TWI757700B - Aircraft route following method - Google Patents

Abstract

An aircraft route following method is performed by an aircraft, the aircraft cuts an image into a plurality of outer ring areas, a plurality of inner ring areas and a central area, and calculates the coordinates of an outer ring target in each outer ring area according to the following target and an inner ring target coordinate in each inner ring area, first generate a reference flight command according to the inner ring target coordinate, and calculate the radian difference between the outer ring target coordinate and the inner ring target coordinate relative to a reference point to update a cumulative radian difference value, and then adjust the reference flight command according to the cumulative radian difference to generate a final flight command; the present invention first generates the reference flight command by the inner ring target coordinates that are closer to the central area, and then uses the cumulative radian difference representing the degree of curvature of the route to generate the reference flight command. The value of the flight command is adjusted to achieve the purpose of precise following and adjusting the speed according to the curve degree of the route.

Description

Aircraft route following method

A flight control method for an aircraft, especially a flight control method for controlling the aircraft to follow a route.

Due to the advantages of small size and stable flight, quadcopters are often used for missions such as reconnaissance and image capture in areas that are difficult to reach by old aircraft. In the flight mission of following a specific route, the aircraft must follow a route that is usually irregularly curved and has an unpredictable extension direction, such as following the river below at high altitude to follow and shoot along the route. The existing route following technologies have no requirements on the accuracy of route following, and most of them only need to be able to follow along the approximate extension direction of the route. The current route following method mainly uses the aircraft to detect the route extension direction of a short section in the flight direction. When the detected route ahead is not the same as the current flight direction, it will steer at a specific steering angle according to the route extension direction. and keep flying forward. However, the existing route detection technology is not perfect. When the UAV deviates from the following route, the setting of the steering angle is prone to errors. The aircraft after turning deviates from the extension direction of the route. In severe cases, the aircraft may lose the following target and cannot continue. The mission, or the aircraft must spend additional detection and correction positioning resources to return to the to-be-followed route again; even if the steering angle error is not large, the aircraft will return to the to-be-followed route after subsequent detection and correction, and the aircraft will fly. The route has also been meandering or drifting.

In addition, the above-mentioned route following method mainly follows the route located under the aircraft, such as the above-mentioned river course or flat road. When the route to be followed is located on a vertical façade, such as a scan for cracks in the wall of a high-rise building, detection of high-voltage electrical towers, etc., since the aircraft must fly along a vertical façade, the aircraft cannot change its progress by turning the plane. direction, because doing so will make the aircraft lose the route it is following, or turn to the part of the route it has already followed.

In view of the low accuracy of the flight control of the existing aircraft route following, when a detection and judgment error occurs, the flight sways and wanders slightly, and in severe cases, it deviates or loses the following target. Therefore, the present invention provides an aircraft route following that can improve the accuracy. In the control method, the main technical means adopted to achieve the aforesaid purpose is to make the aforesaid method be executed by a controller of an aircraft, and the aircraft route following control method includes the following steps: capturing an image frame including a following target, and defining a central area, a plurality of inner ring areas and a plurality of outer ring areas in the image frame; controlling the aircraft to move so that the following target passes through the central area; Calculate an outer ring target coordinate in the outer ring areas according to the following target, and calculate an inner ring target coordinate in the inner ring areas; generating a reference flight instruction according to the inner ring target coordinates; Calculate a radian difference between the outer ring target coordinate and the inner ring target coordinate relative to a reference point, and update a cumulative radian difference accordingly; The reference flight command is adjusted according to the accumulated radian difference to generate a final flight command.

When the aircraft performs a following task of following a target, it first captures an image frame containing the following target, and divides the image frame into a plurality of outer ring areas, a plurality of inner ring areas and a central area. A zone surrounds the central zone, and the plurality of outer ring zones surrounds the plurality of inner ring zones. That is to say, the center area represents the center area where the aircraft is aimed at, and is also the coordinate of the aircraft in the image frame, and the following target sections appearing in the inner ring areas are closer to the center area The segment is also where the aircraft will determine the next flight target. Therefore, the aircraft first generates the reference flight command according to the coordinates of the inner ring target. The outer ring target coordinate is a section farther from the central area, and is used to predict the bending direction of the following target. Therefore, a radian difference between the inner ring target coordinate and the outer ring target coordinate represents that the following target is formed by the inner ring. The zone extends to the difference in the direction of the outer ring zone relative to the reference point. When the radian difference is large, it means that there is a large curvature along the following target. Therefore, according to the updated cumulative radian difference value, the reference flight instruction is further adjusted to generate the final flight instruction, so as to achieve the purpose of adjusting the speed of the aircraft according to the radian change.

To sum up, the present invention uses a virtual target azimuth grid probability model based on an arc, the center area is the bullseye, the inner ring area is used for the selection of the flight direction and the judgment of the flight coordinates, and the outer ring area is used as the speed and speed. The basis for suppression is that when encountering a follow target with too large or too small a curvature, the outer ring area and the inner ring area are further used to obtain the cumulative radian difference to adjust the speed. When it is in a straight line, it becomes faster and faster. When , because the accumulated radian difference becomes larger and larger, the speed of the aircraft will become slower and slower, so reduce the flight speed of the aircraft in advance to prepare to change the flight direction, so as to avoid the speed being too fast and exceeding the route. The aircraft can not only fly accurately toward the inner ring target coordinates on the follow target according to the reference flight instructions, but also adjust and suppress the flight speed in advance according to the degree of curvature of the far route, so as to achieve the aircraft flight control that precisely follows the route.

Please refer to FIG. 1 and FIG. 2 , in a first preferred embodiment of the aircraft route following method of the present invention, the following steps are included: capturing an image frame 10 including a following target 11 , and in the image frame Define a central area G0, complex inner ring areas G1~G4 and complex outer ring areas G5~G8 in 10 (S101); calculate an inner ring target coordinate Q _{in in} the inner ring areas according to the following target, and calculate the Equalize an outer ring target coordinate Q _out in the outer ring area ( S102 ); Generate a reference flight command according to the inner ring target coordinate Q _in ( S103 ); Calculate the outer ring target coordinate Q _out and the inner ring target coordinate Q _in A radian difference relative to a reference point, and updating a cumulative radian difference accordingly ( S104 ); adjusting the reference flight instruction according to the accumulated radian difference to generate a final flight instruction ( S105 ).

Please refer to FIG. 2 , which is a schematic diagram of an image frame 10 captured by the aircraft, wherein G0 is the central area, G1 - G4 are the inner ring area, and G5 - G8 are the outer ring area. Wherein, in the step of defining the center area, the inner ring areas and the outer ring areas in the image frame, the center of the image frame 10 is defined as the center area G0, and the periphery of the center area G0 is defined An inner ring that is concentric with the central area and divided into the inner ring areas G1~G4, and defines on the periphery of the inner ring an inner ring that is concentric with the inner ring and the central area and divided into the inner and outer ring areas G5~G8 The outer ring of , and each inner ring area and each outer ring area correspond to the same central angle. That is, the inner ring regions G1-G4 and the outer ring regions G5-G8 are formed by cutting the inner ring and the outer ring with a plurality of straight lines passing through the common center of the central region G0, the inner ring and the outer ring .

The central area G0 is the central area that the aircraft is facing, that is, represents the current position of the aircraft. In addition, preferably, the central area G0 is a circular central area G0. When the aircraft flies along the following target 11 and the center area G0 is used as a bullseye to aim at the following target 11, the following target 11 extending outward from the center area G0 will inevitably pass through one of the inner ring areas and one of the outer ring areas , the inner ring areas and the outer ring areas are not only used to determine the extension direction of the following target 11, but also used to determine the flight direction. For example, since the aircraft will fly along the following target 11 in the left direction, so The aircraft will travel through the inner ring area G4 and the outer ring area G8 on the left.

為：

More specifically, the aircraft calculates the inner ring target coordinates Q _in =(y _in , z _in ) of the inner ring regions G1 to G4 and the outer ring target coordinates Q _out of the outer ring regions G5 to G8 After =(y _out , z _out ), the steps of generating the reference flight instruction according to the inner ring target coordinate Q _in are specifically generated by the following operations. When a central point of the central area G0 is used as the reference point (y _c , z _c ), the reference flight instruction

for:

為一速率調變常數。in,

is a rate modulation constant.

Referring to FIG. 3, preferably, a radian difference between the outer ring target coordinate Q _out and the inner ring target coordinate Q _in relative to a reference point is calculated, and a cumulative radian difference is updated accordingly (S104 ), which is specifically performed according to the following sub-steps: Calculate the radian value of the outer ring target coordinate Q _out relative to the reference point ( S1041 ); Calculate the radian value of the inner ring target coordinate Q _in relative to the reference point ( S1042 ); The radian difference between the radian value of the outer ring target coordinate Q _out and the radian value of the inner ring target coordinate Q _in ( S1043 ); Obtain a historical radian difference, and add the historical radian difference and the radian difference to obtain The accumulated radian difference (S1044).

=

Since the present invention is based on the circular partition, it is preferable to use the polar coordinate system for calculation and judgment. The above-mentioned radian value of the outer ring target coordinate Q _out and the radian value of the inner ring target coordinate Q _in are calculated according to the following formula:

=

為該外環目標座標Q_out 的弧度值，

為該內環目標座標Q_in 的弧度值。in,

is the radian value of the outer ring target coordinate Q _out ,

is the radian value of the inner ring target coordinate Q _in .

係根據以下公式計算得到:

The radian difference between the radian value of the outer ring target coordinate Q _out and the radian value of the inner ring target coordinate Q _in

It is calculated according to the following formula:

，將該歷史弧度差值

與該弧度差值

相加得到該累積弧度差值

的步驟，係根據以下公式計算得到：

Get a historical radian difference

, the historical radian difference

difference from this radian

Add to get the cumulative radian difference

The steps are calculated according to the following formula:

為第i個影格之影像畫面中，外環目標座標Q_out 的弧度值與該內環目標座標Q_in 的弧度值的弧度差值，該歷史弧度差值

為當下影像畫面10的前b個影格之影像畫面10中弧度差值

之總和。in,

is the radian difference between the radian value of the outer ring target coordinate Q _out and the radian value of the inner ring target coordinate Q _{in in} the image frame of the ith frame, and the historical radian difference

is the radian difference in the image frame 10 of the first b frames of the current image frame 10

the sum.

Please refer to FIG. 4 , preferably, after the accumulated radian difference is obtained, the reference movement command is adjusted according to the accumulated radian difference to generate the final flight instruction ( S105 ), which is specifically based on the following sub-steps conduct: Determine whether an absolute value of the cumulative radian difference is greater than a cumulative error threshold (S1051); When an absolute value of the cumulative radian difference is not less than the cumulative error threshold, perform a rate reduction operation on the reference flight order according to the cumulative radian difference to generate the final flight order (S1052); When an absolute value of the accumulated radian difference is smaller than the accumulated error threshold, a rate-up operation is performed on the reference flight order according to the accumulated radian difference to generate the final flight instruction ( S1053 ).

The cumulative error threshold is used to determine whether the curvature of the following target 11 is greater than a predetermined degree. When the cumulative error threshold is large, it indicates that the following target 11 is located between the center point of the outer ring area and the inner ring area. The orientation of the two center points relative to the center area G0 is continuously different, and the following target 11 is in a state of continuous bending. Therefore, when the cumulative radian difference is greater than the cumulative error threshold, the rate of the reference flight order is reduced by a specific ratio, and when the cumulative radian difference is less than the cumulative error threshold, a specific rate The ratio scales up the rate of the reference flight order. The above judgment and calculation are realized, for example, by the following formula:

為一速率調整比率值，

為該累積誤差臨界值，

為一最大速限值。in,

To adjust the ratio value for a rate,

is the cumulative error critical value,

is a maximum speed limit.

小於該累積誤差臨界值

時，將該參考飛行指令

乘以該累積弧度差值的絕對值

再乘以該速率調整比率

，作為該參考飛行指令

調升的幅度，並將調整後的參考飛行指令

與該最大速限值

之間取一最大值，作為該最終飛行指令

，避免飛行器無限加速。相反的，當該累積弧度差值的絕對值

不小於該累積誤差臨界值

，則是以該參考飛行指令

乘以該累積弧度差值的絕對值

乘以該速率調整比率

，作為該參考飛行指令

調降的幅度並產生該最終飛行指令

。When an absolute value of the accumulated radian difference

less than the cumulative error threshold

, the reference flight instruction

Multiply by the absolute value of this cumulative radian difference

Multiply by this rate adjustment ratio

, as the reference flight instruction

The magnitude of the increase, and the adjusted reference flight order

with the maximum speed limit

Take a maximum value between them as the final flight order

, to avoid infinite acceleration of the aircraft. Conversely, when the absolute value of the accumulated radian difference

not less than the cumulative error threshold

, then use the reference flight instruction

Multiply by the absolute value of this cumulative radian difference

Multiply by this rate to adjust the ratio

, as the reference flight instruction

the magnitude of the downgrade and generate the final flight order

.

小於該累積誤差臨界值

，該最終飛行指令

使得該飛行器的飛行速度漸增，且該累積弧度差值的絕對值

在該累積誤差臨界值

內越大時，該最終飛行指令

的速率增幅越大。當該累積弧度差值的絕對值

不小於該累積誤差臨界值

，該最終飛行指令

使得該飛行器的飛行速度漸減，且該累積弧度差值的絕對值

越大，該最終飛行指令

的速率降幅越大。That is, when the absolute value of the cumulative radian difference

less than the cumulative error threshold

, the final flight order

Make the flight speed of the aircraft gradually increase, and the absolute value of the accumulated radian difference

at this cumulative error threshold

is larger, the final flight order

the greater the rate increase. When the absolute value of the cumulative radian difference

not less than the cumulative error threshold

, the final flight order

Make the flying speed of the aircraft gradually decrease, and the absolute value of the accumulated radian difference

the larger the final flight order

the greater the rate of decline.

2.0、

、

、

為例，圖5為該飛行器由影像畫面右方向左方行進即將轉彎之前的影像畫面10，內環目標座標Q_in 的弧度值

為3.1416，該外環標座標的弧度值

為1.77，弧度差值

，此時累積弧度差值

例如為

，

；圖6為該飛行器進行轉彎之後的影像畫面10，該內環目標座標Q_in 的弧度值

為1.55，該外環標座標的弧度值

為1.57，弧度差值

，此時累積弧度差值

例如為0.06，

。Please refer to FIG. 5 and FIG. 6 . FIGS. 5 and 6 are schematic diagrams of the image screen 10 when the aircraft follows the following target 11 and makes a large angle turn. For example, with

2.0,

,

,

For example, FIG. 5 shows the image frame 10 of the aircraft moving from the right to the left of the image frame before turning, and the radian value of the inner ring target coordinate Q _in

is 3.1416, the radian value of the outer ring coordinates

is 1.77, the difference in radians

, then the cumulative radian difference

for example

,

; Fig. 6 is that this aircraft carries out the image picture 10 after turning, the radian value of this inner ring target coordinate Q _in

is 1.55, the radian value of the outer ring coordinate

is 1.57, the difference in radians

, then the cumulative radian difference

For example, 0.06,

.

參考飛行指令

，該飛行器進行沿著該跟隨目標11進行減速；在圖6中，當飛行器完成轉向，該內環目標座標Q_in 及該外環目標座標在Q_out 在同一方向上且累積弧度差值

極小，產生之最終飛行指令

大於參考飛行指令

，該飛行器進行沿著該跟隨目標11進行加速。It can be seen from the examples in FIGS. 5 and 6 that in FIG. 5 , when the image screen 10 of the aircraft shows that there is a large angle of turn ahead in the flight direction, the final flight command is generated.

reference flight instructions

, the aircraft decelerates along the following target 11; in FIG. 6, when the aircraft completes turning, the inner ring target coordinates Q _in and the outer ring target coordinates Q _out are in the same direction and the accumulated radian difference

very small, resulting final flight order

greater than the reference flight order

, the aircraft accelerates along the following target 11 .

When the cumulative radian difference is too large, the speed of the final flight command will be reduced; when the cumulative radian difference is small, the speed in the final flight command will be increased, and the rate reduction and rate increase operations will be performed according to the cumulative radian difference. Make the aircraft increase the flight speed when following a curve with a small curvature or a straight line. When encountering a curved line with a large curvature, reduce the speed to prepare for turning, avoid the aircraft from deviating from the following target 11, meandering, etc., and improve the following precision.

Please refer to FIG. 7 , preferably, the aircraft calculates an outer ring target coordinate Q _out in the outer ring areas G5 - G8 , and calculates an inner ring target coordinate Q in the inner ring areas G1 - G4 The step of _in ( S102 ) is specifically performed according to the following steps: Calculate the probability values of the following target 11 appearing in the outer ring areas G5 to G8 and the inner ring areas G1 to G4 ( S1021 ); Select the outer rings An outer ring area with the largest probability value in the areas G5 to G8 is a target outer ring area, and a center point of the following target 11 in the target outer ring area is calculated as the outer ring target coordinate Q _out (S1022); An inner ring area with the largest probability value among the inner ring areas G1 to G4 is a target inner ring area, and a center point of the following target 11 in the target inner ring area is calculated as the inner ring target coordinate _Qin (S1023) .

That is to say, the probability values of the following target 11 appearing in the outer ring areas G5-G8 and the inner ring areas G1-G4 are calculated respectively, and an outer ring area and an inner ring area with a larger probability value are selected. The area is the target outer ring area and the target inner ring area, and further calculate a center point of the following target in the target outer ring area as the outer ring target coordinate Q _out , and calculate a center point in the target inner ring area as the inner ring The target coordinate Q _in . Wherein, preferably, the center point of the following target in the target outer ring area or the target inner ring area is determined by calculating an area center of gravity of the following target in the target outer ring area or the target inner ring area; If the area gravity center point is not within the range of the following target 11 , the center point is calculated as a width midpoint closest to the area gravity center point in the following target 11 .

Referring to FIG. 8 , preferably, the probability value of the following target 11 appearing in the inner ring areas G1 - G4 and the outer ring areas G5 - G8 is calculated ( S1021 ), and the specific calculation is performed according to the following sub-steps get: Calculate the area ratio occupied by the following target 11 in the outer ring areas G5-G8 and the inner ring areas G1-G4, and the following areas in the outer ring areas G5-G8 and the inner ring areas G1-G4 The area ratio occupied by the target 11 is set as an original probability value of the outer ring areas G5-G8 and the inner ring areas G1-G4 (S1021a); Determine a flight inertia direction and a flight inertia reverse direction of the aircraft (S1021b); When the original probability value of the outer ring area and the inner ring area located in the opposite direction of the flight inertia is greater than 0, set the probability value of the outer ring area and the inner ring area to "0" (S1021c); When the original probability value of the outer ring region and the inner ring region located in the flight inertia direction is greater than 0, the probability value of the outer ring region and the inner ring region is set to "1" (S1021d).

That is to say, an original probability value of the inner ring areas G1-G4 and the outer ring areas G5-G8 is that the following target 11 is in the inner ring areas G1-G4 and the outer ring areas G5-G8 occupy a proportion of the area. The calculation formulas of the original probability values of the inner ring areas G1~G4 are as follows:

係指該跟隨目標11在該等內環區G1~G4中的面積，

為該跟隨目標11在該等內環區G1~G4中的總面積。in,

refers to the area of the following target 11 in the inner ring regions G1~G4,

is the total area of the following target 11 in the inner ring regions G1-G4.

The formulas for calculating the original probability values of these outer ring regions are as follows:

係指該跟隨目標11在該等外環區G5~G8中的面積，

為該跟隨目標11在該等外環區G5~G8中的總面積。in,

refers to the area of the following target 11 in the outer ring regions G5~G8,

is the total area of the following target 11 in the outer ring regions G5-G8.

After calculating the original probability values of the inner ring areas G1-G4 and the outer ring areas G5-G8, please refer to FIG. 9 and FIG. 10 together. FIG. 9 shows the inner rings in the image frame 10. The original probability values of the following target 1111 obtained from the areas G1 to G4 and the outer ring areas G5 to G8 according to the area calculation formula. For the convenience of description, a Y-axis direction and a Z-axis direction of the image frame 10 are defined, assuming that the aircraft flies from the right side of the image frame 10 to the left side along the following target 11, and a flight inertia direction of the aircraft is a -y The flight inertia direction is a +y direction, the flight inertia direction corresponds to the inner ring area G4 and the outer ring area G8, and the flight inertia direction corresponds to the inner ring area G2 and the outer ring area G6. According to steps S1021 and S2022, after it is determined that the reverse direction of the flight inertia is obtained, the probability values of the inner ring area G4 and the outer ring area G8 in the flight inertia direction are set to "1", and the inner ring in the reverse direction of the flight inertia is set to "1". The probability values of the ring area G2 and the outer ring area G6 are set to "0", and the probability values of the inner ring areas G1 - G4 and the outer ring areas G5 - G8 are shown in FIG. 10 after the correction and setting.

According to the probability values of the inner ring areas G1~G4 and the outer ring areas G5~G8 obtained in the above steps, set the probability values of the inner ring area and the outer ring area in the opposite direction of the aircraft's flight inertia as the probability minimum value "0", and set the probability values of the inner and outer ring areas in the opposite direction of the aircraft's flight inertia to the maximum probability value "1", so that in the next step, select the target outer ring area and the target according to the maximum probability value. In the inner ring area, the following target 11 line segments that the aircraft has already followed are excluded, and the outer ring area and the inner ring area in the flight inertia direction are preferentially selected as the target outer ring area and the target inner ring area, so that in steps S1022 and S1023 , calculate the outer ring target coordinate Q _out and the inner ring target coordinate Q _in . The above steps are used to exclude the inner ring area and outer ring area in the direction of the aircraft at the previous moment, so as to avoid the flight direction determined by the probability values of these inner ring areas G1~G4 and outer ring areas G5~G8 causing the aircraft to repeatedly turn around. situation occurs.

Please refer to FIG. 11 , in a second preferred embodiment of the aircraft route following method of the present invention, the difference from the first preferred embodiment is that “capture an image frame including a following target 11 is executed” 10. After the step of dividing the image frame 10 into a plurality of outer ring areas, a plurality of inner ring areas and a central area G0" (S101), first perform the following steps: Control the aircraft to move so that the following target 11 passes through the central area G0 (S1101); then execute "calculate an outer ring target coordinate Q _out in the outer ring areas G5~G8, and calculate an inner ring target coordinate Q _{in in} the inner ring areas G1~G4" (S102) A step of.

In this preferred embodiment, the aircraft is further considered when the aircraft is in the initial state of performing the mission, or when the aircraft is subjected to an external force such as airflow or collision during the execution of the following flight mission and deviates from the following target 11 , so that the following target 11 is in the image frame 10 , and If the central area G0 is not passed, the aircraft will first move to the following target 11 and pass the central area G0 before starting or continuing the task of following the flight according to the outer ring target coordinate Q _out and the inner ring target coordinate Q _in .

Referring to FIG. 12 , in this preferred embodiment, the step of controlling the aircraft to move so that the following target 11 passes through the central area G0 ( S1101 ) is specifically performed according to the following sub-steps: Calculating that the following target 11 appears at A probability value of the central area G0 (S1101a); Determine whether the probability value of the central area G0 is greater than an accuracy threshold (S1101b); When the probability value of the central area G0 is greater than the accuracy threshold, determine the following target 11 The central area G0 has been passed (S1101c); When the probability value of the central area G0 is less than the accuracy threshold, calculate the outer ring target coordinate Q _out value of the outer ring areas (S1101d); According to the outer ring target coordinate The value of Q _out generates a correction flight command (S1101e).

In addition, the probability value of the following target 11 appearing in the central area G0 can be calculated according to the following formula:

為該跟隨目標11在該中心區G0內的面積，

為該中心區G0的面積。in,

is the area of the following target 11 in the central area G0,

is the area of the central region G0.

The detailed steps of calculating the outer ring target coordinates Q _out of the outer ring regions are the same as step S1022 , and details are not repeated here. The step of generating a correction flight command according to the outer ring target coordinate Q _out is calculated according to the following formula:

That is to say, when the probability value of the following target 11 in the central area G0 is greater than the accuracy threshold, it means that the following target 11 has covered the central area G0 of the image frame 10, and the aircraft is indeed located at the following target Within the range of 11, the following target 11 has been aligned; when the probability value of the following target 11 in the central area G0 is less than the accuracy threshold, it means that the central area G0 of the image frame 10 is not aligned with the following target 11 Target 11, the aircraft has deviated from the following target 11, therefore, an outer ring target coordinate Q _out in the outer ring area is calculated, and the correction flight command is generated accordingly, so that the aircraft is directed to the outer following target in the image frame 10. The position of 11 moves until the probability value of the following target 11 appearing in the central area G0 is greater than the accuracy critical value, and then further enters and generates a reference flight command according to the inner ring target coordinate _Qin and generates a reference flight command according to the radian difference and the accumulated radian difference. The value adjusts the flight rate so that the aircraft follows exactly the steps that follow the target 11.

Please refer to FIG. 13 , in a third preferred embodiment of the present invention, which is different from the first preferred embodiment, _in the step of generating a reference flight instruction according to the inner ring target coordinate Qin ( S103 ) , further comprising the following steps: calculating a current target width in the central area G0 ( S1031 ); calculating the difference between the current target width and a preset target width in the central area G0 ( S1032 ); according to the inner ring target coordinates _Qin and the difference between the following target 11 width and the preset target width generate the reference flight command ( S1033 ).

，而一預設目標寬是

，當前目標寬

與預設目標寬

的差

為

。該影像畫面10中中心區G0內該跟隨目標11的當前目標寬度小於該預設目標寬

，表示該飛行器目前與該跟隨目標的垂直距離大於一預定之距離，因此根據該內環目標座標Q_in 及該跟隨目標11寬與該預設目標寬的差

產生該參考飛行指令

（S1033）的步驟，具體是根據以下公式計算產生：

Taking Fig. 14 as an example, it is assumed that the current target width of the following target 11 in the central area G0 is

, and a preset target width is

, the current target width

with preset target width

difference

for

. The current target width of the following target 11 in the central area G0 of the image frame 10 is smaller than the preset target width

, indicating that the current vertical distance between the aircraft and the following target is greater than a predetermined distance, so according to the inner ring target coordinate _Qin and the difference between the width of the following target 11 and the preset target width

generate the reference flight order

The step of (S1033) is calculated according to the following formula:

、

及

之定義與第一較佳實施例相同，在此不再贅述。in,

,

and

The definition is the same as that of the first preferred embodiment, and will not be repeated here.

與該預設目標寬相等，表示該飛行器與該跟隨目標的垂直距離為該預定距離，達到避免忽遠忽近，保持飛行器與跟隨目標之垂直距離的目的。As shown in FIG. 15 , by generating the above-mentioned reference flight command, the aircraft generates a flying speed perpendicular to the following target 11 until the current target width of the following target 11 in the center area G0 of the image frame 10 is reached.

If it is equal to the preset target width, it means that the vertical distance between the aircraft and the following target is the predetermined distance, so as to avoid sudden distance and nearness, and maintain the vertical distance between the aircraft and the following target.

In this preferred embodiment, the distance between the aircraft and the facade where the following target 11 is located is further considered and adjusted. In the case of following the same following target 11, when the width of the following target 11 in the image frame 10 is smaller, it means that the vertical distance between the aircraft and the following target 11 is relatively far, and a flight speed towards the elevation should be generated ; When the width of the following target 11 in the image screen 10 is larger than the preset target width, it means that the vertical distance between the aircraft and the following target 11 is too close, and a flight speed away from the facade should be generated.

Therefore, in this preferred embodiment, in addition to generating the flying direction parallel to the elevation of the following target 11 according to the vector between the inner ring target coordinate Qin _in the image frame 10 and the reference point (y _c , z _c ) , and according to the difference between the current target width and the preset target width, the flight direction perpendicular to the elevation in the reference flight instruction is generated, so as to correct the vertical distance between the aircraft and the following target 11 at any time.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Personnel, within the scope of not departing from the technical solution of the present invention, can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above, but any content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

10: Image screen 11: Follow target Q _in : Inner ring target Q _out : Outer ring target G0: Central area G1, G2, G3, G4: Inner ring area G5, G6, G7, G8: Outer ring area

FIG. 1 is a flow chart of a first preferred embodiment of a method for following a route of an aircraft of the present invention. FIG. 2 is a schematic diagram of an image captured by an aircraft in the method for following an aircraft route according to the present invention. FIG. 3 is a flow chart of sub-steps of step S104 in the first preferred embodiment of the aircraft route following method of the present invention. FIG. 4 is a flow chart of sub-steps of step S105 in the first preferred embodiment of the aircraft route following method of the present invention. FIG. 5 and FIG. 6 are schematic diagrams of another image frame captured by the aircraft of the aircraft route following method of the present invention. FIG. 7 is a flow chart of sub-steps of step S102 in the first preferred embodiment of the aircraft route following method of the present invention. FIG. 8 is a flow chart of sub-steps of step S1021 in the first preferred embodiment of the aircraft route following method of the present invention. FIG. 9 and FIG. 10 are schematic diagrams of another image frame captured by the aircraft of the aircraft route following method of the present invention. FIG. 11 is a flow chart of the second preferred embodiment of the method for following the route of the aircraft of the present invention. FIG. 12 is a flow chart of more detailed sub-steps in the second preferred embodiment of the aircraft route following method of the present invention. FIG. 13 is a flow chart of sub-steps of step S103 of the third preferred embodiment of the aircraft route following method of the present invention. 14 and 15 are schematic diagrams of another image frame captured by the aircraft of the aircraft route following method of the present invention, respectively.

Claims (9)

An aircraft route following method, executed by an aircraft, includes the following steps: capturing an image frame including a following target, and defining a central area, a plurality of inner ring areas and a plurality of outer ring areas in the image frame; Calculate an outer ring target coordinate in the outer ring areas according to the following target, and calculate an inner ring target coordinate in the inner ring areas; generating a reference flight instruction according to the inner ring target coordinates; Calculate a radian difference between the outer ring target coordinate and the inner ring target coordinate relative to a reference point, and update a cumulative radian difference accordingly; The reference flight command is adjusted according to the accumulated radian difference to generate a final flight command. The aircraft route following method according to claim 1, wherein in the step of defining a central area, a plurality of inner ring areas and a plurality of inner ring areas in the image frame, a central area is defined in the center of the image frame, and The periphery of the central area defines an inner ring that is concentric with the central area and is divided into the inner ring areas, and defines an inner ring that is concentric with the inner ring and the central area and is divided into the outer ring areas on the periphery of the inner ring The outer ring of , and each inner ring area and each outer ring area correspond to the same central angle. The method for following a route of an aircraft as claimed in claim 1, wherein the steps of calculating an outer ring target coordinate in the outer ring areas and calculating an inner ring target coordinate in the inner ring areas include the following steps: step: calculating the probability values of the following target appearing in the outer ring areas and the inner ring areas; Selecting an outer ring area with the largest probability value among the outer ring areas as a target outer ring area, and calculating a center point of the following target in the target outer ring area as the outer ring target coordinate; An inner ring area with the largest probability value among the inner ring areas is selected as a target inner ring area, and a center point of the following target in the target inner ring area is calculated as the inner ring target coordinate. The aircraft route following method as claimed in claim 3, wherein calculating the probability value of the following target appearing in the outer ring areas and the inner ring areas is performed according to the following sub-steps: Calculate the area ratio occupied by the follower target in the outer ring area and the inner ring area, and set the area percentage occupied by the follower target in the outer ring area and the inner ring area as the outer ring area, a raw probability value for the inner ring zones; Determine a flight inertia direction and a flight inertia opposite direction of the aircraft; When the original probability value of the outer ring area and the inner ring area located in the opposite direction of the flight inertia is greater than "0", set the probability value of the outer ring area and the inner ring area to "0"; When the original probability value of the outer ring area and the inner ring area located in the flight inertia direction is greater than "0", the probability value of the outer ring area and the inner ring area is set to "1". The aircraft route following method as claimed in claim 1, wherein the step of calculating a radian difference value according to the outer ring target coordinates and the inner ring target coordinate, and updating a cumulative radian difference value accordingly, includes the following sub-steps: Calculate the radian value of the outer ring target coordinate relative to the reference point; Calculate the radian value of the inner ring target coordinate relative to the reference point; The radian value of the outer ring target coordinate is subtracted from the radian value of the inner ring target coordinate to obtain the radian difference value; A historical radian difference is obtained, and the historical radian difference is added to the radian difference to obtain the accumulated radian difference. The method for following a route of an aircraft as claimed in claim 1, wherein the step of adjusting the reference flight command according to the accumulated radian difference to generate a final flight command comprises the following steps: determining whether an absolute value of the cumulative radian difference is greater than a cumulative error threshold; When an absolute value of the cumulative radian difference is less than the cumulative error threshold, perform a rate-up operation on the reference flight order according to the cumulative radian difference to generate the final flight command; When an absolute value of the cumulative radian difference is not less than the cumulative error threshold, a rate reduction operation is performed on the reference flight command according to the cumulative radian difference to generate the final flight command. The method for following a route of an aircraft as claimed in claim 1, wherein after performing the step of "capturing an image frame including a following target, and defining a central area, a plurality of inner ring areas and a plurality of outer ring areas in the image frame" , first perform the following steps: controlling the aircraft to move so that the following target passes through the central area; Then, the steps of "calculating an outer ring target coordinate in the outer ring areas, and calculating an inner ring target coordinate in the inner ring areas" are executed. The aircraft route following method according to claim 6, wherein the step of controlling the aircraft to move so that the following target passes through the central area is performed according to the following sub-steps: Calculate a probability value of the following target appearing in the central area; Determine whether the probability value of the central area is greater than an accuracy threshold; when the probability value of the central area is greater than the accuracy threshold, determine that the following target has passed through the central area; When the probability value of the central area is less than the accuracy threshold, calculate the outer ring target coordinate values of the outer ring areas; A calibration flight command is generated according to the outer ring target coordinates. The method for following a route of an aircraft as claimed in claim 1, wherein the step of generating a reference flight instruction according to the inner ring target coordinates comprises the following sub-steps: calculating a current target width of the following target in the central area; calculating the difference between the current target width and a preset target width in the central area; The reference flight command is generated according to the inner ring target coordinates and the difference between the following target width and the preset target width.

Images