Unmanned aerial vehicle hovering control method

Abstract

The invention relates to unmanned aerial vehicle control, in particular to an unmanned aerial vehicle hovering control method, and the method comprises the steps: determining a hovering point according to the position of a to-be-cleaned photovoltaic panel, and controlling an unmanned aerial vehicle to fly to the hovering point and execute a hovering action; detecting a current wind direction in real time, taking the current wind direction as a recorded wind direction, and determining a corresponding preset direction; adjusting the direction of the head of the unmanned aerial vehicle by adjusting the rotation speed of each rotor, so that the head of the unmanned aerial vehicle faces the recorded wind direction according to a preset direction; a rotor wing set of the unmanned aerial vehicle is controlled to execute wind resistance operation in a preset direction; s2, the current wind direction is detected in real time, if the deviation angle between the current wind direction and the recorded wind direction is smaller than a preset threshold value, the rotor wing set is controlled to continue to execute wind resistance operation in the preset direction, and otherwise, the S2 is executed again; according to the technical scheme, the defects that in the prior art, an unmanned aerial vehicle is low in hovering precision and poor in stability can be effectively overcome.

Description

Technical Field

[0001] The present invention relates to unmanned aerial vehicle (UAV) control, and in particular to a method for controlling the hovering of an UAV. Background Art

[0002] Multi-rotor drones belong to the cutting-edge high-tech industry. With the advancement of technology, drones are finding an increasingly broad range of applications, not only in military applications but also in civilian fields. Due to their low operating costs, minimal risk of casualties, excellent maneuverability, the ability to fly beyond visual range, and ease of use and efficiency, drones are currently being used in aerial filming, surveying and mapping, high-voltage power line inspections, remote monitoring, disaster relief, pesticide spraying, and commercial performances. More and more industries are looking to replace traditional manual labor with drones.

[0003] In recent years, the number of domestic photovoltaic power generation equipment has increased rapidly. On the one hand, photovoltaic panels are blocked by dust, bird droppings, etc., resulting in reduced power generation efficiency; on the other hand, a large number of photovoltaic sites need to inspect and maintain photovoltaic panels during operation, especially for some distributed photovoltaics, which are generally installed on the roof of the factory building, which brings great inconvenience to the cleaning and maintenance of photovoltaic panels. The existing technical solutions mainly use small cleaning robots to transport them to the photovoltaic panels or clean them manually. Manual cleaning poses a great safety risk. At the same time, due to the relatively scattered distribution of distributed photovoltaics, manual transportation of cleaning robots is also very difficult and also poses a safety risk. However, using drones to lift small cleaning robots can effectively avoid safety risks and solve the problem of difficult transportation. At present, drone lifting has been applied, but drones are easily affected by wind at high altitudes, resulting in low hovering accuracy and poor stability. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for controlling the hovering of a drone, which can effectively overcome the defects of the prior art such as low hovering accuracy and poor stability of the drone.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A method for controlling a drone to hover comprises the following steps:

[0009] S1. Determine the hovering point based on the location of the photovoltaic panel to be cleaned, control the drone to fly to the hovering point and perform the hovering action;

[0010] S2. Detect the current wind direction in real time, use the current wind direction as the recorded wind direction, and determine the corresponding preset direction;

[0011] S3. Adjust the rotation speed of each rotor to adjust the direction of the drone's nose so that the drone's nose faces the recorded wind direction according to the preset direction;

[0012] S4, controlling the rotor assembly of the UAV to perform wind resistance operations in a preset direction;

[0013] S5. Detect the current wind direction in real time. If the deviation angle between the current wind direction and the recorded wind direction is less than a preset threshold, control the rotor assembly to continue to perform wind resistance operations in the preset direction; otherwise, return to S2.

[0014] Preferably, in S1, determining a hovering point according to the position of the photovoltaic panel to be cleaned, and controlling the drone to fly to the hovering point and perform a hovering action include:

[0015] The hovering point position information is determined according to the position of the photovoltaic panel to be cleaned, and the current position information of the drone is obtained in real time through the positioning device on the drone;

[0016] The drone is controlled to fly to the hovering point based on the hovering point position information and the current position information of the drone, and performs a hovering action above the hovering point.

[0017] Preferably, in S2, the current wind direction is detected in real time, the current wind direction is used as the recorded wind direction, and the corresponding preset direction is determined, including:

[0018] Detect the current wind direction in real time, use the current wind direction as the recorded wind direction, and determine the corresponding preset direction based on the changes in the current wind direction.

[0019] Preferably, in S3, adjusting the rotation speed of each rotor to adjust the direction of the drone's nose so that the drone's nose faces the recorded wind direction according to a preset direction includes:

[0020] Obtain the current nose direction of the drone in real time, calculate the deviation angle between the current nose direction of the drone and the preset direction, and determine the attitude adjustment data;

[0021] The attitude of the UAV is adjusted according to the attitude adjustment data so that the nose of the UAV faces the recorded wind direction according to the preset direction.

[0022] Preferably, the performing of attitude adjustment operation on the UAV according to the attitude adjustment data so that the nose of the UAV faces the recorded wind direction according to a preset direction includes:

[0023] Determine the roll angle of the drone based on the attitude adjustment data;

[0024] By adjusting the rotation speed of each rotor and the direction of the drone's nose, the drone can complete the operation corresponding to the roll angle, ensuring that the drone's nose is facing the recorded wind direction according to the preset direction.

[0025] Preferably, controlling the rotor assembly of the drone to perform wind resistance operation in a preset direction in S4 includes:

[0026] According to the change of the current wind direction, the appropriate rotor is selected from the multiple rotors of the drone to form a rotor set;

[0027] The rotors in the rotor set are controlled to perform wind-resistant operations, and the other rotors outside the rotor set are controlled to stop working.

[0028] Preferably, controlling the rotors in the rotor assembly to perform wind resistance operations includes:

[0029] calculating a desired rotor tilt angle when the drone is hovering at the first desired attitude angle based on a first desired attitude angle of the drone and a second desired attitude angle when the drone is hovering with its fuselage horizontally, and controlling the tilt of rotors in the rotor set according to the desired rotor tilt angle;

[0030] The desired rotor speed when the UAV is hovering at a first desired attitude angle is calculated, and the rotation of the rotors in the rotor set is controlled according to the desired rotor speed.

[0031] Preferably, the calculating, based on the first expected attitude angle of the UAV and the second expected attitude angle of the UAV when the UAV is hovering with the fuselage horizontal, the expected rotor tilt angle of the UAV when the UAV is hovering at the first expected attitude angle includes:

[0032] The following formula is used to calculate the desired rotor tilt angle θ when the UAV is hovering at the first desired attitude angle: * :

[0033] θ * =θ2(t)-θ1;

[0034] Wherein, θ1 is the first desired pitch angle, the first desired attitude angle includes the first desired pitch angle θ1, θ2(t) is the second desired pitch angle, the second desired attitude angle includes the second desired pitch angle θ2(t), and t is time.

[0035] Preferably, the step of calculating the expected rotor speed of the UAV when hovering at the first expected attitude angle includes:

[0036] The real-time attitude angle and real-time angular velocity of the UAV are obtained in real time. The PID control is performed using a cascade PID control algorithm according to the real-time attitude angle of the UAV and the first desired attitude angle to obtain the desired angular velocity of the UAV.

[0037] According to the real-time angular velocity and the expected angular velocity of the UAV, a cascade PID control algorithm is used to perform PID control to obtain the expected rotor speed when the UAV is hovering at the first expected attitude angle.

[0038] Preferably, before calculating the expected rotor tilt angle of the UAV when hovering at the first expected attitude angle based on the first expected attitude angle of the UAV and the second expected attitude angle of the UAV when the fuselage is hovering horizontally, the method includes:

[0039] An attitude control signal of the UAV is received, and the attitude control signal is low-pass filtered, and a first expected attitude angle of the UAV is calculated according to the attitude control signal after the low-pass filtering.

[0040] (3) Beneficial effects

[0041] Compared with the existing technology, the drone hovering control method provided by the present invention has the following beneficial effects:

[0042] 1) Determine the hovering point based on the location of the photovoltaic panel to be cleaned, control the drone to fly to the hovering point and perform the hovering action, detect the current wind direction in real time, use the current wind direction as the recorded wind direction, and determine the corresponding preset direction. By adjusting the rotation speed of each rotor, adjust the direction of the drone's nose so that the drone's nose is facing the recorded wind direction according to the preset direction. This can ensure that the deviation angle between the drone's nose and the real-time wind direction is always small when the wind direction changes greatly, effectively improving the stability of the drone's hovering;

[0043] 2) According to the change of the current wind direction, a suitable rotor is selected from the multiple rotors of the UAV to form a rotor set. According to the first expected attitude angle of the UAV and the second expected attitude angle of the UAV when the fuselage is hovering horizontally, the expected rotor tilt angle when the UAV is hovering at the first expected attitude angle is calculated, and the rotor tilt in the rotor set is controlled according to the expected rotor tilt angle. The expected rotor speed when the UAV is hovering at the first expected attitude angle is calculated, and the rotor rotation in the rotor set is controlled according to the expected rotor speed. This can ensure that the nose of the UAV always maintains a slight deviation angle from the real-time wind direction when the wind direction changes slightly, effectively improve the hovering accuracy of the UAV, and further improve the hovering stability of the UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0045] Figure 1 It is a schematic diagram of the process of the present invention;

[0046] Figure 2 For the present invention Figure 1 Detailed process diagram. DETAILED DESCRIPTION

[0047] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] A method for controlling a drone to hover, such as Figure 1 and Figure 2 As shown, S1, determining a hovering point according to the position of the photovoltaic panel to be cleaned, controlling the drone to fly to the hovering point and performing a hovering action, specifically including:

[0049] The hovering point position information is determined according to the position of the photovoltaic panel to be cleaned, and the current position information of the drone is obtained in real time through the positioning device on the drone;

[0050] The drone is controlled to fly to the hovering point based on the hovering point position information and the current position information of the drone, and performs a hovering action above the hovering point.

[0051] S2. Detect the current wind direction in real time, use the current wind direction as the recorded wind direction, and determine the corresponding preset direction, specifically including:

[0052] Detect the current wind direction in real time, use the current wind direction as the recorded wind direction, and determine the corresponding preset direction based on the changes in the current wind direction.

[0053] S3. Adjust the rotation speed of each rotor to adjust the direction of the drone's nose so that the drone's nose faces the recorded wind direction according to the preset direction, specifically including:

[0054] Obtain the current nose direction of the drone in real time, calculate the deviation angle between the current nose direction of the drone and the preset direction, and determine the attitude adjustment data;

[0055] The attitude of the UAV is adjusted according to the attitude adjustment data so that the nose of the UAV faces the recorded wind direction according to the preset direction.

[0056] Specifically, performing an attitude adjustment operation on the UAV according to the attitude adjustment data so that the nose of the UAV faces the recorded wind direction according to a preset direction includes:

[0057] Determine the roll angle of the drone based on the attitude adjustment data;

[0058] By adjusting the rotation speed of each rotor and the direction of the drone's nose, the drone can complete the operation corresponding to the roll angle, ensuring that the drone's nose is facing the recorded wind direction according to the preset direction.

[0059] The above technical solution determines the hovering point according to the position of the photovoltaic panel to be cleaned, controls the UAV to fly to the hovering point and perform the hovering action, detects the current wind direction in real time, uses the current wind direction as the recorded wind direction, and determines the corresponding preset direction. By adjusting the rotation speed of each rotor, the direction of the UAV's nose is adjusted so that the UAV's nose is facing the recorded wind direction according to the preset direction. This ensures that when the wind direction changes significantly, the UAV's nose always maintains a small deviation angle with the real-time wind direction, effectively improving the stability of the UAV's hovering.

[0060] S4. Control the rotor assembly of the UAV to perform wind-resistant operations in a preset direction, specifically including:

[0061] According to the change of the current wind direction, the appropriate rotor is selected from the multiple rotors of the drone to form a rotor set;

[0062] The rotors in the rotor set are controlled to perform wind-resistant operations, and the other rotors outside the rotor set are controlled to stop working.

[0063] Specifically, controlling the rotors in the rotor assembly to perform wind-resistance operations includes:

[0064] calculating a desired rotor tilt angle when the drone is hovering at the first desired attitude angle based on a first desired attitude angle of the drone and a second desired attitude angle when the drone is hovering with its fuselage horizontally, and controlling the tilt of rotors in the rotor set according to the desired rotor tilt angle;

[0065] The desired rotor speed when the UAV is hovering at a first desired attitude angle is calculated, and the rotation of the rotors in the rotor set is controlled according to the desired rotor speed.

[0066] 1) before calculating the expected rotor tilt angle of the UAV when hovering at the first expected attitude angle based on the first expected attitude angle of the UAV and the second expected attitude angle of the UAV when the fuselage is horizontally hovering, the method includes:

[0067] An attitude control signal of the UAV is received, and the attitude control signal is low-pass filtered, and a first expected attitude angle of the UAV is calculated according to the attitude control signal after the low-pass filtering.

[0068] 2) calculating, based on the first desired attitude angle of the UAV and the second desired attitude angle of the UAV when the fuselage is hovering horizontally, an expected rotor tilt angle of the UAV when hovering at the first desired attitude angle, including:

[0069] The following formula is used to calculate the desired rotor tilt angle θ when the UAV is hovering at the first desired attitude angle: * :

[0070] θ * =θ2(t)-θ1;

[0071] Wherein, θ1 is the first desired pitch angle, the first desired attitude angle includes the first desired pitch angle θ1, θ2(t) is the second desired pitch angle, the second desired attitude angle includes the second desired pitch angle θ2(t), and t is time.

[0072] 3) Calculate the expected rotor speed when the UAV is hovering at the first expected attitude angle, including:

[0073] The real-time attitude angle and real-time angular velocity of the UAV are obtained in real time. The PID control is performed using a cascade PID control algorithm according to the real-time attitude angle of the UAV and the first desired attitude angle to obtain the desired angular velocity of the UAV.

[0074] According to the real-time angular velocity and the expected angular velocity of the UAV, a cascade PID control algorithm is used to perform PID control to obtain the expected rotor speed when the UAV is hovering at the first expected attitude angle.

[0075] The above technical solution selects suitable rotors from the multiple rotors of the UAV to form a rotor set according to the change of the current wind direction, calculates the expected rotor tilt angle of the UAV when hovering at the first expected attitude angle according to the first expected attitude angle of the UAV and the second expected attitude angle of the UAV when the fuselage is hovering horizontally, and controls the rotor tilt of the rotor set according to the expected rotor tilt angle, calculates the expected rotor speed when the UAV is hovering at the first expected attitude angle, and controls the rotor rotation in the rotor set according to the expected rotor speed, thereby ensuring that the nose of the UAV always maintains a slight deviation angle from the real-time wind direction when the wind direction changes slightly, effectively improving the hovering accuracy of the UAV and further improving the hovering stability of the UAV.

[0076] S5. Detect the current wind direction in real time. If the deviation angle between the current wind direction and the recorded wind direction is less than a preset threshold, control the rotor assembly to continue to perform wind resistance operations in the preset direction; otherwise, return to S2.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for controlling a drone to hover, characterized by: The following steps are involved: S1. Determine the hovering point based on the location of the photovoltaic panel to be cleaned, control the drone to fly to the hovering point and perform the hovering action; S2. Detect the current wind direction in real time, use the current wind direction as the recorded wind direction, and determine the corresponding preset direction; S3. Adjust the rotation speed of each rotor to adjust the direction of the drone's nose so that the drone's nose faces the recorded wind direction according to the preset direction; S4, controlling the rotor assembly of the UAV to perform wind resistance operations in a preset direction; S5. Detect the current wind direction in real time. If the deviation angle between the current wind direction and the recorded wind direction is less than a preset threshold, control the rotor assembly to continue to perform wind resistance operations in the preset direction; otherwise, return to S2.

2. The method for controlling the hovering of a drone according to claim 1, wherein: In S1, the hovering point is determined based on the location of the photovoltaic panel to be cleaned, and the drone is controlled to fly to the hovering point and perform the hovering action, including: The hovering point position information is determined according to the position of the photovoltaic panel to be cleaned, and the current position information of the drone is obtained in real time through the positioning device on the drone; The drone is controlled to fly to the hovering point based on the hovering point position information and the current position information of the drone, and performs a hovering action above the hovering point.

3. The method for controlling the hovering of a drone according to claim 1, wherein: S2 detects the current wind direction in real time, uses the current wind direction as the recorded wind direction, and determines the corresponding preset direction, including: Detect the current wind direction in real time, use the current wind direction as the recorded wind direction, and determine the corresponding preset direction based on the changes in the current wind direction.

4. The method for controlling the hovering of a drone according to claim 2, wherein: In S3, the rotation speed of each rotor is adjusted to adjust the direction of the drone's nose so that the drone's nose faces the recorded wind direction according to the preset direction, including: Obtain the current nose direction of the drone in real time, calculate the deviation angle between the current nose direction of the drone and the preset direction, and determine the attitude adjustment data; The attitude of the UAV is adjusted according to the attitude adjustment data so that the nose of the UAV faces the recorded wind direction according to the preset direction.

5. The method for controlling the hovering of a UAV according to claim 4, wherein: The performing of attitude adjustment operation on the UAV according to the attitude adjustment data so that the nose of the UAV faces the recorded wind direction according to a preset direction includes: Determine the roll angle of the drone based on the attitude adjustment data; By adjusting the rotation speed of each rotor and the direction of the drone's nose, the drone can complete the operation corresponding to the roll angle, ensuring that the drone's nose is facing the recorded wind direction according to the preset direction.

6. The method for controlling the hovering of a UAV according to claim 4, wherein: S4 controls the drone's rotor assembly to perform wind-resistant maneuvers in a preset direction, including: According to the change of the current wind direction, the appropriate rotor is selected from the multiple rotors of the drone to form a rotor set; The rotors in the rotor set are controlled to perform wind-resistant operations, and the other rotors outside the rotor set are controlled to stop working.

7. The method for controlling the hovering of a UAV according to claim 6, wherein: The controlling of the rotors in the rotor assembly to perform wind resistance operation includes: calculating a desired rotor tilt angle when the drone is hovering at the first desired attitude angle based on a first desired attitude angle of the drone and a second desired attitude angle when the drone is hovering with its fuselage horizontally, and controlling the tilt of rotors in the rotor set according to the desired rotor tilt angle; The desired rotor speed of the UAV when hovering at a first desired attitude angle is calculated, and the rotation of the rotors in the rotor set is controlled according to the desired rotor speed.

8. The method for controlling the hovering of a UAV according to claim 7, wherein: The step of calculating the expected rotor tilt angle of the UAV when the UAV is hovering at the first expected attitude angle according to the first expected attitude angle of the UAV and the second expected attitude angle of the UAV when the UAV is hovering horizontally includes: The following formula is used to calculate the desired rotor tilt angle θ when the UAV is hovering at the first desired attitude angle: * : i * =θ2(t)-θ1; Wherein, θ1 is the first desired pitch angle, the first desired attitude angle includes the first desired pitch angle θ1, θ2(t) is the second desired pitch angle, the second desired attitude angle includes the second desired pitch angle θ2(t), and t is time.

9. The method for controlling the hovering of a UAV according to claim 7, wherein: The step of calculating an expected rotor speed when the drone is hovering at a first expected attitude angle includes: The real-time attitude angle and real-time angular velocity of the UAV are obtained in real time. The PID control is performed using a cascade PID control algorithm according to the real-time attitude angle of the UAV and the first desired attitude angle to obtain the desired angular velocity of the UAV. According to the real-time angular velocity and the expected angular velocity of the UAV, a cascade PID control algorithm is used to perform PID control to obtain the expected rotor speed when the UAV is hovering at the first expected attitude angle.

10. The method for controlling the hovering of a UAV according to any one of claims 7 to 9, characterized in that: Before calculating the expected rotor tilt angle of the UAV when hovering at the first expected attitude angle based on the first expected attitude angle of the UAV and the second expected attitude angle of the UAV when the fuselage is hovering horizontally, the method includes: An attitude control signal of the UAV is received, and the attitude control signal is low-pass filtered, and a first expected attitude angle of the UAV is calculated according to the attitude control signal after the low-pass filtering.

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