A control method for unmanned helicopter target tracking

Abstract

The present application belongs to the field of unmanned helicopter flight control technology, and particularly relates to a control method for target tracking of unmanned helicopter. The method comprises the following steps: S1, after receiving a target tracking instruction and obtaining real-time position information of the target, the unmanned helicopter establishes a circular tracking area with the real-time position coordinates of the target as the center and a radius R, wherein R is the minimum effective distance for realizing target tracking; S2, if the unmanned helicopter is outside the circular tracking area, the remote tracking control stage is entered; in the remote tracking control stage, the unmanned helicopter adjusts the heading to align with the target flight in real time, and tracks the target at a forward flight speed greater than the target moving speed; S3, if the unmanned helicopter is inside the circular tracking area, the short-range following control stage is entered; the unmanned helicopter dynamically adjusts the flight trajectory according to the real-time positions of itself and the target, so as to ensure that the unmanned helicopter is inside the circular tracking area, thereby completing the tracking flight of the target.

Description

Technical Field

[0001] This invention belongs to the field of unmanned helicopter flight control technology, and in particular relates to a control method for target tracking of unmanned helicopters. Background Technology

[0002] With the rapid development of drone technology, drones have been widely used in military and civilian fields. Target tracking technology is one of the key technologies for drone applications. Currently, the methods for target tracking are basically based on the target's historical position and speed information, using motion models to predict the target's future trajectory. These trajectory prediction algorithms have a large computational load, and the accuracy of the prediction cannot be guaranteed to be completely correct, making them unsuitable for direct application in engineering.

[0003] Traditional tracking strategies typically involve tailing the target at a fixed distance, which is suitable for small, highly maneuverable electric multi-rotor drones. However, for medium to large unmanned helicopters with conventional single-rotor tail rotor configurations, they cannot perform the same flexible and rapid turning as small electric multi-rotor drones. Especially when tracking highly maneuverable targets such as ground vehicles or speedboats, directly using the same path as the target for tracking control can cause the unmanned helicopter to experience large attitude angles and heading swings, which can easily lead to overload and induce control oscillations. Furthermore, sudden maneuvers can also easily result in the loss of the target. Summary of the Invention

[0004] The purpose of this invention is to effectively improve the safety of target tracking by unmanned helicopters, while ensuring the accuracy of real-time target tracking control and the coordination of various flight control channels. This invention proposes a control method for target tracking by unmanned helicopters that simplifies the tracking control logic.

[0005] To achieve the above objectives, the present invention employs the following technical solution.

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

[0007] S1. After receiving the target tracking command and obtaining the target's real-time position information, the unmanned helicopter establishes a circular tracking area with a radius of R centered on the target's real-time position coordinates, where R is the minimum effective distance to achieve target tracking.

[0008] S2, If the unmanned helicopter is outside the circular tracking area, it enters the remote tracking and control phase; in the remote tracking and control phase, the unmanned helicopter adjusts its course in real time to fly towards the target and tracks the target at a forward speed greater than the target's moving speed.

[0009] S3. If the unmanned helicopter is within the circular tracking area, it enters the close-range following control phase. 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 within the circular tracking area, thereby completing the tracking flight of the target.

[0010] Furthermore, S2 specifically refers to:

[0011] S21, the unmanned helicopter adjusts its heading Ψ through coordinated turning. ac Once aligned with the target, calculate and generate a new tracking course command, and then fly according to the new tracking course;

[0012] S22, update the position coordinates of the unmanned helicopter and the target in real time, take the sector area formed by the two external common tangents of the circular tracking area of ​​the unmanned helicopter and the target, and calculate the included angle θ of the sector area. t ;

[0013] S23, determine the heading Ψ of the unmanned helicopter ac Is it within the sector angle θ? t Within the range;

[0014] If at θ t Within the area, the unmanned helicopter continued to fly along its course;

[0015] If at θ t Outside the designated range, the unmanned helicopter adjusts its heading Ψ through coordinated turning. ac Once aligned with the target, a new tracking heading command is generated, and the unmanned helicopter maintains its flight along the new heading until it crashes into the circular tracking area.

[0016] Furthermore, new tracking heading instructions are calculated and generated, specifically as follows:

[0017] A new tracking heading instruction is generated according to equation (1), and then the flight follows the new tracking heading.

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

[0019] Where lon represents the longitude of the unmanned helicopter's location, and lat represents the latitude of the unmanned helicopter's location. aim For the target location longitude, lat aim Let f(lon,lat,lon) be the latitude of the target location. aim ,lat aim ) represents the real-time direction of the unmanned helicopter pointing to the target, and psi_cmd represents the heading command of the unmanned helicopter.

[0020] Furthermore, calculate the included angle θ of the sector regions.t Specifically:

[0021] The included angle θ of the sector is calculated according to equation (2). 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 specifically refers to:

[0025] S31, if the unmanned helicopter maintains its tracking course within the circular tracking area, it adjusts its forward speed to the optimal cruise speed, which is not less than the target speed;

[0026] S32 updates the coordinates of the unmanned helicopter and the target in real time, and determines 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 through coordinated turning. ac Realign with the target, calculate and generate a follow-the-heading command according to formula (1), and the unmanned helicopter flies according to the new heading;

[0027] The unmanned helicopter will continue to track targets until it receives a command to end target tracking and exits target tracking control.

[0028] Furthermore, in S1, if the tracking mission in the target tracking command belongs to the reconnaissance or strike category, half of the effective 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 command belongs to the remote guidance of landing, the radius R of the circular tracking area is set to the safe distance required for landing approach descent.

[0030] The present invention also provides an unmanned helicopter, wherein the unmanned helicopter uses the control method as described in any one of claims 1-7 for target tracking.

[0031] The technical solution of this invention designs a fan-shaped heading-keeping zone during remote target tracking, which reduces the number of heading maneuvers of the unmanned helicopter caused by target movement and keeps the tracking process stable. It also designs a circular tracking area for the unmanned helicopter, which always follows the target in a forward-flying manner. If it goes out of the area, it uses a coordinated turning method to adjust its heading and re-align with the target. It does not need to directly tail the target or perform real-time small maneuvers to follow it, which ensures that the unmanned helicopter can safely follow the target and does not lose the target. Attached Figure Description

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

[0033] Figure 2 This is a schematic diagram of the included angle of the tangent heading.

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

[0035] Figure 4 Flight path map for unmanned helicopters tracking fixed targets;

[0036] Figure 5 A graph showing the relative distance between an unmanned helicopter and a fixed target;

[0037] Figure 6 Flight path diagram for guiding unmanned helicopters to land on the ship;

[0038] Figure 7 A graph showing the relative distance between unmanned helicopters and ship targets;

[0039] Figure 8 Flight path map for unmanned helicopters tracking electro-optical image targets;

[0040] Figure 9 This is a graph showing the relative distance between an unmanned helicopter and an electro-optical target. Detailed Implementation

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

[0042] This invention provides a control method for target tracking of an unmanned helicopter, comprising: the target tracking control process is divided into two parts: remote tracking control and short-range following control.

[0043] After receiving the target tracking command and acquiring the target's real-time position information, the unmanned helicopter establishes a circular tracking area with a radius of R kilometers, centered on the target's real-time position coordinates. R represents the minimum effective distance for target tracking. If the unmanned helicopter is outside this area, it enters the remote tracking control process. The unmanned helicopter adjusts its heading to align with the target and begins tracking it at a forward speed greater than the target's speed. During the tracking process, the unmanned helicopter adjusts its flight trajectory as needed based on its own and the target's real-time positions, eventually entering the circular tracking area. Then, it enters the close-range following control phase, dynamically adjusting its flight trajectory based on its own and the target's real-time positions to ensure that the unmanned helicopter remains within the real-time circular tracking area, thus completing the tracking flight within the effective distance R of the target.

[0044] Specific implementation steps:

[0045] Step 1): Time P1 (see...) Figure 1 The unmanned helicopter receives the target tracking command;

[0046] Step 2): At time P1, analyze the target's position coordinates and establish a circular tracking area with a radius of R kilometers centered on the target. R represents the minimum effective distance for target tracking, ensuring observation, reconnaissance, or attack from all directions, and the unmanned helicopter will always hover and follow the target within a radius of R kilometers. For example, if this tracking mission is a reconnaissance or attack mission, half the effective range L of the mission equipment on the unmanned helicopter (L / 2) can be set as the radius R of the circular tracking area. For example, the effective range of an electro-optical pod or a small air-to-ground missile, R can be set to approximately 4 km. If this tracking mission is a long-range ship landing guidance mission, the radius R of the circular tracking area can be set to the safe distance required for the ship landing approach glide, R can be set to approximately 5 km.

[0047] Step 3): At time P2, the unmanned helicopter adjusts its heading Ψ through a coordinated turn. ac Align with the target, calculate and generate a new tracking heading command according to equation (1), and then fly according to the new heading, where lon is the longitude of the unmanned helicopter's position, lat is the latitude of the unmanned helicopter's position, and len is the longitude of the unmanned helicopter's position. aim Target location longitude, lat aim The latitude of the target location This is the real-time direction for the unmanned helicopter to point at the target, and psi_cmd is the heading command for 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 external common tangents of the circular tracking area of ​​the unmanned helicopter and the target, and calculate the included angle θ of the sector according to equation (2). t (See Figure 2 ), where d is the distance between the unmanned helicopter and the target. Determine the unmanned helicopter's heading Ψ. ac Is it within the sector angle θ? t Within the range, if in θ t Within the range, the unmanned helicopter continues to fly along 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 target's movement, the unmanned helicopter deviates from the fan-shaped area by an angle θ along its original course. t scope;

[0052] Step 6): At time P4, the unmanned helicopter adjusts its heading Ψ through a coordinated turn. acOnce the target is aligned, a new tracking heading command is generated, and the unmanned helicopter maintains flight along the new heading.

[0053]

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

[0055] Step 7): Enter the circular tracking area, maintain the tracking course, and adjust the forward speed to the optimal cruising speed that is not less than the target speed;

[0056] Step 8): Update the coordinates of the unmanned helicopter and the target in real time, and 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 coordinating a turn. ac Re-aim at the target (see) Figure 3 According to formula (1), a following heading command is generated, and the unmanned helicopter flies according to the new heading. If the target tracking task has not ended, step 8 is repeated; otherwise, step 9 is entered.

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

[0058] Example 1

[0059] In a flight test of a certain type of unmanned helicopter tracking a fixed target, this method successfully guided the unmanned helicopter to hover near the fixed target point. The flight trajectory results are attached. Figure 4 The relative distance between the unmanned helicopter and the fixed target remains within a set fixed value, see appendix. 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, with a relative distance of approximately 3500 meters from the fixed target, and the radius R of the circular tracking area is set to 2500 meters. After the target tracking flight control is activated, the unmanned helicopter coordinates a turn to adjust its course, flies towards the fixed target, and passes 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., it flies out of the circular tracking area), the unmanned helicopter coordinates a turn to adjust its course again, flies towards the fixed target, and so on in a cycle until it receives a command to exit target tracking flight.

[0061] Example 2

[0062] In a test of locking onto and tracking a ground mobile vehicle using electro-optical imaging of a certain type of unmanned helicopter, this method successfully controlled the unmanned helicopter to hover and follow the ground mobile vehicle after the electro-optical pod locked onto the target. The flight trajectory results are attached. Figure 6The relative distance between the unmanned helicopter and the ground mobile vehicle is maintained within a fixed set value, see appendix. Figure 7 .

[0063] like Figure 6 As shown, initially, the ground mobile vehicle is located at point T1, and the unmanned helicopter is located at point H1 (approximately 8000 meters away from point T1). The radius R of the circular tracking area is set to 4000 meters. After locking onto the target using the electro-optical pod, target tracking flight control is activated. The unmanned helicopter coordinates its turn and adjusts its course to align with the ground mobile vehicle, entering the long-range tracking phase. When the unmanned helicopter reaches point H2, its current course deviates from the included angle θ of the sector area. t The unmanned helicopter then readjusted its course and turned to align with the ground vehicle. It then entered a circular tracking area and began close-range follow-control flight. When the ground vehicle reached point T3, the unmanned helicopter flew to point H3. At this point, the ground vehicle adjusted its direction. Based on the subsequent flight trajectory of the unmanned helicopter, it can be seen that it remained stably hovering and following the ground vehicle within a circular area.

[0064] Example 3

[0065] In a test flight of a certain type of unmanned helicopter for ship landing guidance, this method successfully guided the unmanned helicopter remotely to hover near the ship. The flight trajectory results are attached. Figure 8 The relative distance between the unmanned helicopter and the ship target remained within the set fixed value, see appendix. Figure 9 .

[0066] like Figure 8 As shown, initially, the ship target is located at point T1, and the unmanned helicopter is located at point H1. The radius R of the circular tracking area is set to 5000 meters. After the target tracking flight control is activated, the unmanned helicopter coordinates its turn and adjusts its course to fly towards the ship target. When the ship target moves to point T2, the unmanned helicopter flies to point H2. At this time, the unmanned helicopter's current course deviates from the included angle θ of the sector area. t The unmanned helicopter then readjusted its course and repositioned itself to target the ship. When the ship reached point T3, the unmanned helicopter moved to point H3, at which point its current course deviated again from the included angle θ of the sector. t The unmanned helicopter then coordinated a turn to adjust its course and flew towards the ship target. When the ship target reached point T4, the unmanned helicopter flew to point H4, at which point its current course deviated from the included angle θ of the sector area again. tUpon reaching the target area, the unmanned helicopter again coordinated a turn and adjusted its course to align with the ship target. It then entered a circular tracking area and began close-range follow-and-control flight. Based on its subsequent flight trajectory, it can be seen that the unmanned helicopter was able to stably hover and track the ship target within its circular area, awaiting further landing commands from the ship.

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

Claims

1. A control method for target tracking of an unmanned helicopter, characterized in that, The control method includes: S1. After receiving the target tracking command and obtaining the target's real-time position information, the unmanned helicopter establishes a circular tracking area with a radius of R centered on the target's real-time position coordinates, 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 and control phase; in the remote tracking and control phase, the unmanned helicopter adjusts its course in real time to fly towards the target and tracks the target at a forward speed greater than the target's moving speed; S2 specifically means: S21, the unmanned helicopter adjusts its course through coordinated turning. Once aligned with the target, calculate and generate a new tracking course command, and then fly according to the new tracking course; S22: Update the position coordinates of the unmanned helicopter and the target in real time; calculate the included angle of the sector formed by the two external common tangents of the circular tracking area of ​​the unmanned helicopter and the target. ; S23, Determine the heading of the unmanned helicopter Is it located at the angle of the sector area? Within the range; If in Within the area, the unmanned helicopter continued to fly along its course; If in Outside the designated range, the unmanned helicopter adjusts its course through coordinated turns. Once aligned with the target, a new tracking heading command is generated, and the unmanned helicopter maintains flight according to the new heading until it crashes into the circular tracking area. S3. If the unmanned helicopter is within the circular tracking area, it enters the close-range following control phase. 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 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, The new tracking heading instructions are calculated and generated as follows: A new tracking heading instruction is generated according to formula (1), and then the flight follows the new tracking heading. （1） in, The longitude of the unmanned helicopter's location. The latitude and longitude of the unmanned helicopter's location. The longitude of the target location The latitude of the target location Provides the real-time direction for the unmanned helicopter to point at the target. This is the heading instruction for the unmanned helicopter.

3. The control method for target tracking of an unmanned helicopter according to claim 1, characterized in that, Calculate the included angle of the sector Specifically: Calculate the included angle of the sector according to formula (2). （2） in, d This represents the distance between the unmanned helicopter and the target.

4. The control method for target tracking of an unmanned helicopter according to claim 1, characterized in that, S3 specifically refers to: S31, if the unmanned helicopter maintains its tracking course within the circular tracking area, it adjusts its forward speed to the optimal cruise speed, which is not less than the target speed; S32 updates the coordinates of the unmanned helicopter and the target in real time, and determines 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 through a coordinated turn. Realign with the target, calculate and generate a follow-the-heading command according to formula (1), and the unmanned helicopter flies according to the new heading; The unmanned helicopter will continue to track targets until it receives a command to end target tracking and exits target tracking control.

5. 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 command belongs to the reconnaissance or strike category, half of the effective distance L of the mission equipment on the unmanned helicopter is set as the radius of the circular tracking area.

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 command is a remote landing guidance, the radius R of the circular tracking area is set to the safe distance required for the landing approach glide.

7. An unmanned helicopter, characterized in that, The unmanned helicopter uses the control method described in any one of claims 1-6 to track targets.

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