the following formula:

[0021] ;

[0022] Where, C P is the main rotor power coefficient; R m is the main rotor radius; C t is the tail rotor thrust coefficient; Rt is the tail rotor radius; L It is the distance between the thrust axis or the pull axis of the helicopter tail rotor and the main rotor axis.

[0023] Furthermore, PID control, PI control, adaptive control and other algorithms are used to achieve closed-loop control of the tail rotor speed.

[0024] Therefore, during the ground start-up phase, the tail rotor speed is controlled and adjusted based on the linear relationship between the tail rotor speed and the main rotor speed, which effectively solves the problem of the landing gear spinning in place during the ground start-up phase of the helicopter due to insufficient static friction on the ground and mismatch between the rotational torque of the main rotor and the tail rotor.

[0025] During the ground startup phase, closed-loop control of the tail rotor speed and the main rotor speed is performed, which effectively solves the attitude control problem caused by independent electric drive control of the main rotor and tail rotor, making the helicopter attitude control smoother.

[0026] According to one embodiment of the present invention, the first preset range is 0.5-1.5 times the n-th order natural frequency of the tail boom.

[0027] Preferably, the first preset range is 0.7-1.3 times the nth-order natural frequency of the tail boom.

[0028] According to one embodiment of the present invention, when the helicopter is in the air flight phase, the flight state is determined based on the position information and attitude angle information of the helicopter; the interval width of the second preset range is adjusted according to the flight state;

[0029] The flight states include hovering state, cruising state, normal yaw state and extreme yaw state.

[0030] According to one embodiment of the present invention, when the helicopter is in a hovering state, the second preset range is a range of 0.5-1.5 times the nth order natural frequency of the tail boom;

[0031] When the helicopter is in cruising mode, the second preset range is 0.7-1.3 times the nth order natural frequency of the tail boom;

[0032] When the helicopter is in a normal yaw state, the second preset range is 0.7-1.3 times the nth order natural frequency of the tail boom;

[0033] When the helicopter is in an extreme yaw state, the second preset range is 0.8-1.2 times the nth order natural frequency of the tail boom.

[0034] Preferably, when the helicopter is in a hovering state, the second preset range is 0.7-1.3 times the nth order natural frequency of the tail boom;

[0035] When the helicopter is in cruising mode, the second preset range is 0.75-1.25 times the nth order natural frequency of the tail boom;

[0036] When the helicopter is in a normal yaw state, the second preset range is 0.8-1.2 times the nth order natural frequency of the tail boom;

[0037] When the helicopter is in an extreme yaw state, the second preset range is 0.9-1.1 times the nth order natural frequency of the tail boom.

[0038] Therefore, regulating the helicopter tail rotor speed to avoid the specific range of the tail boom's nth-order natural frequency can effectively avoid the problem of high-order resonance of the tail boom, thereby reducing the vibration level of the tail boom, improving the structural stability of the helicopter, especially unmanned helicopters, and ensuring good flight attitude and flight status.

[0039] According to one embodiment of the present invention, when the operating phase is the ground startup phase, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids a first preset range; when the operating phase is the airborne flight phase, the step of avoiding a second preset range includes:

[0040] Determining the interval widths of the first preset range and the second preset range, as well as the nth-order natural frequency of the tail boom and the rated speed of the tail rotor;

[0041] Determining a time threshold for the tail rotor speed to avoid the first preset range based on the rated speed of the tail rotor, the nth-order natural frequency of the tail boom, and the interval width of the first preset range;

[0042] A time threshold for the tail rotor speed to avoid the second preset range is determined based on the rated speed of the tail rotor, the nth-order natural frequency of the tail boom, and the interval width of the second preset range.

[0043] Therefore, according to the time threshold, the time for the tail rotor rotation to fall into the first preset range or the second preset range during the helicopter navigation process can be shortened as much as possible, that is, the specific range of the tail rotor's nth-order natural frequency can be crossed as quickly as possible, thereby reducing the vibration amplitude of the tail boom as much as possible and improving the smoothness of navigation.

[0044] According to one embodiment of the present invention, the time threshold for the tail rotor speed to avoid the first preset range and the second preset range are calculated in the same manner, and are calculated according to the following formula:

[0045] ;

[0046] Where, t is the time threshold, DO The width of the first preset range or the second preset range; Oh is the rated speed of the tail rotor; Jis the moment of inertia of the tail rotor motor; T is the rated torque of the tail rotor motor; oh n is the nth order natural frequency of the tail boom; k 2 is the empirical coefficient.

[0047] Empirical coefficient k 2 is calculated according to the following formula:

[0048] ;

[0049] Where C is a dimensionless proportional constant, and the initial value is generally set to 0.2~0.3; A max is the allowable vibration acceleration amplitude of the tail boom; g is the damping ratio of the tail boom structure; Oh is the tail rotor speed; J is the moment of inertia of the tail rotor motor; T is the rated torque of the tail rotor motor.

[0050] According to one aspect of the present invention, there is provided a helicopter tail rotor speed control device, comprising:

[0051] Data acquisition module, used to obtain the location information of the helicopter;

[0052] An analysis module is used to determine the operation phase of the helicopter according to the position information, and the operation phase includes a ground start phase and an air flight phase;

[0053] The speed control module is used to control the speed of the tail rotor according to the operating stage; wherein, when the operating stage is the ground start-up stage, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids a first preset range; when the operating stage is the air flight stage, the tail rotor speed is avoided from a second preset range; the first preset range is the preset range in which the tail rotor and the tail boom resonate during the ground start-up stage, and the second preset range is the preset range in which the tail rotor and the tail boom resonate during the air flight stage.

[0054] According to one aspect of the present invention, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for controlling the helicopter tail rotor speed according to any one of the above-mentioned embodiments is implemented.

[0055] According to one aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the helicopter tail rotor speed control method of any one of the above-mentioned embodiments is implemented.

[0056] Compared with the prior art, the present invention has at least the following beneficial effects:

[0057] 1. During the ground start-up phase, the present invention controls and adjusts the tail rotor speed based on the linear relationship between the tail rotor speed and the main rotor speed, effectively solving the problem of the landing gear spinning in place during the ground start-up phase of the helicopter due to insufficient static friction on the ground and mismatch between the rotational torque of the main rotor and the tail rotor.

[0058] 2. The present invention performs closed-loop control on the tail rotor speed and the main rotor speed during the ground startup phase, effectively solving the attitude control problem caused by independent electric drive control of the main rotor and tail rotor, making the helicopter attitude control smoother.

[0059] 3. The present invention can effectively avoid the problem of high-order resonance of the tail beam by regulating the speed of the helicopter tail rotor to avoid the specific range of the nth-order natural frequency of the tail beam, thereby reducing the vibration level of the tail beam, reducing the displacement of the tail beam end, improving the structural stability of the helicopter, especially the unmanned helicopter, and ensuring a good flight attitude and flight state. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0061] Figure 1 This is a structural block diagram of a method for controlling the tail rotor speed of a helicopter according to embodiment 1 of the present invention, in which PID control is used to implement closed-loop control of the tail rotor and main rotor speeds;

[0062] Figure 2 This is a structural block diagram of a method for controlling the tail rotor speed of a helicopter according to embodiment 1 of the present invention, in which other controls are used to implement closed-loop control of the tail rotor and main rotor speeds. DETAILED DESCRIPTION

[0063] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0064] The following detailed description is an exemplary description and is intended to provide further detailed description of the present invention. Unless otherwise indicated, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.

[0065] Example 1

[0066] A method for controlling the tail rotor speed of a helicopter, particularly an unmanned helicopter, comprises the following steps:

[0067] Get the location information of the helicopter;

[0068] Determining an operating phase of the helicopter according to the position information, wherein the operating phase includes a ground startup phase and an airborne flight phase;

[0069] The tail rotor speed is regulated according to the operation stage; when the operation stage is the ground start-up stage, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids a first preset range; when the operation stage is the air flight stage, the tail rotor speed is avoided within a second preset range.

[0070] The first preset range is the preset range in which the tail rotor and the tail boom resonate during the ground startup phase; the second preset range is the preset range in which the tail rotor and the tail boom resonate during the air flight phase.

[0071] It should be noted that "when the helicopter is stable" means that the main rotor speed and tail rotor speed reach the preset idle or ground operation values, and the fluctuation range is within the allowable threshold. Generally, the allowable fluctuation range threshold is ± (3-5)%. At this time, the engine torque or power output is stable without abnormal fluctuations.

[0072] By adopting the above technical solution, for helicopters with independently controlled main rotor and tail rotor, it is possible to avoid the helicopter spinning in place during the ground startup phase due to the mismatch in torque generated by the rotation of the main rotor and tail rotor. It can also effectively reduce the vibration level of the helicopter's tail boom during the flight phase, reduce the displacement of the tail boom end, and improve structural stability.

[0073] Specifically, the helicopter tail rotor speed control method of this embodiment includes the following steps:

[0074] S1. Get the location information of the helicopter.

[0075] Use sensors to obtain the coordinates (x, y, z) of the helicopter in the ground coordinate system; and obtain the attitude angle information of the helicopter, including the pitch angle i , yaw angle ψ and roll angle F .

[0076] S2. Determine an operating phase of the helicopter based on the position information, where the operating phase includes a ground startup phase and an airborne flight phase.

[0077] The operation phase of the helicopter is determined according to the z-axis coordinate of the helicopter in the ground coordinate system. The operation phase includes a ground startup phase and an air flight phase.

[0078] When the helicopter's z-axis coordinate in the ground coordinate system is 0 or close to 0, it is considered to be in the ground launch phase. When the helicopter's z-axis coordinate in the ground coordinate system is much greater than 0, it is considered to be in the airborne phase. Generally, if the helicopter's pressure altitude is ≤ (landing gear height + 0.5m), it is considered to be in the ground launch phase, and if the pressure altitude is greater than (landing gear height + 3m), it is considered to be in the airborne phase.

[0079] In order to improve the accuracy of the judgment of the operation stage, other parameter indicators can also be combined to determine it. For example, the engine torque value is obtained and combined with the position information of the helicopter. If the engine torque is <20% and the change rate is ≤5% / s, it is judged to be in the ground start-up stage. If the engine torque is >25% or the change rate is ≥10% / s, it is judged to be in the air flight stage. In addition, the operation stage of the helicopter can also be determined by combining indicators such as the main rotor speed and vertical speed.

[0080] S3. Regulate the tail rotor speed according to the operational phase; wherein, during the ground launch phase, the tail rotor speed is closed-loop controlled so that the tail rotor speed during helicopter stabilization is within a first preset range; and during the flight phase, the tail rotor speed is within a second preset range.

[0081] S3-1. During the ground start phase, closed-loop control of the tail rotor speed is performed to ensure that the tail rotor speed during helicopter stabilization remains within a first preset range, including:

[0082] When the main rotor starts to rotate, the tail rotor control speed should be linearly related to the main rotor speed. The linear relationship between the tail rotor speed and the main rotor speed is as follows:

[0083] ;

[0084] Where, k 1 is the correlation coefficient, Oh t is the tail rotor speed; Oh m Main rotor speed.

[0085] Among them, the correlation coefficient k The initial value of 1 can be calculated according to the following formula:

[0086] ;

[0087] Where, C P is the main rotor power coefficient; R m is the main rotor radius; C t is the tail rotor thrust coefficient; Rt is the tail rotor radius; L It is the distance between the thrust axis or the pull axis of the helicopter tail rotor and the main rotor axis.

[0088] After the helicopter starts, the rotation speed of the main rotor and tail rotor gradually increases, and the correlation coefficient k The value of 1 can be corrected based on the initial value according to the changes in the rotation speed of the main rotor and tail rotor.

[0089] Correlation coefficient k 1 Correct according to the following formula:

[0090] ;

[0091] Where, is the corrected correlation coefficient, is the initial value of the correlation coefficient; F ρ is the air density correction factor, oh ρ for F ρ The weight of F Ω is the main rotor speed correction factor, oh Ω for F Ω The weight of , weights can be allocated based on experience or actual impact.

[0092] ;

[0093] Where, r is the actual air density, unit is kg / m 3 ; r 0 is the standard air density, unit is kg / m 3 .

[0094] ;

[0095] Where, Oh m The real-time speed of the main rotor, in RPM; Oh m,ref The rated speed of the main rotor in the hovering state, in RPM; is the speed coupling coefficient, which is an empirical coefficient and is generally taken as 0.15, reflecting the sensitivity of the main rotor speed change; It is a nonlinear correction index, an empirical index, generally taken as 1.2, which characterizes the nonlinear response of the aerodynamic load.

[0096] Since the main rotor and tail rotor of a helicopter are controlled independently, the two electric drive systems corresponding to the main rotor and tail rotor may have timing or speed mismatch problems during operation. Therefore, the tail rotor speed control method uses closed-loop control based on the linear relationship between the tail rotor speed and the main rotor speed. Figure 1 , Figure 1 In the formula, r(t) represents the input of the PID closed-loop control, which is the expected value of the tail rotor speed calculated based on the main rotor speed in this scheme; y(t) represents the feedback of the PID closed-loop control, which is the actual value of the tail rotor speed in this scheme; e(t) represents the error in the PID closed-loop control, which is the error between the expected value and the actual value of the tail rotor speed in this scheme; u(t) represents the output of the PID closed-loop control, which is the tail rotor speed command in this scheme.

[0097] The specific control process includes:

[0098] (1) Use sensors to obtain the current main rotor speed and tail rotor speed.

[0099] (2) Based on the linear relationship between the tail rotor speed and the main rotor speed, the expected value of the tail rotor speed is calculated using the collected main rotor speed; the error e(t) is calculated based on the expected value of the tail rotor speed and the current tail rotor speed obtained by the collection;

[0100] The error e(t) is input into the proportional, integral and differential links of the PID controller respectively, and the outputs of the proportional, integral and differential links are superimposed to obtain the adjustment amount of the tail rotor speed and the tail rotor speed command u(t) based on this, and the tail rotor speed command u(t) is sent to the controlled object, that is, the tail rotor drive motor.

[0101] (3) The tail rotor drive motor controls the speed of the tail rotor according to the received tail rotor speed command u(t).

[0102] In addition, the PID control in this embodiment can also be replaced by PI control, adaptive control and other algorithms to achieve closed-loop control of the tail rotor speed. The control structure block diagram is shown in FIG. Figure 2 .

[0103] When the helicopter is stable, that is, when the main rotor speed and tail rotor speed reach the preset idle speed or ground operation value, and the fluctuation range is within the allowable threshold, the tail rotor speed is regulated to avoid the first preset range. The first preset range is the tail boom nth order natural frequency ω n The range is 0.7-1.3 times.

[0104] S3-2. When the operational phase is airborne, the tail rotor speed is kept outside the second preset range, including:

[0105] The flight state is determined according to the position information and attitude angle information of the helicopter; and the interval width of the second preset range is adjusted according to the flight state.

[0106] When the helicopter is in the air flight phase, the flight state is determined based on the coordinates (x, y, z) of the helicopter in the ground coordinate system obtained by the sensor, as well as the attitude angle information in the body coordinates; the flight state includes hovering state, cruising state, normal yaw state and extreme yaw state.

[0107] Attitude angle information includes: pitch angle i , yaw angle ψ and roll angle F , the three angular velocity components of the body coordinate system p 、 q 、 r , and the three velocity components of the body coordinates u 、 v 、 w .

[0108] Three angular velocity components of the body coordinate system p 、 q 、 r It is the component of the angular velocity of the helicopter's body coordinate system relative to the ground coordinate system on each axis of the body coordinate system; p With the body axis ox b coincidence, angular velocity q With the body axis oh b coincidence, angular velocity r With the body axis oz b The three velocity components of the body coordinates are consistent. u 、 v 、 w is the component of the helicopter's flight speed v on each axis of the body coordinate system; u With the body axis ox b coincide with each other, v With the body axis oh b coincide with each other, w With the body axis oz b Coincidence.

[0109] Furthermore, the attitude angle information also includes the yaw angular velocity ; If necessary, the pitch angular velocity can also be included and roll angular velocity .

[0110] Among them, when in hovering state: the x, y, and z coordinates of the helicopter remain unchanged, and the pitch angle i , yaw angle ψ and roll angle F unchanged, the angular velocity component p 、 q 、 r are all 0, the velocity component u 、 v 、 w Both are 0.

[0111] In cruising state: the Y and Z coordinates of the helicopter remain unchanged, and the pitch angle i , yaw angle ψ and roll angle F unchanged, the angular velocity component p 、 q 、 r are all 0, the velocity component u is a constant, and v and w are both 0.

[0112] The initial conditions of normal yaw state and extreme yaw state are the same, that is, the z-axis coordinate of the helicopter remains unchanged and the pitch angle i and roll angle F Unchanged, yaw angle ψ Linear change, angular velocity component p 、 q All are 0, r is a constant value, the velocity component w After a certain period of time, the yaw rate can be adjusted according to the Distinguish between normal yaw state and extreme yaw state. If 30° / s≤ <60° / s, the helicopter is in normal yaw state; if 60° / s≤ ≤120° / s, the helicopter is in extreme yaw state.

[0113] When the helicopter is in a hovering state, in order to offset certain external interference, the tail rotor is fine-tuned to maintain the hovering state. The yaw rate range is usually small. Assuming it is set within the range of 5~15° / s, the speed adjustment control scheme of the helicopter tail rotor is set to avoid the nth order natural frequency ω of the tail beam. n Specifically, the second preset range is adjusted to the tail beam n-order natural frequency ω n 0.7-1.3 times the range;

[0114] When the helicopter is in a cruising state, in order to maintain a certain heading state, the heading state is maintained by adjusting the tail rotor. The yaw rate is usually set in the range of 10~30° / s. The speed adjustment control scheme of the helicopter tail rotor is set to avoid the nth order natural frequency ω of the tail beam. n Specifically, the second preset range is adjusted to the tail beam n-order natural frequency ωn 0.75-1.25 times the range;

[0115] When the helicopter is yawed normally, in order to achieve a certain heading state flight, the tail rotor is adjusted to perform yaw motion. The yaw angular velocity is usually set in the range of 30~60° / s. The speed adjustment control scheme of the helicopter tail rotor is set to avoid the nth order natural frequency ω of the tail beam. n Specifically, the second preset range is adjusted to the tail beam n-order natural frequency ω n 0.8-1.2 times the range;

[0116] When the helicopter reaches the extreme yaw state, in order to achieve a certain heading state flight, the tail rotor is adjusted to perform yaw motion. The yaw angular velocity is usually set in the range of 60~120° / s. The speed adjustment control scheme of the helicopter tail rotor is set to avoid the nth order natural frequency ω of the tail beam. n Specifically, the second preset range is adjusted to the tail beam n-order natural frequency ω n The range is 0.9-1.1 times.

[0117] By regulating the helicopter's tail rotor speed to avoid a specific range of the tail boom's nth-order natural frequency, the problem of high-order resonance of the tail boom can be effectively avoided, thereby reducing the vibration level of the tail boom, improving the structural stability of the helicopter, especially unmanned helicopters, and ensuring a good flight attitude and flight state.

[0118] Furthermore, in the process of regulating the rotation speed of the tail rotor, the time during which the tail rotor rotation falls into the first preset range or the second preset range during the flight of the helicopter is shortened as much as possible, that is, the specific range of the nth order natural frequency of the tail rotor is crossed as quickly as possible, thereby reducing the vibration amplitude of the tail beam as much as possible and improving the smoothness of the flight.

[0119] Therefore, when the operation phase is the ground start phase, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids the first preset range; when the operation phase is the airborne flight phase, the step of avoiding the tail rotor speed from the second preset range includes the following steps:

[0120] Determining the interval widths of the first preset range and the second preset range, as well as the nth-order natural frequency of the tail boom and the rated speed of the tail rotor;

[0121] Determining a time threshold for the tail rotor speed to avoid the first preset range based on the rated speed of the tail rotor, the nth-order natural frequency of the tail boom, and the interval width of the first preset range;

[0122] A time threshold for the tail rotor speed to avoid the second preset range is determined based on the rated speed of the tail rotor, the nth-order natural frequency of the tail boom, and the interval width of the second preset range.

[0123] The calculation method for the time threshold of the tail rotor speed avoiding the first preset range and the second preset range is the same, and is calculated according to the following formula:

[0124] ;

[0125] Where, t is the time threshold, DO The width of the first preset range or the second preset range; Oh is the rated speed of the tail rotor; J is the moment of inertia of the tail rotor motor; T is the rated torque of the tail rotor motor; oh n is the nth order natural frequency of the tail boom; k 2 is the empirical coefficient.

[0126] Empirical coefficient k 2 is calculated according to the following formula:

[0127] ;

[0128] Where C is a dimensionless proportional constant, and the initial value is generally set to 0.2~0.3; A max is the allowable vibration acceleration amplitude of the tail boom; g is the damping ratio of the tail boom structure; Oh is the tail rotor speed; J is the moment of inertia of the tail rotor motor; T is the rated torque of the tail rotor motor.

[0129] Therefore, by adopting the helicopter tail rotor speed control method of this embodiment, the helicopter tail rotor speed is regulated to avoid the specific range of the nth order natural frequency of the tail boom, which can avoid the problem of the helicopter spinning on the ground, and can also effectively avoid the problem of high-order resonance of the tail boom, thereby reducing the vibration level of the tail boom, reducing the displacement of the tail boom end, improving the structural stability of the helicopter, especially the unmanned helicopter, and ensuring a good flight attitude and flight state.

[0130] Example 2

[0131] This embodiment provides a method for controlling the speed of a helicopter tail rotor, which differs from the first embodiment in that:

[0132] During the ground startup phase, the first preset range is 0.7-1.3 times the nth order natural frequency of the tail boom;

[0133] During the flight phase, when the helicopter is in a hovering state, the second preset range is 0.5-1.5 times the nth order natural frequency of the tail boom;

[0134] When the helicopter is in cruising mode, the second preset range is 0.7-1.3 times the nth order natural frequency of the tail boom;

[0135] When the helicopter is in a normal yaw state, the second preset range is 0.7-1.3 times the nth order natural frequency of the tail boom;

[0136] When the helicopter is in an extreme yaw state, the second preset range is 0.8-1.2 times the nth order natural frequency of the tail boom.

[0137] Example 3

[0138] A helicopter tail rotor speed control device, comprising:

[0139] Data acquisition module, used to obtain the location information of the helicopter;

[0140] An analysis module is used to determine the operation phase of the helicopter according to the position information, and the operation phase includes a ground start phase and an air flight phase;

[0141] The speed control module is used to control the speed of the tail rotor according to the operating stage; wherein, when the operating stage is the ground start-up stage, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids a first preset range; when the operating stage is the air flight stage, the tail rotor speed is avoided from a second preset range; the first preset range is the preset range in which the tail rotor and the tail boom resonate during the ground start-up stage, and the second preset range is the preset range in which the tail rotor and the tail boom resonate during the air flight stage.

[0142] Example 4

[0143] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the helicopter tail rotor speed control method of the first or second embodiment is implemented.

[0144] Example 5

[0145] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the helicopter tail rotor speed control method of the above-mentioned embodiment 1 or embodiment 2.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for controlling the speed of a helicopter tail rotor, characterized in that: The following steps are involved: Get the location information of the helicopter; Determining an operating phase of the helicopter according to the position information, wherein the operating phase includes a ground startup phase and an airborne flight phase; The tail rotor speed is regulated according to the operation stage; wherein, when the operation stage is the ground start-up stage, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids a first preset range; when the operation stage is the air flight stage, the tail rotor speed is avoided from a second preset range; the first preset range is a preset range in which the tail rotor and the tail boom resonate during the ground start-up stage, and the second preset range is a preset range in which the tail rotor and the tail boom resonate during the air flight stage.

2. The helicopter tail rotor speed control method according to claim 1, characterized in that: When the operation phase is a ground start phase, the step of performing closed-loop control on the tail rotor speed so that the tail rotor speed when the helicopter is stable is kept outside a first preset range includes: Get the current main rotor speed and tail rotor speed; According to the current main rotor speed and tail rotor speed, the adjustment amount of the tail rotor speed is obtained based on the linear relationship between the tail rotor speed and the main rotor speed; The tail rotor speed is adjusted according to the adjustment amount of the tail rotor speed, so that the tail rotor speed when the helicopter is stable avoids the first preset range.

3. The helicopter tail rotor speed control method according to claim 1, characterized in that: The first preset range is 0.5-1.5 times the nth order natural frequency of the tail boom.

4. The helicopter tail rotor speed control method according to claim 1, characterized in that: When the helicopter is in the air flight phase, the flight state is determined according to the position information and attitude angle information of the helicopter; and the width of the interval of the second preset range is adjusted according to the flight state; The flight states include a hovering state, a cruising state, a normal yaw state and an extreme yaw state.

5. The helicopter tail rotor speed control method according to claim 4, characterized in that: When the helicopter is in a hovering state, the second preset range is 0.5-1.5 times the nth order natural frequency of the tail boom; When the helicopter is in a cruising state, the second preset range is 0.7-1.3 times the nth order natural frequency of the tail boom; When the helicopter is in a normal yaw state, the second preset range is 0.7-1.3 times the nth order natural frequency of the tail boom; When the helicopter is in an extreme yaw state, the second preset range is 0.8-1.2 times the nth order natural frequency of the tail boom.

6. The helicopter tail rotor speed control method according to claim 1, characterized in that: When the operation phase is a ground start phase, closed-loop control is performed on the tail rotor speed so that the tail rotor speed when the helicopter is stable is kept away from a first preset range; When the operation phase is the airborne flight phase, the step of making the tail rotor rotation speed avoid the second preset range includes: Determining the interval widths of the first preset range and the second preset range, as well as the nth-order natural frequency of the tail boom and the rated speed of the tail rotor; Determining a time threshold for the tail rotor speed to avoid the first preset range according to the rated speed of the tail rotor, the nth-order natural frequency of the tail boom, and the interval width of the first preset range; A time threshold for the tail rotor speed to avoid the second preset range is determined according to the rated speed of the tail rotor, the nth-order natural frequency of the tail boom, and the interval width of the second preset range.

7. The helicopter tail rotor speed control method according to claim 6, characterized in that: The calculation method for the time threshold of the tail rotor speed avoiding the first preset range and the second preset range is the same, and is calculated according to the following formula: ； Where, t is the time threshold, ΔΩ The width of the first preset range or the second preset range; Ω' is the rated speed of the tail rotor; J is the rated torque of the tail rotor motor; T is the moment of inertia of the tail rotor motor; ω is the natural frequency of the tail boom; k 2 is the empirical coefficient.

8. A helicopter tail rotor speed control device, characterized in that: include: Data acquisition module, used to obtain the location information of the helicopter; an analysis module, configured to determine an operation phase of the helicopter according to the position information, wherein the operation phase includes a ground startup phase and an air flight phase; The speed control module is used to control the speed of the tail rotor according to the operating stage; wherein, when the operating stage is the ground start-up stage, the tail rotor speed is closed-loop controlled so that the tail rotor speed when the helicopter is stable avoids a first preset range; when the operating stage is the air flight stage, the tail rotor speed is avoided from a second preset range; the first preset range is the preset range in which the tail rotor and the tail boom resonate during the ground start-up stage, and the second preset range is the preset range in which the tail rotor and the tail boom resonate during the air flight stage.

9. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement the helicopter tail rotor speed control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed by the processor, the helicopter tail rotor speed control method according to any one of claims 1 to 7 is implemented.

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