CN112334781A

CN112334781A - Return voyage method, and method and device for determining power consumption for return voyage

Info

Publication number: CN112334781A
Application number: CN201980038800.3A
Authority: CN
Inventors: 张子豪; 商志猛; 彭昭亮; 耿畅
Original assignee: SZ DJI Technology Co Ltd
Current assignee: SZ DJI Technology Co Ltd
Priority date: 2019-10-29
Filing date: 2019-10-29
Publication date: 2021-02-05
Also published as: WO2021081740A1

Abstract

A method of return voyage comprising: estimating wind speed information falling from the current position to the target position according to the acquired historical wind speed information; determining ground speed information of falling from the current position to the target position; determining the return electricity consumption according to the wind speed information and the ground speed information; and determining whether to execute the return operation or not according to the return electricity consumption and the current residual electricity. A method and a device for determining the return trip electricity consumption are also provided. According to the method and the device, the wind speed information during the return voyage is estimated through the historical wind speed, and the estimation of the return voyage power consumption is carried out, so that the estimated return voyage power consumption is more accurate.

Description

Return voyage method, and method and device for determining power consumption for return voyage

Technical Field

The application relates to the technical field of intelligent return voyage, in particular to a return voyage method, a return voyage power consumption determination method and a return voyage power consumption determination device.

Background

In many scenes, the return electricity consumption of the aircraft in the flight process needs to be estimated so as to control the aircraft to smoothly return to a target position. For example, unmanned aerial vehicle need predict the power consumption of returning a journey at the flight process to trigger the automatic returning journey of unmanned aerial vehicle in suitable time, avoid appearing the electric quantity and lead to leading to unable automatic returning a journey to the target point and cause unmanned aerial vehicle to fly to lose or the phenomenon of descending failure inadequately. Therefore, it is important to improve the accuracy and the qualification of the estimation of the return power consumption. At present, when the return power consumption is estimated, the return power consumption is generally estimated by constant flight ground speed and flight power. However, during actual flight, there are many factors that affect the accuracy of the estimation. Therefore, there is a need for an improved return method to accurately estimate the amount of return power and to control the return of the aircraft in a timely manner.

Disclosure of Invention

In view of the above, the present application provides a return journey method, a return journey power consumption determination method and a return journey power consumption determination device.

According to a first aspect of the present application, there is provided a return journey method, the method comprising:

estimating wind speed information falling from the current position to the target position according to the acquired historical wind speed information;

determining ground speed information of falling from the current position to the target position;

determining the return electricity consumption according to the wind speed information and the ground speed information;

and determining whether to execute the return operation or not according to the return electricity consumption and the current residual electricity.

According to a second aspect of the present application, there is provided a return trip power consumption determination method, the method comprising:

and determining the return electricity consumption according to the wind speed information and the ground speed information.

According to a third aspect of the present application, there is provided an apparatus comprising a processor, a memory, and a computer program stored on the memory, the processor implementing the following steps when executing the computer program:

By applying the scheme, when the return electricity consumption at the current moment is estimated, the wind speed information during the return voyage can be estimated through the historical wind speed information, the return electricity consumption is determined based on the estimated wind speed information and the ground speed information during the return voyage, and whether the return operation is executed or not is determined according to the residual electricity quantity at the current moment and the estimated return electricity consumption. The wind speed during the return voyage is estimated according to the historical wind speed, and the wind speed is used for estimating the return voyage power consumption, so that the estimated return voyage power consumption is more accurate.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.

Fig. 1 is a schematic diagram of a return path of an unmanned aerial vehicle according to an embodiment of the present invention.

Fig. 2 is a flowchart of a return journey method according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of solving the return-voyage ground speed according to the return-voyage wind speed and the return-voyage airspeed according to an embodiment of the invention

Fig. 4 is a schematic diagram of a method for calculating a return wind speed according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of a method for calculating a return airspeed and a flight power according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of a method for calculating a return travel ground speed and a return travel time according to an embodiment of the present invention.

FIG. 7 is a flow chart of a method for determining return trip power consumption according to an embodiment of the invention.

Fig. 8 is a schematic diagram of a logical structure of an apparatus according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In many scenes, the return electricity consumption of the aircraft in the flight process needs to be estimated so as to control the aircraft to smoothly return to a target position. For example, unmanned aerial vehicle need predict the power consumption of returning a journey at the flight process to trigger the automatic phenomenon that returns a journey of unmanned aerial vehicle in suitable time, avoid appearing the electric quantity and lead to leading to unable automation to return a journey to the initial point and cause unmanned aerial vehicle to fly to lose inadequately. Generally, a relatively common return route of an unmanned aerial vehicle is shown in fig. 1, return from a current position to a target position (home point) includes an ascending section H1, a cruising section L and a descending section H2, at present, when the return power consumption is estimated, the flight ground speed of each phase is known and constant by default, so that the time required by the unmanned aerial vehicle to return from the current position to an original point according to a predetermined return track can be calculated, and then the electric quantity C1 required by the unmanned aerial vehicle to return can be obtained according to the set flight power consumption of the unmanned aerial vehicle.

However, in the return flight process, the change of the wind speed and the wind direction may occur, so that the actual flight power or the actual return flight time of the unmanned aerial vehicle has a large deviation. From the safety point of view, in order to avoid the situation that the drone cannot return to the origin as much as possible, a certain reserved electric quantity C0 is usually added on the basis of calculating the required electric quantity C1.

According to the return electric quantity calculation method in the related art, the unmanned aerial vehicle can effectively return to the original point under the scene of most headwind return by adding the reserved electric quantity C0. But after wind speed exceeded certain threshold value, received the restriction of unmanned aerial vehicle maximum flight airspeed, the groundspeed of returning a journey can reduce, and the required electric quantity of unmanned aerial vehicle returning a journey can show the increase, adopts and predicts electric quantity C1 and reserves electric quantity C0's scheme and often can make unmanned aerial vehicle can't get back to the original point.

And under the scene of returning a journey great downwind, required consumption can reduce when unmanned aerial vehicle returns a journey according to the ground speed of returning a journey of presetting, and the electric quantity that actually returns a journey required can be exceeded to the electric quantity of returning a journey of at this moment estimation, and unmanned aerial vehicle often still remains more electric quantity after getting back to the original point, therefore has sacrificed certain effective activity duration.

Therefore, the wind speed in the environment has great influence on the return electricity quantity, so that the estimated return electricity consumption is inaccurate, the aircraft does not have enough electricity quantity to return to the original point, or a lot of electricity quantity remains after the aircraft returns to the original point, and the operation time is sacrificed. Therefore, the return air speed information is accurately estimated, and the return electricity consumption is determined according to the return air speed information, so that the method is very key when the unmanned aerial vehicle is controlled to return.

In order to accurately estimate the power consumption for return voyage, the return voyage method provided by the application considers the wind speed information when estimating the power consumption for return voyage, and calculates the power consumption for return voyage according to the estimated wind speed information for return voyage and the return voyage route of the aircraft by estimating the wind speed information in the return voyage process, so that the estimation of the power consumption for return voyage is more accurate.

The return flight method is suitable for various aircrafts such as unmanned planes and airplanes. The method for returning the flight provided by the present application is explained below by taking an unmanned aerial vehicle as an example, but the method for returning the flight provided by the present application is not limited to the unmanned aerial vehicle.

Specifically, the return journey method provided by the application is shown in fig. 2, and comprises the following steps:

s202, estimating wind speed information falling from the current position to the target position according to the acquired historical wind speed information;

s204, determining the ground speed information of the object position from the current position;

s206, determining the return trip electricity consumption according to the wind speed information and the ground speed information;

and S208, determining whether to execute the return operation according to the return electricity consumption and the current residual electricity quantity.

In order to facilitate understanding of the return flight method, some concepts related to the flight process of the unmanned aerial vehicle are explained first. First, the airspeed information, wind speed information, and ground speed information referred to herein may be vectors containing the module length and direction.

During the flight of the unmanned aerial vehicle, there are generally two speeds representing the flight speed, one of which is the airspeed, that is, the speed of the unmanned aerial vehicle relative to the air. One is ground speed, i.e. the speed of the drone relative to the ground. In general, the ground speed is equal to the airspeed plus the wind speed, i.e. the ground speed will be equal to the vector sum of the airspeed and the wind speed, and the ground speed, the airspeed and the wind speed satisfy the trigonometric relation. Generally speaking, when the user has set the groundspeed that unmanned aerial vehicle flies, unmanned aerial vehicle will fly according to the groundspeed that sets up, and when wind speed changed, unmanned aerial vehicle's airspeed also can carry out corresponding adjustment according to the wind speed for final groundspeed is invariable at the groundspeed that the user set up.

Unmanned aerial vehicle's electric quantity of returning a journey mainly receives two factors to influence: return flight power P and return time T. Under ideal environment, the return flight power is only related to the airspeed of the unmanned aerial vehicle in the return flight process, and the power consumption P of the unmanned aerial vehicle in stable flight is a fixed value. And the return time is related to the ground speed of the unmanned aerial vehicle in the return process, the distance between the current position and the target position and the return track. Taking the return journey trajectory shown in fig. 1 as an example, it can be assumed that the flight power of the ascending and descending segment is similar to the flight power of the cruise segment, and certainly, in practical application, the flight power can be distinguished, and the return journey power consumption can be calculated in the following manner:

1. in the process of return flight, the change range of the battery voltage U is small, and at this moment, the current in the process of return flight can be obtained, wherein I is P/U.

2. According to the coordinates of the current position and the target position of the unmanned aerial vehicle, and knowing the return path (as shown in fig. 1, H1-L-H2), assuming that the preset cruising ground speed is Vg and the ascending and descending speed is Vl, the time required for return can be found as follows:

T＝(H1+H2)/Vl+(L/Vg)

it should be noted that the return path is only an example, and in an implementation, the reverse path may be H2 in fig. 1, so that the time required for return is T2/V1.

3. The calculated return electric quantity C ═ T + C0, C0 is a reserved electric quantity designed to cope with environmental or other uncontrollable factors.

When unmanned aerial vehicle remaining capacity Cr is less than the electric quantity C of returning a journey, unmanned opportunity suggestion user need return a journey automatically at once usually.

Because unmanned aerial vehicle is at the flight in-process, the change of wind speed in the environment can arouse the change of the ground speed and the airspeed that unmanned aerial vehicle flies, and then can influence unmanned aerial vehicle and return time and flight power that the use of navigating, therefore can influence the power consumption of navigating. Therefore, when the power consumption for return voyage is calculated, the wind speed information of the return voyage from the current position to the target position can be estimated according to the historical wind speed information, then the power consumption for return voyage is determined according to the estimated wind speed information and the ground speed information during return voyage, and whether the return voyage operation is to be executed or not is determined according to the current residual electric quantity of the unmanned aerial vehicle and the power consumption for return voyage. The wind speed information during the return voyage is estimated through the historical wind speed information, and then the wind speed information is used for estimating the return voyage power consumption, so that the estimation result is more accurate.

In this application, unmanned aerial vehicle can go to estimate the power consumption that returns to navigate at the present moment in real time at the flight in-process, also can estimate once at regular intervals of time certainly, for example, estimate once every 1 minute, then compare with current residual capacity, judge whether need carry out the operation of returning to navigate.

In other alternative embodiments, the return journey method is triggered to be executed when a preset event is detected. The preset events may be set according to aircraft parameters and/or preset instructions. For example, the preset event may be any event that a change in wind speed is detected to be greater than a preset air volume threshold, an operation instruction for instructing execution of a new task is received, it is detected that a battery temperature is greater than a preset threshold, a flight inclination angle is greater than a preset threshold, a battery output power is greater than a preset threshold, and the like. The electric quantity consumption of the events is high, and when the preset events occur, the step of executing the return flight method is triggered, so that whether the return flight operation needs to be executed or not can be judged in time, and the situations of aircraft return flight failure and the like are avoided.

When determining the wind speed information in the return voyage process, in some embodiments, historical wind speed information may be acquired, and then the wind speed information in the return voyage may be estimated according to the acquired historical wind speed information. Of course, in some embodiments, if the drone has access to the internet, the drone may also obtain wind speed information for a future period of time from the interconnected meteorological information, and then estimate the return wind speed information based on the wind speed information for the future period of time obtained from the internet.

In some embodiments, estimating wind speed information to land from the current location to the target location from the acquired historical wind speed information includes estimating wind speed information to land from the current location to the target location based on the acquired historical wind speed information and a pre-trained wind speed prediction model, or estimating wind speed information to land from the current location to the target location based on historical wind speed information over a specified time period.

For example, a wind speed prediction model may be obtained by pre-training, and then future wind speed information may be predicted according to the obtained historical wind speed information and the pre-trained wind speed prediction model. For example, a deep learning model may be used to predict wind speed information at a future time, for example, a large amount of data of historical wind speed information may be obtained, then wind speed data 30min before a certain time is taken as input of the model, an average value of wind speeds 10min after the certain time is taken as output, and the deep learning model is trained, so that a correlation relationship between wind speeds 30min before the certain time and average wind speeds 10min in the future may be obtained, and a wind speed prediction model may be obtained. When the unmanned aerial vehicle needs to predict the average wind speed 10min in the future at the current moment, historical wind speed information 30min before the current moment can be obtained and input into a pre-trained wind speed prediction model, the average wind speed information within 10min in the future can be predicted, and then the average wind speed information within 10min in the future can be used as the return wind speed for calculating the return power consumption. Of course, the above is only a simple example for explaining the scheme, and actually, when the wind speed prediction model is constructed, more factors can be considered, and the model can be trained by using more data to obtain a more accurate wind speed prediction model.

In some implementations, wind speed information for returning from the current location to the target location may also be estimated based on historical wind speed information for a specified period of time. The designated time period is a time period which is screened out and can accurately estimate wind speed information in the future return journey process, and then the return journey wind speed is estimated according to the wind speed information in the time period.

In certain embodiments, estimating the wind speed information based on historical wind speed information over a specified time period comprises: determining a historical wind speed average value or a historical wind speed maximum value based on historical wind speed information in the specified time period; the wind speed information is then determined based on the historical wind speed average or historical wind speed maximum. For example, the average wind speed in a specified time period may be taken as the wind speed information at the time of the return voyage. Certainly, in order to ensure that enough electric quantity supports the unmanned aerial vehicle to return to the target position as much as possible, the maximum wind speed value in the specified time period can be used as the wind speed during the return flight when the return flight wind speed is estimated to be conservative.

In some embodiments, the specified time period is a time period shifted from the current time in the direction of the previous time along the time axis by a specified length of time. The wind speed information may be obtained by moving the wind speed information to a previous time along the time axis for a specified time period, starting from the current time, and then calculating the return wind speed based on the wind speed information in the time period, for example, taking an average value or a maximum value of the time period as the return wind speed. Generally speaking, the wind speed changes are relatively stable, so that the wind speed information in a short period of time in the past at the current moment can be acquired to estimate the wind speed at the return time, and the obtained return wind speed information is relatively close to the real condition, for example, the wind speed in the past 5min or the wind speed in the past 10min can be acquired, and then the wind speed information at the return time can be estimated according to the wind speed in the time period. Of course, since the wind speed is generally relatively stable and the wind speed is less likely to suddenly change, the wind speed can be determined with reference to the stability of the wind speed when determining the designated time period. In certain embodiments, the variance of the historical wind speeds over the specified time period is less than a preset threshold. For example, in order to obtain a section of relatively stable wind speed information to estimate the return wind speed information, it may be determined whether a variance of the wind speed information in a specified time period is smaller than a preset threshold, and if so, the wind speed is considered to be relatively stable. For example, the wind speed information within 5min past from the current time may be first taken, the variance may be calculated, if the variance is smaller than the preset threshold, the specified time period may be 5min past at the current time, and of course, if the calculated variance is larger than the preset threshold, the time length may be increased, for example, the wind speed information of 6min past may be taken, and then the variance value may be calculated until the variance is smaller than the preset value, so as to determine the specified time period. Of course, in order to avoid that the time period taken is too long and not so close to the current time, which results in the estimated return wind speed being not accurate enough, in some embodiments, the time period of the specified time period may be limited, and when the total time period increases to a certain value, the total time period is not increased.

In some embodiments, when the specified time period is determined, the sliding window with the length of the first preset time period may also slide from the current time to the previous time along the time axis according to the step length of the second preset time period, then obtain the historical wind speed information of each time period falling into the sliding window, sequentially calculate the variance of the historical wind speed of each time period falling into the sliding window according to the sequence of falling into the sliding window, and select the time period falling into the sliding window first and having the variance smaller than the preset threshold as the specified time period. For example, the time length of 5min may be used as a sliding window, 5min may be used as a sliding step length, the time is slid from the current time to the past time, a plurality of time periods falling into the sliding window may be obtained, then the wind speed information of each time period is respectively obtained, and the variance of the wind speed information is sequentially calculated, assuming that the wind speed variance of 5min in the first sliding window is less than a preset threshold value, the first 5min is used as a specified time period, and then the return wind speed is estimated according to the wind speed information in the time period. Of course, if the variance of the wind speed in the first 5min is greater than the preset threshold, the wind speed information in the 5min in the next sliding window is taken out, and the variance value is calculated until the variance is less than the preset threshold. The designated time period is the time period which is closest to the current moment and the wind speed variance value is smaller than the preset threshold value. And then taking the average wind speed or the maximum wind speed of the determined wind speeds in the specified time period as the wind speed during the back-voyage.

For example, the unmanned aerial vehicle may continuously obtain the wind speed information at the latest moment in the flight process, when the duration corresponding to the obtained wind speed information is longer than 5min, the average value and the variance of the wind speed within the past 5min may be calculated, and then it is determined whether the variance of the wind speed within the past 5min is smaller than a preset threshold value, if so, the average value of the wind speed within the past 5min is considered as an effective value, and may be used as the return wind speed. If the wind speed average value is larger than the maximum wind speed average value, the average value of the wind speeds in the past 5min is considered to be an invalid value, and the effective value calculated last time is obtained to serve as the return wind speed. The historical wind speed information at each moment can be determined by a sensor, and can also be determined according to the stress state of the airplane. The historical wind speed information can be stored in a cache queue module, for example, a FIFO queue can be used for caching, and when the stored wind speed information exceeds 5 minutes in duration, the wind speed information of the cache queue module is updated, so that only the wind speed information of the past 5 minutes is reserved, the value exceeding 5 minutes is deleted, and the memory can be saved.

After the return air speed is determined, the ground speed information of the unmanned aerial vehicle from the current position to the target position can be determined. The ground speed information can be set by a user in advance, for example, the user can set the unmanned aerial vehicle to return to a target position at a certain speed in advance. In some embodiments, the time that the current electric quantity can support the flight of the unmanned aerial vehicle can be determined according to the maximum power that can be reached during the flight of the unmanned aerial vehicle, and then the minimum speed that the unmanned aerial vehicle needs to return to the target position at the time is determined as the ground speed according to the distance between the current position and the target position.

In some embodiments, in order to obtain more accurate ground speed information, the ground speed information may be determined based on estimated wind speed information, first airspeed information may be determined according to the wind speed information and a preset ground speed, whether the first airspeed information meets a preset airspeed condition is determined, the preset airspeed condition is set according to the maximum airspeed of the unmanned aerial vehicle, and if the first airspeed information meets the preset airspeed condition, the ground speed information is determined according to the preset ground speed.

Generally speaking, after setting up the information of good speed, unmanned aerial vehicle can return voyage according to preset ground speed information, and after the wind speed changes, unmanned aerial vehicle can adjust the airspeed for the ground speed keeps at the default. However, when the wind speed is high, even if the airspeed of the unmanned aerial vehicle is adjusted to the maximum airspeed value, the ground speed cannot be kept at the preset value, and at this time, the ground speed changes and cannot reach the previous ground speed any more. Therefore, in some embodiments, the first airspeed information may be determined according to the estimated return air speed information and the preset ground speed, where the first airspeed information is an airspeed that needs to be achieved when flying at the estimated ground speed. And then judging whether the first airspeed information meets a preset airspeed condition, wherein the preset airspeed condition can be the maximum flight airspeed of the unmanned aerial vehicle, and can also be the numerical values of other parameters such as the maximum power or the maximum throttle amount. And if the first airspeed information meets the preset maximum airspeed condition, taking the preset ground speed as the ground speed information when the unmanned aerial vehicle returns. Of course, in some embodiments, if the first airspeed information does not satisfy the preset maximum airspeed condition, the return groundspeed information may be re-determined based on the wind speed information and the maximum flight airspeed.

When determining the ground speed information during the return flight according to the wind speed information and the maximum flight airspeed, the ground speed information can be determined according to the triangular relation among the wind speed, the airspeed and the ground speed. As shown in fig. 3, the relationship between three velocities in the geodetic coordinate system is given, where Va represents airspeed, Vg represents ground velocity, and Vw represents wind velocity. The circles in fig. 3 represent the mode lengths for maximum airspeed for flight. The left side graph shows that the return airspeed modular length is greater than the maximum airspeed, and the right side graph shows that the return airspeed is reversely solved according to the maximum airspeed. And solving the process of the ground speed during the return voyage, namely finding out a proper airspeed direction and ground speed model length in a unit circle, so that the vector relation Va is Vg + Vw.

In the triangular relationship, the direction of the ground speed during return flight can be determined according to the return flight trajectory, and the maximum flight airspeed model length, the wind speed model length during return flight and the direction are also known. Therefore, the included angle between the ground speed and the wind speed can be determined according to the direction of the ground speed and the direction of the wind speed during the return voyage, and then the modular length of the return voyage can be obtained by utilizing the cosine law. The solution can be solved by the following formula:

where Vg represents the ground speed during the return voyage, Vw represents the wind speed during the return voyage, Va represents the airspeed during the return voyage, and θ represents the angle between the ground speed and the wind speed.

The above equation can be considered as a one-dimensional quadratic equation, and when solving the above one-dimensional quadratic equation, there are four possible cases:

1. solve for a positive value, a negative value:

the situation is a main scene, a triangle relation needed by people is found in a unit circle, and a positive value is taken as the ground speed model length of the return journey.

2. Two positive value solutions occur:

this kind of scene appears when very big downwind is rewound, and the actual ground speed that unmanned aerial vehicle rewound will be greater than 8 m/s. The larger of the two positive solutions is (wind speed + maximum airspeed), and the smaller is (wind speed-maximum airspeed), and the latter is in accordance with the actual flight condition, so that the smaller is taken as the modular length of the return ground speed.

3. Two negative solutions occur:

this condition occurs during very large headwind return flights, in which case the drone may not be able to fly towards the target location, and return ground speed has no effective solution.

4. Solution of equation without real numbers

In this case, the large side wind (side downwind and side upwind) occurs, and the return ground speed, the wind speed and the maximum flying airspeed cannot form a closed plane triangle due to the overlarge wind speed, so that the return ground speed is unresolved.

After the wind speed information and the ground speed information during the return voyage are determined, the return voyage power consumption of the unmanned aerial vehicle returning to the target position from the current position can be determined according to the wind speed information and the ground speed information. In some embodiments, the time of flight to return from the current location to the target location may be determined from the ground speed information, then the power of flight may be determined from the wind speed information and the ground speed information, and the return power usage may be determined based on the time of flight and the power of flight.

The flight power and the flight airspeed of the unmanned aerial vehicle in the return flight process are related. In some embodiments, when determining the flight power according to the wind speed information and the ground speed information, the method specifically includes: determining second airspeed information according to the wind speed information and the ground speed information, converting a coordinate system of the second airspeed information based on a preset coordinate system corresponding to a power meter, wherein the power meter is used for recording a corresponding relation between flight airspeed and power, and determining the flight power according to the second airspeed information after converting the coordinate system and the power meter.

The second airspeed information can be determined through the wind speed information and the ground speed information during the return flight, the second airspeed information is the actual airspeed information of the return flight process, and then the flight power of the return flight process of the unmanned aerial vehicle is determined according to the second airspeed information. Generally speaking, through calibration experiments, a power meter of the unmanned aerial vehicle in the ideal environment and flying at different flying airspeeds along different directions under the aircraft system can be obtained. Therefore, a power meter can be preset, after the second airspeed information is determined through the wind speed information and the ground speed information, because the second airspeed information is the airspeed under a geodetic coordinate system, the second airspeed information can be converted to the same coordinate system as the power meter, namely, the airspeed information under a body coordinate system, the converted second airspeed information is obtained, and then the table lookup and the interpolation are carried out from the preset power meter to obtain the flight power corresponding to the converted second airspeed information.

After the estimated return power consumption of the unmanned aerial vehicle at the current moment is determined, whether the return operation is executed or not can be determined according to the residual power consumption at the current moment and the estimated return power consumption. For example, if the difference between the current remaining power amount and the estimated return trip power consumption amount is less than the preset power amount, the return trip operation is executed. In consideration of safety, in order to avoid the situation that the unmanned aerial vehicle cannot return to the original point as far as possible, a certain reserved electric quantity C0 is added on the basis of the estimated required electric quantity C1 for return voyage to ensure that enough electric quantity is provided for the unmanned aerial vehicle to return to the target position, so that the reserved electric quantity C0 can be used as the preset electric quantity, and when the current remaining electric quantity of the unmanned aerial vehicle and the estimated electric quantity for return voyage are less than or equal to the reserved electric quantity, return voyage operation is executed.

This application is when estimating the power consumption of returning a journey of unmanned aerial vehicle at present moment, go to estimate the wind speed information of returning a journey process through historical wind speed information, then ground speed information and flight power are confirmed dynamically based on wind speed information and maximum airspeed information, make flight time and flight power more be close to the numerical value under the actual scene, the power consumption of returning a journey of estimation is also more accurate, can avoid unmanned aerial vehicle to return a journey in-process because of the electric quantity is not enough and can't return a journey to the target location, or the electric quantity remains a lot when too early returning a journey to the target location, sacrifice the problem of effective activity duration.

To further explain the return journey method of the present application, a specific example is explained below.

The wind speed influences the ground speed and the power during the return voyage, so that the flight time and the flight power are influenced, and the estimation of the return voyage power consumption is finally influenced. In the present embodiment, the return path shown in fig. 1 is taken as an example, and explanation is made on the premise that the flight power of the ascent and descent segment and the flight power of the cruise segment are approximated to each other. The embodiment can adopt the following scheme to optimize the calculation of the return voyage power P and the return voyage time T so as to estimate the return voyage power consumption. The detailed calculation steps are as follows:

1. estimating return air speed;

the environmental wind speed during the return voyage is one of the main factors influencing the power consumption of the unmanned aerial vehicle during the return voyage, and in order to accurately estimate the return voyage, the wind speed information during the return voyage needs to be known. Aiming at the scene that the wind speed changes slowly, the change of the environmental wind of the unmanned aerial vehicle in a single flying frame can be considered to accord with a certain rule. Under the assumption, the historical wind speed information in the flight process can be used for predicting the wind speed information in the return flight process. Historical wind speed information in the flight process can be obtained through calculation by an accurate atmosphere computer on the unmanned aerial vehicle or through the stress state of the unmanned aerial vehicle. For the sake of calculation, the present embodiment considers only the influence of wind on the northeast horizontal plane under the northeast coordinate system.

In the present embodiment, a sliding average of the past 5 minutes of wind speed information may be used as the return wind speed. Wherein 5 minutes is a set value and can be modified according to actual scenes. After the unmanned aerial vehicle takes off, wind speed information is obtained at a fixed frequency, the obtained wind speed information is cached, when the duration of the stored wind speed information exceeds 5 minutes, a wind speed information caching queue is updated, only the wind speed information of the past 5 minutes is reserved, the value exceeding 5 minutes is deleted, the mean value and the variance of the wind speed of the past 5 minutes are calculated, when the variance is smaller than a certain threshold value, the wind speed is considered to be stable, and the value can be used as the return wind speed to participate in the prediction of the return electric quantity. Referring to fig. 4 specifically, the calculation of the return wind speed may be performed by first continuously acquiring the wind speed information at the latest time (S401), then determining whether the time duration corresponding to the acquired wind speed information is longer than 5 minutes (S402), if so, continuously acquiring the wind speed information, and if so, calculating the average value and the variance of the wind speed information within 5 minutes (S403). And judging whether the variance is smaller than a preset threshold value (S404), if so, taking the average value of the wind speeds as an effective value to serve as a return wind speed (S405), and if so, taking the effective value which is the last time to serve as the return wind speed (S406).

2. And calculating the airspeed during the return flight and the flight power P during the return flight.

The vector relation is satisfied between airspeed Va, ground speed Vg and the wind speed Vw when unmanned aerial vehicle flies, namely Va Vg + Vw.

In the known preset return flight track, the preset return flight ground speed of the cruise section is

In the case of (2), the estimated return wind speed is recorded as

Under this wind speed can be solved, the airspeed that unmanned aerial vehicle navigates back when unmanned aerial vehicle navigates back according to presetting the groundspeed is:

since the flying airspeed of the drone has a maximum limit, note

When the airspeed of the unmanned aerial vehicle is less than the maximum airspeed, then

As the airspeed when returning to the navigation, and when the wind speed is great, can make unmanned aerial vehicle return the model length of airspeed and be greater than the unmanned aerial vehicle maximum flight airspeed:

in this case, the unmanned aerial vehicle may return at the maximum flying airspeed, and thus the maximum flying airspeed is used as the airspeed at the time of return flight.

Because the flight power of the unmanned aerial vehicle is only related to the airspeed vector under the body system, through the calibration experiment, the power meter of the unmanned aerial vehicle in the ideal environment and flying at different speeds in different directions under the body coordinate system can be obtained. After the return airspeed of the unmanned aerial vehicle during return voyage is determined, the return airspeed is the airspeed under the geodetic coordinate system, so that coordinate system conversion can be performed firstly, and the conversion is performed into the airspeed under the body coordinate system. And then the power of the unmanned aerial vehicle flying according to the return airspeed can be obtained through table lookup and interpolation.

In the specific return flight process, the calculation process of the return flight airspeed and the return flight power of the unmanned aerial vehicle is shown in fig. 5. Calculating according to a preset return ground speed and an estimated return wind speed to obtain a return airspeed (S501), judging whether the return airspeed is greater than a maximum airspeed (S502), if so, outputting the return airspeed (S503), if so, outputting the maximum airspeed (S504), then converting the output airspeed by a coordinate system, converting the output airspeed to a body coordinate system (S505), and then obtaining a flight power (S506) corresponding to the airspeed after converting the coordinate system by interpolation and table look-up.

3. And calculating the ground speed and the return time T during the return voyage.

The whole calculation process of the return ground speed and the return time is shown in figure 6,

judging whether the return airspeed is greater than the maximum airspeed (S601), and when the return airspeed is greater than the maximum airspeed

In time, the drone may return at a predetermined return ground speed (S602).

But when the return airspeed

When the unmanned aerial vehicle is used, under the influence of wind, the unmanned aerial vehicle cannot return to the ground speed according to the preset return to the air, and at the moment, the return time of the unmanned aerial vehicle is influenced to cause inaccurate electric quantity estimation. Therefore, the return ground speed in the return process can be obtained according to the triangular relation among the airspeed, the ground speed and the wind speed (S603).

And then determining the return time according to the return ground speed and the distance from the current position to the target position (S604).

When a scene that the return airspeed is greater than the maximum airspeed occurs, the actual return airspeed of the unmanned aerial vehicle flying at the maximum airspeed in the environment needs to be solved reversely. As shown in fig. 3, the relationship between three velocities in the geodetic coordinate system is given, where Va represents airspeed, Vg represents ground velocity, and Vw represents wind velocity. The circles in fig. 3 represent the mode lengths for maximum airspeed for flight. The left side graph shows that the return airspeed modular length is greater than the maximum airspeed, and the right side graph shows that the return airspeed is reversely solved according to the maximum airspeed. And solving the process of the ground speed during the return voyage, namely finding out a proper airspeed direction and ground speed model length in a unit circle, so that the vector relation Va is Vg + Vw.

In the triangular relationship, the direction of the ground speed during return flight can be determined according to the return flight trajectory, and the maximum flight airspeed model length, the wind speed model length during return flight and the direction are also known. Therefore, the included angle theta of the ground speed and the wind speed can be determined according to the direction of the ground speed and the direction of the wind speed during the return voyage, and then the modular length of the return voyage can be obtained by utilizing the cosine law. The solution can be solved by the following relation:

1. solve for a positive value, a negative value:

2. Two positive value solutions occur:

3. Two negative solutions occur:

4. Solution of equation without real numbers

Under the condition that the ground speed of returning a journey does not have effective solution, unmanned aerial vehicle will be unable to return a journey under this environment, must inform the operating personnel, and unmanned aerial vehicle probably can't return a journey.

Through above three steps, can calculate more accurate electric quantity of returning a journey according to unmanned aerial vehicle's flight environment.

Through combining the influence of environment wind, improved the estimation precision of the power consumption of returning a journey in this embodiment, can obviously reduce because the headwind environment can't return to the probability that the departure point leads to unmanned aerial vehicle to fly to lose, but as many as simultaneously assurance unmanned aerial vehicle operation flight time has promoted the security that unmanned aerial vehicle flies under the strong wind environment.

The application also provides a method for determining the return trip power consumption, which is shown in fig. 7 and comprises the following steps:

s702, estimating wind speed information falling from the current position to the target position according to the acquired historical wind speed information;

s704, determining the ground speed information of the target position from the current position;

and S706, determining the return trip electricity consumption according to the wind speed information and the ground speed information.

In one embodiment, the determining the ground speed information of the landing from the current position to the target position comprises:

and determining the ground speed information from the current position to the target position according to the wind speed information.

In one embodiment, the determining the ground speed information falling from the current position to the target position according to the wind speed information comprises:

determining first airspeed information according to the wind speed information and a preset ground speed;

judging whether the first airspeed information meets a preset airspeed condition, wherein the preset airspeed condition is set according to the maximum airspeed of the unmanned aerial vehicle;

and if so, determining the ground speed information according to the preset ground speed.

In one embodiment, if the first airspeed information does not satisfy a preset airspeed condition, the ground speed information is determined according to the maximum airspeed and the wind speed information.

In one embodiment, estimating wind speed information to land from a current location to a target location based on the obtained historical wind speed information comprises:

estimating wind speed information falling from a current position to a target position based on the acquired historical wind speed information and a pre-trained wind speed prediction model; or

Wind speed information falling from a current location to a target location is estimated based on historical wind speed information over a specified time period.

In one embodiment, the specified time period is a time period shifted from the current time in the direction of the previous time along the time axis by a specified length of time.

In one embodiment, the variance of the historical wind speeds over the specified time period is less than a preset threshold.

In one embodiment, the specified time period is obtained by:

sliding a sliding window with the length of a first preset duration from the current time to the previous time along a time axis according to the step length of a second preset duration;

acquiring historical wind speed information of each time period falling into the sliding window;

sequentially calculating the variance of the historical wind speed of each time period in the sliding window according to the sequence of falling into the sliding window;

and selecting the time period which firstly falls into the sliding window and the variance is smaller than a preset threshold value as the designated time period.

In one embodiment, estimating the wind speed information based on historical wind speed information over a specified time period comprises:

determining a historical wind speed average value or a historical wind speed maximum value based on historical wind speed information in the specified time period;

determining the wind speed information based on the historical wind speed average or historical wind speed maximum.

In one embodiment, determining the return trip power consumption according to the wind speed information and the ground speed information comprises:

determining the flight time from the current position to the target position according to the ground speed information;

determining flight power according to the wind speed information and the ground speed information;

determining the return electric quantity based on the flight time and the flight power.

In one embodiment, determining flight power from wind speed information and the ground speed information comprises:

determining second airspeed information according to the wind speed information and the ground speed information;

converting the coordinate system of the second airspeed information based on a preset coordinate system corresponding to a power meter, wherein the power meter is used for recording the corresponding relation between the flying airspeed and the power;

and determining the flight power according to the second airspeed information after the coordinate system is converted and the power meter.

The specific details for determining the return trip power consumption may refer to the description of the return trip method, and are not described herein again.

Furthermore, the present application also provides an apparatus, as shown in fig. 8, the apparatus 80 includes a processor 82, a memory 84, and a computer program stored on the memory, and the processor implements the following steps when executing the computer program:

In one embodiment, when the processor is configured to determine the ground speed information falling from the current position to the target position, the method specifically includes:

In an embodiment, when the processor is configured to determine the ground speed information falling from the current position to the target position according to the wind speed information, the processor specifically includes:

In one embodiment, when the processor is configured to estimate wind speed information falling from the current position to the target position according to the acquired historical wind speed information, the method specifically includes:

In one embodiment, the specified time period is obtained by:

In an embodiment, when the processor estimates the wind speed information based on historical wind speed information in a specified time period, the method specifically includes:

In one embodiment, when the processor is configured to determine the return trip power consumption according to the wind speed information and the ground speed information, the processor specifically includes:

In one embodiment, when the processor is configured to determine the flight power according to the wind speed information and the ground speed information, the processor specifically includes:

In one embodiment, the apparatus may be applied to an unmanned aerial vehicle. The specific details may refer to the description in the return journey method, and are not described herein again.

The embodiment of the application also provides an unmanned vehicles, unmanned vehicles includes any one of the device of returning.

For the device embodiments, since they substantially correspond to the method embodiments, reference may be made to the partial description of the method embodiments for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The method and apparatus provided by the embodiments of the present invention are described in detail above, and the principle and the embodiments of the present invention are explained in detail herein by using specific examples, and the description of the embodiments is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A method of return, the method comprising:

2. The return leg method according to claim 1, wherein the determining the ground speed information for landing from the current position to the target position comprises:

3. The return leg method according to claim 2, wherein the determining ground speed information of landing from a current position to a target position according to the wind speed information includes:

4. A method of homebacking as claimed in claim 3, comprising:

and if the first airspeed information does not meet the preset airspeed condition, determining the ground speed information according to the maximum airspeed and the wind speed information.

5. The return voyage method according to claim 1-4, wherein estimating the wind speed information from the current location to the target location based on the obtained historical wind speed information comprises:

6. The return leg method according to claim 5, wherein the specified time period is a time period shifted from a current time in a direction of a previous time along a time axis by a specified length of time.

7. The method of claim 6, wherein the variance of the historical wind speeds over the specified time period is less than a preset threshold.

8. The return leg method according to claim 5, wherein the specified time period is obtained by:

9. The return leg method according to any one of claims 5-8, wherein estimating the wind speed information based on historical wind speed information over a specified time period comprises:

10. The return voyage method according to claim 1, wherein determining the return voyage power consumption according to the wind speed information and the ground speed information comprises:

11. The return leg method of claim 9, wherein determining flight power from wind speed information and the ground speed information comprises:

12. A method for determining return trip power consumption is characterized by comprising the following steps:

13. An apparatus comprising a processor, a memory, and a computer program stored on the memory, the processor when executing the computer program implementing the steps of:

14. The apparatus of claim 13, wherein the processor, when configured to determine the groundspeed information for landing from the current location to the target location, specifically comprises:

15. The apparatus according to claim 14, wherein the processor, when determining the ground speed information falling from the current position to the target position according to the wind speed information, specifically comprises:

16. The apparatus of claim 15, wherein the ground speed information is determined from the maximum airspeed and the wind speed information if the first airspeed information does not satisfy a preset airspeed condition.

17. The apparatus according to claim 14, wherein the processor, when estimating wind speed information falling from the current position to the target position according to the acquired historical wind speed information, specifically comprises:

18. The apparatus according to claim 17, wherein the specified period is a period shifted from a current time to a previous time along a time axis by a specified length of time.

19. The apparatus of claim 18, wherein the variance of the historical wind speeds over the specified time period is less than a preset threshold.

20. The apparatus of claim 17, wherein the specified time period is obtained by:

21. The apparatus according to any one of claims 17-20, wherein the processor, when estimating the wind speed information based on historical wind speed information over a specified time period, specifically comprises:

22. The apparatus according to claim 13, wherein the processor, when determining the electric power consumption for return voyage according to the wind speed information and the ground speed information, specifically comprises:

23. The apparatus of claim 22, wherein the processor is configured to determine the flight power according to the wind speed information and the ground speed information, and specifically comprises:

24. The device according to any one of claims 13-23, wherein the device is applied to an unmanned aerial vehicle.