CN116627180A

CN116627180A - Unmanned aerial vehicle patrol planning method and device, electronic equipment and storage medium

Info

Publication number: CN116627180A
Application number: CN202310909283.0A
Authority: CN
Inventors: 孔佑原; 左珮良; 缪宸硕; 魏嘉欣; 王彦琛; 王逸扬; 刘学文; 李浩亮; 王旋; 杨树; 李长春; 邓曦
Original assignee: Guizhou Bright Science Technology Development Co ltd
Current assignee: Guizhou Bright Science Technology Development Co ltd
Priority date: 2023-07-24
Filing date: 2023-07-24
Publication date: 2023-08-22
Anticipated expiration: 2043-07-24
Also published as: CN116627180B

Abstract

The invention relates to a unmanned aerial vehicle patrol planning method, a device, electronic equipment and a storage medium, which comprise the following steps: and acquiring related parameters to determine a patrol target. And calculating the first suspension power of the unmanned aerial vehicle corresponding to the first suspension height through a dichotomy to obtain a second suspension height, and converting the second suspension height to obtain a third suspension height. When the third suspension height is smaller than the maximum suspension height of the unmanned aerial vehicle, calculating first fly-through power corresponding to the first fly-through height of the unmanned aerial vehicle by a dichotomy to obtain a second fly-through height, and converting the second fly-through height to obtain the third fly-through height. And when the third fly-through height is smaller than the first threshold value, acquiring a first fly-through speed corresponding to the unmanned aerial vehicle when the first fly-through power is minimum through a dichotomy. And calling a first function to calculate the first fly-through speed, the third fly-through height and the third suspension height to obtain a first result, and outputting a unmanned aerial vehicle fly-through planning result when the value of the first result is smaller than a second threshold value.

Description

Unmanned aerial vehicle patrol planning method and device, electronic equipment and storage medium

Technical Field

The invention relates to the technical field of unmanned aerial vehicles, in particular to a method and a device for unmanned aerial vehicle flight planning, electronic equipment and a storage medium.

Background

Unmanned aerial vehicle technology development makes unmanned aerial vehicle application increasingly wide, such as logistics distribution, disaster monitoring, agricultural spraying etc., and this requires unmanned aerial vehicle system to have automatic route planning's ability to realize high-efficient, safe flight. Advances in unmanned aerial vehicle technology, optimization theory, artificial intelligence, and related standards create advantages for unmanned aerial vehicle routing, and increasingly wide unmanned aerial vehicle applications have stimulated the development of unmanned aerial vehicle routing technology. Unmanned aerial vehicle track planning is the necessary premise that unmanned aerial vehicle inspection system is operated, based on the difference of inspection environment and inspection target, unmanned aerial vehicle track planning's content generally includes but is not limited to flight path point, fly altitude, speed of flight, hover position, hover duration, unmanned aerial vehicle camera mount focal length, video resolution etc. taking into account unmanned aerial vehicle's characteristics, the optimization target of track planning includes that inspection duration is minimum, inspection energy consumption is minimum, inspection effect is optimized etc. in order to instruct unmanned aerial vehicle's process of flight, and ensure unmanned aerial vehicle inspection system's work utility.

At present, the existing unmanned aerial vehicle patrol planning method comprises the following steps: (1) The method comprises the steps of obtaining map information of a region to be predicted by means of existing map information, establishing a mathematical model of a target, and constructing a cost function by combining the flight environment of the unmanned aerial vehicle and self conditions, so as to provide a method for planning a path of the unmanned aerial vehicle by means of an artificial bee colony algorithm. (2) By carrying out three-time difference processing on the terrain data, a relatively accurate terrain environment is simulated, a flight path planning model of the unmanned aerial vehicle is established by combining the inspection task, parameters such as the path length, the flight height, the flight cost around the flying obstacle, the smooth cost and the like of the unmanned aerial vehicle are comprehensively considered, and the flight cost of the unmanned aerial vehicle is reduced. (3) And constructing an objective function of unmanned aerial vehicle flight path planning according to the environmental threat cost and the unmanned aerial vehicle flight fuel cost, dividing a region to be planned into grids, and calculating and updating antibody groups of node sets corresponding to the grids by using an immune cloning algorithm to obtain an optimal antibody corresponding to the optimal flight path. (4) Aiming at the problem of unmanned aerial vehicle collaborative track planning in a dynamic obstacle environment, a feedback strategy is provided for the unmanned aerial vehicle by means of an improved Q-learning algorithm, so that the unmanned aerial vehicle is ensured to master guiding information and risk awareness in the training process, and the multi-unmanned aerial vehicle low-cost risk-free collaborative track planning is realized. (5) According to the unmanned aerial vehicle track planning method aiming at the urban low-altitude environment, three obstacle avoidance sub-paths are generated aiming at an obstacle space by means of a three-dimensional tangent line method, and the unmanned aerial vehicle is assisted to bypass the obstacle from the two sides or the upper side of the obstacle by combining with heuristic rules, so that the unmanned aerial vehicle can reach a patrol terminal smoothly.

However, the related technology of unmanned aerial vehicle track planning is mostly focused on planning of unmanned aerial vehicle space positions in a general scene, and the planning method is mostly high in complexity and weak in generalization capability for the scene, and is rarely researched and specially used for expressway scenes, namely the proposed algorithm is not generally combined with a natural curve of ground space, so that the inspection experience of the inspection process is ensured and improved, and the related research is rarely comprehensively optimized by considering factors such as unmanned aerial vehicle height, flight speed, suspension duration, communication quality and the like facing the inspection target, so that the utility of the related method for the scene considered by the patent is limited.

Therefore, due to the limitation of the use scene, the existing unmanned aerial vehicle track planning method has the defects that the quality of the obtained flight data is poor and the remote control efficiency is low when the flight data is matched with the special scene of a highway, which has a large flight range and a large number of flight targets.

Disclosure of Invention

Based on the above, it is necessary to provide a method, a device, an electronic device and a storage medium for unmanned aerial vehicle flight planning, which can ensure the feedback quality of flight data and have high remote control efficiency in a scene of a highway with a large flight range and a large number of flight targets.

The invention provides a unmanned aerial vehicle patrol planning method, which comprises the following steps:

acquiring a first parameter and a second parameter, determining a patrol target, wherein the first parameter is an unmanned aerial vehicle parameter, the second parameter is a highway parameter, the patrol target is a target object to be patrol of the unmanned aerial vehicle on a highway, the first parameter comprises a focal length of an onboard camera of the unmanned aerial vehicle and a lens radius of an onboard camera equivalent CCD camera, and the second parameter comprises a space radius of the patrol target;

calculating first suspension power of the unmanned aerial vehicle corresponding to a first suspension height through a dichotomy based on the first parameter to obtain a second suspension height, and performing equivalent transformation on the second suspension height to obtain a third suspension height;

judging whether the third suspension height is smaller than a first threshold value, wherein the first threshold value is the maximum suspension height of the unmanned aerial vehicle; if yes, then

Calculating a first flying power of the unmanned aerial vehicle corresponding to a first flying height by a dichotomy based on the first parameter to obtain a second flying height, and converting the second flying height to obtain a third flying height;

Judging whether the third fly-through height is smaller than the first threshold value; if yes, then

Based on the first flight power, acquiring a first flight speed by a dichotomy, wherein the first flight speed is the flight speed corresponding to the unmanned aerial vehicle when the first flight power is minimum;

invoking a first function to calculate the first fly-through speed, the third fly-through height and the third suspension height to obtain a first result, and judging whether the value of the first result is smaller than a second threshold value; if yes, then

Outputting the first flight patrol speed, the third flight patrol height and the third suspension height to obtain the unmanned aerial vehicle flight patrol planning result.

In one embodiment, the first parameter includes a focal length of an onboard camera of the unmanned aerial vehicle and a lens radius of the onboard camera equivalent to a CCD camera, and the second parameter includes a spatial radius of the inspection target;

the method comprises the steps of obtaining a first parameter and a second parameter, determining a patrol target, and then further comprising:

calculating a minimum flight speed of the unmanned aerial vehicle based on the first parameter and the second parameter；

Wherein f is the focal length of the unmanned aerial vehicle-mounted camera, R _CCD And the lens radius of the airborne camera equivalent to a CCD camera is r, and the space radius of the inspection target is r.

In one embodiment, the calculating, based on the first parameter, the first levitation power of the unmanned aerial vehicle at the first levitation altitude by a dichotomy to obtain a second levitation altitude, and converting the second levitation altitude to obtain a third levitation altitude includes:

calculating the first levitation power based on a plurality of the first levitation heights

；

Wherein ρ is the air density,the rotor area is equal to the rotor area, omega is the angular speed of the blade, R is the rotor radius, X is the increment correction coefficient of the induction power, and W is the weight of the unmanned aerial vehicle.

In one embodiment, based on the first fly-around power, a first fly-around speed is obtained by a dichotomy, where the first fly-around speed is a fly-around speed corresponding to the unmanned aerial vehicle when the first fly-around power is the minimum, and before the step of further including:

calculating the first fly-by power based on the first levitation power

；

wherein , and />Respectively the first two items in the first suspension power, V is the flying speed of the unmanned aerial vehicle,v for the speed of the rotor blade ₀ For the average speed of the rotor wing generated when the unmanned aerial vehicle hovers, d ₀ The resistance ratio of the unmanned aerial vehicle body is that of the unmanned aerial vehicle body.

In one embodiment, the calculating the first fly-by power based on the first levitation power includes:

calculating power consumption of the unmanned aerial vehicle during ascending and descending based on the first suspension power and the first patrol power

；

wherein ,for thrust-weight ratio, when the unmanned aerial vehicle is ascending, the unmanned aerial vehicle is +.>Otherwise, when the unmanned aerial vehicle descends, the unmanned aerial vehicle is left on the ground>。

In one embodiment, the method further comprises:

obtaining the inspection effect coefficient of the unmanned aerial vehicle, wherein ,/>The inspection flying height of the unmanned aerial vehicle aiming at the inspection target is set;

based on the inspection effect coefficient, calculating the inspection overall effect of the unmanned aerial vehicle

；

wherein ,j=1, 2,..n is the importance of the patrol object j.

In one embodiment, the first function is

，（/>Representing power consumption when the drone is hovering);

wherein ,for the speed of the ascent and descent process of the drone +.> and />The weight pushing ratio of the ascending and descending processes of the unmanned aerial vehicle is respectively +.> and />And respectively obtaining power consumption corresponding to the rising and falling processes of the unmanned aerial vehicle, wherein E is the second threshold value.

The invention also provides an unmanned aerial vehicle patrol planning device, which comprises:

The system comprises a first acquisition module, a second acquisition module and a third acquisition module, wherein the first acquisition module is used for acquiring a first parameter and a second parameter and determining a patrol target, the first parameter is an unmanned aerial vehicle parameter, the second parameter is a highway parameter, the patrol target is a target object to be patrol of the unmanned aerial vehicle on a highway, the first parameter comprises a focal length of an onboard camera of the unmanned aerial vehicle and a lens radius of the onboard camera equivalent to a CCD camera, and the second parameter comprises a space radius of the patrol target;

the first processing module is used for calculating first suspension power of the unmanned aerial vehicle corresponding to the first suspension height through a dichotomy based on the first parameter to obtain a second suspension height, and converting the second suspension height to obtain a third suspension height;

the first judging module is used for judging whether the third suspension height is smaller than a first threshold value, and the first threshold value is the maximum suspension height of the unmanned aerial vehicle; if yes, then

The second processing module is used for calculating first fly-following power of the unmanned aerial vehicle corresponding to the first fly-following height through a dichotomy based on the first parameter to obtain a second fly-following height, and converting the second fly-following height to obtain a third fly-following height;

The second judging module is used for judging whether the third fly-through height is smaller than the first threshold value or not; if yes, then

The third processing module is used for acquiring a first flight speed through a dichotomy based on the first flight power, wherein the first flight speed is the flight speed corresponding to the unmanned aerial vehicle when the first flight power is minimum;

the fourth processing module is used for calling a first function to calculate the first fly-through speed, the third fly-through height and the third suspension height so as to obtain a first result, and judging whether the value of the first result is smaller than a second threshold value or not; if yes, then

And the result output module is used for outputting the first flight patrol speed, the third flight patrol height and the third suspension height as unmanned aerial vehicle flight patrol planning results.

The invention also provides electronic equipment, which comprises a memory and a processor, wherein the memory stores a computer program, and the processor realizes the unmanned aerial vehicle patrol planning method according to any one of the above when executing the computer program.

The invention also provides a computer storage medium storing a computer program which when executed by a processor realizes the unmanned aerial vehicle patrol planning method according to any one of the above.

According to the unmanned aerial vehicle flight patrol planning method, the unmanned aerial vehicle flight patrol planning device, the electronic equipment and the storage medium, in the flight patrol process on the expressway, the unmanned aerial vehicle parameters and the expressway parameters are obtained, the target object to be patrol of the unmanned aerial vehicle's patrol target on the expressway is determined, the levitation power of the unmanned aerial vehicle corresponding to any levitation height is calculated through a dichotomy, a new levitation height is obtained, the new levitation height is converted, and the levitation height required by the unmanned aerial vehicle flight patrol planning is obtained, namely, a third levitation height. And then, judging whether the third suspension height is smaller than the upper limit of the suspension height of the unmanned aerial vehicle, if so, reserving the third suspension height, calculating and processing the flight power corresponding to any flight height of the unmanned aerial vehicle through a dichotomy again based on unmanned aerial vehicle parameters to obtain a new flight height, and converting the new flight height to obtain the flight height required by the unmanned aerial vehicle flight planning, namely the third flight height. And then, judging whether the fly-by-wire height is smaller than the upper limit of the suspension height of the unmanned aerial vehicle, if so, reserving the third fly-by-wire height, and acquiring the fly-by-wire speed corresponding to the unmanned aerial vehicle when the fly-by-wire power is minimum, namely the first fly-by-wire speed, based on the fly-by-wire power of the unmanned aerial vehicle at any fly-by-wire height. And finally, calling an unmanned aerial vehicle flight planning evaluation function which is prestored in the system to calculate the obtained first flight speed, third flight height and third suspension height to obtain a final result, and outputting the first flight speed, third flight height and third suspension height as the unmanned aerial vehicle flight planning result if the value of the result is smaller than a set threshold value. According to the method, the quality of the data to be patrolled and flown is ensured in a special scene with a large patrolling range and a large number of patrolling targets, such as a highway, by means of mass limitation of the patrolling power, the suspending power and the patrolling speed of the unmanned aerial vehicle and flexible conversion of the returned data by a dichotomy, so that the remote control efficiency of the unmanned aerial vehicle is ensured.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic flow chart of an unmanned aerial vehicle flight planning method provided by the invention;

FIG. 2 is a second schematic flow chart of the unmanned aerial vehicle flight planning method according to the present invention;

FIG. 3 is a third flow chart of the unmanned aerial vehicle flight planning method according to the present invention;

fig. 4 is a schematic flow chart of a method for unmanned aerial vehicle flight planning in an embodiment provided by the invention;

fig. 5 is a schematic structural diagram of an unmanned aerial vehicle flight planning device provided by the invention;

fig. 6 is an internal structural diagram of a computer device provided by the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without creative efforts, based on the described embodiments of the present invention fall within the protection scope of the present invention.

Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "first," "second," and the like, as used herein, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the terms "a," "an," or "the" and similar terms do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

It should be noted that "upper", "lower", "left", "right", "front", "rear", and the like are used in the present invention only to indicate a relative positional relationship, and when the absolute position of the object to be described is changed, the relative positional relationship may be changed accordingly.

The unmanned aerial vehicle cruise planning method, the unmanned aerial vehicle cruise planning device, the electronic equipment and the storage medium are described below with reference to fig. 1-6.

As shown in fig. 1, in one embodiment, a method for unmanned aerial vehicle cruise planning includes the steps of:

step S110, a first parameter and a second parameter are obtained, a patrol target is determined, the first parameter is an unmanned aerial vehicle parameter, the second parameter is a highway parameter, the patrol target is a target object to be patrol of the unmanned aerial vehicle on a highway, the first parameter comprises a focal length of an unmanned aerial vehicle onboard camera and a lens radius of an onboard camera equivalent CCD camera, and the second parameter comprises a space radius of the patrol target.

Specifically, in the process of the unmanned aerial vehicle inspecting the expressway, the server firstly acquires the parameters of the unmanned aerial vehicle and the parameters of the inspected expressway, and determines the inspection target on the inspected expressway.

It should be noted that the first parameter includes a focal length of an onboard camera of the unmanned aerial vehicle and a lens radius of the onboard camera equivalent to a CCD camera, and the second parameter includes a spatial radius of the inspection target. After acquiring the first parameter and the second parameter and determining the inspection target, the server firstly calculates the minimum flying speed of the unmanned aerial vehicle based on the first parameter and the second parameter:

。

Wherein f is the focal length of an onboard camera of the unmanned aerial vehicle, R _CCD The lens radius of the airborne camera equivalent to the CCD camera is r, and the space radius of the inspection target is r.

Step S120, calculating first suspension power of the unmanned aerial vehicle corresponding to the first suspension height through a dichotomy based on the first parameter to obtain a second suspension height, and performing equivalent transformation on the second suspension height to obtain a third suspension height.

Specifically, the server calculates the levitation power of the unmanned aerial vehicle corresponding to any levitation height through a dichotomy based on the unmanned aerial vehicle parameters obtained in step S110, so as to obtain a new levitation height, namely a second levitation height. And then, carrying out equivalent transformation on the second suspension height to obtain a transformed suspension height, namely a third suspension height, which is used as the flight planning data required by the subsequent unmanned aerial vehicle flight planning to be verified.

Step S130, judging whether the third suspension height is smaller than a first threshold value, wherein the first threshold value is the maximum suspension height of the unmanned aerial vehicle.

Specifically, the server determines whether the third levitation height obtained in step S120 is less than the upper levitation height limit of the known unmanned aerial vehicle.

Step S140, calculating first fly-through power of the unmanned aerial vehicle corresponding to the first fly-through altitude by a dichotomy based on the first parameter to obtain a second fly-through altitude, and converting the second fly-through altitude to obtain a third fly-through altitude.

Specifically, when the determination result in step S130 shows that the third suspension height is less than the upper limit of the suspension height of the unmanned aerial vehicle, then the server calculates the flight power corresponding to any flight height of the unmanned aerial vehicle again by the dichotomy based on the unmanned aerial vehicle parameters obtained in step S110, so as to obtain a new flight height, i.e. the second flight height. And then, carrying out equivalent transformation on the second fly-following height to obtain a transformed fly-following height, namely a third fly-following height, which is used as fly-following planning data required by the follow-up unmanned aerial vehicle fly-following planning to be verified.

Step S150, judging whether the third fly-through height is smaller than the first threshold value.

Specifically, the server determines whether the third fly height obtained in step S140 is less than the upper limit of the suspension height of the unmanned aerial vehicle.

Step S160, based on the first fly-through power, acquiring a first fly-through speed by a dichotomy, wherein the first fly-through speed is the fly-through speed corresponding to the unmanned aerial vehicle when the first fly-through power is minimum.

Specifically, when the determination result in step S150 shows that the third fly-by-wire height is less than the upper limit of the suspension height of the unmanned aerial vehicle, then the server obtains the fly-by-wire speed corresponding to the unmanned aerial vehicle when the fly-by-wire power is minimum, that is, the first fly-by-wire speed, based on the fly-by-wire power of the unmanned aerial vehicle at any fly-by-wire height.

Step S170, a first function is called to calculate the first fly-through speed, the third fly-through height and the third suspension height so as to obtain a first result, and whether the value of the first result is smaller than a second threshold value is judged.

Specifically, the server calls the first function to calculate the first fly-through speed, the third fly-through height and the third suspension height obtained in the steps, a final result is obtained, namely a first result, and whether the value of the first result is smaller than a set threshold value of the system, namely a second threshold value is judged.

It should be noted that, the first function is:

。

in the formula ,for the speed of the ascent and descent process of the unmanned aerial vehicle, +.> and />Push-to-weight ratio of the ascending and descending processes of the unmanned aerial vehicle respectively, < -> and />Respectively corresponding power consumption in the ascending and descending processes of the unmanned aerial vehicle, wherein E is a second threshold value and tau is calculated _k+1 and τ_k Respectively representing two items, P, of the unmanned aerial vehicle in the inspection height sequence of the whole highway scene _h For the first levitation power, +.>Unmanned plane power corresponding to target speed, t _i For the flight time of the unmanned aerial vehicle->For the target speed, L _i Is unmannedThe flight path of the aircraft.

And step S180, outputting a first flight patrol speed, a third flight patrol height and a third suspension height which are unmanned aerial vehicle flight patrol planning results.

Specifically, when the determination result in step S170 shows that the value of the first result is smaller than the second threshold, the verification of the first fly speed, the third fly height and the third suspension height obtained in the above steps is completed, and the verification is successful, and the server outputs the first fly speed, the third fly height and the third suspension height which are successfully verified as the planning data required by the unmanned aerial vehicle fly planning.

According to the unmanned aerial vehicle flight patrol planning method, in the flight patrol process on the expressway, the unmanned aerial vehicle parameters and the expressway parameters are obtained, the target object to be patrol of the unmanned aerial vehicle on the expressway is determined, the levitation power of the unmanned aerial vehicle corresponding to any levitation height is calculated through the dichotomy, a new levitation height is obtained, the new levitation height is converted, and the levitation height required by unmanned aerial vehicle flight patrol planning is obtained, namely, the third levitation height. And then, judging whether the third suspension height is smaller than the upper limit of the suspension height of the unmanned aerial vehicle, if so, reserving the third suspension height, calculating and processing the flight power corresponding to any flight height of the unmanned aerial vehicle through a dichotomy again based on unmanned aerial vehicle parameters to obtain a new flight height, and converting the new flight height to obtain the flight height required by the unmanned aerial vehicle flight planning, namely the third flight height. And then, judging whether the fly-by-wire height is smaller than the upper limit of the suspension height of the unmanned aerial vehicle, if so, reserving the third fly-by-wire height, and acquiring the fly-by-wire speed corresponding to the unmanned aerial vehicle when the fly-by-wire power is minimum, namely the first fly-by-wire speed, based on the fly-by-wire power of the unmanned aerial vehicle at any fly-by-wire height. And finally, calling an unmanned aerial vehicle flight planning evaluation function which is prestored in the system to calculate the obtained first flight speed, third flight height and third suspension height to obtain a final result, and outputting the first flight speed, third flight height and third suspension height as the unmanned aerial vehicle flight planning result if the value of the result is smaller than a set threshold value. According to the method, the quality of the data to be patrolled and flown is ensured in a special scene with a large patrolling range and a large number of patrolling targets, such as a highway, by means of mass limitation of the patrolling power, the suspending power and the patrolling speed of the unmanned aerial vehicle and flexible conversion of the returned data by a dichotomy, so that the remote control efficiency of the unmanned aerial vehicle is ensured.

As shown in fig. 2, in an embodiment, according to the unmanned aerial vehicle flight planning method provided by the invention, based on a first parameter, a second suspension height is obtained by calculating a first suspension power of an unmanned aerial vehicle corresponding to the first suspension height through a dichotomy, and the second suspension height is converted to obtain a third suspension height, and the method comprises the following steps:

step S210, calculating a first levitation power based on the plurality of first levitation heights.

Specifically, the server calculates, based on the plurality of first levitation heights, a first levitation power as:

。

where ρ is the air density,the rotor area is equal to the rotor area, omega is the angular speed of the blade, R is the rotor radius, X is the increment correction coefficient of the induction power, and W is the weight of the unmanned aerial vehicle.

Step S220, calculating a first fly-by power based on the first levitation power.

Specifically, the server calculates the first fly power based on the first suspension power calculated in step S210, where the first fly power is:

。

in the formula , and />The first two items in the first suspension power are respectively, V is the flying speed of the unmanned aerial vehicle, < ->V for the speed of the rotor blade ₀ For the average speed of the rotor wing generated when the unmanned aerial vehicle hovers, d ₀ The resistance ratio of the unmanned aerial vehicle body is that of the unmanned aerial vehicle body.

Step S230, calculating power consumption of the unmanned aerial vehicle during rising and falling based on the first levitation power and the first cruise power.

Specifically, the server calculates, based on the first levitation power and the first cruise power obtained in steps S210 and S220, power consumption of the unmanned aerial vehicle when the unmanned aerial vehicle rises and falls as follows:

。

in the formula ,for thrust-weight ratio, when the unmanned aerial vehicle is ascending, the unmanned aerial vehicle is in the ++>Otherwise when the unmanned aerial vehicle is descending +.>。

As shown in fig. 3, in an embodiment, the unmanned aerial vehicle patrol planning method provided by the invention further includes the following steps:

step S310, obtaining the inspection effect coefficient of the unmanned aerial vehicle.

Specifically, the server acquires the inspection effect coefficient of the unmanned aerial vehicle, in the formula ,/>Inspection flight for unmanned aerial vehicle aiming at inspection targetHeight of the steel plate.

Step S320, calculating the inspection overall effect of the unmanned aerial vehicle based on the inspection effect coefficient.

Specifically, the server calculates, based on the inspection effect coefficient obtained in step S310, the overall inspection effect of the unmanned aerial vehicle as follows:

。

in the formula ,j=1, 2,..n is the importance of the patrol object j.

In a specific embodiment, according to the unmanned aerial vehicle patrol planning method provided by the invention, the patrol process of the unmanned aerial vehicle is set from a starting point S point to a destination D point, and N key patrol targets are included between the starting point S point and the destination D point. In view of the characteristics of the expressway, the inspection sequence of the inspection targets is determined, and the number of inspection paragraphs of the unmanned aerial vehicle is n+1, and the corresponding straight line lengths are respectively represented as L ₀ ,L ₁ ,...,L _N If the flying height in each section of the unmanned aerial vehicle is fixed, the flying height of the corresponding inspection section can be expressed as h ₀ ，h ₁ ，...，h _N . In order to not lose generality, all important inspection targets in the expressway scene are set to be in a circular state, and the space radius is expressed as r ₁ ，r ₂ ，...，r _N The unmanned aerial vehicle performs photographing or shooting operation on key patrol targets in a manner of suspending around the key patrol targets, and the suspension duration of each key patrol target is represented as t ₁ ，t ₂ ，...，t _N The inspection suspension height of each key target is h respectively ₁ ^H ,h ₂ ^H, ...,h ₃ ^H . Aiming at the inspection paragraph and the key inspection target, in order to ensure the space integrity of the unmanned aerial vehicle on-board camera for the inspection paragraph and the inspection target, the minimum flying height of the unmanned aerial vehicle can be calculated as follows:

。

In a highway scenario, the flight-around process of an unmanned aerial vehicle may frequently encounter a signal non-line-of-sight link (NLOS) transmission, and the probability of line-of-sight transmission (LOS) of the unmanned aerial vehicle is expressed as:

。

in the formula ,a and b represent parameters related to the output environment, and h and L represent the flying height of the unmanned aerial vehicle and the distance interval between the vertical projection of the unmanned aerial vehicle on the ground and the ground signal transceiver, respectively. Accordingly, the expected power of the received signal of the unmanned aerial vehicle at the position is:

。

in the formula ,、/> and />The transmission power of the signal, the corresponding path LOSs in the LOS environment, and the winning path LOSs in the NLOS environment, respectively.

The inspection height of the rotary wing type inspection unmanned aerial vehicle in the whole section of expressway scene is expressed as:. For ease of presentation, the sequence numbers are re-expressed as τ ₀ ，τ ₁ ，τ ₂ ，...，τ _M And m=2n+2 is true, the power consumption of the unmanned aerial vehicle in the suspension process is as follows:

。

The power of unmanned aerial vehicle in the flight process is:

。

The power consumption of the drone at both up and down can be expressed as:

。

in the formula ,for thrust-weight ratio, when the unmanned aerial vehicle is ascending, the unmanned aerial vehicle is in the ++>Whether or notThen when the drone descends +.>. For simplicity, the speed of the unmanned aerial vehicle in the ascending and descending process is set to be constant at V _UD The push-to-weight ratio is fixed to +. > and />The power consumption of the corresponding procedure can be expressed as +.> and />。

In this embodiment, the flight inspection effect of the unmanned aerial vehicle is important, and the minimum flight height of the unmanned aerial vehicle is referred to, so that the flight inspection effect coefficient is set as, in the formula ,/>The method is characterized by comprising the step of detecting the flight height of the unmanned aerial vehicle aiming at a certain inspection target. Is provided with->The whole effect of patrolling and examining of unmanned aerial vehicle is represented, and it can calculate through following formula:

。

in the formula ,j=1, 2,..n is the importance of the patrol object j.

Because unmanned aerial vehicle's communication power compares comparatively tiny in flight consumption, this patent ignores the former to the effect optimization is patrolled and examined to highway sceneThe method is characterized in that the unmanned aerial vehicle energy-available support inspection process, the flying height, the flying speed and the signal transmission quality are taken as limiting conditions, and the optimization problem of the unmanned aerial vehicle inspection process can be summarized and expressed as follows: (Indicating the expected/desired/and/or desired/received signal power in the inspection range of the i-th segment>Representing the desire for received signal power for the ith inspection target

(a)

（b）

（c）

（d）

（e）

（f）

in the formula ,is the equivalent radius of the expressway,is the upper limit of the fly-following height of the unmanned plane,is the upper limit of the speed of unmanned aerial vehicle for patrol flight,representing the threshold requirement for the desired average value of the unmanned aerial vehicle return signal received power.

Referring to fig. 4, in this embodiment, the steps of executing the unmanned aerial vehicle flight planning method provided by the present invention may be described as follows:

(1) Initializing and inputting related parameters of the unmanned aerial vehicle, key inspection targets and related parameters of the expressway.

(2) Combining formula (c), letI=1, 2,..n, solving by dichotomy to obtain +.>And further transformed to obtain +.>。

(3) Determination ofIf so, executing the step (4), otherwise, ending the method and failing to obtain a feasible solution.

(4) Combining formula (c), letI=0, 1,..n, solving by dichotomy to obtain +.>And further transformed to obtain +.>。

(5) Determination ofIf yes, executing step (6), otherwise ending the method, and failing to obtain availabilityAnd (5) performing row solution.

(6) Combining relation type

And solving by using a dichotomy to obtain +.>Simultaneously, all the fly speeds are set to be +.>。

(7) Determining the currentIf the value of the three items of the output is satisfied as the planning result, executing the step (8) if the value of the three items of the output is not satisfied.

(8) Searching in the current result to obtainAnd orderAnd skipping to execute the step (7).

According to the unmanned aerial vehicle patrol planning method, based on understanding of scenes and analysis of problems to be solved, if the signal receiving quality of the corresponding position of each unmanned aerial vehicle can meet the threshold requirement of a formula through observing the expression (c), the expression (c) can meet constraint conditions, meanwhile, calculation of the unmanned aerial vehicle height belongs to a one-dimensional search problem, so that the unmanned aerial vehicle patrol planning method is solved in the step (2) by using a dichotomy, the height range of the unmanned aerial vehicle for a highway curve and a key patrol target is defined in the step (2) and the step (4), the minimum requirement of the expressions (d) and (e) is met, and the method is added with the limit of the highest patrol height in the step (3) and the step (5), and corresponds to the flight parameters of the unmanned aerial vehicle, because the patrol field or the communication signal corresponding to the flight parameters of the unmanned aerial vehicle cannot be executed after the flight performance limit of the unmanned aerial vehicle is exceeded. In the method, in the step (7), the calculation of the flight speed on the premise of minimizing the propulsion energy consumption of the unmanned aerial vehicle is set so as to maximize the flight duration of the unmanned aerial vehicle, and the flight duration is matched with the objective actual requirement of unmanned aerial vehicle inspection.

Considering that a one-dimensional influence relation exists between the flight speed and the energy consumption of the unmanned aerial vehicle, the method still provides that the corresponding unmanned aerial vehicle patrol speed is obtained by using a dichotomy. Finally, the method carries out compliance judgment on parameters such as the flight height and the flight speed of the unmanned aerial vehicle and the like and the limiting condition (b), if the conditions are met, the method means that all the limiting conditions are met currently, the requirements of targets on the maximization of the inspection effect can be met well, if the related parameters do not meet the limiting condition (b) currently, the difference between the flight height of the unmanned aerial vehicle and the suspension height aiming at the important inspection targets is large, the energy consumption of the unmanned aerial vehicle is increased due to the change between the flight height and the suspension height of the unmanned aerial vehicle, and the unmanned aerial vehicle has the minimum value on the premise of meeting the inspection quality at the moment, so that unified operation is carried out on the flight height and the suspension height of the unmanned aerial vehicle by the method, and the unmanned aerial vehicle starts from the adjacent height value with the largest difference.

In this embodiment, the method mainly involves three binary solutions for N element sequences, and a limited number of operations for finding the maximum value in the order of 2N elements, and the complexity of the method operation is O (N), which is obviously very low, and the solution complexity for the problem is as high as O (N3) by taking the traversal method as a reference. Therefore, in a comprehensive view, the method provided by the patent has stronger rationality and very low operation complexity, and the practical feasibility of the method is higher. The planning performance of the proposed method is represented by adopting two methods, namely a traversal method and a genetic algorithm, wherein the traversal method inputs a combined solution in a solution space into an optimization problem, and obtains an optimal solution by comparing the compliance of each combined solution to a constraint condition of the problem and the maximization of a target.

In addition, the advantages of the proposed method are demonstrated by using two performance indicators, respectively the operation speed of the method and the planning effect of the method corresponding to the solving target (a). Through a large number of simulations and average values, the result shows that the algorithm has the fastest operation speed, the operation speed ratio of the genetic algorithm to the traversal method is 1:15:2978, which indicates that the method can be better suitable for a scene of unmanned aerial vehicle patrol rapid planning, and meanwhile, in the aspect of planning effect, the patrol satisfaction parameter ratio corresponding to solutions obtained by the method, the genetic algorithm and the traversal method is 0.976:0.885:1, although the performance does not completely reach the optimal level, the performance is relatively close to the optimal level, and the method is obviously superior to a genetic algorithm with inferior operation performance in the aspect of inspection quality, which shows the excellent performance of the method in the aspect of inspection quality.

According to the unmanned aerial vehicle flight patrol planning method, the flight patrol planning method with high efficiency performance is provided for the unmanned aerial vehicle for the expressway patrol scene, and compared with the current and best related technologies, the advantages of the provided method are mainly represented in the following four aspects: the method is essentially different from the prior art in that the method takes the expressway scene as a guide, takes important inspection target points and high-speed curves as inspection contents, fixes the inspection sequence, sets corresponding inspection suspension time length, and optimizes the inspection visual field effect as an inspection target; secondly, the inspection quality and the communication quality are fully considered, the current related research generally takes the sequence of flight points of the unmanned aerial vehicle as an optimization target, the height and the speed parameters of the inspection flight are mainly considered, and the inspection field of the unmanned aerial vehicle and the signal transmission quality in the inspection flight process are rarely concerned, which is the unique point of the method; thirdly, the method is low in complexity and high in operation efficiency, the method relies on analysis and observation of the problem to be optimized, an operation whole formed by a plurality of sub-operations with lower complexity is formed, the sub-operations can be executed in parallel, and compared with the existing method, the method is low in complexity and high in operation efficiency; fourthly, the planning performance of the patrol parameter is better, and because the proposed method is matched with the scene depth, the optimization target and the limiting condition of the problem to be solved are fully considered, and the problem is reasonably, equivalently and simplified, so that the proposed method has better planning performance compared with a plurality of existing methods.

The unmanned aerial vehicle flight-patrol planning device provided by the invention is described below, and the unmanned aerial vehicle flight-patrol planning device described below and the unmanned aerial vehicle flight-patrol planning method described above can be correspondingly referred to each other.

As shown in fig. 5, in one embodiment, the unmanned aerial vehicle flight planning apparatus includes a first obtaining module 510, a first processing module 520, a first judging module 530, a second processing module 540, a second judging module 550, a third processing module 560, a fourth processing module 570, and a result output module 580.

The first obtaining module 510 is configured to obtain a first parameter and a second parameter, and determine a patrol target, where the first parameter is an unmanned aerial vehicle parameter, the second parameter is an expressway parameter, the patrol target is a target object to be patrol by the unmanned aerial vehicle on an expressway, the first parameter includes a focal length of an onboard camera of the unmanned aerial vehicle and a lens radius of the onboard camera equivalent to a CCD camera, and the second parameter includes a space radius of the patrol target.

The first processing module 520 is configured to calculate, based on the first parameter, a first levitation power of the unmanned aerial vehicle at a first levitation height according to a dichotomy, to obtain a second levitation height, and perform equivalent transformation on the second levitation height to obtain a third levitation height.

The first determining module 530 is configured to determine whether the third levitation height is less than a first threshold, which is a maximum levitation height of the unmanned aerial vehicle. If yes, then

The second processing module 540 is configured to calculate, based on the first parameter, a first fly-by-wire power of the unmanned aerial vehicle corresponding to the first fly-by-wire altitude, to obtain a second fly-by-wire altitude, and convert the second fly-by-wire altitude to obtain a third fly-by-wire altitude.

The second determining module 550 is configured to determine whether the third fly height is less than the first threshold. If yes, then

The third processing module 560 is configured to obtain, based on the first fly-by-wire power, a first fly-by-wire speed by a dichotomy, where the first fly-by-wire speed is a fly-by-wire speed corresponding to the unmanned aerial vehicle when the first fly-by-wire power is minimum.

The fourth processing module 570 is configured to call a first function to calculate the first fly-by-wire speed, the third fly-by-wire height, and the third levitation height to obtain a first result, and determine whether a value of the first result is less than a second threshold. If yes, then

The result output module 580 is configured to output the first fly-by-wire speed, the third fly-by-wire altitude, and the third levitation altitude as the unmanned aerial vehicle fly-by-wire planning result.

In this embodiment, the unmanned aerial vehicle patrol planning device provided by the invention further includes a first calculation module, configured to:

Based on the first parameter and the second parameter, calculating a minimum flight speed of the unmanned aerial vehicle。

Wherein f is the focal length of the onboard camera of the unmanned aerial vehicle, R _CCD The lens radius of the airborne camera equivalent to the CCD camera is r, and the space radius of the inspection target is r.

In this embodiment, the unmanned aerial vehicle patrol planning device provided by the invention further includes a second calculation module, configured to:

calculating a first levitation power based on the plurality of first levitation heights

。

Wherein ρ is the air density,is the section resistance coefficient, s is the rotor firmness coefficient, A is the rotor area size, omega is the blade angular velocity, and R is the rotorAnd the radius, X is an increment correction coefficient of the induction power, and W is the weight of the unmanned aerial vehicle.

In this embodiment, the unmanned aerial vehicle patrol planning device provided by the invention further includes a third calculation module, configured to:

calculating a first fly power based on the first levitation power

。

wherein , and />The first two items in the first suspension power respectively, V is the flying speed of the unmanned aerial vehicle, < +.>V for the speed of the rotor blade ₀ For the average speed of the rotor wing generated when the unmanned aerial vehicle hovers, d ₀ The resistance ratio of the unmanned aerial vehicle body is that of the unmanned aerial vehicle body.

In this embodiment, the unmanned aerial vehicle patrol planning device provided by the invention further includes a fourth calculation module, configured to:

Based on the first levitation power and the first cruise power, power consumption of the unmanned aerial vehicle during ascending and descending is calculated

。

wherein ,for thrust-weight ratio, when the unmanned aerial vehicle is ascending, the unmanned aerial vehicle is in the ++>Otherwise when the unmanned aerial vehicle is descending +.>。

In this embodiment, the unmanned aerial vehicle patrol planning device provided by the invention further includes a fifth calculation module, configured to:

obtaining inspection effect coefficient of unmanned aerial vehicle, wherein ,/>The unmanned aerial vehicle is aimed at the inspection flying height of the inspection target.

。

wherein ,j=1, 2,..n is the importance of the patrol object j.

Fig. 6 illustrates a physical structure diagram of an electronic device, which may be an intelligent terminal, and an internal structure diagram thereof may be as shown in fig. 6. The electronic device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the electronic device is configured to provide computing and control capabilities. The memory of the electronic device includes a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the electronic device is used for communicating with an external terminal through a network connection. The computer program, when executed by a processor, implements a method for unmanned aerial vehicle fly-by-fly planning, the method comprising:

Acquiring a first parameter and a second parameter, and determining a patrol target, wherein the first parameter is an unmanned aerial vehicle parameter, the second parameter is a highway parameter, and the patrol target is a target object of the unmanned aerial vehicle to be patrol on a highway;

based on the first parameter, calculating first suspension power of the unmanned aerial vehicle corresponding to the first suspension height through a dichotomy to obtain a second suspension height, and converting the second suspension height to obtain a third suspension height;

Calculating first fly-following power of the unmanned aerial vehicle corresponding to the first fly-following height by a dichotomy based on the first parameter to obtain a second fly-following height, and converting the second fly-following height to obtain a third fly-following height;

judging whether the third fly-through height is smaller than a first threshold value; if yes, then

Based on the first fly-through power, acquiring a first fly-through speed by a dichotomy, wherein the first fly-through speed is the fly-through speed corresponding to the unmanned aerial vehicle when the first fly-through power is minimum;

invoking a first function to calculate a first fly-through speed, a third fly-through height and a third suspension height so as to obtain a first result, and judging whether the value of the first result is smaller than a second threshold value; if yes, then

Outputting the first flight patrol speed, the third flight patrol height and the third suspension height to obtain the flight patrol planning result of the unmanned aerial vehicle.

It will be appreciated by those skilled in the art that the structure shown in fig. 6 is merely a block diagram of a portion of the structure associated with the present inventive arrangements and is not limiting of the electronic device to which the present inventive arrangements are applied, and that a particular electronic device may include more or fewer components than shown, or may combine certain components, or have a different arrangement of components.

On the other hand, the invention also provides a computer storage medium storing a computer program, which when executed by a processor, realizes the unmanned aerial vehicle flight planning method, and the method comprises the following steps:

In yet another aspect, a computer program product or computer program is provided, the computer program product or computer program comprising computer instructions stored in a computer readable storage medium. A processor of an electronic device reads the computer instructions from a computer readable storage medium, and when the processor executes the computer instructions, the processor implements a method for unmanned aerial vehicle flight planning, the method comprising:

Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory.

By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. The unmanned aerial vehicle patrol planning method is characterized by comprising the following steps:

Outputting the first flight patrol speed, the third flight patrol height and the third suspension height as unmanned aerial vehicle flight patrol planning results;

wherein the first function is:

；

in the formula ,for the speed of the ascent and descent process of the unmanned aerial vehicle, +.> and />Push-to-weight ratio of the ascending and descending processes of the unmanned aerial vehicle respectively, < -> and />Respectively corresponding power consumption in the ascending and descending processes of the unmanned aerial vehicle, wherein E is the secondThreshold τ _k+1 and τ_k Respectively representing two items, P, of the unmanned aerial vehicle in the inspection height sequence of the whole highway scene _h For the first levitation power, +.>Unmanned plane power corresponding to target speed, t _i For the flight time of the unmanned aerial vehicle->For the target speed, L _i The flight path of the unmanned aerial vehicle is the flight path of the unmanned aerial vehicle, and M and N are any positive integers.

2. The unmanned aerial vehicle flight planning method of claim 1, wherein the first parameter comprises a focal length of an onboard camera of the unmanned aerial vehicle and a lens radius of the onboard camera equivalent to a CCD camera, and the second parameter comprises a spatial radius of the inspection target;

calculating a minimum flying height of the unmanned aerial vehicle based on the first parameter and the second parameter

；

Wherein f is the focal length of the unmanned aerial vehicle-mounted camera, R _CCD And the lens radius of the CCD camera is equivalent to the onboard camera of the unmanned aerial vehicle, and r is the space radius of the inspection target.

3. The unmanned aerial vehicle flight planning method according to claim 1, wherein the calculating the first levitation power of the unmanned aerial vehicle corresponding to the first levitation height by a dichotomy based on the first parameter to obtain a second levitation height, and converting the second levitation height to obtain a third levitation height, comprises:

；

4. The unmanned aerial vehicle flight planning method according to claim 3, wherein the acquiring a first flight speed by a dichotomy based on the first flight power, the first flight speed being a flight speed corresponding to the unmanned aerial vehicle when the first flight power is minimum, further comprises:

Calculating the first fly-by power based on the first levitation power

；

wherein , and />The first two items in the first suspension power are respectively, V is the flying speed of the unmanned aerial vehicle, and +.>V for the speed of the rotor blade ₀ For the average speed of the rotor wing generated when the unmanned aerial vehicle hovers, d ₀ The resistance ratio of the unmanned aerial vehicle body is that of the unmanned aerial vehicle body.

5. The unmanned aerial vehicle flight planning method of claim 4, wherein the calculating the first flight power based on the first levitation power, then comprises: calculating power consumption of the unmanned aerial vehicle during ascending and descending based on the first suspension power and the first patrol power

；

6. The unmanned aerial vehicle cruise control method of claim 1, further comprising:

obtaining the inspection effect coefficient of the unmanned aerial vehicle, wherein ,/>The inspection flying height of the unmanned aerial vehicle aiming at the inspection target is set; wherein (1)>Is the minimum flying height of the unmanned aerial vehicle;

7. Unmanned aerial vehicle patrols and flies planning device, its characterized in that, the device includes:

the first processing module is used for calculating first suspension power of the unmanned aerial vehicle corresponding to a first suspension height through a dichotomy based on the first parameter to obtain a second suspension height, and carrying out equivalent transformation on the second suspension height to obtain a third suspension height;

The result output module is used for outputting the first flight patrol speed, the third flight patrol height and the third suspension height as unmanned aerial vehicle flight patrol planning results;

wherein the first function is:

;

in the formula ,for the speed of the ascent and descent process of the unmanned aerial vehicle, +.> and />Push-to-weight ratio of the ascending and descending processes of the unmanned aerial vehicle respectively, < -> and />Respectively corresponding power consumption in the ascending and descending processes of the unmanned aerial vehicle, wherein E is a second threshold value and tau is calculated _k+1 and τ_k Respectively representing two items, P, of the unmanned aerial vehicle in the inspection height sequence of the whole highway scene _h For the first levitation power, +.>Unmanned plane power corresponding to target speed, t _i For the flight time of the unmanned aerial vehicle->For the target speed, L _i The flight path of the unmanned aerial vehicle is the flight path of the unmanned aerial vehicle, and M and N are any positive integers.

8. An electronic device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any one of claims 1 to 6 when the computer program is executed.

9. A computer storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the method of any one of claims 1 to 6.