JP7818829B2 - Unmanned Aerial Vehicle Control System - Google Patents

Description

The present invention relates to an unmanned aerial vehicle control system that takes over remote control of an unmanned aerial vehicle.

Unmanned aerial vehicles (drones) controlled by a control terminal such as a controller are also used to transport relatively heavy loads such as construction materials and tools. When the distance from the starting point to the destination is long, for example in mountainous or forested areas where it is difficult to ensure visibility for the entire journey, control is handed over to another person mid-flight (see, for example, Patent Document 1).

Patent Publication No. 2017-74826

According to Patent Document 1, when a flight control signal from one control terminal is no longer received, the unmanned aerial vehicle enters a hovering state, and then upon receiving a flight control signal from another control terminal, the unmanned aerial vehicle cancels the hovering and transitions to a flying state, thereby achieving a handover. However, separate communication is required between the operators of the one control terminal and the other control terminal at the time of the handover. However, Patent Document 1 makes no mention of communication regarding the timing of the handover. To ensure a smooth handover, simple and quick communication between operators is required. Furthermore, GPS receivers have traditionally been used to obtain the location information of unmanned aerial vehicles, but this requires receiving radio waves from multiple satellites.

The problem that this invention aims to solve is to provide an unmanned aerial vehicle control system that makes it possible to obtain position information of an unmanned aerial vehicle using radio waves from a single satellite.

In order to solve the above problems, the unmanned aerial vehicle control system of the present invention is an unmanned aerial vehicle control system having an unmanned aerial vehicle, a control terminal that remotely controls the unmanned aerial vehicle, and a control unit that controls the unmanned aerial vehicle and the control terminal based on operation instructions, wherein the unmanned aerial vehicle has two GPS receivers that receive radio waves from one satellite and a position information acquisition means that acquires position information of a predetermined position along its flight path, and the position information acquisition means acquires the position information of the unmanned aerial vehicle based on measurements taken by the GPS receivers.

This configuration has two GPS receivers that receive radio waves from one satellite, making it possible to use a GPS receiver with a simple structure when obtaining location information for an unmanned aerial vehicle.

The unmanned aerial vehicle control system of the present invention may be configured to include an additional GPS receiver that receives radio waves from at least four satellites, and the location information acquisition means may acquire the location information based on measurements from the additional GPS receiver.

With this configuration, location information is obtained from measurements by other GPS receivers that receive radio waves from four artificial satellites, making it possible to use a GPS receiver with a simple structure and other GPS receivers to obtain location information.

In the unmanned aerial vehicle control system of the present invention, the position information acquisition means acquires the position information based on the measurement values of the other GPS receiver or the measurement values of the two GPS receivers and the measurement values of a sensor mounted on the unmanned aerial vehicle.

With this configuration, in addition to obtaining location information from measurements by another GPS receiver that receives radio waves from four satellites, location information can also be obtained from measurements by two GPS receivers installed at predetermined locations on the unmanned aerial vehicle, each receiving radio waves from one satellite, and measurements by sensors installed on the unmanned aerial vehicle. The sensors include a barometric sensor and ultrasonic sensor that can measure altitude, as well as an acceleration sensor, angular velocity sensor (gyro sensor), and geomagnetic sensor that can measure the direction of movement, tilt, and orientation of the unmanned aerial vehicle. Utilizing the various sensors installed on the multicopter enables the use of a second GPS receiver with a simple structure to obtain location information.

This invention has two GPS receivers that receive radio waves from a single satellite, making it possible to use GPS receivers with a simple structure when acquiring position information for an unmanned aerial vehicle. When remote control of an unmanned aerial vehicle is taken over mid-flight, notification of the takeover is sent between the control terminals, making it easy to do so without providing the unmanned aerial vehicle with a device configuration for the takeover.

FIG. 1 is a schematic perspective view of a multicopter, which is an unmanned aerial vehicle according to an embodiment of the present invention. FIG. 2 is a block diagram of the multicopter shown in FIG. 1 . FIG. 3 is a block diagram of the control terminal according to the embodiment of the present invention. FIG. 4 is a flow diagram showing the procedure for taking over remote control of a multicopter. FIG. 5 is a schematic diagram illustrating a takeover of remote control of the multicopter shown in FIG. 1 . FIG. 6 is a schematic explanatory diagram illustrating the acquisition of position information of the multicopter shown in FIG. 1 .

An embodiment of the present invention will be explained using the drawings.

As shown in Figure 1, the unmanned aerial vehicle, a multicopter 11 (drone), has a main body 12 on which equipment such as a power source and control devices are mounted, four rod-shaped arm sections 13 (13a, 13b, 13c, 13d) (hereinafter referred to as "arm sections 13") protruding in all directions from the main body 12, four drive units 15 (15a, 15b, 15c, 15d) (hereinafter referred to as "drive units 15") provided at the tips of the arm sections 13 (13a, 13b, 13c, 13d), four rotors 17 (17a, 17b, 17c, 17d) (hereinafter referred to as "rotor sections 17") provided at the upper ends of the drive units 15 (15a, 15b, 15c, 15d), and a pair of legs 18a, 18b provided on the bottom surface of the main body 12. Another GPS receiver 28 is located in the center of the main body 12, and GPS receivers 51 and 52 are located at both ends of the main body 12 in symmetrical positions.

The drive units 15 (15a, 15b, 15c, 15d) each include a motor 21 (21a, 21b, 21c, 21d) (referred to as "motor 21" where appropriate) that drives the rotors 17 (17a, 17b, 17c, 17d) to rotate, and a drive controller 22 (22a, 22c, 22d) (referred to as "drive controller 22" where appropriate) that controls the rotation of the motor 21 (see FIG. 2). The rotors 17 are connected to the motor 21 via a rotating shaft (not shown). The motor 21 may be, for example, a servo motor. In this embodiment, there are four rotors 17, but this is not limited to four. Six, eight, etc. may also be used. However, an even number is required to maintain stable flight. This is because adjacent rotors 17 rotate in opposite directions, canceling out the action and reaction caused by the rotational moment and stabilizing the attitude of the multicopter 11.

The main body 12, located at the center of the multicopter 11, is a cylindrical box. The legs 18a and 18b attached to the bottom of the main body 12 are made of roughly U-shaped members and serve as attachment points when the multicopter 11 is transporting cargo. Materials used for the multicopter 11 include synthetic resin and aluminum, and when particular strength and rigidity are required, CFRP (Carbon Fiber Reinforced Plastics) is used.

Next, the configuration of the multicopter 11 will be described with reference to the block diagram of Figure 2. The main body 12 of the multicopter 11 includes a communication unit 25 that transmits and receives signals to and from the control terminal 31 (31a, 31b: see Figure 3), a power source 26 (battery) that supplies power to the motor 21, etc., a camera 27 that captures images of the surroundings of the multicopter 11, another GPS receiver 28 that receives radio waves from artificial satellites to measure position information, GPS receivers 51 and 52, a sensor unit 30 that stores various sensors such as an acceleration sensor, a control unit 33 that controls the communication unit 25, camera 27, other GPS receivers 28, GPS receivers 51 and 52, sensor unit 30, etc., and a non-volatile memory storage unit 35 (e.g., flash memory, etc.) that stores programs for controlling the various functions of the multicopter 11, measured data, etc. The drive control unit 22 included in the drive unit 15 receives instructions from the control unit 33 and controls the motor 21, such as increasing/decreasing the rotation speed, operating, and stopping. The control unit 33 allows each drive control unit 22 (22a, 22b, 22c, 22d) to independently control the drive of each motor 21 (21a, 21b, 21c, 21d), thereby individually driving the rotors 17 (17a, 17b, 17c, 17d), allowing the multicopter 11 to ascend, descend, turn left or right, hover, etc.

The control unit 33 is what is commonly called a flight controller and is equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), etc., and executes various controls according to various programs stored in the ROM or memory unit 35. The camera 27 may be a general camera, an infrared camera, a stereo camera, etc. Images captured by the camera 27 are transmitted by the control unit 33 via the communication unit 25 to the control terminal 31 (see Figure 3) and displayed on the display unit 55 (see Figure 3) of the control terminal 31.

The other GPS receiver 28, located in the center of the main body 12 of the multicopter 11, receives radio waves from at least four satellites to acquire position information for the multicopter 11 (see Figure 1). The GPS receivers 51 and 52 (see Figure 1), located at opposite ends of the main body 12, receive radio waves from one satellite and acquire position information for the multicopter 11 using measurements from the barometric pressure sensor, altitude sensor (ultrasonic sensor), acceleration sensor, angular velocity sensor (gyro sensor), and geomagnetic sensor of the sensor unit 30 (described below). For example, after initially acquiring position information using the other GPS receiver 30, use of the other GPS receiver 30 can be stopped, and subsequent position information can be acquired using the information received from the satellites by the GPS receivers 51 and 52 and the measurements acquired from each of the above sensors. The control unit 33 and the other GPS receiver 28 constitute a position information acquisition means, or the control unit 33, the GPS receivers 51 and 52, and the sensor unit 30 constitute a position information acquisition means. The memory unit 35, which stores the program for acquiring location information and the acquired location information, corresponds to the storage means.

As mentioned above, the sensor unit 30 includes a barometric pressure sensor, altitude sensor (ultrasonic sensor), acceleration sensor, angular velocity sensor (gyro sensor), geomagnetic sensor, etc. The barometric pressure sensor detects changes in air pressure and can determine the drone's altitude, but since the barometric pressure sensor may not function properly due to weather conditions, etc., an ultrasonic sensor is also used. The ultrasonic sensor detects the distance from the ground by emitting ultrasonic waves and measuring the time it takes for them to bounce back. The acceleration sensor detects the distance traveled by detecting acceleration, and the angular velocity sensor (gyro sensor) detects the number of times the aircraft rotates within a certain period of time. The geomagnetic sensor detects direction using magnetic force. The control unit 33 and the various sensors in the sensor unit 30 constitute a leveling means that ensures the unmanned aerial vehicle remains level.

Next, the device configuration of the control terminal 31 (31a, 31b) will be described with reference to Figure 3. As shown in Figure 3, the control terminal 31 includes a communication unit 56 that transmits and receives signals to and from the communication unit 25 of the multicopter 11 to remotely control the multicopter 11; an operation unit 57 that controls the multicopter 11 via the communication unit 56; a display unit 55 that displays images captured by the camera 27 of the multicopter 11 and various instructions on an operation touch panel; a switch unit 58 that issues transmission instructions for transmitting notification signals between the first control terminal 31a and the second control terminal 31b; a speaker 59 and output circuit 60 that generate a ringtone when a notification signal is received; an indicator light 54 that lights up when a notification signal is received; a control unit 61 that controls these functions; and a memory unit 62 that stores programs for controlling and controlling each device, measurement data, etc. Note that the control terminal 31 also includes a built-in battery (not shown) that serves as a power source.

The multicopter 11 is controlled using the operation unit 57 by, for example, operating the sticks (not shown) aligned on the left and right sides of the surface of the control terminal 31. Tilt the right stick up to "ascend," down to "descend," left to "move left," and right to "move right." Tilt the left stick up to "move forward," down to "move backward," left to "turn left," and right to "turn right." By "ascending" and slowly stopping the ascent, and balancing the lift and gravity of the multicopter 11, the hovering state can be achieved. It is also possible to automatically set the multicopter 11 to the hovering state by operating the operation touch panel displayed on the display unit 55.

In addition to the image captured by the camera 27 and the operation touch panel, the display unit 55's screen also displays the current position information (latitude, longitude, and altitude) of the flying multicopter 11. The displayed current position information can be stored in the memory unit 62 and/or the memory unit 35 of the multicopter 11 by performing a specific operation on the display unit 55's operation touch panel. The switch unit 58 transmits a notification signal to the other control terminal 31 when operated during a takeover. The control terminal 31b that receives the notification signal generates a receiving sound from the speaker 59 and also lights up the indicator light 54. It is also possible to set the transmitting control terminal 31a that operates the switch unit 58 to also generate a transmitting sound and light up the indicator light. The control unit 61, switch unit 58, and communication unit 56 constitute the notification signal transmission/reception means. The control unit 61, output circuit 60, and speaker 59 constitute the receiving sound generation means, and the control unit 61 and indicator light 54 constitute the light up display means (receiving and display means). Additionally, the operation touch panel displayed on the display unit 55 and the control unit 61 constitute the predetermined position flight means and the position information acquisition instruction means. Operation (pressing, etc.) of the switch unit 58 issues a transmission instruction.

Next, the handover of control of the multicopter 11 will be described with reference to Figure 4. Remote control of the multicopter 11 is initiated by the first control terminal 31a (S1). For example, when flying a multicopter 11 carrying cargo or the like from the base of a mountain to a site at the top, it is difficult for the pilot of the first control terminal to visually confirm the landing point at the top or the terrain near the top. Although the pilot can check images of the surrounding area captured by the camera 27 of the multicopter 11, stable flight and landing may be difficult if the terrain is complex. In such cases, by handing over control from the pilot at the base of the mountain to another pilot near the top, the pilot can safely land at the target point near the top by visual confirmation.

When the multicopter 11, which has been moved from the starting point by the first control terminal 31a, reaches a predetermined handover point, the switch unit 58 is operated to send a transmission instruction to notify the second control terminal 31b of the handover from the first control terminal 31a. The control unit 61 then transmits a notification signal to the first control terminal 31b (S2: notification signal transmission/reception means). Upon receiving this notification signal, the control unit 61 generates a ringtone from the speaker 59 via the output circuit 60 (received sound generation means) and also turns on the indicator light 54 (illumination display means). When the switch unit 58 is operated to send a transmission instruction, the control unit 61 transmits a notification signal to the first control terminal 31a to confirm receipt (S3: notification signal transmission/reception means).

When the first control terminal 31a receives the above-mentioned reception confirmation notification signal, the control unit 61 generates a ringtone from the speaker 59 via the output circuit 60 (reception sound generation means), turns on the indicator light 54 (lighting display means), and stops remote control of the multicopter 11 (S4). When the second control terminal 31b transmits the reception confirmation notification signal, it promptly begins remote control after transmission (S5). This allows control of the multicopter 11 to be quickly taken over, minimizing flight disruptions and completing the remote control handover (S6). Since a ringtone is generated and the indicator light is turned on when the notification signal is received, the reliability of communication with the receiving party is improved.

Next, with reference to Figure 5, we will explain handover using position information of intermediate points on the flight path. Take the example of transporting luggage using a multicopter 11 from a starting point S at the foot of a mountain to a destination point E at the top of the mountain. The luggage is loaded onto the multicopter 11 at the starting point S, and the first control terminal 31 is used to fly it upwards toward the top. The flight route sets relay point A above starting point A (higher than the top), and relay point B is set above destination point E, proceeding horizontally from relay point A.

The location information (position coordinates) of relay points A and B is obtained by conducting a preliminary flight before the actual cargo transport. The preliminary flight is conducted during the day when natural conditions are favorable, and the location information (position coordinates) of relay points A and B is obtained by appropriately selecting other GPS receivers 28, GPS receivers 51 and 52, various sensors, etc. The aircraft ascends from departure point S, and an arbitrary point slightly higher than the summit is set as relay point A. The control unit 33 acquires the location information (latitude, longitude, altitude) displayed on the display unit 55 through operation of the touch panel, and stores it in the memory unit 62 (storage means) of the control terminal 31 and/or the memory unit 35 (storage means) of the multicopter 11 (location information acquisition instruction means, location information acquisition means). Similarly, the aircraft flies horizontally from relay point A, and acquires the location information of relay point B, which is located above arrival point E, and stores it in the memory unit 62 and/or the memory unit 35. During actual remote control, the position information of relay points A and B can be input as the flight route, and the control unit 33 enables the multicopter 11 to fly via relay points A and B (predetermined position flight means).

In this way, the position information of relay points A and B is obtained in advance during a preliminary flight (empty). Therefore, even when the actual cargo is being transported in bad weather, with poor visibility, or at night, remote control can be performed based on the position information of relay points A and B. The handover from the first control terminal 31a to the second control terminal 31b can also be performed at either relay point A or B. For example, the first control terminal 31a launches the multicopter 11 from departure point S. Because remote control utilizes the position information of relay points A and B, the multicopter 11 flies via relay points A and B. When the multicopter 11 reaches either relay point A or B, the first control terminal 31a transmits a notification signal for handover to the second control terminal 31b. Upon receiving the notification signal, the second control terminal 31b sends a confirmation notification signal to the first control terminal 31a, which then stops remote control. The second control terminal 31b, which transmitted the confirmation notification signal, then begins remote control, completing the handover.

By having the handover take place at either relay point A or B, the reliability of the handover operation is improved, enabling stable cargo transport flights. For example, in areas where visual flight by solo pilot is difficult, such as mountain tops, high altitudes, or forested areas, remote flying using relay point position information makes handover easier even during night flights or flights in bad weather, and improves transport efficiency in cases where repeated round-trip transport is required.

Next, with reference to Figure 6, we will explain how position information (latitude, longitude, altitude) is obtained using the GPS receivers 51 and 52 of the multicopter 11. As mentioned above, while the other GPS receivers 28 receive radio waves from at least four satellites to obtain position information (position coordinates), the GPS receivers 51 and 52 receive radio waves from one satellite 71 and obtain the position information of the multicopter 11 using the measurement values of various sensors installed on the multicopter 11.

The GPS receivers 51 and 52 receive radio waves from the satellite 71 and use the satellite's 71 position information and time difference to determine the distance between the satellite 71 and the GPS receivers 51 and 52. Since the distance between the GPS receivers 51 and 52 is known, the triangle formed by the satellite 71 and the GPS receivers 51 and 52 and the altitude H of the multicopter 11 are determined using a barometric pressure sensor and an altitude sensor (ultrasonic sensor), and the position information (latitude, longitude, altitude) of the multicopter 11 is determined. Furthermore, for example, only the position information of the departure point A shown in Figure 5 can be determined using the other GPS receiver 28, and then the position information of intermediate points on the way to the destination point E can be determined using the GPS receiver, barometric pressure sensor, altitude sensor (ultrasonic sensor), acceleration sensor, angular velocity sensor (gyro sensor), and geomagnetic sensor measurements. In this way, instead of using other conventional GPS receivers 28, the GPS receivers 51 and 52 with simple device configurations and various on-board sensors can be used to obtain multicopter position information (position coordinates).

The multicopter 11 of this embodiment may need to transport relatively heavy cargo to locations with significant elevation changes, requiring remote control that takes into account environments susceptible to natural phenomena such as wind. In addition to the normal flight program, it is necessary to maintain horizontality in the event that a heavy load becomes misaligned during flight. Based on measurements from the barometric pressure sensor, altitude sensor (ultrasonic sensor), acceleration sensor, angular velocity sensor (gyro sensor), and geomagnetic sensor, the control unit 33 of the multicopter 11 can maintain horizontality by controlling the rotation speed of each of the rotors 17 (17a, 17b, 17c, 17d) using the drive control units 22 (22a, 22b, 22c, 22d) in accordance with a horizontality maintenance program stored in the memory unit 35 (horizontal maintenance means).

The multicopter 11 in this embodiment has four rotors, but this is not limited to this and may have six, eight, etc. Furthermore, while remote control is handed over between the first and second control terminals, the number of control terminals is not limited to two and may be three, four, etc. Furthermore, the handover may be performed after the multicopter 11 is in a low-speed flight or hovering state. In this embodiment, the control unit 61 provided in each of the first and second control terminals 31a and 31b controls the transmission and reception of notification signals by the notification signal transmission and reception means and the reception and display by the reception and display means, but this is not limited to this and these may also be controlled by the control unit of the multicopter 11 (unmanned aerial vehicle), for example.

The above describes several embodiments of the present invention and variations of each part, but these embodiments and variations are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments described above can be embodied in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and variations are included within the scope and spirit of the invention, and are also included in the invention described in the claims.

As explained above, the unmanned aerial vehicle control system and unmanned aerial vehicle control method according to the present invention allow for handover notifications to be sent between control terminals, which has the advantage of enabling the handover to be easily performed without providing the unmanned aerial vehicle with a device configuration for handover. Therefore, the present invention is useful as a control system and control method for an unmanned aerial vehicle that has an unmanned aerial vehicle and a control terminal that remotely controls the unmanned aerial vehicle.

11. Multicopter (unmanned aerial vehicle)
DESCRIPTION OF SYMBOLS 12 Main body 13 (13a, 13b, 13c, 13d) Arm 15 (15a, 15b, 15c, 15d) Drive unit 17 (17a, 17b, 17c, 17d) Rotor 18a, 18b Leg 21 (21a, 21b, 21c, 21d) Motor 22 (22a, 22b, 22c, 22d) Drive control unit 25 Communication unit 26 Power supply 27 Camera 28 Other GPS
30 Sensor unit 31 Control terminal 31a First control terminal 31b Second control terminal 33 Control unit 35 Storage unit 51, 52 GPS
54 Indicator light 55 Display unit 56 Communication unit 57 Operation unit 58 Switch unit 61 Control unit 62 Memory unit 71 Artificial satellite

Claims (1)

An unmanned aerial vehicle control system having an unmanned aerial vehicle, a control terminal that remotely controls the unmanned aerial vehicle, and a control unit that controls the unmanned aerial vehicle and the control terminal based on operation instructions,
The unmanned aerial vehicle has two GPS receivers that receive radio waves from one artificial satellite,
a position information acquisition means for acquiring position information of a predetermined position along the flight path;
the location information acquisition means acquires location information of the unmanned aerial vehicle based on measurement values of the GPS receiver,
Furthermore, the unmanned aerial vehicle has another GPS receiver that receives radio waves from at least four artificial satellites,
the location information acquisition means acquires the location information based on measurement values of the other GPS receivers;
Furthermore, in this unmanned aerial vehicle control system, after the location information acquisition means first acquires the location information based on the measurement values of the other GPS receiver, it stops using the other GPS receiver and acquires subsequent location information based on the measurement values of the two GPS receivers and the measurement values of the sensor mounted on the unmanned aerial vehicle.