JP2021172318A - Descending system for unmanned flight body - Google Patents

Abstract

To provide a descending system that can land an unmanned flight body at an accurate target position.SOLUTION: Target markers are comprised of layer markers at several stages that have different outer shape sizes in a horizontal direction. A layer marker with a relatively small outer shape is arranged on an inner side of a layer marker with a relatively large outer shape. When the layer marker with the relatively large outer shape is recognizable within a photographic range of image acquiring means, an unmanned flight body descends while performing control so that the layer marker with the relatively large outer shape is positioned within the photographic range. If the layer marker with the relatively large outer shape becomes unrecognizable within the photographic range as a result of lowering the unmanned flight body, the unmanned flight body descends while performing control so that the layer marker with the relatively small outer shape is positioned within the photographic range.SELECTED DRAWING: Figure 13

Description

The present invention relates to a descent system for an unmanned aircraft.

Conventionally, the use of small unmanned aerial vehicles (also called "drones") has been proposed. When such a drone lands, a technique has been proposed in which the drone descends toward a target (also referred to as a "marker") placed on the ground (for example, Patent Document 1).

Japanese Patent Application No. 2019-501868

In the techniques described above, the drone shoots the target with a camera and descends towards the target. The camera has a shooting range (for example, defined by the "angle of view"; hereinafter referred to as the "shooting range"), and the lower the flight altitude of the drone, the narrower the ground area within the shooting range. Become. Therefore, when the drone lowers the altitude, part or all of the markers will eventually go out of the shooting range, and the drone may not be able to land accurately at the predetermined landing position.

The present invention has attempted to solve such a problem, and an object of the present invention is to provide a descent system for an unmanned aircraft capable of descending to an accurate target position.

The first invention is a descent system for landing an unmanned vehicle that flies by controlling the rotation of propellers connected to the rotation axes of a plurality of motors at a target position, in a region including the target position. The target marker having a target marker to be arranged, the target marker is composed of a plurality of stages of hierarchical markers having different outer dimensions in the horizontal direction, and the hierarchical marker having a relatively small outer shape has a relatively large outer shape. Arranged inside the hierarchical sign, the multi-stage hierarchical sign includes the target position inside in the horizontal direction, and the unmanned vehicle is information indicating the relative positional relationship of each part constituting the hierarchical sign. When the hierarchical sign having a relatively large outer shape can be recognized within the shooting range of the image acquisition means, which has a certain relative information and an image acquisition means capable of photographing the lower part, the relatively outer shape is said. The unmanned aviator descends while controlling the unmanned aviator so that the hierarchical sign having a large size is located within the imaging range, and as a result of the unmanned aviation descending, the hierarchical sign having a relatively large outer shape within the imaging range. Is a descent system in which the unmanned vehicle is controlled and descended so that the hierarchical sign having a relatively small outer shape is located within the photographing range when the unmanned vehicle becomes unrecognizable.

First, the technical idea of the present invention will be described with reference to FIGS. 23 to 25. As shown in FIG. 23, if the hollow tubular frame member W1 is arranged in the air between the position of the unmanned vehicle 1 located in the air and the target position CP0, the unmanned vehicle 1 is inside the frame member W1. By descending while controlling the position so as to pass through, it is possible to land at the target position CP0 accurately. Further, as shown in FIG. 24, if the frame member W2 whose inner shape gradually decreases from the upper side to the lower side is arranged instead of the frame member W1, the unmanned flying object 1 passes through the frame member W2. By descending while controlling the position, the horizontal position approaches the vertical direction of the target position CP0 as the descending occurs. Further, as shown in FIG. 25, the same is true even if a plurality of frames W2a to W2d are arranged in the air instead of one frame member W2, and as the upper frame W2a moves toward the lower frame W2d, By reducing the size of the frame, the unmanned aircraft 1 approaches the target position CP0 as it descends. However, it is not realistic to arrange the frame members W1, W2 and W2a to W2d in any air. In this respect, the present invention is configured to exert an effect technically equivalent to passing through a plurality of frames W2a and the like by descending while recognizing a plurality of stages of hierarchical signs. That is, according to the configuration of the first invention, when the unmanned aircraft 1 has a relatively high flight altitude and the outer hierarchical sign can be recognized within the photographing range, the outer hierarchical sign is within the photographing range. If the outer hierarchical sign cannot be recognized within the shooting range as a result of the unmanned aircraft descending while maintaining the level, the inner layered sign can be maintained within the shooting range. The unmanned vehicle 1 controls the position of the unmanned vehicle 1 so that the hierarchical sign falls within the shooting range (hereinafter, referred to as “shooting position control”). The technique of descending while controlling the shooting position is technically equivalent to descending while passing through a plurality of frames W2a and the like. In addition, at relatively high altitudes it descends based on the outer tier markings and at relatively low altitudes it descends based on the inner tier markings, resulting in unmanned flight as the unmanned aircraft descends. The horizontal position of the body approaches the vertical line passing through the target position (hereinafter referred to as "descent approach effect"). This makes it possible to descend to an accurate target position with reference to the target sign. Further, since the unmanned aircraft has relative information, it can descend while adjusting the nose direction to a predetermined direction.

In the second aspect of the invention, in the configuration of the first invention, the unmanned vehicle descends while controlling the unmanned vehicle so that the hierarchical sign having a relatively large outer shape is located within the photographing range. Occasionally, the hierarchical sign having a relatively small outer shape is also recognized, and as a result of the unmanned vehicle descending, the hierarchical sign having a relatively large outer shape becomes unrecognizable within the photographing range. It is a descent system that switches to a descent control while controlling the hierarchical sign having a relatively small outer shape to be located within the photographing range.

According to the configuration of the second invention, when the unmanned air vehicle descends while controlling the outer hierarchical sign to be located within the shooting range, the unmanned air vehicle is already aware of the inner hierarchical sign, and the outer hierarchical sign is also recognized. Since the control is switched to the descent control while controlling the inner hierarchical sign to be located within the shooting range before the sign becomes unrecognizable, the shooting position control can be performed without interruption.

The third invention is the configuration of either the first invention or the second invention, in which the innermost layered marker is within the imaging range of the unmanned vehicle even when the unmanned vehicle lands. It is a descent system specified in the size of the outer shape that can be recognized in.

According to the configuration of the third invention, since the shooting position control can be continued until the moment of landing, it is possible to surely land at the target position.

In the fourth invention, in any of the configurations of the first invention to the third invention, the hierarchical label having a plurality of stages is composed of a plurality of element labels, and the relative information is based on each element label. Information indicating the direction and distance of the target position, and the unmanned vehicle controls the nose direction of the unmanned vehicle itself in a predetermined direction based on the direction and distance of the target position indicated on the element sign. It is a descent system.

According to the configuration of the fourth invention, the unmanned air vehicle can descend toward the target position while controlling the nose direction in a predetermined direction by recognizing the element sign.

In the fifth aspect of the invention, in the configuration of the fourth invention, the unmanned vehicle has an estimation means for estimating the whole of the layered label by the elemental markers of a part of the layered indicator, and the estimated layer. It is a descent system that descends while controlling the sign to be located within the imaging range.

According to the configuration of the fifth invention, even if a part of the hierarchical sign cannot be recognized due to a shadow or the like, the entire hierarchical sign can be estimated and the shooting position can be controlled while descending.

In the sixth invention, in the configuration of the fourth invention or the fifth invention, a charging device for charging the rechargeable power source of the unmanned vehicle is arranged in the region including the target position, and the unmanned vehicle is described. The aircraft is a descent system configured to land at the target position with the nose direction facing the predetermined direction and to charge the power supply of the unmanned aircraft by the charging device.

According to the configuration of the sixth invention, the unmanned aircraft can land while controlling the nose direction in a predetermined direction. Therefore, for example, when the charging terminal of the charging device is set to a specific position. In, the charging terminal on the unmanned vehicle side can be connected to the charging terminal on the charging device side.

A seventh invention, in any of the configurations of the first to sixth inventions, the descent system has a plurality of the unmanned vehicle and a plurality of target markers, each of the unmanned vehicle. , Different target markers are assigned, and each said unmanned vehicle is a descent system configured to descend towards the target position indicated by the assigned target marker.

According to the configuration of the seventh invention, a plurality of unmanned aircraft can accurately descend to their respective target positions.

The eighth invention, in any of the configurations of the first invention to the seventh invention, is obtained by the data indicating the characteristics of the target marker which the unmanned vehicle has in advance and the image acquisition means. It is configured to recognize the target marker based on the degree of correlation with the feature data extracted from the image in the image data, and the data showing the feature of the target marker is generated by deep learning. The descent system according to any one of claims 1 to 7, which includes data.

Even with the same target sign, various appearances are exhibited depending on the intensity of light in the environment. In this regard, according to the configuration of the eighth invention, it is possible to deeply learn various appearances of the same target marker and recognize the target marker by using the data showing the characteristics of the target marker generated as a result. Therefore, it is possible to accurately recognize the target marker even if it is affected by changes in the environment.

According to the present invention, it is possible to land at an accurate target position.

It is the schematic which shows an example of the operation of the descent system which concerns on 1st Embodiment of this invention. It is a schematic perspective view which shows an unmanned flying body. It is a schematic diagram of the functional block of an unmanned air vehicle. It is a schematic plan view which shows an example of a target sign. It is a schematic plan view which shows the outer hierarchical sign. It is a schematic plan view which shows the inner hierarchical sign. It is a conceptual diagram which shows the structure of the data about the target marker which an unmanned vehicle memorizes. It is a schematic plan view which shows the relationship between the hierarchical sign and the photographing range of an image acquisition means. It is a schematic plan view which shows the relationship between the outer hierarchical sign and the photographing range of an image acquisition means. It is a schematic plan view which shows the relationship between the inner hierarchical sign and the photographing range of an image acquisition means. It is a schematic diagram which shows the relationship between the altitude of an unmanned aircraft and a shooting range. It is a schematic diagram which shows the relationship between the altitude of an unmanned aircraft and a shooting range. It is a schematic diagram which shows an example of the trajectory that an unmanned vehicle descends. It is a schematic flowchart for demonstrating the operation of an unmanned vehicle. It is a schematic flowchart for demonstrating the operation of the unmanned air vehicle of the 2nd Embodiment of this invention. It is a schematic flowchart for demonstrating the operation of the unmanned flying body of the 3rd Embodiment of this invention. It is the schematic which shows an example of the operation of the descent system which concerns on 4th Embodiment of this invention. It is the schematic which shows an example of the operation of the descent system. It is a schematic diagram which shows an example of image estimation. It is a schematic diagram which shows an example of image estimation. It is the schematic which shows an example of the operation of the descent system which concerns on 5th Embodiment of this invention. It is a conceptual diagram which shows the structure of the data about the target marker stored in the unmanned air vehicle which concerns on the 6th Embodiment of this invention. It is a conceptual diagram for demonstrating the technical idea of this invention. It is a conceptual diagram for demonstrating the technical idea of this invention. It is a conceptual diagram for demonstrating the technical idea of this invention.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail. In the following description, the same reference numerals are given to similar configurations, and the description thereof will be omitted or abbreviated. The description of the configuration that can be appropriately implemented by those skilled in the art will be omitted, and only the basic configuration of the present invention will be described.

The unmanned aerial vehicle 1 shown in FIG. 1 is configured to be able to autonomously fly on a predetermined route by obtaining thrust by rotating a propeller. The unmanned aerial vehicle 1 is an example of an unmanned aerial vehicle.

The unmanned aerial vehicle 1 autonomously flies in the predetermined area 300 according to the route R1. The unmanned aircraft 1 can receive positioning radio waves from navigation satellites such as GPS satellites (Global Positioning System), position the unmanned aircraft 1 itself, and fly autonomously according to the route R1.

The predetermined area 300 includes components such as mountains 200A to 200F, a golf course 202, a zoo 204, a field 206, a pond 208, and a road 210. The unmanned aerial vehicle 1 flies while photographing the predetermined area 300. The unmanned aerial vehicle 1 starts from the departure / arrival area 90 and returns to the departure / arrival area 90. The target position CP0 for the unmanned aerial vehicle 1 to land is located within the departure / arrival area 90.

As shown in FIG. 2, the unmanned aerial vehicle 1 has a housing 2. A computer that controls each part of the unmanned aircraft 1, an autonomous flight device, a wireless communication device, a positioning device that uses radio waves for positioning from a navigation satellite system such as GPS (Global Positioning System), a battery, and the like are arranged in the housing 2. Has been done. Further, a camera 14 is arranged in the housing 2 via a fixing device 12. The camera 14 is an example of an image acquisition means.

The unmanned aerial vehicle 1 acquires an image of an external region (lower region) by the camera 14. The unmanned aerial vehicle 1 can also take a picture in the direction directly below the unmanned aerial vehicle 1 by the camera 14. The camera 14 is a visible light camera, but unlike this, it may be a hybrid camera capable of switching between a visible light camera and a near infrared camera. However, the unmanned aerial vehicle 1 uses a visible light camera when descending toward the target position CP0. Hereinafter, the image obtained by taking a picture with the camera 14 is referred to as a “camera image”.

The fixing device 12 is a three-axis fixing device (so-called gimbal) that can minimize blurring of the camera image and control the optical axis of the camera 14 in an arbitrary direction.

A round bar-shaped arm 4 is connected to the housing 2. A motor 6 is connected to each arm 4, and a propeller 8 is connected to each motor 6. Each motor 6 is a DC motor (brushless DC motor). Each motor 6 is independently controlled so that the unmanned aerial vehicle 1 can be freely moved up and down and horizontally, stopped in the air (hovering), and changed in the nose direction. When the unmanned aerial vehicle 1 moves back and forth and left and right, the rotation speed of the two motors 6 on the rear side with respect to the traveling direction is made higher than the rotation speed of the two motors 6 on the traveling direction side. When the unmanned aircraft 1 changes the nose direction while maintaining the horizontal position, the rotation speed of the two diagonal motors 6 is higher than the rotation speed of the other two diagonal motors 6. Do more. The unmanned aerial vehicle 1 is configured to rotate adjacent motors 6 in opposite directions to cancel out the reaction force. The unmanned aerial vehicle 1 is used without canceling the reaction force when changing the nose direction while maintaining the horizontal position. The unmanned aerial vehicle 1 can descend in the vertical direction by gradually reducing the rotation speeds of all the motors 6.

A protective frame 10 is connected to the arm 4 to prevent the propeller 8 from coming into direct contact with an external object. The arm 4 and the protective frame 10 are made of, for example, carbon fiber reinforced plastic, and are lightweight while maintaining strength.

FIG. 3 is a diagram showing a functional configuration of the unmanned aerial vehicle 1. As shown in FIG. 3, the unmanned device 1 includes a CPU (Central Processing Unit) 50, a storage unit 52, a wireless communication unit 54, a satellite positioning unit 56, an inertial sensor unit 58, a drive control unit 60, an image processing unit 62, and an image processing unit 62. , Has a power supply unit 64.

The unmanned aerial vehicle 1 can communicate with a control device (not shown) that wirelessly transmits an instruction such as starting to the unmanned aerial vehicle 1 by the wireless communication unit 54. The control device is a computer operated by the administrator of the unmanned aerial vehicle 1, and is a computer capable of wireless communication.

The unmanned aerial vehicle 1 can measure the position of the unmanned aerial vehicle 1 itself by the satellite positioning unit 56. The satellite positioning unit 56 basically receives positioning radio waves from four or more navigation satellites and measures the position of the unmanned aerial vehicle 1. As described above, the unmanned aerial vehicle 1 autonomously flies on the route R1 based on the measured position. The inertial sensor unit 58 outputs the movement of the unmanned aerial vehicle 1 by, for example, an acceleration sensor and a gyro sensor. The information from the inertial sensor unit 58 is output to the autonomous flight device and used for attitude control of the unmanned aerial vehicle 1. Attitude control means to correct when the unmanned aerial vehicle 1 deviates from the planned inclination. For example, assuming that the horizontal state is when the heights of the rotating surfaces of the four propellers 8 of the unmanned aerial vehicle 1 are the same, the inclination is a deviation from the horizontal state. For example, when the unmanned aerial vehicle 1 is stopped in the air (hovering) or when it descends in the vertical direction, the planned inclination is 0, and the unmanned aerial vehicle 1 maintains a horizontal state.

The unmanned aircraft 1 controls the rotation of the propeller 8 (see FIG. 2) connected to each motor 6 (see FIG. 2) by the drive control unit 60, and controls the vertical horizontal movement, the aerial stop, and the nose direction. It has become like.

The image processing unit 62 allows the unmanned aerial vehicle 1 to operate the camera 14 (see FIG. 2) to acquire an external image (camera image). The optical axis of the camera 14 is fixed downward in the vertical direction when the drone 1 descends toward the target position CP0.

The power supply unit 64 is, for example, a replaceable rechargeable battery, and is adapted to supply electric power to each unit of the unmanned aerial vehicle 1.

The storage unit 52 stores various data and programs necessary for autonomous movement such as data indicating a movement plan for autonomous movement from the starting point to the target position, data on the target marker 100, and a landing program. There is. The CPU 50 and the landing program are examples of landing control means.

The landing program is a program for controlling the unmanned aerial vehicle 1 to lower the flight altitude and descend toward the target position CP0. When the unmanned aerial vehicle 1 determines that it has reached the sky above the target position CP0 by positioning the current position by the satellite positioning unit 56, the unmanned aerial vehicle 1 controls the rotation of the motor 6 via the drive control unit 60 by the landing program, and gradually increases its altitude. Is lowered and descends toward the target position CP0.

Here, the target sign 100 arranged in the landing area 90 will be described with reference to FIGS. 4 to 8. The target sign 100 shown in FIG. 4 is arranged in the landing area 90. The target sign 100 is an example of a target sign. The landing area 90 is an example of an area including the target position CP0. The drone 1 and the target sign 100 constitute a descent system.

As shown in FIG. 4, the target sign 100 is composed of a plurality of stages of hierarchical signs 102 and 104 having different outer shape sizes in the horizontal direction. The inner layered sign 104 has a smaller outer shape in the horizontal direction than the outer layered sign 102. The inner hierarchical sign 104 is located inside the outer hierarchical sign 102. The outer shape of the outer hierarchical sign 102 is square, and the length L1 on one side is, for example, 130 cm (centimeter). The outer shape of the inner hierarchical sign 104 is square, and the length L2 on one side is, for example, 20 cm (centimeter). Even when the unmanned aerial vehicle 1 lands, the inner layered sign 104 is defined as having an outer shape that can be recognized by the unmanned aerial vehicle 1 so that the entire area is within the shooting range of the camera 14. Specifically, the inner hierarchical sign 104 is defined as the size of the outer shape of the limit that the entire unmanned aerial vehicle 1 falls within the shooting range of the camera 14 when the unmanned aerial vehicle 1 lands. In the present embodiment, the diagonal length of the square outer shape 104out (see FIG. 6) of the inner hierarchical sign 104 is equal to the diameter of the circle which is the shooting range of the camera 14 at the time of landing of the unmanned aircraft 1.

The target position CP0 for the drone 1 to land is located inside the hierarchical signs 102 and 104. That is, the hierarchical markers 102 and 104 include the target position CP0 inside each of them. The target position CP0 is a coordinate indicated by a specific latitude and longitude. In the present embodiment, the target position CP0 is the center position of the outer shape 102out of the hierarchical sign 102 (see FIG. 5). The target position CP0 is also the center position of the outer shape 104out of the hierarchical sign 104 (see FIG. 6).

The hierarchical markers 102 and 104 are each composed of a plurality of element markers. As shown in FIGS. 4 and 5, the outer hierarchical marker 102 is composed of element markers 102a to 102h and 102in. The element marker 102in is configured as a square outline, and the element markers 102a to 102h are formed in contact with the outer periphery of the element marker 102in. As shown in FIG. 6, the inner hierarchical marker 104 is composed of partial markers 104a to 104i.

FIG. 7 is a conceptual diagram for explaining an example of data relating to the target marker 100. In FIG. 7, the target marker is the target indicator X1, the target indicator X1 is composed of the outer hierarchical indicator A and the inner hierarchical indicator B, the hierarchical indicator A is composed of the element markers Aa and Ab, and the hierarchical indicator B is an element. It is assumed to be composed of labels Ba and Bb.

The data relating to the target marker X1 includes position data indicating the coordinates of the target indicator X1, identification data of the target indicator X1, feature data indicating the features of the target indicator X1, and data indicating the relationship between the target indicator X1 and the target position. .. The position shown in the position data of the target sign X1 is the same as the position of the target position. The feature data is data showing features such as feature points, contours, and directions of individual configurations of an object. Feature data is data used in feature point-based image-based tracking methods such as the KLT (Canada-Lucas-Tomasi) method and SIFT (Scale INvariant Feature Transfer Transfer). The feature data of the target sign X1 is, for example, data showing features such as feature points, contours, and directions of individual configurations of the target sign X1 as a whole.

The data relating to the hierarchical indicator A includes the position data of the hierarchical indicator A, the identification data of the hierarchical indicator A, the feature data of the hierarchical indicator A, and the data showing the relationship between the hierarchical indicator A and the target position. The content of the feature data is the same as the feature data of the target marker X1 described above. The position shown in the position data of the hierarchical sign A is the same as the position of the target position. The structure of the data relating to the hierarchical indicator B is the same as the above data structure of the hierarchical indicator A.

The data relating to the element marker Aa includes the position data of the element indicator Aa, the identification data of the element indicator Aa, the feature data of the element indicator Aa, and the data showing the relationship between the element indicator Aa and the target position. The position data of the element marker Aa is data indicating the reference position of the element marker Aa itself, and is different from the target position. The reference position of the element marker Aa is, for example, the center position of the element marker Aa in the horizontal direction. The data indicating the relationship between the position data of the element marker Aa and the target position is data indicating the direction and distance of the target position with reference to the reference position of the element indicator Aa. The configurations of the other element labels Ab, Ba and Bb are the same as described above. That is, the unmanned aerial vehicle 1 stores information indicating the direction and distance of the target position with respect to each element sign in the storage unit 52. The information indicating the direction and distance of the target position with respect to each element marker is an example of relative information.

The landing program includes a recognition target determination program and a target sign recognition program. The recognition target determination program and the CPU 50 are examples of the recognition target determination means, and the target sign recognition program and the CPU 50 are examples of the target sign recognition means. The recognition target determination program is a program for determining the recognition target to be recognized by the unmanned aerial vehicle 1 in the camera image. In the present embodiment, the unmanned aerial vehicle 1 makes one of the hierarchical signs 102 and 104 a recognition target by the recognition target determination program. The target sign recognition program is a program for the unmanned aerial vehicle 1 to recognize the recognition target.

When the unmanned aerial vehicle 1 determines that it has reached the sky above the target position CP0, the camera 14 photographs the lower part in the vertical direction. Then, the unmanned aerial vehicle 1 sets the outer hierarchical sign 102 as a recognition target by the recognition target determination program. As will be described later, when the outer hierarchical sign 102 deviates from the camera image and cannot be recognized as a result of descending, the unmanned aerial vehicle 1 sets the inner hierarchical sign 104 as a recognition target.

The unmanned machine 1 extracts features in the camera image by the target sign recognition program, and sets them as recognition targets in the camera image based on the feature data of the hierarchical signs 102 and 104 stored in the storage unit 52 in advance. Recognize the hierarchical sign 102 or 104. Specifically, the unmanned machine 1 compares the features in the camera image with the feature data stored in the storage unit 52 to determine the correlation (correlation degree), thereby determining the hierarchical marker 102 or 104. Recognize. Further, the unmanned machine 1 recognizes the element signs constituting the hierarchical sign 102 or 104 set as the recognition target by the target sign recognition program.

The drone 1 implements a feature point-based tracking method by means of a target marker recognition program. For example, the unmanned machine 1 extracts a large number of features such as contours and directions of individual configurations from the camera image, and recognizes the features of the object projected on the camera image (hereinafter, referred to as “features of the camera image”). The unmanned aerial vehicle 1 determines the correlation (correlation degree) by comparing the features of the camera image with the feature data stored in the storage unit 52. The higher the degree of correlation, the more likely the object in the camera image is the hierarchical markers 102 and 104, or specific element markers. For example, when the correlation degree is 0, the possibility that the area in the camera image is a specific hierarchical marker or element marker (hereinafter referred to as "category common probability") is 0%, and the correlation degree is the maximum value. Is defined as having a common category probability of 100%. The unmanned aerial vehicle 1 determines that the object in the camera image is a specific hierarchical sign or an element sign when the category common probability is a predetermined reference value, for example, 95% or more.

FIG. 8 shows the relationship between the shooting range of the camera 14 of the unmanned aerial vehicle 1 and the hierarchical signs 102 and 104. When the unmanned aerial vehicle 1 descends with the shooting direction of the camera 14 facing downward in the vertical direction, the area of the ground surface within the shooting range of the camera 14 becomes narrower as the altitude of the unmanned aerial vehicle 1 decreases. The angle of view of the camera 14 is constant. Further, the optical axis of the camera 14 is fixed vertically downward. For example, as the altitude of the unmanned aircraft 1 decreases, the area of the ground surface within the shooting range of the camera 14 is within the range of the circle S1, within the range of the circle S2, within the range of the circle S3, within the range of the circle S4, and so on. It becomes narrower within the range of the circle S5. Then, as the altitude of the unmanned aerial vehicle 1 decreases, the size of the hierarchical signs 102 and 104 in the camera image increases. From another point of view, it means that as the altitude of the unmanned aerial vehicle 1 decreases, the ratio of the hierarchical markers 102 and 104 to the pixels in the camera image increases.

As the altitude of the unmanned aircraft 1 decreases, both the outer hierarchical sign 102 and the inner hierarchical sign 104 fall within the shooting range of the camera 14, and the outer hierarchical sign 102 moves out of the shooting range. The state shifts to a state in which only the inner hierarchical sign 104 falls within the shooting range.

The unmanned aircraft 1 controls the position of the unmanned aircraft 1 so that the outer hierarchical sign 102 enters the shooting range by the landing program and the entire hierarchical sign 102 can be recognized in the camera image. While descending. In other words, the unmanned aerial vehicle 1 descends while performing shooting position control based on the hierarchical sign 102. Then, as a result of the unmanned machine 1 descending, when the hierarchical sign 102 cannot be accommodated in the camera image and the entire hierarchical sign 102 cannot be recognized, the unmanned machine 1 has the inner hierarchical sign 104 in the camera image. It is configured to descend while controlling the position of the unmanned aircraft 1 so that it is positioned. That is, the unmanned aerial vehicle 1 first descends while performing the shooting position control based on the hierarchical sign 102, and when the hierarchical sign 102 goes out of the shooting range, it switches to the shooting position control based on the hierarchical sign 104. However, since the attitude and position of the unmanned aerial vehicle 1 fluctuate due to the influence of wind and the like, the target position CP0, which is the center position of the hierarchical signs 102 and 104, is always located at the center of the camera image as shown in FIG. is not it.

The control of the unmanned aerial vehicle 1 descending will be specifically described with reference to FIGS. 9 and 10. As shown in FIG. 9, the unmanned aerial vehicle 1 descends while controlling the position of the unmanned aerial vehicle 1 so that the outer hierarchical sign 102 enters the camera image. In a relatively high altitude state, for example, as shown in FIG. 9, in the shooting range S11 of the camera image, even if the center position of the hierarchical sign 102 is shifted to the left, the unmanned aircraft 1 lowers the altitude. As the shooting range becomes S12, S13, S14, and S15, the center position of the hierarchical marker 102 gradually approaches the center as a whole while moving closer to or farther from the center of the camera image, and finally to the center. It becomes a state close to. In this way, by descending while controlling the shooting position, the descending approach effect is achieved.

The same applies to the inner hierarchical sign 104. For example, as shown in FIG. 10, in the shooting range S21 of the camera image, even if the center position of the hierarchical sign 104 is shifted to the right, the unmanned aircraft 1 lowers the altitude. As the shooting range becomes S22, S23, S24, and S25, the center position of the hierarchical indicator 104 in the camera image moves closer to or farther from the center of the camera image, but gradually approaches the center as a whole, and finally. Therefore, the center position of the hierarchical marker 104 is close to the center of the camera image. That is, it has a descent approach effect.

The unmanned machine 1 continues to descend when the layered sign 102 or 104 to be recognized enters the camera image, and the horizontal position of the unmanned machine 1 so that the center position of the layered sign 102 is located at the center of the camera image. To control. On the other hand, when the layered indicator 102 or 104 to be recognized does not enter the camera image, the unmanned machine 1 stops descending or reduces the descending speed to recognize the layered indicator 102 or 104. The horizontal position of the unmanned machine 1 is adjusted so that 104 enters the camera image, and when the hierarchical indicator 102 or 104 to be recognized enters the camera image, the descent is restarted while performing the shooting position control.

As shown in FIG. 11, when the unmanned aerial vehicle 1 reaches the sky above the landing area 90, the camera 14 photographs the lower part in the vertical direction, which is the direction indicated by the arrow Z1. The shooting range of the camera 14 is indicated by, for example, the angle of view θ1. In the state of FIG. 11, the photographing range of the angle of view θ1 is the range of the circle S31, and both the hierarchical sign 102 and the hierarchical sign 104 can be recognized. However, the unmanned aerial vehicle 1 is configured to recognize only the outer hierarchical sign 102 by the recognition target determination program. The unmanned aerial vehicle 1 recognizes the hierarchical sign 102 and the element signs 102a to 102h and 102in.

The unmanned machine 1 controls the nose direction in a predetermined direction by referring to the position data of the hierarchical sign 102 stored in the storage unit 52 and the data indicating the relationship between the element signs 102a to 102h and the target position CP0. .. Then, the unmanned aerial vehicle 1 descends while performing shooting position control so that the entire outer shape 102out of the hierarchical sign 102 is included in the camera image.

As shown in FIG. 12, as a result of the unmanned aircraft 1 descending, when the hierarchical indicator 102 is displaced outside the camera image and the entire hierarchical indicator 102 cannot be recognized in the shooting range of the camera 14, the recognition target determination program recognizes it. The target to be displayed is switched to the inner hierarchical indicator 104. Then, the unmanned machine 1 recognizes the hierarchical sign 104 and the element signs 104a to 104i by the target sign recognition program, and the position data of the hierarchical sign 104 stored in the storage unit 52 and the target position of the element signs 104a to 104i. The nose direction is controlled in a predetermined direction with reference to the data showing the relationship with. Then, the unmanned aerial vehicle 1 descends while performing shooting position control so that the outer shape 104out of the hierarchical sign 104 is included in the camera image.

As shown in FIG. 13, the unmanned aerial vehicle 1 has the target position CP0 by descending while performing the shooting position control so that the outer shapes 102out and 104out of the layer signs 102 and 104 are within the shooting range of the camera image. You can descend while gradually approaching the horizontal position. FIG. 13 shows a frame 102air and a frame 104air as fictitious frames in the air on the vertical line of the target position. The frame 102air corresponds to the outer layered sign 102, and the frame 104air corresponds to the inner layered sign 104. Descent while performing shooting position control based on the hierarchical signs 102 and 104 is technically equivalent to descending with the aim of the unmanned aerial vehicle 1 passing through the frame 102air and passing through the frame 104air. .. Therefore, as the unmanned aerial vehicle 1 descends while performing shooting position control based on the multi-stage hierarchical signs 102 and 104, the horizontal position of the unmanned aerial vehicle 1 changes as the unmanned aerial vehicle 1 descends. It has a descent approach effect that approaches the vertical line including the target position CP0. As a result, the drone 1 can descend to the accurate target position CP0 with reference to the target sign 100. Further, since the unmanned aerial vehicle 1 has relative information, it can descend while maintaining the nose direction in a predetermined direction.

Hereinafter, the outline of the operation of the unmanned aerial vehicle 1 will be described with reference to the flowchart of FIG. When the unmanned aerial vehicle 1 reaches the sky above the target position CP0 (step ST1 in FIG. 14), the descent control by the landing program is started. The unmanned aerial vehicle 1 photographs the lower part in the vertical direction, and sets the outer hierarchical sign 102 as the recognition target by the recognition target determination program (step ST2). Subsequently, when the unmanned machine 1 recognizes the outer hierarchical sign 102 by the target sign recognition program (step ST3), the unmanned machine 1 controls the horizontal position of the unmanned machine 1 so as to project the entire hierarchical sign 102 onto the camera image. It descends while doing (step ST4). When the altitude of the unmanned machine 1 decreases and the hierarchical sign 102 deviates from the shooting range of the camera 14 (step ST5), the recognition target is changed to the inner hierarchical sign 104 by the recognition target determination program (step ST6), and the target sign is recognized. When the program recognizes the hierarchical sign 104, descends while controlling the horizontal position of the unmanned aircraft 1 so as to project the entire hierarchical sign 104 onto the camera image (step ST7), and determines that it has landed (step ST8). ,Stop. The landing determination may be made, for example, by determining from the output of the inertial sensor unit 58 (see FIG. 3) that the downward movement has stopped.

In the present embodiment, the hierarchical marking has two stages of hierarchical markings 102 and 104. Since the present invention is characterized in that a plurality of levels of hierarchical markings are used, unlike the present embodiment, the hierarchical markings are not limited to two layers, and may be, for example, three or more layers. Further, unlike the present embodiment, priority may be given in posture control and shooting position control. For example, the shooting position control may be performed when the hierarchical sign 102 or 104 does not approach the center of the camera image due to the posture control. Alternatively, unlike the present embodiment, the photographing position control may be performed at a time interval longer than the time interval of the posture control. For example, if the attitude control is performed every 1/1000 second, the shooting position control is performed every 1/110 second. Further, unlike the present embodiment, the center position of the hierarchical markers 102 and 104 is the camera instead of descending while controlling the horizontal position of the unmanned machine 1 so as to project the entire hierarchical markers 102 and 104 onto the camera image. You may descend while controlling the horizontal position of the unmanned machine 1 so that it is located at the center position of the image. In this case, the center position of the hierarchical signs 102 and 104 is recognized by recognizing the entire hierarchical signs 102 and 104. Further, the technique for controlling the descending direction by projecting the hierarchical signs 102 and 104 onto the camera image is not limited as described above. For example, when the hierarchical sign 102 is adopted for the horizontal position control of the unmanned machine 1, the number of pixels of the hierarchical sign 102 in the camera image is controlled to increase, and when the hierarchical sign 104 is adopted, the number of pixels is controlled to increase. The number of pixels of the hierarchical indicator 104 in the camera image may be controlled to increase.

<Second embodiment>
Next, a second embodiment will be described with reference to FIG. The description of the matters common to the first embodiment will be omitted, and the matters different from the first embodiment will be mainly described. In the second embodiment, as shown in steps ST4A and ST7A of FIG. 15, the unmanned aerial vehicle 1 has a horizontal position of the unmanned aerial vehicle 1 so as to project the center positions of the hierarchical signs 102 and 104 onto the center position of the camera image. Descent while controlling.

<Third embodiment>
Next, a third embodiment will be described with reference to FIG. The description of the matters common to the first embodiment will be omitted, and the matters different from the first embodiment will be mainly described. In the third embodiment, when the unmanned aircraft 1 reaches the sky above the target position CP0, it recognizes the outer hierarchical sign 102, and the entire outer shape 102out of the hierarchical sign 102 is projected in the horizontal direction so as to be projected on the camera image. At this time, the inner hierarchical sign 104 is also recognized. Then, immediately before the entire outer shape 102out of the outer layered sign 102 cannot be projected onto the camera image, the control is switched to the control of descending while projecting the entire outer shape 104out of the inner layered sign 104 onto the camera image. Immediately before the entire outer shape 102out of the outer hierarchical sign 102 cannot be projected onto the camera image, for example, a part of the outer shape 102out reaches the outermost side of the camera image, but the present invention is not limited to this.

As shown in step ST4B of FIG. 16, when the unmanned aircraft descends while controlling the horizontal position so as to project the entire hierarchical sign 102 onto the camera image, the unmanned aircraft simultaneously presses the inner hierarchical sign 104. It has recognized. However, the inner hierarchical sign 104 is not used for shooting position control. When the unmanned machine 1 determines that a part of the outer shape 102out of the outer layered sign 102 is about to deviate from the camera image (step ST5B), the unmanned machine 1 projects the outer shape 104out of the inner layered sign 104 onto the camera image. It switches to the control of descending while controlling the horizontal position of 1 (step ST6). According to this control, the unmanned aerial vehicle 1 can descend while performing shooting position control without interruption.

<Fourth Embodiment>
Next, a fourth embodiment will be described with reference to FIGS. 17 to 20. The description of the matters common to the first embodiment will be omitted, and the matters different from the first embodiment will be mainly described. In a fourth embodiment, the target marker 100 is located at the charging base 400, as shown in FIGS. 17 and 18. The charging base 400 is composed of a base 402 and left and right mobile housings 404A and 404B.

The left and right movable housings 404A and 404B can reciprocate in the horizontal direction as shown in the arrow X1 direction and the arrow X2 direction as shown in FIGS. 17 and 18, and are shown in the open state shown in FIG. 17 and in FIG. Form the indicated closed state.

The target marker 100 is arranged at the center of the base 402 in the horizontal direction so as to be exposed to the outside in the open state shown in FIG. 17 and covered by the moving housings 404A and 404B in the closed state shown in FIG. It is configured in.

The unmanned aerial vehicle 1 descends toward the target position indicated by the target sign 100 when the charging base 400 is open. When the unmanned aerial vehicle 1 lands on the base 402, the charging base 400 is closed and the unmanned aerial vehicle 1 is charged.

The shape estimation program is stored in the storage unit 52 of the unmanned aerial vehicle 1. The unmanned aerial vehicle 1 can estimate the overall shape of the hierarchical sign 102 when only a part of the hierarchical sign 102 can be recognized by the shape estimation program. Then, the unmanned aircraft 1 maintains the state in which the estimated hierarchical sign 102 falls within the shooting range of the camera image by the landing program, and controls the shooting position so that the entire estimated hierarchical sign 102 falls within the camera image. While carrying out, descend. The above control is the same for the hierarchical indicator 104. The shape estimation program and the CPU 50 are examples of shape estimation means.

For example, as shown in FIGS. 19 and 20, some of the hierarchical markers 102 and 104 may be difficult to recognize due to the shadows SD1 and SD2.

The unmanned machine 1 can recognize the element signs of the layered sign 102 and the layered sign 104 by the target sign recognition program, and can estimate the overall shape of the layered sign 102 and the layered sign 104 based on the recognized element signs.

For example, as shown in FIG. 19, among the element signs of the outer hierarchical sign 102, the element signs 102a, 102b, 102g and 102h can be recognized, and the other element signs 102c and the like cannot be recognized. The overall shape of the outer layer label 102 is estimated from the element labels 102a, 102b, 102g and 102h. This is the same even when some element markers of the inner hierarchical indicator 104 are recognizable, as shown in FIG.

Then, the unmanned aircraft 1 descends while performing shooting position control so that the estimated layered sign 102 or layered sign 104 is located within the shooting range of the camera image by the landing program.

Although the use of artificial intelligence is not essential in the present embodiment, the unmanned machine 1 utilizes the results of machine learning using image data taken under various environmental conditions, and the hierarchical indicator 102 and the hierarchical indicator 104. It may be configured to recognize the hierarchical markers 102 and 104 from a part of. By learning images of various appearances of the target marker 100, features of a predetermined part are extracted, and learning result data for identifying a predetermined part regardless of the appearance is generated. be able to. The features shown in the feature data include both features that are invariant under various environmental conditions and features for each of the various environmental conditions. In this case, the unmanned aerial vehicle 1 stores the learning result data in the storage unit 52.

The machine learning does not have to be carried out by the unmanned aerial vehicle 1 itself, but may be carried out by an external computer, and the unmanned aerial vehicle 1 may use the learning result. As the machine learning method, for example, deep learning is adopted. Deep learning is machine learning using a multi-layered neural network, and the field of image recognition is one of the promising fields of utilization. The neural network is, for example, a convolutional neural network (CNN). A convolutional neural network is composed of an input layer, a convolution layer, a pooling layer, a fully connected layer, and an output layer, and is composed of a convolutional layer and an output layer. Repeats multiple times to form a deep layer, followed by multiple fully connected layers. The unmanned aerial vehicle 1 can identify the hierarchical marker 102 or 104 in any way by using the learning result data generated by deep learning.

<Fifth Embodiment>
Next, a fifth embodiment will be described with reference to FIG. The explanation of the matters common to the first embodiment or the second embodiment will be omitted, and the explanation will be focused on different matters. In the fifth embodiment, as shown in FIG. 21, a plurality of unmanned aerial vehicles 1A, 1B and 1C are operated, and target markers 100A, 100B and 100C are assigned to each unmanned aerial vehicle 1A and the like, respectively.

Each unmanned aerial vehicle 1A or the like is configured to descend toward the target position indicated by the target sign 100A or the like assigned to each unmanned aerial vehicle 1A or the like by a landing program.

<Sixth Embodiment>
Next, a sixth embodiment will be described with reference to FIG. The explanation of the matters common to the fifth embodiment will be omitted, and the explanation will be focused on different matters. In the sixth embodiment, a specific target sign is assigned to the plurality of unmanned aerial vehicles 1A, 1B, and 1C, but the unmanned aerial vehicle 1A and the like can be changed by an administrator.

For example, as shown in FIG. 22, data about the target signs X1 and X2 are stored as a plurality of target signs in the storage unit of the unmanned machine 1A. Similar to the unmanned machine 1A, the storage unit of the unmanned machine 1B also stores data about the target signs X1 and X2 as a plurality of target signs. It is assumed that the target sign initially assigned to the unmanned machine 1A is the target sign X1 and the target sign initially assigned to the unmanned machine 1B is the target sign X2. In the present embodiment, the administrator can change the target sign initially assigned to the unmanned aerial vehicle 1A or the like to another target sign. As a result, for example, when the unmanned aerial vehicle 1A breaks down, the target sign of the unmanned aerial vehicle 1B is changed to the target sign X1, and the mission of the unmanned aerial vehicle 1A can be performed.

The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention. In addition, each of the above-described embodiments can be combined as appropriate.

1,1A, 1B, 1C Unmanned machine 2 Housing 6 Motor 14 Camera 52 Storage unit 56 Satellite positioning unit 90 Departure / arrival area 100 Target sign 102,104 Hierarchical sign 102a, 102b, 102c, 102d, 102e, 102f, 102g, 102h, 102in, 104a, 104b, 104c, 104d, 104e, 104f, 104g, 104h, 104i element labeling

Claims (8)

It is a descent system for landing an unmanned aircraft that flies by controlling the rotation of propellers connected to the rotation axes of multiple motors at a target position.
Having a target marker placed in the area containing the target position
The target sign is composed of a plurality of levels of hierarchical signs having different outer dimensions in the horizontal direction.
The hierarchical sign having a relatively small outer shape is arranged inside the hierarchical sign having a relatively large outer shape.
The plurality of stages of the hierarchical marker include the target position inside in the horizontal direction.
The unmanned aircraft
Relative information, which is information indicating the relative positional relationship of each part constituting the hierarchical sign, and
An image acquisition means that can take a picture of the bottom,
Have,
When the layered sign having a relatively large outer shape can be recognized within the photographing range of the image acquisition means, the unmanned flying object has the layered sign having a relatively large outer shape located within the photographing range. Descent while controlling
When the layered sign having a relatively large outer shape becomes unrecognizable as a result of the unmanned flying object descending, the layered sign having a relatively small outer shape is within the shooting range. Descent while controlling the unmanned aircraft so that it is located at
Descent system. When the unmanned vehicle descends while controlling the unmanned vehicle so that the layered sign having a relatively large outer shape is located within the photographing range, the unmanned vehicle also recognizes the layered sign having a relatively small outer shape. Then, as a result of the unmanned flying object descending, the layered sign having a relatively small outer shape becomes unrecognizable before the layered sign having a relatively large outer shape becomes unrecognizable within the photographing range. Switch to descent control while controlling to be within the shooting range.
The descent system according to claim 1. The innermost hierarchical sign is defined by the size of the outer shape that the unmanned vehicle can recognize within the shooting range even when the unmanned vehicle lands.
The descent system according to claim 1 or 2. The multi-stage hierarchical sign is composed of a plurality of element signs.
The relative information is information indicating the direction and distance of the target position with respect to each element marker.
The unmanned vehicle controls the nose direction of the unmanned vehicle itself in a predetermined direction based on the direction and distance of the target position indicated on the element marker.
The descent system according to any one of claims 1 to 3. The unmanned aircraft
It has an estimation means for estimating the whole of the hierarchical label by the element label which is a part of the hierarchical label.
The estimated hierarchical sign descends while being controlled so as to be located within the shooting range.
The descent system according to claim 4. In the area including the target position, a charging device for charging the rechargeable power source of the unmanned vehicle is arranged.
The unmanned aircraft is configured to land at the target position with the nose direction facing the predetermined direction, and to charge the power supply of the unmanned aircraft by the charging device.
The descent system according to claim 4 or 5. The descent system has a plurality of the unmanned aircraft and a plurality of the target markers.
Each said unmanned vehicle is assigned a different said target marker.
Each unmanned vehicle is configured to descend towards the target position indicated by the assigned target sign.
The descent system according to any one of claims 1 to 6. The unmanned aircraft
It is configured to recognize the target marker based on the degree of correlation between the data indicating the characteristics of the target marker held in advance and the feature data extracted from the image in the image data acquired by the image acquisition means. Ori
The descent system according to any one of claims 1 to 7, wherein the data indicating the characteristics of the target marker includes data generated by deep learning.

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