Aircraft flight path control method

Abstract

The application discloses an aircraft track control method, which comprises the following steps: firstly, obtaining a preset track of an aircraft; and then, determining the position of the aircraft through a laser ranging sensor and a camera, wherein the laser ranging sensor is fixed with the camera and the optical axes of the laser ranging sensor and the camera are parallel; in order to make the aircraft always appear in the center of the camera, horizontal rotation and vertical rotation are needed; the coordinates of the aircraft can be determined according to the corresponding rotation angle and distance, so that track control is performed. The positioning of the aircraft is more accurate and fast, the aircraft can fly along the preset track accurately, the influence of the environment is small, and the application range is wide.

Description

Technical Field

[0001] This invention relates to the field of aircraft control, specifically to a high-precision trajectory control method for aircraft. Background Technology

[0002] Currently, aircraft positioning methods mainly include inertial positioning, ground-based radio positioning, satellite positioning, and visual positioning. Satellite positioning combined with visual positioning can achieve positioning accuracy at the decimeter level. For example, patent application CN201480079892.7, entitled "System and Method for Monitoring Using Visual Markers," uses multiple visual markers for auxiliary positioning. However, in practical applications, many scenarios are not suitable for affixing visual markers, thus greatly limiting the use of this method. Indoor positioning mainly relies on visual or laser SLAM navigation, such as patent application CN201610362320.0, entitled "An Aircraft Positioning Method Based on a Positioning Sensor Device," which uses optical flow to navigate the aircraft. This method depends on the complexity of the environment and the extraction of feature points, resulting in highly unstable performance and significant influence from the indoor environment, making it difficult to achieve high-precision positioning and accurate track setting. The invention patent with application number 201810163125.4 and titled "Active Navigation and Positioning Device and Navigation and Positioning Method for Aircraft" installs a laser on the aircraft, which increases the aircraft's load and consumes a lot of power, resulting in a shorter operating time for the aircraft, which already has a short flight time. Summary of the Invention

[0003] The purpose of this invention is to provide an aircraft trajectory control method that provides more accurate and faster aircraft positioning, enables precise flight along a preset trajectory, is less affected by the environment, and has a wide range of applications.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: An aircraft trajectory control method includes the following steps: S1: Obtain the aircraft's preset flight path; S2: Obtain the aircraft's location, including: S21: Fix the relative positions of the camera and the laser rangefinder. When the aircraft is in its initial position, it appears in the center of the camera's field of view. The aircraft is equipped with reflective components for alignment by the laser rangefinder. S22: When the aircraft is in flight, the control system detects the position of the aircraft in real time by collecting video streams, and controls the drive motor equipped with the camera and laser range sensor to rotate, so that the aircraft always appears in the center of the camera's field of view and the reflective component is simultaneously aligned with the laser range sensor to measure the distance. The current position of the aircraft is determined by the rotation angle of the drive motor and the distance measured by the laser range sensor. S3: The control system controls the flight of the aircraft based on the current position of the aircraft and the preset trajectory, so that the position of the aircraft continuously tends towards the preset trajectory.

[0005] Preferably, in step S22, the optical axis of the laser rangefinder is parallel to the optical axis of the camera, and the drive motor includes a first motor and a second motor. The first motor rotates horizontally to generate a horizontal rotation angle, and the second motor rotates vertically to generate a vertical rotation angle. The current position of the aircraft is determined based on the horizontal rotation angle, the vertical rotation angle, and the distance measured by the laser rangefinder.

[0006] Preferably, in step S22, the rotation of the first motor and the second motor is adjusted according to the direction and speed of the horizontal and vertical rotation angles in the current time period, so that the position of the aircraft always appears in the center of the camera's field of view in the next time period.

[0007] Preferably, in step S22, the shaft of the first motor is perpendicular to the horizontal plane, the shaft of the second motor is perpendicular to the shaft of the first motor, the first motor drives the second motor, the camera, and the laser rangefinder to rotate horizontally to generate a horizontal rotation angle α, the second motor drives the camera and the laser rangefinder to rotate vertically to generate a vertical rotation angle β, and the distance measured by the laser rangefinder is L. Then, the current position of the aircraft in Cartesian coordinates is calculated using the following formula: Where a is the distance from the laser ranging sensor chip to the axis of the first motor, b is the distance from the laser ranging sensor chip to the axis of the second motor, the Z-axis of the rectangular coordinate system coincides with the axis of the first motor and is vertically upward, the XY-axis plane is on the chassis, the Y-axis is marked on the chassis and is directed outward along the radius of the circular chassis, the X-axis is determined by the right-hand screw rule, and the initial position of the second motor coincides with the Y-axis.

[0008] Preferably, in step S1, the preset trajectory includes the aircraft's preset position information and flight attitude information. In step S2, while acquiring the aircraft's position information, the aircraft's flight attitude information is also acquired through the aircraft's inertial measurement unit. In step S3, the aircraft's flight is controlled according to the aircraft's position information, flight attitude information, and preset trajectory, so that the aircraft's position and attitude continuously tend towards the preset trajectory.

[0009] Preferably, in step S1, the preset trajectory is obtained by handing the aircraft to the target location to determine its position and flight attitude, or by determining the position and flight attitude of the aircraft through a three-dimensional simulation of the aircraft's flight.

[0010] In the above technical solution, a camera captures flight video of the aircraft, and the horizontal and vertical angles of the camera are adjusted visually to ensure the aircraft always appears in the center of the camera's field of view. Simultaneously, the relative positions of the camera and the laser rangefinder are fixed, and their optical axes are parallel. This ensures that when the aircraft remains in the center of the field of view, the laser rangefinder can always be aligned with the aircraft and measure distances, preventing target loss and the inability to measure distances. Then, the aircraft's position in a Cartesian coordinate system can be calculated using the angle and distance information. This invention first presets a flight trajectory, and during control, the aircraft's position continuously approaches the preset trajectory, thus achieving precise control and minimizing environmental influences. During aircraft positioning, the next position of the aircraft is predicted based on the direction and speed of the horizontal and vertical angles, and the rotation of the first and second motors is actively adjusted accordingly. This allows the camera to more actively capture the aircraft in the center of the field of view, reducing latency and preventing target loss, resulting in more accurate positioning. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the target tracking system structure; Figure 2 for Figure 1 A schematic diagram showing the positional relationship between the first motor axis, the second motor axis, the camera, and the laser rangefinder chip. Detailed Implementation

[0012] The present invention will be further described below with reference to the accompanying drawings: The present invention controls the trajectory of an aircraft using the following method: First, the operator manually positions the aircraft at the various spatial points it is expected to navigate through. The aircraft's location is then acquired using a target tracking system and converted into three-dimensional coordinates for each point, thus forming a pre-defined flight path. The target tracking system used is the same as the one used during the aircraft's flight process described below. Besides manual positioning, a pre-defined flight path can also be obtained through three-dimensional simulation of the aircraft.

[0013] Then, during takeoff and flight, the aircraft's position is obtained through a target tracking system. Specifically: The target tracking system includes: platform 1, first motor 2, second motor 3, camera 4, and laser rangefinder 5. The first motor is mounted on a horizontal platform with its axis perpendicular to the platform. The first motor drives the second motor, camera, and laser rangefinder to rotate horizontally, generating a horizontal rotation angle α. The axis of the second motor is perpendicular to the axis of the first motor, driving the camera and laser rangefinder to rotate vertically, generating a vertical rotation angle β. The laser rangefinder and camera are fixed in relative position and their optical axes are parallel. When the aircraft appears in the center of the camera's field of view, the laser emitted by the laser rangefinder always hits the aircraft's reflective component. The reflective component reflects the laser back to the laser rangefinder. The laser rangefinder determines the distance between itself and the aircraft's reflective component by receiving the reflected laser.

[0014] Establish a spatial rectangular coordinate system. The z-axis coincides with the axis of the first motor, and its positive direction is the same as the direction in which the output shaft of the first motor extends, both vertically upwards. The axis of the second motor coincides with the y-axis, and the positive direction of the y-axis is the same as the direction in which the output shaft of the second motor extends. The x-axis and y-axis lie in the same horizontal plane and are determined by the right-hand screw rule. The xy-plane can be considered the surface of the chassis platform, and the intersection of the xy-plane and the z-axis is the origin O.

[0015] When the aircraft is in its initial position, the first and second motors of the target tracking system are also in their initial positions, and the aircraft appears at the center of the camera's field of view. As the aircraft takes off and moves to the next position, the camera captures flight video of the aircraft and uses machine vision and the YOLO algorithm to determine the aircraft's position within the camera's field of view. The control system then controls the first and second motors to rotate, bringing the aircraft back to the center of the camera's field of view. The horizontal angle α rotated by the first motor and the vertical angle β rotated by the second motor are acquired by the control system. The laser rangefinder then measures the distance L between the aircraft and the laser rangefinder and sends this information to the control system. The control system can then calculate the aircraft's coordinates (x, y, z) in a Cartesian coordinate system based on the horizontal angle α, the vertical angle β, and the distance L. Clockwise rotation is negative, and counterclockwise rotation is positive. For example, based on the above setting of the Cartesian coordinate system, the coordinates (x, y, z) can be calculated using the following formula: In the formula, a represents the distance from the center position of the laser ranging sensor chip to the axis of the first motor (p). Figure 2 The distance from axis 1 in the diagram, where b is the distance from the laser ranging sensor chip to the second motor (axis 1). Figure 2 The distance between the two axes in the diagram.

[0016] Finally, based on the calculated position of the aircraft and the preset trajectory, the control system controls the aircraft to continuously move towards the preset trajectory, ultimately making the aircraft's flight path consistent with the preset trajectory, thereby achieving high-precision trajectory control.

[0017] In a preferred embodiment, when setting the flight path, the aircraft's flight attitude is simultaneously set. The inertial measurement unit inside the aircraft then transmits the flight attitude information to the control system, thus ensuring that the preset flight path includes the aircraft's preset position and flight attitude information. In this way, the control system can simultaneously control the flight attitude and flight path during aircraft flight, ensuring that the aircraft's flight attitude meets requirements. For example, when the aircraft is photographing and inspecting a train, it needs to take pictures in a suitable attitude, and attitude control and flight path control can meet these requirements.

[0018] Considering the aircraft's continuous position changes during flight, if the control system only drives the first and second motors to rotate after the camera has captured the aircraft's position at a certain moment, a delay will occur. This will cause the camera's rotation to lag behind the aircraft's position changes, making it difficult for the aircraft to appear in the center of the camera's field of view, leading to laser measurement and angle calculation errors. Therefore, in one embodiment, the camera's target acquisition accuracy is improved by enhancing the control system's computing power and response speed. In another embodiment, machine learning and filtering prediction algorithms (such as Kalman filtering) are used to predict the aircraft's position in the next time period based on the direction and speed of horizontal and vertical rotation in the current time period. The rotation speeds of the first and second motors are then pre-adjusted so that the camera's rotation can accompany the aircraft's flight and ensure that the aircraft's position always appears in the center of the camera's field of view. To adapt to changes in the aircraft's distance and obtain clearer images, the camera can employ a zoom lens.

[0019] This embodiment is merely an illustration of the concept and implementation of the present invention and is not intended to limit it. Under the concept of the present invention, technical solutions without substantial changes are still within the scope of protection.

Claims

1. A method for controlling the trajectory of an aircraft, characterized in that... Includes the following steps: S1: Obtain the aircraft's preset flight path; S2: Obtain the aircraft's location, including: S21: Fix the relative positions of the camera and the laser rangefinder. When the aircraft is in its initial position, it appears in the center of the camera's field of view. The aircraft is equipped with reflective components for alignment by the laser rangefinder. S22: When the aircraft is in flight, the control system detects the position of the aircraft in real time by collecting video streams, and controls the drive motor equipped with the camera and laser range sensor to rotate, so that the aircraft always appears in the center of the camera's field of view and the reflective component is simultaneously aligned with the laser range sensor to measure the distance. The current position of the aircraft is determined by the rotation angle of the drive motor and the distance measured by the laser range sensor. S3: The control system controls the flight of the aircraft based on the current position of the aircraft and the preset trajectory, so that the position of the aircraft continuously tends toward the preset trajectory; In step S22, the optical axis of the laser rangefinder is parallel to the optical axis of the camera. The drive motor includes a first motor and a second motor. The first motor rotates horizontally to generate a horizontal rotation angle, and the second motor rotates vertically to generate a vertical rotation angle. The current position of the aircraft is determined based on the horizontal rotation angle, the vertical rotation angle, and the distance measured by the laser rangefinder.

2. The aircraft trajectory control method according to claim 1, characterized in that, In step S22, the rotation of the first motor and the second motor is adjusted according to the direction and speed of the horizontal and vertical rotation angles in the current time period, so that the position of the aircraft always appears in the center of the camera's field of view in the next time period.

3. The aircraft trajectory control method according to claim 1, characterized in that, In step S1, the preset trajectory includes the aircraft's preset position information and flight attitude information. In step S2, while acquiring the aircraft's position information, the aircraft's flight attitude information is also acquired through the aircraft's inertial measurement unit. In step S3, the aircraft's flight is controlled according to the aircraft's position information, flight attitude information, and preset trajectory, so that the aircraft's position and attitude continuously tend toward the preset trajectory.

4. The aircraft trajectory control method according to claim 3, characterized in that, In step S1, the preset trajectory is obtained by determining the position and flight attitude of the aircraft by hand-holding it to the target location, or by determining the position and flight attitude of the aircraft through a three-dimensional simulation of the aircraft's flight.

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