Target tracking control method for unmanned helicopter

Abstract

The invention belongs to the technical field of unmanned helicopter flight control, and particularly relates to an unmanned helicopter target tracking control method. Comprising the steps that S1, after the unmanned helicopter receives a target tracking instruction and obtains real-time position information of a target, a circular tracking area with the real-time position coordinate of the target as the center and the radius being R is established, and R is the lowest effective distance for achieving target tracking; s2, if the unmanned helicopter is outside the circular tracking area, entering a remote tracking control stage; in the remote tracking control stage, the unmanned helicopter adjusts the course in real time to fly in alignment with a target, and tracks the target at a forward flying speed greater than the target moving speed; s3, if the unmanned helicopter is in the circular tracking area, entering a short-range following control stage; the unmanned helicopter dynamically adjusts the flight path according to the real-time position of the unmanned helicopter and the real-time position of the target, it is guaranteed that the unmanned helicopter is located in the circular tracking area, and therefore tracking flight of the target is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of unmanned helicopter flight control, and in particular relates to a control method for unmanned helicopter target tracking. Background Art

[0002] With the rapid development of UAV technology, UAVs have been widely used in military and civilian fields. Target tracking technology is one of the key technologies for UAV applications. At present, the methods for target tracking are basically based on the historical position and speed information of the target, and the motion model is used to predict the future trajectory of the target. These trajectory prediction algorithms have a large amount of calculation, and the accuracy of the prediction cannot be guaranteed to be completely correct, which is not suitable for direct application in engineering.

[0003] Traditional tracking strategies generally involve fixed-distance tracking of the target, which is more suitable for small electric multi-rotor drones with strong maneuverability. However, for medium and large unmanned helicopters with conventional single-rotor and tail rotor configurations, they cannot make quick turns as flexibly and freely as small electric multi-rotor drones. Especially when tracking targets with super maneuverability such as ground vehicles or sea speedboats, if the same path as the target is directly used for tracking control, the unmanned helicopter will have a large attitude angle and heading swing, which can easily lead to the unmanned helicopter's load exceeding the limit and inducing control oscillation. Moreover, sudden maneuvers can easily lead to loss of the target. Summary of the invention

[0004] The purpose of the present invention is to effectively improve the safety of target tracking of unmanned helicopters, while ensuring the accuracy of real-time target tracking control and the coordination of various flight control channels, and to propose a control method for target tracking of unmanned helicopters to simplify the tracking control logic.

[0005] In order to achieve the above object, the present invention adopts the following technical solution to achieve it.

[0006] A control method for unmanned helicopter target tracking, the control method comprising:

[0007] S1, after the unmanned helicopter receives the target tracking command and obtains the target real-time position information, it establishes a circular tracking area with a radius of R and the target real-time position coordinates as the center, where R is the minimum effective distance for target tracking;

[0008] S2, if the unmanned helicopter is outside the circular tracking area, it enters the remote tracking control stage; in the remote tracking control stage, the unmanned helicopter adjusts its heading in real time to fly towards the target, and tracks the target at a forward flight speed greater than the target moving speed;

[0009] S3, if the unmanned helicopter is within the circular tracking area, it enters the short-range following control stage; the unmanned helicopter dynamically adjusts the flight trajectory according to the real-time position of itself and the target to ensure that the unmanned helicopter is within the circular tracking area, thereby completing the tracking flight of the target.

[0010] Furthermore, S2 is specifically:

[0011] S21, unmanned helicopter adjusts its heading by coordinated turning ac Aim at the target, calculate and generate a new tracking heading instruction, and then fly according to the new tracking heading;

[0012] S22, updating the position coordinates of the unmanned helicopter and the target in real time, taking the sector area formed by the two outer common tangent lines of the unmanned helicopter and the target circular tracking area, and calculating the sector area angle θ t ;

[0013] S23, determine the heading of the unmanned helicopter ac Is it in the sector angle θ t within the scope;

[0014] If in θ t Within the range, the unmanned helicopter continues to fly according to the heading;

[0015] If in θ t Outside the range, the unmanned helicopter adjusts its heading by coordinated turning ac Aim at the target, generate a new tracking heading instruction, and the unmanned helicopter keeps flying according to the new heading; until the unmanned helicopter crashes into the circular tracking area.

[0016] Furthermore, a new tracking heading instruction is calculated and generated, specifically:

[0017] A new tracking heading instruction is calculated according to formula (1), and then the aircraft flies according to the new tracking heading;

[0018] psi_cmd = f(lon,lat,lon aim ,lat aim ) (1)

[0019] Among them, lon is the longitude of the unmanned helicopter position, lat is the latitude of the unmanned helicopter position, lon aim is the target location longitude, lat aim is the latitude of the target location, f(lon,lat,lon aim ,lat aim ) is the real-time direction of the unmanned helicopter pointing to the target, and psi_cmd is the heading command of the unmanned helicopter.

[0020] Further, calculate the fan-shaped area angle θt , specifically:

[0021] According to formula (2), the fan-shaped area angle θ is calculated t

[0022] θ t =2ar sin(R / d) (2)

[0023] Where d is the distance between the unmanned helicopter and the target.

[0024] Furthermore, S3 is specifically:

[0025] S31, if the unmanned helicopter maintains the tracking heading flight within the circular tracking area, the forward flight speed is adjusted to an optimal cruising speed not less than the target speed;

[0026] S32, updating the coordinates of the unmanned helicopter and the target in real time, judging whether the distance between the unmanned helicopter and the target is greater than R, if greater than R, the unmanned helicopter adjusts the heading Ψ by coordinated turning ac Re-align the target, calculate and generate the following heading instruction according to formula (1), and the unmanned helicopter flies according to the new heading;

[0027] Until the unmanned helicopter receives the command to end target tracking and exits target tracking control.

[0028] Furthermore, in S1, if the tracking task in the target tracking instruction belongs to the reconnaissance or strike category, half of the action distance L of the mission equipment on the unmanned helicopter is set as the radius of the circular tracking area.

[0029] Furthermore, in S1, if the tracking task in the target tracking instruction belongs to the landing remote guidance, the radius R of the circular tracking area is set to the safe distance required for the landing approach glide.

[0030] The present invention also provides an unmanned helicopter, which uses the control method described in any one of claims 1 to 7 to track a target.

[0031] The technical solution of the present invention designs a fan-shaped heading keeping area when tracking a long-range target, thereby reducing the number of heading maneuvers of the unmanned helicopter caused by target movement and maintaining a smooth tracking process; a circular tracking area is designed for the unmanned helicopter, and the target is always followed in a forward flying manner. After exceeding the area, the heading is adjusted to realign with the target in a coordinated turning manner, without the need to directly tail the target or to follow in real-time small maneuvers, thereby ensuring that the unmanned helicopter safely follows the target and does not lose the target. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the remote tracking control process;

[0033] Figure 2 This is a schematic diagram of the circle tangent heading angle;

[0034] Figure 3 It is a schematic diagram of the short-range tracking control process;

[0035] Figure 4 Provide flight path chart for unmanned helicopters to track fixed targets;

[0036] Figure 5 This is the relative distance data diagram between the unmanned helicopter and the fixed target;

[0037] Figure 6 Provide flight path charts for unmanned helicopter landings;

[0038] Figure 7 This is the relative distance data diagram between the unmanned helicopter and the ship target;

[0039] Figure 8 Provide flight path diagram for unmanned helicopters to track electro-optical image targets;

[0040] Fig. 9 This is the relative distance data diagram between the unmanned helicopter and the optoelectronic target. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0042] The embodiment of the present invention provides a control method for target tracking of an unmanned helicopter, including: dividing the target tracking control process into two parts: long-range tracking control and short-range following control.

[0043] After the unmanned helicopter receives the target tracking instruction and obtains the target's real-time position information, it establishes a circular tracking area with a radius of R kilometers centered on the target's real-time position coordinates. R is the minimum effective distance for achieving target tracking. At this time, if the unmanned helicopter is outside this area, it enters the long-range tracking control process. The unmanned helicopter adjusts its heading to fly toward the target and begins to track the target at a forward flight speed greater than the target's moving speed. During the tracking process, the unmanned helicopter adjusts its flight trajectory according to its own and the target's real-time positions, and eventually crashes into the circular tracking area, and then enters the short-range following control stage. The unmanned helicopter dynamically adjusts its flight trajectory according to its own and the target's real-time positions to ensure that the unmanned helicopter is always in the real-time circular tracking area, thereby completing the tracking flight within the effective distance R of the target.

[0044] Specific implementation steps:

[0045] Step 1): P1 time (see Figure 1 ), the unmanned helicopter receives the target tracking command;

[0046] Step 2): At time P1, analyze the target position coordinates and establish a circular tracking area with a radius of R kilometers centered on the target. R is the minimum effective distance for target tracking. It is necessary to ensure that the target can be observed, reconnaissance or attack from all directions, and the unmanned helicopter will always hover and follow the target within R kilometers. For example, if this tracking mission belongs to the reconnaissance or attack category, half of the effective distance L (L / 2) of the mission equipment on the unmanned helicopter can be set as the radius R of the circular tracking area, such as the effective distance of an optoelectronic pod or a small air-to-ground missile, R can be set to about 4km; if this tracking mission belongs to long-range guidance for landing, the radius R of the circular tracking area can be set to the safe distance required for landing approach descent, and R can be set to about 5km;

[0047] Step 3): At P2, the unmanned helicopter adjusts its heading by coordinated turning ac Aim at the target, calculate and generate a new tracking heading instruction according to formula (1), and then fly according to the new heading. lon is the longitude of the unmanned helicopter, lat is the latitude of the unmanned helicopter, and len is aim Target location longitude, lat aim is the target location latitude, is the real-time direction of the unmanned helicopter pointing to the target, and psi_cmd is the heading command of the unmanned helicopter.

[0048] psi_cmd = f(lon, lat, lon sim ,lat aim ) (1)

[0049] Step 4): Update the position coordinates of the unmanned helicopter and the target in real time, take the sector formed by the two outer common tangents of the unmanned helicopter and the target circular tracking area, and calculate the sector angle θ according to formula (2): t (See Figure 2 ), d is the distance between the unmanned helicopter and the target. Determine the heading of the unmanned helicopter Ψ ac Is it in the sector angle θ t In the range of θ t Within the range, the unmanned helicopter continues to fly according to the heading; if it deviates, see steps 5-6;

[0050] θ t =2arsin(R / d) (2)

[0051] Step 5): At time P3, due to the movement of the target, the unmanned helicopter flies along the original heading and deviates from the fan-shaped area by an angle θ t scope;

[0052] Step 6): At P4, the unmanned helicopter adjusts its heading by coordinated turning acAim at the target, generate a new tracking heading instruction, and the unmanned helicopter keeps flying according to the new heading.

[0053]

[0054] Until the unmanned helicopter crashes into the circular tracking area;

[0055] Step 7): Crash into the circular tracking area, keep flying on the tracking heading, and adjust the forward flight speed to the optimal cruising speed not less than the target speed;

[0056] Step 8): Update the coordinates of the unmanned helicopter and the target in real time to determine whether the distance between the unmanned helicopter and the target is greater than R. If it is greater than R, the unmanned helicopter adjusts its heading Ψ by coordinated turning. ac Re-target (see Figure 3 ), calculate and generate the following heading instruction according to formula (1), and the unmanned helicopter flies according to the new heading. If the target tracking task is not completed, repeat step 8, otherwise go to step 9;

[0057] Step 9): The unmanned helicopter receives the target tracking end command and exits the target tracking control.

[0058] Example 1

[0059] In a flight test of a certain type of unmanned helicopter tracking a fixed target, this method was used to successfully guide the unmanned helicopter to hover near the fixed tracking target point. The flight track results are shown in the attached Figure 4 ; The relative distance between the unmanned helicopter and the fixed target is kept within the set fixed value, see attached Figure 5 .

[0060] like Figure 4 As shown, the fixed target is located at point T1; initially, the unmanned helicopter is located at point H1, and the relative distance from the fixed target is about 3500 meters, and the radius R of the circular tracking area is set to 2500 meters. After starting the target tracking flight control, the unmanned helicopter coordinates the turn to adjust the heading, flies towards the fixed target, and flies over the fixed target. When the distance between the unmanned helicopter and the fixed target exceeds the set fixed value of 2500 meters (i.e. flies out of the circular tracking area), the unmanned helicopter coordinates the turn again to adjust the heading, flies towards the fixed target, and so on and so forth until receiving the exit target tracking flight instruction.

[0061] Example 2

[0062] In a flight test of a certain type of unmanned helicopter using optoelectronic images to lock onto a ground moving vehicle and track it, after the optoelectronic pod locked onto the target, the unmanned helicopter was successfully controlled to hover and follow the ground moving vehicle through this method. The flight track results are shown in the attached Figure 6; The relative distance between the unmanned helicopter and the ground mobile vehicle is kept within the set fixed value, see attached Figure 7 .

[0063] like Figure 6 As shown in the figure, initially, the ground moving vehicle is located at point T1, the unmanned helicopter is located at point H1 (about 8000 meters away from point T1), and the radius R of the circular tracking area is set to 4000 meters. After the target is locked by the optoelectronic pod, the target tracking flight control is started, and the unmanned helicopter coordinates the turn to adjust the heading, aiming at the ground moving vehicle, and begins to enter the long-range tracking stage. The unmanned helicopter flies to point H2, at which time the current heading of the unmanned helicopter deviates from the angle θ of the fan-shaped area t The unmanned helicopter re-coordinated the turn and adjusted its heading to fly towards the ground vehicle. After that, the unmanned helicopter entered the circular tracking area and began to follow the control flight in a short distance. When the ground vehicle reached point T3, the unmanned helicopter flew to point H3. At this time, the ground vehicle adjusted its driving direction. According to the flight trajectory of the unmanned helicopter afterwards, it can be seen that the unmanned helicopter still stably remained in the circular area centered on the ground vehicle and followed the flight.

[0064] Example 3

[0065] In a certain type of unmanned helicopter landing guidance test flight, this method was used to successfully remotely guide the unmanned helicopter to hover near the ship and wait. The flight track results are shown in the attached Figure 8 ; The relative distance between the unmanned helicopter and the ship target is kept within the set fixed value, see attached Fig. 9 .

[0066] like Figure 8 As shown in the figure, initially, the ship target is located at point T1, the unmanned helicopter is located at point H1, and the circular tracking area radius R is set to 5000 meters. After starting the target tracking flight control, the unmanned helicopter coordinates the turn to adjust the heading and fly towards the ship target. When the ship target moves to point T2, the unmanned helicopter flies to point H2. At this time, the current heading of the unmanned helicopter deviates from the angle θ of the fan-shaped area t The range, so the unmanned helicopter re-coordinates the turn and adjusts the heading to fly towards the ship target. When the ship target moves to point T3, the unmanned helicopter flies to point H3. At this time, the current heading of the unmanned helicopter deviates from the fan-shaped area angle θ again. t The unmanned helicopter coordinates the turn again to adjust the heading and fly towards the ship target. When the ship target moves to point T4, the unmanned helicopter flies to point H4, and the current heading of the unmanned helicopter deviates from the fan-shaped area angle θ again. tThe unmanned helicopter then coordinates to turn and adjust its heading again, aiming at the ship target. After that, the unmanned helicopter enters the circular tracking area and starts close-range follow-up control flight. According to the subsequent flight trajectory, it can be seen that the unmanned helicopter can stably hover and track the circular area of ​​the ship target, waiting for the ship to send the next landing flight instruction.

[0067] The unmanned helicopter designed by the present invention uses a long-range tracking and short-range following control method based on a circular tracking area, simplifies the target tracking logic, and improves the safety of the unmanned helicopter itself when tracking the target.

Claims

1. A control method for unmanned helicopter target tracking, characterized in that: The control method comprises: S1, after the unmanned helicopter receives the target tracking command and obtains the target real-time position information, it establishes a circular tracking area with the target real-time position coordinates as the center and a radius of R, where R is the minimum effective distance to achieve target tracking; S2, if the unmanned helicopter is outside the circular tracking area, it enters the remote tracking control stage; in the remote tracking control stage, the unmanned helicopter adjusts its heading in real time to fly towards the target, and tracks the target at a forward flight speed greater than the target moving speed; S3, if the unmanned helicopter is within the circular tracking area, it enters the short-range following control stage; the unmanned helicopter dynamically adjusts the flight trajectory according to the real-time position of itself and the target to ensure that the unmanned helicopter is within the circular tracking area, thereby completing the tracking flight of the target.

2. The control method for target tracking of an unmanned helicopter according to claim 1, characterized in that: S2 is specifically: S21, unmanned helicopter adjusts its heading by coordinated turning ac Aim at the target, calculate and generate a new tracking heading instruction, and then fly according to the new tracking heading; S22, updating the position coordinates of the unmanned helicopter and the target in real time, taking the sector area formed by the two outer common tangent lines of the unmanned helicopter and the target circular tracking area, and calculating the sector area angle θ t ; S23, determine the heading of the unmanned helicopter ac Is it in the sector angle θ t within the scope; If in θ t Within the range, the unmanned helicopter continues to fly according to the heading; If in θ t Outside the range, the unmanned helicopter adjusts its heading by coordinated turning ac Aim at the target, generate a new tracking heading instruction, and the unmanned helicopter keeps flying according to the new heading; until the unmanned helicopter crashes into the circular tracking area.

3. The control method for target tracking of an unmanned helicopter according to claim 2, characterized in that: Calculate and generate new tracking heading instructions, specifically: A new tracking heading instruction is calculated according to formula (1), and then the aircraft flies according to the new tracking heading; psi_cmd=f(lon,lat,lon aim ,lat aim ) (1) Among them, lon is the longitude of the unmanned helicopter, lat is the latitude of the unmanned helicopter, lon aim is the longitude of the target location, lat aim is the latitude of the target location, f(lon,lat,lon aim ,lat aim ) is the real-time direction of the unmanned helicopter pointing to the target, and psi_cmd is the heading command of the unmanned helicopter.

4. The control method for target tracking of an unmanned helicopter according to claim 2, characterized in that: Calculate the fan-shaped area angle θ t , specifically: According to formula (2), the fan-shaped area angle θ is calculated t <h2 style=";text-align:left;direction:ltr">θ<h2 style=";text-align:left;direction:ltr"> t <h2 style=";text-align:left;direction:ltr"> =2arsin(R / d) (2) Where d is the distance between the unmanned helicopter and the target.

5. The control method for target tracking of an unmanned helicopter according to claim 2, characterized in that: S3 is specifically: S31, if the unmanned helicopter maintains tracking heading flight within the circular tracking area, the forward flight speed is adjusted to an optimal cruising speed not less than the target speed; S32, updating the coordinates of the unmanned helicopter and the target in real time, judging whether the distance between the unmanned helicopter and the target is greater than R, if greater than R, the unmanned helicopter adjusts the heading Ψ by coordinated turning ac Re-align the target, calculate and generate the following heading instruction according to formula (1), and the unmanned helicopter flies according to the new heading; Until the unmanned helicopter receives the command to end target tracking and exits target tracking control.

6. The control method for target tracking of an unmanned helicopter according to claim 1, characterized in that: In S1, if the tracking task in the target tracking instruction belongs to the reconnaissance or strike category, half of the action distance L of the mission equipment on the unmanned helicopter is set as the radius of the circular tracking area.

7. The control method for target tracking of an unmanned helicopter according to claim 1, characterized in that: In S1, if the tracking task in the target tracking instruction belongs to the landing remote guidance, the radius R of the circular tracking area is set to the safe distance required for the landing approach glide.

8. An unmanned helicopter, characterized in that: The unmanned helicopter uses the control method described in any one of claims 1-7 to track the target.

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