CN105005342B - The method for controlling aircraft automatic takeoff - Google Patents

Abstract

The present invention provides a method for controlling automatic take-off of an aircraft, the method comprising acquiring the take-off target pitch angle and target speed of the above-mentioned aircraft; controlling the above-mentioned aircraft to automatically take off according to the above-mentioned take-off target pitch angle and the above-mentioned target speed. The invention solves the problem that the automatic take-off of the aircraft cannot be precisely controlled, and further achieves the effect of precisely controlling the automatic take-off of the aircraft.

Description

Method for controlling aircraft to take off automatically

technical field

The invention relates to the technical field of automatic flight control systems, in particular to a method for controlling an aircraft to take off automatically.

Background technique

Automatic take-off is the process of controlling the aircraft to automatically roll on the runway, turn the nose wheel, lift off the ground, climb to the end of the take-off section. In the whole flight process, the most important and most dangerous flight phases are takeoff and landing, and the most difficult, most complicated and finally involved in designing an autopilot are also the landing and takeoff phases. The advanced transport aircraft in active service, whether military or civilian, basically have autopilots with automatic landing functions. The only difference lies in the automatic landing level, which can reach level IIIa. However, no transport aircraft has the automatic take-off function so far. The difference between the UAV automatic take-off control method lies in the longitudinal control, which is divided into fixed pitch angle control and constant track inclination/vertical speed control. Use the above control method to control the aircraft to a safe height (a height of several meters to tens of meters) for navigation controls. The take-off of a transport aircraft is more complicated. When leaving the ground, the tail angle of the anti-scratch aircraft must be considered. When pulling up, the nose-up rate must be considered. When the climb rate is increased in the air, the airspeed must be increased. The design of the control law must also consider a certain anti-interference ability. and anti-turbulence capability. These all are that existing automatic take-off control mode can't solve at present.

Contents of the invention

The invention provides a method for controlling the automatic take-off of an aircraft to at least solve the problem that the automatic take-off of the aircraft cannot be accurately controlled.

According to one aspect of the present invention, a method for controlling an automatic take-off of an aircraft is provided, the method comprising: acquiring the take-off target pitch angle and target speed of the aircraft; controlling the take-off target pitch angle and the target speed according to the take-off The aircraft takes off automatically.

Preferably, controlling the automatic take-off of the aircraft according to the take-off target pitch angle and the target speed includes: when the aircraft accelerates to the speed VR of the front wheel, controlling the rate of the aircraft's head-up, automatically pulling up the From the aircraft to the take-off target pitch angle; detect and obtain the current vertical velocity Vz of the aircraft; in the case that the current vertical velocity Vz is less than the preset first vertical velocity threshold Vz1, according to the take-off target pitch angle Controlling the aircraft to automatically take off; when the current vertical speed Vz is greater than or equal to the first vertical speed threshold Vz1 and less than the preset second vertical speed threshold Vz2, according to the pitch angle of the take-off target and the target Speed control of the aircraft to automatically take off; when the current vertical speed Vz is greater than or equal to the second vertical speed threshold Vz2, the aircraft is controlled to automatically take off according to the target speed.

Preferably, controlling the aircraft to automatically take off according to the take-off target pitch angle includes controlling the aircraft to maintain the take-off pitch angle; and/or controlling the aircraft to automatically take off according to the target speed includes controlling the aircraft to maintain the target speed.

Preferably, controlling the automatic take-off of the aircraft according to the take-off target pitch angle and the target speed includes: generating a first automatic take-off control instruction according to the take-off target pitch angle; generating a second automatic take-off control instruction according to the target speed ; compare the first automatic take-off control instruction with the second automatic take-off control instruction, and take the larger value between the first automatic take-off control instruction and the second automatic take-off control instruction as the current an automatic take-off control command; or, linearly fade out the first automatic take-off control command, and linearly fade in the second automatic take-off control command.

Preferably, obtaining the take-off target pitch angle and the target speed of the aircraft includes: determining the take-off target pitch angle, take-off safety speed, and ground-off speed according to the aircraft's own parameters; and the liftoff speed determine the target speed.

Preferably, determining the target speed according to the take-off safety speed and the take-off speed includes: the target speed is the larger value between the take-off safety speed and the take-off speed and the first one. The sum of speed thresholds; when the current speed of the aircraft is greater than the target speed and the duration exceeds the first time threshold, the target speed takes the sum of the safe speed and the second speed threshold and the value of the The current speed is the smaller of the two.

Preferably, the first speed threshold is 28km/h, the second speed threshold is 46km/h, and the first time threshold is 5s.

Preferably, in the case of failure of one engine of the aircraft, the method includes: when the aircraft accelerates to the nose-turning speed VR, controlling the nose-up rate of the aircraft to automatically pull up the aircraft to the pitch angle of the take-off target; detect and obtain the current vertical velocity Vz of the aircraft; in the case that the current vertical velocity Vz is less than the preset second vertical velocity threshold Vz2, according to the pitch angle of the take-off target and the The target speed controls the aircraft to automatically take off; when the current vertical speed Vz is greater than or equal to the second vertical speed threshold Vz2, the aircraft is controlled to automatically take off according to the target speed.

Preferably, controlling the aircraft to automatically take off according to the take-off target pitch angle includes controlling the aircraft to maintain the take-off pitch angle; and/or controlling the aircraft to automatically take off according to the target speed includes controlling the aircraft to maintain the target speed.

Preferably, controlling the automatic take-off of the aircraft according to the take-off target pitch angle and the target speed includes: generating a first automatic take-off control instruction according to the take-off target pitch angle; generating a second automatic take-off control instruction according to the target speed ; compare the first automatic take-off control instruction with the second automatic take-off control instruction, and take the larger value between the first automatic take-off control instruction and the second automatic take-off control instruction as the current an automatic take-off control command; or, linearly fade out the first automatic take-off control command, and linearly fade in the second automatic take-off control command.

Through the present invention, the take-off target pitch angle and target speed of the aircraft are obtained; the automatic take-off of the aircraft is controlled according to the take-off target pitch angle and the target speed, which solves the problem that the automatic take-off of the aircraft cannot be accurately controlled, and then achieves It achieves the effect of precisely controlling the automatic take-off of the aircraft.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is a flow chart of a method for controlling an aircraft to automatically take off according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of an automatic take-off process according to an embodiment of the present invention;

Fig. 3 is a control block diagram of automatic take-off and pitch angle maintenance according to an embodiment of the present invention;

Fig. 4 is a block diagram of automatic take-off speed maintenance control according to an embodiment of the present invention;

Fig. 5 is a control block diagram of automatic take-off mixed commands according to an embodiment of the present invention;

Fig. 6 is a control block diagram of another automatic take-off hybrid command according to an embodiment of the present invention.

detailed description

Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

The embodiment of the present invention provides a new automatic take-off control method, which is not only suitable for unmanned aerial vehicles, but also can be used for the automatic take-off of manned fixed-wing aircraft, filling the gap in the automatic take-off control method of manned fixed-wing aircraft, so that manned Fixed-wing aircraft can also take off automatically, laying the foundation for the automatic control of the full flight phase of manned fixed-wing aircraft, and it is also an improvement on the existing automatic take-off of drones.

An embodiment of the present invention provides a control method for automatic take-off of an aircraft. This new control method uses two control commands, one is pitch angle control and the other is speed control. When the rate reaches a certain value, use the mixed command of pitch angle and speed to control the aircraft to climb. The rate of climb continues to increase until it reaches a certain value, and the speed is completely used as the control target to climb at a constant speed until the end of the take-off segment. The target pitch angle and target speed are related to the weight, center of gravity, performance, etc. of the aircraft. This automatic take-off control method combined with the aircraft state and performance can ensure safe take-off while taking into account the economy. The control method combining the two control commands can maximize the anti-interference ability of the aircraft during take-off. This take-off method is applicable to both the taxi take-off of the UAV and the automatic take-off of the manned fixed-wing aircraft. It fills the gap in the automatic take-off control method of manned fixed-wing aircraft, and also improves the instability and anti-interference of the traditional automatic take-off control method of UAVs.

In this embodiment, the automatic take-off of the aircraft is controlled according to the two control commands of pitch angle and speed. After the ascent rate, maintain the ascent rate while increasing the speed, transition from pitch angle maintenance to speed maintenance, and use the mixed command of pitch angle and speed in the transition section, which can ensure the stability and safety of the aircraft to the greatest extent while meeting the take-off requirements. Maximum anti-jamming; then use speed hold to control the aircraft to maintain airspeed climb. This control method captures the key points and control focus of each stage of takeoff. It is similar to the manual control takeoff procedure and is consistent with the flight guidance control method. The takeoff guidance has been applied to many manned fixed-wing aircraft, which is completely provable. Such a control method is useful for manned fixed-wing aircraft, suitable for manned fixed-wing aircraft, and can also be applied to unmanned aerial vehicles.

In this embodiment, a method for controlling an aircraft to automatically take off is provided. Fig. 1 is a flowchart of a method for controlling an aircraft to automatically take off according to an embodiment of the present invention. As shown in Fig. 1, the process includes the following steps:

Step S102, acquiring the take-off target pitch angle and target speed of the aircraft;

Step S104, controlling the aircraft to automatically take off according to the takeoff target pitch angle and the target speed.

When the aircraft's engines are normal:

When the aircraft accelerates to the speed VR of the front wheel, control the head-up rate of the aircraft, automatically pull the aircraft to the take-off target pitch angle; detect and obtain the current vertical speed Vz of the aircraft; When the current vertical speed Vz is less than the preset first vertical speed threshold Vz1, the aircraft is controlled to automatically take off according to the pitch angle of the take-off target; when the current vertical speed Vz is greater than or equal to the first vertical speed threshold When Vz1 is less than the preset second vertical speed threshold Vz2, control the aircraft to automatically take off according to the take-off target pitch angle and the target speed; when the current vertical speed Vz is greater than or equal to the second vertical speed In the case of the threshold Vz2, the aircraft is controlled to automatically take off according to the target speed.

Wherein, controlling the automatic take-off of the aircraft according to the take-off target pitch angle includes controlling the aircraft to maintain the take-off pitch angle; controlling the automatic take-off of the aircraft according to the target speed includes controlling the aircraft to maintain the target speed.

In one embodiment, controlling the automatic take-off of the aircraft according to the take-off target pitch angle and the target speed includes: generating a first automatic take-off control instruction according to the take-off target pitch angle; generating a second automatic take-off control instruction according to the target speed. take-off control instruction; compare the first automatic take-off control instruction with the second automatic take-off control instruction, and take the larger value between the first automatic take-off control instruction and the second automatic take-off control instruction One is the current automatic take-off control instruction; or, the first automatic take-off control instruction is linearly faded out, and the second automatic take-off control instruction is linearly faded in.

In another embodiment, obtaining the take-off target pitch angle and the target speed of the aircraft includes: determining the take-off target pitch angle, take-off safety speed, and ground-off speed according to the aircraft's own parameters; The target speed is determined based on the take-off safety speed and the lift-off speed.

In yet another embodiment, determining the target speed according to the take-off safety speed and the take-off speed includes: the target speed is the larger value between the take-off safety speed and the take-off speed The sum of one and the first speed threshold; when the current speed of the aircraft is greater than the target speed and the duration exceeds the first time threshold, the target speed is the sum of the safe speed and the second speed threshold The smaller of the value and the current speed. Wherein, the first speed threshold is 28km/h, the second speed threshold is 46km/h, and the first time threshold is 5s.

In the event of failure of one engine of said aircraft:

When the aircraft is accelerated to the speed VR of the front wheel, the rate of head-up of the aircraft is controlled, and the aircraft is automatically pulled up to the pitch angle of the take-off target; the current vertical velocity Vz of the aircraft is detected and obtained; When the current vertical speed Vz is less than the preset second vertical speed threshold Vz2, the aircraft is controlled to automatically take off according to the take-off target pitch angle and the target speed; when the current vertical speed Vz is greater than or equal to the In the case of the second vertical speed threshold Vz2, the aircraft is controlled to automatically take off according to the target speed.

Wherein, controlling the automatic take-off of the aircraft according to the take-off target pitch angle includes controlling the aircraft to maintain the take-off pitch angle; controlling the automatic take-off of the aircraft according to the target speed includes controlling the aircraft to maintain the target speed.

In one embodiment, controlling the automatic take-off of the aircraft according to the take-off target pitch angle and the target speed includes: generating a first automatic take-off control instruction according to the take-off target pitch angle; generating a second automatic take-off control instruction according to the target speed. take-off control instruction; compare the first automatic take-off control instruction with the second automatic take-off control instruction, and take the larger value between the first automatic take-off control instruction and the second automatic take-off control instruction One is the current automatic take-off control instruction; or, the first automatic take-off control instruction is linearly faded out, and the second automatic take-off control instruction is linearly faded in.

The embodiment of the present invention also provides a control method for automatic take-off of an aircraft, the method comprising the following steps:

(1) According to the weight of the aircraft, the center of gravity, the performance of the aircraft, the current ambient temperature, etc., determine the pitch angle Theta, take-off thrust, nose wheel speed VR, lift-off speed VLOF, take-off safety speed V2, etc. when the aircraft leaves the ground;

(2) At the beginning of takeoff, push the throttle stick to the takeoff thrust, keep the horizontal heading consistent with the runway heading, keep the wings level, and accelerate to VR;

(3) After reaching VR, the pitch command controls the aircraft to automatically pull up to maintain the target pitch angle at an appropriate rate of head-up, the aircraft establishes a positive rate of rise and leaves the ground, the vertical velocity Vz increases, and the speed increases;

(4) When Vz is below the preset first vertical velocity threshold Vz1, the pitch command maintains the target pitch angle;

(5) When Vz is greater than or equal to Vz1 and less than the second vertical speed threshold Vz2, the pitch command is a mixed command of the target pitch angle and target speed;

(6) After Vz is greater than or equal to Vz2, the pitch command maintains the target airspeed;

(7) If one engine fails during takeoff and Vz is less than Vz2, the pitch command is a mixed command of the target pitch angle and target speed. After Vz is greater than or equal to Vz2, the pitch command maintains the target airspeed;

Among them, the greater of the target airspeed V2+28km/h and VLOF+28km/h; if the current airspeed is greater than the target airspeed by more than 5s, the target airspeed becomes the smaller of the current airspeed and V2+46km/h, Wherein, 28km/h is the first speed threshold, 46km/h is the second speed threshold, and 5s is the first time threshold.

(8) When the aircraft is at a certain height from the ground after it lifts off the ground, the lateral heading command becomes track hold;

(9) During the process, the throttle is always at the take-off thrust.

The preferred embodiment of the present invention also provides a control method for automatic take-off of an aircraft, the method comprising:

This embodiment takes a manned fixed-wing aircraft as an example, with a take-off weight of 135t, a normal center of gravity, a take-off airport altitude of 500m, and an airport temperature of 15°, in a normal take-off configuration.

(1) According to the weight, center of gravity, and current ambient temperature of the aircraft, the stall speed Vs, nose wheel rotation speed VR, ground lift speed VLOF, and take-off safety speed V2 are determined to be 209km/h, 216km/h, 235km/h, and 250km/h respectively. h, the limited pitch angle when the aircraft leaves the ground is 12.5°, the recommended pitch angle is 9°, and the thrust is the take-off thrust;

(2) At the beginning of take-off, push the throttle stick to the take-off thrust, keep the horizontal heading consistent with the runway heading, keep the wings level, and accelerate to the speed of turning the nose wheel at 216km/h (point a in Figure 2); among them, in Figure 2 , a is the nose wheel turning point of the aircraft, a1 is the command exchange point, b is the command exchange point, and c is the climbing section.

(3) After reaching 216km/h, the pitch command controls the aircraft to automatically pull up with a head-up rate of 2.5°/s to maintain the target pitch angle of 9°, the aircraft establishes a positive ascent rate and leaves the ground, the vertical velocity Vz increases, and the speed increases (in Figure 2 a to a1 process);

(4) When Vz is below 3m/s, the pitch command maintains the target pitch angle of 9° (the process from a1 to b in Fig. 2, Fig. 3 is a pitch angle maintenance control block diagram, in Fig. 3, Pitch_c is the target pitch angle, Pitch is the pitch angle, K_P is the pitch angle gain, Lim_P1 is the target pitch angle limit, Lim_P2 is the pitch angle control command limit, AP_PIT_P is the pitch angle control command).

(5) When Vz is greater than or equal to 3m/s and less than 6m/s, the pitch command is a mixed command of the target pitch angle and target speed, which is a combination of the pitch command (the first automatic take-off control command) and the speed command (the second automatic take-off control command) command) is greater (the process from b to c in Figure 2), and the specific method of mixing commands is shown in Figure 5. In Figure 5, Max is the greater of the pitch angle control command and the speed control command. In another embodiment, the specific method of obtaining the mixed command may also be shown in FIG. 6 , where the pitch command is linearly faded out, and the speed command is linearly faded in.

(6) After Vz is greater than or equal to 6m/s, the pitch command maintains the target airspeed (the process after c in Figure 2, and Figure 4 is the speed maintenance control block diagram);

If the aircraft leaves the ground at 235km/h, the target airspeed is the greater of 250km/h+27.78km/h or 235km/h+28km/h;

If the speed of the aircraft is greater than the target airspeed for more than 5 seconds when it leaves the ground, the target airspeed becomes the smaller of the current airspeed and 250km/h+46km/h.

Among them, in Figure 4, V_c is the target speed, V is the speed, K_V is the speed gain, nx is the axial overload, K_nx is the axial overload gain, Lim_V is the limit of the speed control command, and AP_PIT_V is the speed control command.

(7) If one engine fails during takeoff and Vz is less than 6m/s, the pitch command is a mixed command of the target pitch angle and target speed. After Vz is greater than or equal to 6m/s, the pitch command maintains the target airspeed;

(8) When the aircraft is 5m above the ground after leaving the ground, the lateral heading command changes to track hold (point m in Figure 2);

(9) During the process, the throttle is always at the take-off thrust.

Embodiments of the present invention have the following beneficial effects:

The invention not only improves the automatic take-off control method of the unmanned aerial vehicle, makes the automatic take-off of the unmanned aerial vehicle more stable and stronger in anti-interference, but also provides a control method for the automatic take-off of manned fixed-wing aircraft. It is possible to automatically control the whole flight phase of the wing aircraft. For drones, it only needs to be improved on the basis of the original algorithm, without any hardware modification, which saves modification costs and shortens the development cycle. For manned fixed-wing aircraft, it is only necessary to add an automatic take-off algorithm to the automatic flight control calculation, without changing the hardware, only to upgrade the software, which can save R&D and modification costs and shorten the R&D and modification cycle.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Alternatively, they may be implemented in program code executable by a computing device so that they may be stored in a storage device to be executed by a computing device, and in some cases, in an order different from that shown here The steps shown or described are carried out, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps among them are fabricated into a single integrated circuit module for implementation. As such, the present invention is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. it is a kind of control aircraft automatic takeoff method, it is characterised in that including：

Obtain take off target pitch angle and the target velocity of the aircraft；

According to target pitch angle and the target velocity control aircraft automatic takeoff of taking off；

The aircraft automatic takeoff is controlled to include according to take off target pitch angle and the target velocity：

In the case where the aircraft accelerates to rotation speed VR, the new line rate of the aircraft, automatic pull-up institute are controlled State aircraft to the target pitch angle of taking off；

Detect and obtain the current vertical speed Vz of the aircraft；

In the case where the current vertical speed Vz is less than default first vertical speed threshold value Vz1, according to the mesh that takes off The mark angle of pitch controls the aircraft automatic takeoff；

In the current vertical speed Vz more than or equal to the first vertical speed threshold value Vz1 and less than the default second vertical speed In the case of degree threshold value Vz2, according to target pitch angle and the target velocity control aircraft automatic takeoff of taking off；

In the case where the current vertical speed Vz is more than or equal to the second vertical speed threshold value Vz2, according to the target Aircraft automatic takeoff described in speed control.

2. method according to claim 1, it is characterised in that

The aircraft automatic takeoff is controlled according to the target pitch angle of taking off includes that the control aircraft rises described in keeping Fly target pitch angle；And/or

The aircraft automatic takeoff is controlled to keep the target velocity including the control aircraft according to the target velocity.

3. method according to claim 1, it is characterised in that according to target pitch angle and the target velocity of taking off Controlling the aircraft automatic takeoff includes：

First automatic takeoff control instruction is generated according to the target pitch angle of taking off；

Second automatic takeoff control instruction is generated according to the target velocity；

Compare the first automatic takeoff control instruction and the second automatic takeoff control instruction, take first automatic takeoff Control instruction and the second automatic takeoff control instruction value therebetween larger one refers to for the control of current automatic takeoff Order；Or, the first automatic takeoff control instruction of linearly fading out, and the second automatic takeoff control instruction of linearly fading in.

4. method according to claim 1, it is characterised in that obtain the aircraft it is described take off target pitch angle and The target velocity includes：

Take off target pitch angle, safe speed of taking off and flying speed described in inherent parameters determination according to the aircraft；

Safe speed is taken off according to described and the flying speed determines the target velocity.

5. method according to claim 4, it is characterised in that according to it is described take off safe speed and the flying speed it is true The fixed target velocity includes：

The target velocity is described to take off safe speed and the flying speed is worth therebetween larger one with the first speed Spend the sum of threshold value；

It is more than the target velocity in the present speed of the aircraft and the duration exceedes the situation of very first time threshold value Under, the target velocity takes take off safe speed and the second speed threshold value and value and the present speed therebetween compared with Small person.

6. method according to claim 5, it is characterised in that the First Speed threshold value is 28km/h, second speed Degree threshold value is 46km/h, and the very first time threshold value is 5s.

7. method according to claim 1, it is characterised in that in a situation for power failure of the aircraft Under, methods described includes：

In the case where the aircraft accelerates to rotation speed VR, the new line rate of the aircraft, automatic pull-up institute are controlled State aircraft to the target pitch angle of taking off；

Detect and obtain the current vertical speed Vz of the aircraft；

In the case where the current vertical speed Vz is less than default second vertical speed threshold value Vz2, according to the mesh that takes off The mark angle of pitch and the target velocity control the aircraft automatic takeoff；

In the case where the current vertical speed Vz is more than or equal to the second vertical speed threshold value Vz2, according to the target Aircraft automatic takeoff described in speed control.

8. method according to claim 7, it is characterised in that according to target pitch angle and the target velocity of taking off Controlling the aircraft automatic takeoff includes：

First automatic takeoff control instruction is generated according to the target pitch angle of taking off；

Second automatic takeoff control instruction is generated according to the target velocity；

Compare the first automatic takeoff control instruction and the second automatic takeoff control instruction, take first automatic takeoff Control instruction and the second automatic takeoff control instruction value therebetween larger one refers to for the control of current automatic takeoff Order；Or, the first automatic takeoff control instruction of linearly fading out, and the second automatic takeoff control instruction of linearly fading in.