Safe flight method of unmanned aerial vehicle in interference environment

Abstract

The invention discloses a safe flight method for an unmanned aerial vehicle in an interference environment, and belongs to the technical field of unmanned aerial vehicle control. The method comprises the following steps: acquiring a pitch angle, a roll angle, a falling speed and a falling acceleration of the four-axis unmanned aerial vehicle after a remote control signal is lost; the heights of the four axes are obtained according to the pitch angles and the roll angles; the shaft height, the falling speed and the acceleration are processed through a shaft power control model, and the control power of the corresponding shaft is obtained; after first-stage control is carried out on the shaft, compensation control power is carried out based on a height optimization ratio and a speed optimization ratio; and performing second-stage control by adopting the compensation control power until the unmanned aerial vehicle enters a stable state. Stable control over the falling posture of the unmanned aerial vehicle after the remote control signal is lost in the interference environment is achieved, and the flight safety of the unmanned aerial vehicle is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle control, and particularly to a method for safe flight of an unmanned aerial vehicle in an interference environment. Background Art

[0002] During actual flight, unmanned aerial vehicles often face complex and changeable interference environments, such as electromagnetic interference, signal occlusion, etc. These interferences can easily cause the unmanned aerial vehicle to lose the remote control signal. At present, the existing technologies have relatively single processing methods after the unmanned aerial vehicle loses the remote control signal. Most of them only rely on preset emergency procedures, and it is difficult to accurately regulate the attitude and motion state of the unmanned aerial vehicle in real time. It is impossible to effectively collect key data of the unmanned aerial vehicle in an out-of-control state, resulting in difficulty in achieving stable attitude control during the falling process of the unmanned aerial vehicle, thus triggering a crash accident, causing economic losses and safety hazards. Summary of the Invention

[0003] Aiming at the above deficiencies in the prior art, a method for safe flight of an unmanned aerial vehicle in an interference environment provided by the present invention solves the problem that the prior art cannot stably control the attitude of the unmanned aerial vehicle during its falling process after losing the remote control signal.

[0004] In order to achieve the above invention object, the technical solution adopted by the present invention is: A method for safe flight of an unmanned aerial vehicle in an interference environment, including the following steps:

[0005] S1. Collect the pitch angle and roll angle of the quadcopter unmanned aerial vehicle after losing the remote control signal, as well as the falling speed and falling acceleration;

[0006] S2. Obtain the heights of the four axes according to the pitch angle and roll angle;

[0007] S3. Process the heights of the four axes, the falling speed and the falling acceleration by using an axis power control model to obtain the control power of the corresponding axis;

[0008] S4. Perform the first-stage control on the axis by using the control power of the axis, and compensate the control power of the axis based on the height optimization ratio and the speed optimization ratio to obtain the compensated control power of the axis;

[0009] S5. Perform the second-stage control on the axis by using the compensated control power of the axis until the quadcopter unmanned aerial vehicle enters a stable state.

[0010] Further, in S2, obtaining the heights of the four axes:

[0011] ,

[0012] ,

[0013] ,

[0014] ,

[0015] Wherein, h1 is the height of the first axis, h2 is the height of the second axis, h3 is the height of the third axis, h4 is the height of the fourth axis, r is the arm length, θ is the pitch angle, is the roll angle, and sin is the sine function.

[0016] Furthermore, the axis power control model in S3 includes: four axis local power output units, a global power output unit, adder A1, adder A2, adder A3, and adder A4;

[0017] Each axis local power output unit is used to obtain the axis local power according to the difference between the height of the axis and the maximum height, where the maximum height is the maximum value among the heights of the four axes;

[0018] The global power output unit is used to obtain the global power according to the falling speed and the falling acceleration;

[0019] Adder A1 is used to add the global power, the axis local power of the first axis, and the control power of the first axis at the previous moment to obtain the control power of the first axis at the current moment; Adder A2 is used to add the global power, the axis local power of the second axis, and the control power of the second axis at the previous moment to obtain the control power of the second axis; Adder A3 is used to add the global power, the axis local power of the third axis, and the control power of the third axis at the previous moment to obtain the control power of the third axis; Adder A4 is used to add the global power, the axis local power of the fourth axis, and the control power of the fourth axis at the previous moment to obtain the control power of the fourth axis.

[0020] Furthermore, the expressions of the axis local power output units are all: , where P p,t,i is the axis local power of the i-th axis at the t-th moment, P t-1,i is the control power of the i-th axis at the (t - 1)-th moment, h t,max is the maximum height at the t-th moment, h t,i is the height of the i-th axis at the t-th moment, μ is the denominator coefficient, i is the axis number, and t is the moment number.

[0021] Furthermore, the expression of the global power output unit is: , where P o,t is the global power at the t-th moment, P t-1,avg is the average value of the control powers of the four axes at the (t - 1)-th moment, α is the falling acceleration, v is the falling speed, μ is the denominator coefficient, k a is the falling acceleration weight coefficient, k vis the falling speed weight coefficient, and t is the number of the moment.

[0022] Further, S4 includes the following sub-steps:

[0023] S41. Perform the first-stage control on the shaft using the control power of the shaft, record the control duration of the first-stage control, and enter step S42 when the control duration of the first-stage control reaches the duration threshold;

[0024] S42. In the first-stage control, extract the heights of the four shafts at the starting moment and the ending moment;

[0025] S43. At the same moment, subtract the height of each shaft from the maximum height to obtain the height difference;

[0026] S44. According to the height differences of each shaft at the starting moment and the ending moment, obtain the height optimization ratio of the corresponding shaft;

[0027] S45. In the first-stage control, extract the falling speeds at the starting moment and the ending moment to obtain the speed optimization ratio;

[0028] S46. According to the height optimization ratio, obtain the local compensation power of the shaft;

[0029] S47. According to the speed optimization ratio, obtain the global compensation power;

[0030] S48. Add the global compensation power, the local compensation power of the shaft, and the control power output by the first-stage control of the corresponding shaft at the current moment to obtain the compensation control power of the shaft.

[0031] Further, S44 is specifically as follows: For the same shaft, subtract the height difference at the starting moment from the height difference at the ending moment to obtain the optimized height, and use the ratio of the optimized height to the height difference at the starting moment as the height optimization ratio of the corresponding shaft;

[0032] S45 is specifically as follows: Subtract the falling speed at the starting moment from the falling speed at the ending moment to obtain the optimized speed, and use the ratio of the optimized speed to the falling speed at the starting moment as the speed optimization ratio.

[0033] Further, the specific process of S46 includes: When the height optimization ratio is greater than or equal to the height optimization target ratio, the local compensation power of the shaft is 0. When the height optimization ratio is less than the height optimization target ratio, calculate the local compensation power of the shaft according to the difference between the height optimization target ratio and the height optimization ratio: , where P p,H,t,i is the local compensation power of the i-th shaft at the t-th moment, P t,i is the control power of the i-th shaft at the t-th moment, θ H is the local power adjustment step, ε H,iis the height optimization ratio for the i-th axis, ε H,tar is the height optimization target ratio, and t is the time number.

[0034] Furthermore, S47 is specifically as follows: when the speed optimization ratio is greater than or equal to the speed optimization target ratio, the global compensation power is 0; when the speed optimization ratio is less than the speed optimization target ratio, the global compensation power is calculated according to the difference between the speed optimization target ratio and the speed optimization ratio: , where P p,v,t is the global compensation power at the t-th moment, P t,avg is the average value of the control powers of the 4 axes at the t-th moment, θ v is the global power adjustment step, ε v is the speed optimization ratio, ε v,tar is the speed optimization target ratio, and t is the time number.

[0035] Furthermore, S5 includes the following sub-steps:

[0036] S51. During the second-stage control process, determine whether the falling speed of the quadcopter drone is less than or equal to 0, and whether the difference between the maximum height and the minimum height among the heights of the four axes is less than the height difference threshold. If so, the quadcopter drone enters the stable state; if not, continue the second-stage control until it enters the stable state.

[0037] S52. Keep the control power of each current axis.

[0038] In summary, the beneficial effects of the present invention are as follows: The present invention first collects the pitch angle, roll angle, falling speed, and acceleration of the drone, and then uses the axis power control model for precise power distribution. Through the compensation mechanisms of the height optimization ratio and the speed optimization ratio, precise control of each axis of the drone is achieved. Compared with the traditional passive protection scheme, the present invention can quickly respond at the moment of signal loss, minimize the falling risk to the greatest extent, significantly improve the attitude control accuracy of the drone during the out-of-control falling process, quickly enable the drone to enter the stable state, greatly reduce the crashing risk caused by attitude loss of control, and improve the safety and reliability of the drone in a complex interference environment. Description of the Drawings

[0039] Figure 1 is a flowchart of a method for safe flight of a drone in an interference environment.

[0040] Figure 2 is a schematic structural diagram of the axis power control model. Detailed Embodiments

[0041] The specific embodiments of the present invention will be described below to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions made using the concept of the present invention are within the scope of protection.

[0042] As Figure 1 shown, a method for safe flight of an unmanned aerial vehicle (UAV) in an interference environment includes the following steps:

[0043] S1. Collect the pitch angle, roll angle, falling speed, and falling acceleration of a quadrotor UAV after losing the remote control signal;

[0044] S2. Obtain the heights of the four axes according to the pitch angle and roll angle;

[0045] S3. Process the heights, falling speed, and falling acceleration of the four axes using an axis power control model to obtain the control power of the corresponding axes;

[0046] S4. Perform a first-stage control on the axes using the control power of the axes, and compensate the control power of the axes based on the height optimization ratio and speed optimization ratio to obtain the compensated control power of the axes;

[0047] S5. Perform a second-stage control on the axes using the compensated control power of the axes until the quadrotor UAV enters a stable state.

[0048] In this embodiment, in S2, obtaining the heights of the four axes:

[0049] ,

[0050] ,

[0051] ,

[0052] ,

[0053] where h1 is the height of the first axis, h2 is the height of the second axis, h3 is the height of the third axis, h4 is the height of the fourth axis, r is the arm length, θ is the pitch angle, is the roll angle, and sin is the sine function.

[0054] In this embodiment, as Figure 2 shown, the axis power control model in S3 includes: 4 axis local power output units, a global power output unit, adder A1, adder A2, adder A3, and adder A4;

[0055] Each axis local power output unit is used to obtain the axis local power according to the difference between the height of the axis and the maximum height, where the maximum height is the maximum value among the heights of the four axes;

[0056] The global power output unit is used to obtain the global power according to the falling speed and the falling acceleration;

[0057] Adder A1 is used to add the global power, the axis local power of the first axis, and the control power of the first axis at the previous moment to obtain the control power of the first axis at the current moment; Adder A2 is used to add the global power, the axis local power of the second axis, and the control power of the second axis at the previous moment to obtain the control power of the second axis; Adder A3 is used to add the global power, the axis local power of the third axis, and the control power of the third axis at the previous moment to obtain the control power of the third axis; Adder A4 is used to add the global power, the axis local power of the fourth axis, and the control power of the fourth axis at the previous moment to obtain the control power of the fourth axis.

[0058] The first axis local power output unit is used to obtain the axis local power of the first axis according to the difference between the height of the first axis and the maximum height; the second axis local power output unit is used to obtain the axis local power of the second axis according to the difference between the height of the second axis and the maximum height; the third axis local power output unit is used to obtain the axis local power of the third axis according to the difference between the height of the third axis and the maximum height; the fourth axis local power output unit is used to obtain the axis local power of the fourth axis according to the difference between the height of the fourth axis and the maximum height.

[0059] The four-axis drone realizes attitude and motion control through the power cooperation of the four axes. Each axis undertakes different force and attitude adjustment tasks during flight. Setting 4 axis local power output units can calculate power compensation separately for the height differences of each axis (caused by pitch and roll angles). For example, if an axis is at a relatively low height due to the tilt of the drone, the axis local power output unit adjusts the power according to the height difference between it and the highest axis, so that the power of the axis adapts to the position requirements of itself.

[0060] When the drone loses the remote control signal and falls, there are both global motion states such as the overall falling speed and acceleration, and local height differences generated by each axis due to different attitudes (pitch angle, roll angle). The global power output unit gives a power adjustment benchmark from the overall level according to the falling speed and acceleration to cope with the overall falling trend of the drone; the axis local power output unit processes the height differences of each axis to solve local attitude imbalance.

[0061] In this embodiment, the expressions of the axis local power output units are all: , where P p,t,i is the axis local power of the i-th axis at the t-th moment, P t-1,iis the control power of the i-th axis at the (t - 1)-th moment, h t,max is the maximum height at the t-th moment, h t,i is the height of the i-th axis at the t-th moment, μ is the denominator coefficient, i is the axis number, and t is the moment number.

[0062] The attitude control of a quadcopter drone depends on the power difference of each axis. The axis height difference is an intuitive manifestation of attitude imbalance (e.g., the front and rear axis heights are different during pitching). In the expression, h t,max −h t,i is the "feedback quantity", which converts the axis height difference into a basis for power adjustment, making the local power of the axis change dynamically with the height difference - the greater the height difference, the stronger the adaptability of the power correction amplitude.

[0063] The denominator coefficient μ is used to avoid a zero denominator and can take a small constant, such as 1 and 0.5.

[0064] In the present invention, in h t,max −h t,i the greater the gap, the greater it is, the greater the local power of the axis obtained. Therefore, for the axis at the highest position, the local power of the axis is 0, and for the axis at the lowest position, the local power of the axis is the largest. During the control process, as the difference gradually decreases, the local power of the axis gradually approaches 0.

[0065] In this embodiment, the expression of the global power output unit is: , where P o,t is the global power at the t-th moment, P t-1,avg is the average value of the control powers of the 4 axes at the (t - 1)-th moment, α is the falling acceleration, v is the falling speed, μ is the denominator coefficient, k a is the falling acceleration weight coefficient, k v is the falling speed weight coefficient, and t is the moment number.

[0066] When the drone loses the remote control signal and falls, the falling acceleration α reflects the "degree of severity of change" in the falling trend (such as suddenly accelerating rapidly while falling), and the falling speed v reflects the "speed of falling" at present. The two jointly characterize the global motion risk. The present invention incorporates α and v into the calculation, and uses and to respectively perform adaptive conversion on the influences of acceleration and speed, enabling the global power to simultaneously respond to the "change in falling trend" and the "current falling rate".

[0067] In this embodiment, the value range of the falling speed weight coefficient k v and the falling acceleration weight coefficient k a is 0 to 1.

[0068] In this embodiment, S4 includes the following sub-steps:

[0069] S41. Control the shaft in the first stage using the control power of the shaft, record the control duration of the first-stage control, and when the control duration of the first-stage control reaches the duration threshold, proceed to step S42;

[0070] S42. In the first-stage control, extract the heights of the four shafts at the starting moment and the ending moment;

[0071] S43. At the same moment, subtract the height of each shaft from the maximum height to obtain the height difference;

[0072] S44. Based on the height differences of each shaft at the starting moment and the ending moment, obtain the height optimization ratio of the corresponding shaft;

[0073] S45. In the first-stage control, extract the falling speeds at the starting moment and the ending moment to obtain the speed optimization ratio;

[0074] S46. Based on the height optimization ratio, obtain the local compensation power of the shaft;

[0075] S47. Based on the speed optimization ratio, obtain the global compensation power;

[0076] S48. Add the global compensation power, the local compensation power of the shaft, and the control power output by the first-stage control of the corresponding shaft at the current moment to obtain the compensation control power of the shaft.

[0077] In this embodiment, the duration threshold is set to 0.3S.

[0078] After the first-stage control of the present invention, the height differences at the starting moment and the ending moment are extracted. For the same shaft, the difference between the height differences at the starting moment and the ending moment is obtained to get the height optimization ratio, which is used to evaluate the optimization of the height difference of each shaft. Then, based on the falling speeds at the starting moment and the ending moment, the speed optimization ratio is obtained to evaluate the speed optimization situation. Based on the height optimization and speed optimization situations, the compensation powers are respectively obtained to accelerate the stabilization of the drone.

[0079] In this embodiment, S44 is specifically as follows: For the same shaft, subtract the height difference at the starting moment from the height difference at the ending moment to obtain the optimized height, and use the ratio of the optimized height to the height difference at the starting moment as the height optimization ratio of the corresponding shaft.

[0080] The formula for calculating the height optimization ratio is: , where ε H,i is the height optimization ratio of the i-th shaft, H s,i is the height difference of the i-th shaft at the starting moment, and H e,i is the height difference of the i-th shaft at the ending moment.

[0081] Specifically, S45 is as follows: subtract the falling speed at the starting moment from the falling speed at the ending moment to obtain the optimized speed, and use the ratio of the optimized speed to the falling speed at the starting moment as the speed optimization ratio.

[0082] The formula for calculating the speed optimization ratio in S45 is: , where ε v is the speed optimization ratio, v s is the falling speed at the starting moment, v e is the falling speed at the ending moment.

[0083] In this embodiment, the specific process of S46 includes: when the height optimization ratio is greater than or equal to the height optimization target ratio, the local shaft compensation power is 0; when the height optimization ratio is less than the height optimization target ratio, calculate the local shaft compensation power according to the difference between the height optimization target ratio and the height optimization ratio: , where P p,H,t,i is the local shaft compensation power of the i-th shaft at the t-th moment, P t,i is the control power of the i-th shaft at the t-th moment (P t,i obtained through the first stage), θ H is the local power adjustment step, ε H,i is the height optimization ratio of the i-th shaft, ε H,tar is the height optimization target ratio, and t is the serial number of the moment.

[0084] The present invention is guided by the height optimization target ratio, avoids overcorrection through threshold judgment, prevents attitude oscillation, calculates the compensation power using the difference between the height optimization target ratio and the actual height optimization ratio, and enables the compensation intensity to precisely match the degree of attitude imbalance.

[0085] In the first-stage control output of the present invention, according to the height optimization ratio, obtain the local shaft compensation power of each shaft, according to the speed optimization ratio, obtain the global compensation power, and add the local shaft compensation power of each shaft, the control power of the corresponding shaft in the first-stage control output at the current moment, and the global compensation power to obtain the compensation control power of the corresponding shaft.

[0086] In this embodiment, S47 is specifically as follows: when the speed optimization ratio is greater than or equal to the speed optimization target ratio, the global compensation power is 0; when the speed optimization ratio is less than the speed optimization target ratio, calculate the global compensation power according to the difference between the speed optimization target ratio and the speed optimization ratio: , where P p,v,t is the global compensation power at the t-th moment, P t,avg is the average value of the control powers of the 4 shafts at the t-th moment, θ v is the global power adjustment step, ε v is the speed optimization ratio, εv,tar is the speed optimization target ratio, and t is the number of the time instant.

[0087] In the present invention, with the speed optimization target ratio as a reference, through threshold judgment, no additional compensation is made when the speed optimization ratio reaches the standard, avoiding power redundancy; when it does not reach the standard, the difference between the speed optimization target ratio and the actual ratio is used to calculate the global compensation power, making the compensation intensity adapt to the degree of speed out of control, correlating the average value of the control powers of 4 axes, so that the compensation is based on the overall power level to ensure coordinated power output.

[0088] In this embodiment, for small unmanned aerial vehicles (such as aerial photography drones, with a weight < 2 kg), the small drones have small inertia, and θ v and θ H are set to 0.1 - 0.3. For small industrial-grade unmanned aerial vehicles (such as plant protection drones, with a weight of 2 - 5 kg), θ v and θ H are set to 0.3 - 0.5. The power adjustment step sizes θ H and θ v can be adjusted according to requirements, not limited to the settings of this embodiment.

[0089] In this embodiment, the height optimization target ratio and the speed optimization target ratio can be set to 0.5. When it reaches 0.5, the height and speed have been optimized by half.

[0090] In this embodiment, S5 includes the following sub-steps:

[0091] S51. During the second-stage control process, judge whether the falling speed of the quadcopter drone is less than or equal to 0, and whether the difference between the maximum height and the minimum height among the heights of the four axes is less than the height difference threshold. If so, the quadcopter drone enters the stable state; if not, continue the second-stage control until entering the stable state.

[0092] S52. Keep the control power of each current axis.

[0093] After entering the stable state, keep the control power of each axis unchanged.

[0094] For small consumer-grade unmanned aerial vehicles (such as aerial photography drones, with a wheelbase of 20 - 30 cm), the value range of the height difference threshold is 5 - 10 cm. For small industrial-grade unmanned aerial vehicles (such as plant protection drones, with a wheelbase of 30 - 50 cm), the value range of the height difference threshold is 10 - 15 cm.

[0095] In this embodiment, the falling speed is positive downward and negative upward.

[0096] During the second-stage control process, the control power of the first-stage control is not directly applied to the quadcopter. Compensation is required during the second-stage control process to obtain the compensated control power before it can act on the quadcopter.

[0097] The present invention first collects the pitch angle, roll angle, falling speed and acceleration of the drone, and then uses the shaft power control model for precise power distribution. Through the compensation mechanism of the height optimization ratio and the speed optimization ratio, precise control of each axis of the drone is achieved. Compared with the traditional passive protection scheme, the present invention can quickly respond at the moment of signal loss, minimize the falling risk to the greatest extent, significantly improve the attitude control accuracy of the drone during the out-of-control falling process, quickly bring the drone into a stable state, greatly reduce the crashing risk caused by attitude out-of-control, and improve the safety and reliability of the drone in a complex interference environment.

[0098] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for safe flight of an unmanned aerial vehicle in an interference environment, characterized in that It includes the following steps: S1. Collect the pitch angle, roll angle, falling speed, and falling acceleration of the quadcopter drone after losing the remote control signal; S2. Obtain the heights of the four axes according to the pitch angle and roll angle; S3. Use the axis power control model to process the heights, falling speed, and falling acceleration of the four axes to obtain the control power of the corresponding axis; S4. Use the control power of the axis to perform the first-stage control on the axis, and based on the height optimization ratio and speed optimization ratio, compensate the control power of the axis to obtain the compensated control power of the axis; S5. Use the compensated control power of the axis to perform the second-stage control on the axis until the quadcopter drone enters a stable state.

2. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 1, wherein Obtaining the heights of the four axes in S2: ， ， ， ， Among them, h1 is the height of the first axis, h2 is the height of the second axis, h3 is the height of the third axis, h4 is the height of the fourth axis, r is the arm length, θ is the pitch angle, is the roll angle, and sin is the sine function.

3. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 1, wherein, The axis power control model in S3 includes: 4 axis local power output units, a global power output unit, adder A1, adder A2, adder A3, and adder A4; Each of the axis local power output units is used to obtain the axis local power according to the difference between the height of the axis and the maximum height, where the maximum height is the maximum value among the heights of the four axes; The global power output unit is used to obtain the global power according to the falling speed and falling acceleration; The adder A1 is used to add the global power, the axis local power of the first axis, and the control power of the first axis at the previous moment to obtain the control power of the first axis at the current moment; the adder A2 is used to add the global power, the axis local power of the second axis, and the control power of the second axis at the previous moment to obtain the control power of the second axis; the adder A3 is used to add the global power, the axis local power of the third axis, and the control power of the third axis at the previous moment to obtain the control power of the third axis; the adder A4 is used to add the global power, the axis local power of the fourth axis, and the control power of the fourth axis at the previous moment to obtain the control power of the fourth axis.

4. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 3, wherein The expressions of the shaft local power output unit are all as follows: , where P p,t,i is the shaft local power of the i-th shaft at the t-th moment, P t-1,i is the control power of the i-th shaft at the (t - 1)-th moment, h t,max is the maximum height at the t-th moment, h t,i is the height of the i-th shaft at the t-th moment, μ is the denominator coefficient, i is the shaft number, and t is the moment number.

5. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 3, wherein The expression of the global power output unit is as follows: , where P o,t is the global power at the t-th moment, P t-1,avg is the average value of the control powers of the four axes at the (t - 1)-th moment, α is the falling acceleration, v is the falling speed, μ is the denominator coefficient, k a is the falling acceleration weight coefficient, k v is the falling speed weight coefficient, and t is the number of the moment.

6. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 1, wherein S4 includes the following sub-steps: S41. Use the control power of the axis to perform the first-stage control on the axis, record the control duration of the first-stage control, and when the control duration of the first-stage control reaches the duration threshold, enter step S42; S42. In the first-stage control, extract the heights of the four axes at the starting moment and the ending moment; S43. At the same moment, subtract the height of each axis from the maximum height to obtain the height difference; S44. According to the height differences of each axis at the starting moment and the ending moment, obtain the height optimization ratio of the corresponding axis; S45. In the first-stage control, extract the falling speeds at the starting moment and the ending moment to obtain the speed optimization ratio; S46. According to the height optimization ratio, obtain the axis local compensation power; S47. According to the speed optimization ratio, obtain the global compensation power; S48. Add the global compensation power, the axis local compensation power, and the control power output by the first-stage control of the corresponding axis at the current moment to obtain the compensated control power of the axis.

7. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 6, wherein Specifically, S44 is: for the same axis, subtract the height difference at the starting moment from the height difference at the ending moment to obtain the optimized height, and use the ratio of the optimized height to the height difference at the starting moment as the height optimization ratio of the corresponding axis; Specifically, S45 is as follows: subtract the falling speed at the starting moment from the falling speed at the ending moment to obtain the optimized speed, and use the ratio of the optimized speed to the falling speed at the starting moment as the speed optimization ratio.

8. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 6, wherein The specific process of S46 includes: when the height optimization ratio is greater than or equal to the height optimization target ratio, the local shaft compensation power is 0; when the height optimization ratio is less than the height optimization target ratio, the local shaft compensation power is calculated according to the difference between the height optimization target ratio and the height optimization ratio: , where P p,H,t,i is the local shaft compensation power of the i-th shaft at the t-th moment, P t,i is the control power of the i-th shaft at the t-th moment, θ H is the local power adjustment step, ε H,i is the height optimization ratio of the i-th shaft, ε H,tar is the height optimization target ratio, and t is the number of the moment.

9. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 6, wherein Specifically, S47 is as follows: when the speed optimization ratio is greater than or equal to the speed optimization target ratio, the global compensation power is 0; when the speed optimization ratio is less than the speed optimization target ratio, the global compensation power is calculated based on the difference between the speed optimization target ratio and the speed optimization ratio: , where P p,v,t is the global compensation power at the t-th moment, P t,avg is the average value of the control powers of the 4 axes at the t-th moment, θ v is the global power adjustment step, ε v is the speed optimization ratio, ε v,tar is the speed optimization target ratio, and t is the serial number of the moment.

10. The method for safe flight of an unmanned aerial vehicle in an interference environment according to claim 1, wherein, S5 includes the following sub-steps: S51. During the second-stage control process, determine whether the falling speed of the quadcopter drone is less than or equal to 0, and whether the difference between the maximum height and the minimum height among the heights of the four axes is less than the height difference threshold. If so, the quadcopter drone enters the stable state; if not, continue the second-stage control until it enters the stable state. S52. Maintain the control power of each current axis.

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