JP2020117223A - Drone, control method for drone, control program for drone - Google Patents

Abstract

To provide a highly-safe drone.SOLUTION: A drone 1 comprises a plurality of rotor blades 101-1a to 101-4b, a plurality of motors 102-1a to 102-4b for driving the rotor blades, a flight control unit 23 for operating the motors, and an operation state detection unit 24 for determining operation states of the motors. The drone includes a plurality of rotor blade sets in which the plurality of rotor blades and the plurality of motors are paired, respectively and are arranged vertically to each other. When the operation state detection unit determines that the operation state of the rotor blade is abnormal, the flight control unit stops the motor driving said rotor blade, continues rotation of the other rotor blade in the rotor blade set having said rotor blade that is determined to be abnormal, stops one of the plurality of rotor blades included in the rotor blade set different from the rotor blade set having said rotor blade that is determined to be abnormal, and continues rotation of the other rotor blade.SELECTED DRAWING: Figure 6

Description

The present invention relates to an aircraft (drone), in particular, a drone with improved safety, and a control method and control program therefor.

The application of small helicopters (multicopters) generally called drones is progressing. One of its important fields of application is spraying chemicals such as pesticides and liquid fertilizers on farmland (field) (for example, Patent Document 1). In Japan, where farmland is smaller than in Europe and the United States, it is often the case that drones are more suitable than manned airplanes and helicopters.

With technologies such as the quasi-zenith satellite system and RTK-GPS (Real Time Kinematic-Global Positioning System), it became possible for a drone to accurately know its absolute position in centimeters during flight. Even in a farmland with a narrow and complicated terrain typical of the above, it is possible to autonomously fly with minimal manual operation, and to perform chemical spraying efficiently and accurately.

On the other hand, there were cases in which it was hard to say that safety considerations were sufficient for autonomous flight drones for agricultural drug spraying. A drone loaded with medicines weighs several tens of kilograms, which could have serious consequences in the event of an accident such as falling onto a person. In addition, the drone operator is usually not an expert, so a fool-proof mechanism is necessary, but the consideration for this was insufficient. Until now, there have been drone safety technologies that are premised on human control (for example, Patent Document 2), but in particular, address the safety issues peculiar to autonomous flying drones for drug spraying for agriculture. There was no technology to do this.

Japanese Patent Laid-Open No. 2001-120151 Patent publication gazette JP, 2017-163265, A

Provides a drone (aircraft) that can maintain high safety even during autonomous flight.

In order to achieve the above object, a drone according to one aspect of the present invention includes a flight unit, a flight control unit that operates the flight unit, and an operation state detection unit that determines an operation state of the flight unit. In the case of a drone, the flight control unit, when the operating state detection unit determines that the operating state of the flying means is excessive, stops the operation of the flying means and specifies the degree of operation to the flying means. At least one of a preliminary withdrawal action for reducing the command value and a partial stop action for stopping a part of the operation of the flight means is performed.

The flight means may be a rotor and a motor that rotates the rotor, and the operating state detection unit may detect whether or not the rotor is over-rotating.

The flight control unit may decrease the command value of the rotation speed to the motor when the operating state detection unit detects excessive rotation of the rotary blade.

The flight control unit may stop the rotation of the motor when the operating state detection unit detects excessive rotation of the rotary blade.

After the flight control unit reduces the command value of the rotation speed to the motor based on the operation state detection unit detecting over-rotation of the rotor blade, the rotor blade is still over-rotated. The flight control unit may stop the rotation of the motor.

The flight control unit may rotate the rotary blade and generate a downward lift force when the operating state detection unit detects excessive rotation of the rotary blade.

The flying means has a plurality of rotor blades that are set to each other and a plurality of motors that respectively control the number of rotations of the plurality of rotor blades, and the operating state detection unit controls the over-rotating rotor blades. The flight control unit rotates the motor corresponding to the rotor blade that is set with the over-rotating rotor blade so as to generate a lift force in the direction opposite to the lift force generated by the over-rotation. It may be one.

The flying means has a plurality of rotating blades that are set in a two-stage configuration and a plurality of motors that control the number of rotations of each of the plurality of rotating blades. It is also possible to specify a rotary blade to be rotated and stop one of the over-rotating rotary blade and one of the plurality of rotary blades set to each other.

The drug control unit for controlling whether or not to discharge the drug from the drone to the outside, further, the drug control unit, when the operating state detection unit determines that the operating state of the flying means is excessive, The discharge may be stopped.

In order to achieve the above object, a drone control method according to another aspect of the present invention is a flight control step of operating a flight means, an operation state detection step of determining an operation state of the flight means, and a flight means of the flight means. A step of stopping the operation of the flying means based on a judgment that the operating state is excessive, a step of performing a preliminary evacuation action for decreasing a command value designating the degree of the operation to the flying means, and the flying means. Of at least one of the steps of performing a partial stop action for stopping a part of the operation of.

The flying means may be a rotor and a motor that rotates the rotor, and the operating state detecting step may detect whether or not the rotor is over-rotating.

The method may further include a step of reducing a command value of a rotation speed to the motor when detecting over-rotation of the rotary blade.

The rotation of the motor may be stopped when the excessive rotation of the rotary blade is detected in the operating state detecting step.

After the step of reducing the command value of the rotation speed to the motor based on the detection of the over-rotation of the rotor in the operating state detecting step, if the rotor is still over-rotating, The step of stopping the rotation may be performed.

When the excessive rotation of the motor is detected in the operation state detecting step, the step of rotating the rotary blade to generate a downward lift may be performed.

The flying means includes a plurality of rotor blades that are set to each other and a plurality of motors that respectively control the number of rotations of the plurality of rotor blades, and the operating state detection step controls the over-rotating rotor blades. The motor corresponding to the rotor blade that is set with the over-rotating rotor blade is rotated so that a lift force opposite to the lift force generated by the over-rotation is generated in the flight control step. It may be one.

The flying means has a plurality of rotor blades that are set in an upper and lower two-stage configuration and a plurality of motors that respectively control the number of revolutions of the plurality of rotor blades, and specifies a rotor blade that is over-rotating. And a step of stopping each of the over-rotating blades and the one of the plurality of rotating blades that are set to each other.

A drug control step of controlling whether or not to discharge the drug from the drone to the outside, wherein the drug control step stops the discharge of the drug when detecting that the operating state of the flying means is excessive. May be

In order to achieve the above object, a drone control program according to another aspect of the present invention, a flight control command for operating the flight means, an operating state detection command for determining the operating state of the flight means,
An instruction to stop the operation of the flying means based on the determination that the operating state of the flying means is excessive, an instruction to perform a preliminary withdrawal action to reduce a command value that specifies the degree of operation to the flying means, And causing the computer to execute at least one command of a partly stopping action for stopping part of the operation of the flying means.

The flying means may be a rotary blade and a motor that rotates the rotary blade, and the operating state detection command may include a command that detects an excessive rotation of the motor.

When the operating state detection command detects over-rotation of the rotary blade, the computer may be caused to execute a command to decrease the command value of the rotation speed to the motor.

The operation state detection command may include a command to stop the rotation of the motor when detecting the excessive rotation of the rotary blade.

Based on the detection of over-rotation of the rotor in the operating state detection command, causing the computer to execute a command to reduce the command value of the rotation speed to the motor, if the rotor is still over-rotation, The computer may be caused to execute an instruction to stop the rotation of the motor.

If the operating state detection command detects excessive rotation of the motor, the computer may further execute a command to rotate the rotary blade and generate a downward lift force.

The flight means has a plurality of rotor blades that are set to each other and a plurality of motors that respectively control the number of rotations of the plurality of rotor blades, and the operating state detection command controls the over-rotating rotor blades. And a command for specifying the motor to be driven, wherein the flight control command causes the motor corresponding to the rotor that is set with the over-rotating rotor to generate a lift force in a direction opposite to the lift force generated by the over-rotation. The computer may be caused to further execute the instruction to rotate the.

The flying means has a plurality of rotating blades that are set in an upper and lower two-stage configuration and a plurality of motors that respectively control the number of rotations of the plurality of rotating blades, and an instruction for specifying an over-rotating rotating blade. And a command to stop one of the over-rotating blades and the one of the plurality of rotating blades set to each other may be further executed by the computer.

Further, the computer is caused to execute a drug control command for controlling whether or not to discharge the drug from the drone to the outside, and the drug control command determines that the operating state of the flying means is excessive in the operating state detection command. Then, the computer may further execute an instruction to stop the ejection of the medicine.
The computer program can be provided by being downloaded via a network such as the Internet, or can be provided by being recorded in various computer-readable recording media such as a CD-ROM.

Provides a drone (aircraft) that can maintain high safety even during autonomous flight.

It is a top view of the example of the drone concerning the invention in this application. It is a front view of the Example of the drone concerning this invention. It is a right side view of the example of the drone concerning the invention in this application. It is an example of an overall conceptual diagram of a drug spraying system using an example of a drone according to the present invention. It is a schematic diagram showing the control function of the Example of the drone which concerns on this invention. It is a functional block diagram regarding the function which detects the operating state of the flight means which the said drone performs, and performs an evacuation action. 6 is a flowchart in which the drone determines an operating state of the flying means and performs a retreat action. 9 is a flowchart in a case where the drone determines an operating state of the flying means and performs a retreat action in another embodiment of the drone according to the present invention.

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. The figures are all examples.

FIG. 1 is a plan view of an embodiment of a drug spraying drone 100 according to the present invention, FIG. 2 is a front view (viewed from the traveling direction side), and FIG. 3 is a right side view thereof. In the specification of the present application, the drone means any power means (electric power, prime mover, etc.), control method (whether wireless or wired, and whether it is an autonomous flight type or a manual control type). Instead, it refers to all aircraft with multiple rotors.

Rotators 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-4a, 101-4b (also called rotors) are means for flying the drone 100. Considering the balance of flight stability, airframe size, and battery consumption, it is desirable to have 8 aircraft (4 sets of 2-stage rotary blades).

The motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 102-4a, 102-4b are rotor blades 101-1a, 101-1b, 101-2a, 101-. 2b, 101-3a, 101-3b, 101-4a, 101-4b is a means for rotating (typically an electric motor, but may be a motor, etc.), one for each rotor It is desirable that the The upper and lower rotor blades (eg 101-1a and 101-1b) and their corresponding motors (eg 102-1a and 102-1b) in one set are for drone flight stability etc. It is desirable that the axes be collinear and rotate in opposite directions. Although some rotor blades 101-3b and the motor 102-3b are not shown, their positions are self-explanatory, and if there is a left side view, they are at the positions shown. As shown in FIG. 2 and FIG. 3, it is desirable that the radial member for supporting the propeller guard provided so that the rotor does not interfere with foreign matter has a structure that is not horizontal but has a tower shape. This is for promoting the buckling of the member to the outside of the rotor blade at the time of collision and preventing the member from interfering with the rotor.

The medicine nozzles 103-1, 103-2, 103-3, 103-4 are means for spraying the medicine downward, and are preferably provided in four units. In the specification of the present application, the term "medicine" generally refers to pesticides, herbicides, liquid fertilizers, insecticides, seeds, and liquids or powders applied to fields such as water.

The drug tank 104 is a tank for storing the drug to be sprayed, and is preferably provided at a position close to the center of gravity of the drone 100 and a position lower than the center of gravity from the viewpoint of weight balance. The drug hoses 105-1, 105-2, 105-3, 105-4 are means for connecting the drug tank 104 and each drug nozzle 103-1, 103-2, 103-3, 103-4, and are rigid. It may be made of the above-mentioned material and also have a role of supporting the medicine nozzle. The pump 106 is a means for discharging the medicine from the nozzle.

FIG. 4 shows an overall conceptual diagram of a system using an example of a drug spraying application of the drone 100 according to the present invention. This figure is a schematic diagram and the scale is not accurate. The pilot 401 is a means for transmitting a command to the drone 100 by the operation of the user 402 and displaying information received from the drone 100 (for example, position, drug amount, battery level, camera image, etc.). Yes, and may be realized by a portable information device such as a general tablet terminal that runs a computer program. Although it is desirable that the drone 100 according to the present invention be controlled to perform autonomous flight, it is desirable to be able to perform manual operation during basic operations such as takeoff and return, and in an emergency. In addition to the portable information device, you may use an emergency operating device (not shown) that has a function dedicated to emergency stop (a large emergency stop button, etc., that allows the emergency operating device to respond quickly in an emergency). It is desirable that it is a dedicated device equipped with). It is desirable that the pilot 401 and the drone 100 perform wireless communication by Wi-Fi or the like.

The field 403 is a rice field, a field, or the like to which the drug is sprayed by the drone 100. Actually, the topography of the farm field 403 is complicated, and there are cases where the topographic map cannot be obtained in advance or the topographic map and the situation at the site are inconsistent. Normally, the farm field 403 is adjacent to a house, a hospital, a school, another crop farm field, a road, a railroad, and the like. In addition, there may be obstacles such as buildings and electric wires in the field 403.

The base station 404 is a device that provides a master device function of Wi-Fi communication and the like, and it is desirable that the base station 404 also functions as an RTK-GPS base station and can provide an accurate position of the drone 100 (Wi-Fi Communication master unit function and RTK-GPS base station may be independent devices). The farm cloud 405 is typically a group of computers operated on a cloud service and related software, and is preferably wirelessly connected to the controller 401 by a mobile phone line or the like. The farming cloud 405 may analyze the image of the field 403 captured by the drone 100, grasp the growing condition of the crop, and perform a process for determining a flight route. Further, the drone 100 may be provided with the stored topographical information of the field 403 and the like. In addition, the history of the drone 100 flight and captured images may be accumulated and various analysis processes may be performed.

Usually, the drone 100 takes off from a landing point 406 outside the field 403 and returns to the landing point 406 after spraying a drug on the field 403 or when it becomes necessary to replenish the drug or charge the battery. The flight route (intrusion route) from the landing point 406 to the target field 403 may be stored in advance in the farm cloud 405 or the like, or may be input by the user 402 before the start of takeoff.

FIG. 5 is a schematic diagram showing the control function of the embodiment of the drug spraying drone according to the present invention. The flight controller 501 is a component that controls the entire drone, and specifically may be an embedded computer including a CPU, memory, related software, and the like. The flight controller 501, based on the input information received from the controller 401 and the input information obtained from various sensors described later, via the control means such as ESC (Electronic Speed Control), the motor 102-1a, 102-1b , 102-2a, 102-2b, 102-3a, 102-3b, 104-a, 104-b are controlled to control the flight of the drone 100. The actual rotation speed of the motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 104-a, 104-b is fed back to the flight controller 501 to perform normal rotation. It is desirable to have a configuration that can monitor whether or not it is. Alternatively, the rotary blade 101 may be provided with an optical sensor or the like so that the rotation of the rotary blade 101 is fed back to the flight controller 501.

The software used by the flight controller 501 is preferably rewritable through a storage medium or the like for function expansion/change, problem correction, or the like, or through communication means such as Wi-Fi communication or USB. In this case, it is desirable to protect by encryption, checksum, electronic signature, virus check software, etc. so that rewriting by unauthorized software is not performed. In addition, a part of the calculation process used by the flight controller 501 for control may be executed by another computer existing on the controller 401, the farm cloud 405, or another place. Since the flight controller 501 is highly important, some or all of its constituent elements may be duplicated.

The battery 502 is a means of supplying power to the flight controller 501 and other components of the drone and is preferably rechargeable. The battery 502 is preferably connected to the flight controller 501 via a power supply unit including a fuse or a circuit breaker. The battery 502 is preferably a smart battery that has a function of transmitting its internal state (amount of stored electricity, accumulated usage time, etc.) to the flight controller 501 in addition to a power supply function.

The flight controller 501 communicates with the controller 401 via the Wi-Fi slave unit function 503 and further via the base station 404, receives a necessary command from the controller 401, and transmits necessary information to the controller. It is desirable to be able to send to 401. In this case, it is desirable to encrypt the communication so as to prevent illegal acts such as interception, spoofing, and hijacking of equipment. The base station 404 preferably has an RTK-GPS base station function in addition to a Wi-Fi communication function. By combining the signal from the RTK base station and the signal from the GPS positioning satellite, the GPS module 504 can measure the absolute position of the drone 100 with an accuracy of about several centimeters. Since the GPS module 504 is highly important, it is desirable to duplicate and multiplex it. Also, in order to cope with the failure of a specific GPS satellite, each redundant GPS module 504 should use another satellite. It is desirable to control.

The 6-axis gyro sensor 505 is a means for measuring the acceleration of the drone body (further, a means for calculating the speed by integrating the acceleration). The geomagnetic sensor 506 is a means for measuring the direction of the drone body by measuring the geomagnetism. The atmospheric pressure sensor 507 is a means for measuring atmospheric pressure, and can indirectly measure the altitude of the drone. The laser sensor 508 is a means for measuring the distance between the drone body and the ground surface by utilizing the reflection of laser light, and it is preferable to use an IR (infrared) laser. The sonar 509 is a means for measuring the distance between the drone body and the ground surface by utilizing the reflection of sound waves such as ultrasonic waves. These sensors may be selected depending on the drone's cost goals and performance requirements. Further, a gyro sensor (angular velocity sensor) for measuring the tilt of the machine body, a wind force sensor for measuring wind force, and the like may be added. Moreover, it is desirable that these sensors be duplicated or multiplexed. If there are multiple sensors for the same purpose, the flight controller 501 may use only one of them, and if it fails, switch to an alternative sensor. Alternatively, a plurality of sensors may be used simultaneously, and if the measurement results do not match, it may be considered that a failure has occurred.

The flow rate sensor 510 is a means for measuring the flow rate of the medicine, and is preferably provided at a plurality of places on the path from the medicine tank 104 to the medicine nozzle 103. The liquid shortage sensor 511 is a sensor that detects that the amount of the medicine has become equal to or less than a predetermined amount. The multi-spectral camera 512 is a means for photographing the field 403 and acquiring data for image analysis. The obstacle detection camera 513 is a camera for detecting a drone obstacle. Since the image characteristics and the orientation of the lens are different from those of the multispectral camera 512, it is desirable that the obstacle detection camera 513 be a device different from the multispectral camera 512. The switch 514 is a means for the user 402 of the drone 100 to make various settings. The obstacle contact sensor 515 is a sensor for detecting that the drone 100, in particular, its rotor or propeller guard portion has come into contact with an obstacle such as an electric wire, a building, a human body, a tree, a bird, or another drone. .. The cover sensor 516 is a sensor that detects that the operation panel of the drone 100 and the cover for internal maintenance are open. The drug injection port sensor 517 is a sensor that detects that the injection port of the drug tank 104 is open. These sensors may be selected according to the cost target and performance requirements of the drone, and may be duplicated or multiplexed. In addition, a sensor may be provided at the base station 404 outside the drone 100, the controller 401, or another place, and the read information may be transmitted to the drone. For example, a wind sensor may be provided in the base station 404, and information regarding wind force/wind direction may be transmitted to the drone 100 via Wi-Fi communication.

The flight controller 501 sends a control signal to the pump 106 to adjust the medicine ejection amount and stop the medicine ejection. It is desirable that the current status of the pump 106 (for example, the number of revolutions) is fed back to the flight controller 501.

The LED 107 is a display means for informing the drone operator of the status of the drone. Display means such as a liquid crystal display may be used instead of or in addition to the LEDs. The buzzer 518 is an output means for notifying a drone state (especially an error state) by a voice signal. The Wi-Fi slave device function 519 is an optional component for communicating with an external computer or the like, for example, for software transfer, in addition to the controller 401. In addition to or in addition to the Wi-Fi cordless handset function, other wireless communication means such as infrared communication, Bluetooth (registered trademark), ZigBee (registered trademark), NFC, or wired communication means such as USB connection May be used. The speaker 520 is an output means for notifying the drone state (particularly, the error state) by the recorded human voice, synthesized voice, or the like. Depending on the weather conditions, it may be difficult to see the visual display of the drone 100 in flight, and in such a case, it is effective to communicate the situation by voice. The warning light 521 is a display means such as a strobe light for notifying the state of the drone (in particular, an error state). These input/output means may be selected according to the cost target and performance requirements of the drone, and may be duplicated/multiplexed.

In a drone that flies by autonomous flight, there is a possibility that the number of rotations of the rotor will exceed a predetermined value and run away or continue rising due to an abnormality that occurs in the control system of the rotor. Therefore, if the rotor blades over-rotate in the direction of continued ascent, it must have a function to prevent runaway or unintentional continuous ascent by detecting over-rotation and performing a retracting action to drop the drone. Is desirable.

(First embodiment)
As shown in FIG. 6, the drone 100 according to the first embodiment of the present invention has rotor blades 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-. 4a, 101-4b, motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 104-a, 104-b, flight control unit 23, operating state detection A unit 24 and a drug control unit 30 are provided. Rotors are an example of flight means. Hereinafter, the reference numerals of the rotor and the motor may be omitted.

The flight control unit 23 controls the motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 104-a, 104-b by rotating each rotor 101-1a, It is a functional unit that controls the rotation speed and rotation direction of 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-4a, 101-4b. Further, the flight control unit 23 controls the takeoff and landing of the drone 100 by controlling the motor. Specifically, the flight control unit 23 is a CPU implemented by a microcomputer or the like. The flight control unit 23 and a drug control unit 30 described later are realized by a flight controller.

In addition, the flight control unit 23 can take a preliminary evacuation action to reduce the command value that specifies the degree of operation of the flight means. Specifically, the flight control unit 23 can reduce the rotation speeds of all the motors by a fixed ratio. When detecting the over-rotation of the rotor blade, for example, if the difference between the command value of the rotation speed and the actual rotation speed is more than a predetermined value, it is judged as over-rotation, but by lowering the command value of the rotation speed, This is because the difference between the value and the actual rotation speed may be within a predetermined range.

Further, the flight control unit 23 controls the takeoff and landing of the drone 100 by controlling the motor.

Furthermore, the flight control unit 23 has a function of stopping the motor. When all rotors are stopped, the drone 100 will drop down from the spot.

Furthermore, the flight control unit 23 can take a “partial stop action” to stop a part of the operation of the flight means. When the flying means is a rotor and a motor, "partially stopping action" means that among the motors that control the rotors that are set up and down, the motor that controls the over-rotating rotor and the motors that control each other are set. The motor that controls one of the rotating blades is stopped. In the present embodiment, since there are four sets of rotary blades, the four blades including the over-rotating rotary blade are stopped, and the four rotary blades that are each set with the four blades to be stopped rotate. continue. When one of the rotor blades of the set is stopped and only the other rotor blade is rotating, the drone 100 will have less lift than when it is flying with eight motors, but it will be autonomous. The drone 100 can continue its minimal flight. In addition, the rotating blades to be stopped may be such that one of the rotating blades included in the set is stopped, all of the upper four blades may be stopped, or all of the lower four blades may be stopped. Good. Further, the upper stage may be stopped in one set and the lower stage may be stopped in another set.

With this configuration, the drone 100 can perform “emergency return” or “normal return”, which will be described later, even when some motors are over-rotating, and return to a predetermined return point. be able to. In addition, the flight may be continued on the planned flight route, although there is a risk of further abnormality. The same applies when the operating state of the lower motor becomes excessive.

The flight control unit 23 may operate to control the flight of the drone 100 in the normal operation of the drone 100, or may be configured separately from the flight control means in the normal operation. In the latter case, the flight control unit 23 operates only when taking a retreat action when the rotor blades are excessively rotating.

Further, the drone 100 is provided with a plurality of flight control units 23 having the same function, and when an over-rotation of a rotor occurs due to an abnormality in one flight control unit 23, another flight control unit 23 detects it. Then, the drone 100 may be made to take evacuation action. In this case, it may have a selection means for receiving control signals from the plurality of flight control units 23 and selecting a control signal to be transmitted to the motor.

The evacuation action may be a fall or a normal landing action, an aerial stop such as hovering, or an "emergency return" to immediately move to a predetermined return point by the shortest route. Good. The predetermined return point is a point stored in the flight control unit 23 in advance, for example, a point at which the flight has taken off. The predetermined return point is, for example, a land-based point where the user 402 can approach the aircraft 21, and the user 402 can inspect the drone 100 reaching the return point or manually carry it to another place. can do.

Further, the evacuation action may be a “normal return” in which the route is optimized to move to a predetermined return point. The optimized route is, for example, a route calculated by referring to the route in which the medicine is sprayed before receiving the normal return command. For example, the drone 100 moves to a predetermined return point while spraying the drug via a route that has not yet sprayed the drug.

The operating state detection unit 24 is a functional unit that detects the operating state of the flying means and detects whether the flying means is operating excessively. In the present embodiment, the operating state detection unit 24 detects whether or not the rotary blade is over-rotating. In addition, the operating state detection unit 24 can detect the operating state of each rotor or each motor and identify the motor that is causing excessive rotation.

The operating state detecting unit 24 has an operating state measuring unit 241 and a determining unit 242.

The operating state measuring unit 241 indicates, for example, a rotation measuring function arranged inside the motor itself. That is, the operating state detection unit 24 detects whether or not the rotor controlled by the motor is over-rotating by measuring the rotation speed of the motor.

The operating state measuring unit 241 may measure the rotation speed of the rotary blade itself. For example, the operating state measuring unit 241 may be a non-contact tachometer. In this case, the operating state measuring unit 241 counts the number of rotations of the rotary blade by irradiating at least one location of the rotary blade with laser and measuring the reflected light from the rotary blade of the laser. The determination unit 242 notifies the flight control unit 23 that it is over-rotated when the number of rotations of the rotary blade is equal to or more than a predetermined number. The laser is, for example, an infrared laser.

The operating state measurement unit 241 may measure the current supplied to the motor, and the determination unit 242 may detect whether or not the rotary blade is over-rotating, based on the current supplied to the motor. More specifically, the actual current supplied to the motor is compared with the command value of the current that the flight control unit 23 sends to the motor, and if the difference between the actual current value and the command value is greater than or equal to a predetermined value. If there is, the determination unit 242 may determine that the rotary blade is over-rotating.

The operating state detection unit 24 may have a configuration for detecting the direction of rotation of the rotary blade. In this case, the determination unit 242 transmits to the flight control unit 23 that the rotation direction of the rotor blades is the direction in which the drone 100 is raised, and is over-rotation when the rotation number is a predetermined number or more. When the rotating direction of the rotor blades is the direction in which the drone 100 is lowered, the determination unit 242 does not transmit that it is over-rotating. This is because in this case, the drone 100 falls without performing any flight control, and therefore it is not necessary to take a retreat action.

The determination unit 242 compares the measured actual rotation speed of the motor with the command value of the rotation speed that the flight control unit 23 sends to the motor, and determines that the difference between the actual rotation speed and the command value is equal to or greater than a predetermined value. In this case, it may be determined that the rotary blade is over-rotating. According to this configuration, it is possible to detect the abnormal rotation before the actual rotation speed reaches the maximum value according to the actual power of the motor and retract the drone 100.

The threshold value of the rotation speed that the determination unit 242 determines to be over-rotation and the threshold value of the difference between the actual rotation speed and the command value may be a fixed threshold value stored in advance in the operating state detection unit 24. However, it may be a varying threshold that is changed according to the situation. In the case of a changing threshold value, it may be changed automatically by an appropriate configuration that is connected to the operating state detection unit 24 wirelessly or by wire, or may be manually changed by the user.

The determination unit 242 may determine whether it is over-rotation based on the rotation speed at a certain time point to be measured, or may determine whether it is over-rotation based on the measurement results of the rotation speeds of the past multiple times. May be. In this case, for example, the latest measurement results of the number of revolutions may be averaged and used for determining over-revolution.

The operating state detection unit 24 may display the fact that over-rotation is detected on the controller 401 monitored by the user 402 by an appropriate communication means included in the drone 100. In addition, when the user 402 acquires the information of the drone 100 using the eyewear-type wearable terminal, it may be displayed or projected on the screen of the eyewear. In addition, when the user 402 acquires the information of the drone 100 by the earphone type wearable terminal, the user 402 may notify by sound.

In addition, the operating state detection unit 24 may be configured to display that the drone 100 has detected an over-rotation by a display unit of the drone 100, for example, the LED 107. Also, an appropriate sound may be output from the drone 100 speaker.

The drug control unit 30 is a control unit that controls the amount or timing of spraying the drug solution from the drug tank 104. The drug control unit 30 sprays the drug onto a field spread below the drone 100 during normal flight. The drug controller 30 may block the release of the drug solution by the opening/closing means before the flight controller 23 stops the rotor blades. For example, the drug control unit 30 has an opening/closing means for opening and closing the drug solution path somewhere along the path from the drug tank 104 to each drug nozzle 103-1, 103-2, 103-3, 103-4. Good. Further, the medicine control unit 30 may stop the pump 106 before the flight control unit 23 stops the rotor blades. This is because if the drug is continuously sprayed during or after the drone 100 is dropped, the amount of the drug sprayed will be excessive, or the drug will be sprayed in a place where it should not be sprayed.

As shown in FIG. 7, while the drone 100 is in normal flight or hovering (step S1), the operating state measuring unit 241 measures the operating state of the motor or the rotor (step S2).

The determination unit 242 determines whether or not the rotary blade is over-rotated, based on the result measured by the operating state measurement unit 241 (step S3).

When it is determined that the rotor blades are not over-rotating, the process returns to step S1 and normal flight or hovering is continued.

When it is determined that the rotary blades are over-rotating, the drug control unit 30 stops the spraying of the drug (step S4).

Next, the flight control unit 23 performs a preparatory evacuation action to reduce the command values of the rotational speeds of all the rotor blades by a fixed ratio (step S5).

The operating state measuring unit 241 measures the actual rotation speed of the motor again (step S6), and the determining unit 242 determines whether or not the rotary blade is over-rotating (step S7). When it is determined that the rotor blades are not over-rotating, the flight control unit 23 performs the normal feedback operation while keeping the command value of the motor rotation speed reduced by a fixed ratio (step S8).

The flight control unit 23 may perform an emergency return operation instead of the normal return operation. In addition, the flight control unit 23 may continue the flight along the planned flight path while keeping the command value of the motor rotation speed reduced by a fixed ratio. In this case, the medicine control unit 30 similarly continues the planned medicine application. In either case, the controller 401 displays that effect. When the flight is continued, the command transmitted from the controller 401 may be restricted so that the command value of the rotation speed higher than a predetermined value cannot be transmitted to the flight control unit 23.

When it is determined that the rotor blades are over-rotating even after the preliminary evacuation action, the flight control unit 23 stops the rotation of all the rotor blades (step S9). Then, drone 100 falls downward on the spot.

According to this configuration, the drone 100 can be safely retracted even if the rotor blades become over-rotated.

(Second embodiment)
The second embodiment of the drone according to the present invention will be described focusing on the part different from the above-mentioned embodiment. In the present embodiment, when the rotary blade causes over-rotation, the flight control unit rotates the controllable rotary blade to generate downward lift force on the drone.

As shown in FIG. 8, while the drone 100 is in normal flight or hovering (step S1), the operating state measuring unit 241 measures the operating state of the motor or the rotor (step S2).

The determination unit 242 determines whether the rotary blade is over-rotated (step S3). In addition, the operating state detection unit 24 detects that any of the eight rotor blades 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-4a, 101-4b is overloaded. Detects whether the motor is rotating and identifies the motor that is over rotating.

When it is determined that the rotor blades are not over-rotating, the process returns to step S1 and normal flight or hovering is continued.

When it is determined that the rotary blades are over-rotating, the drug control unit 30 stops the spraying of the drug (step S4).

Next, the flight control unit 23 performs a preparatory evacuation action to reduce the command values of the rotational speeds of all the rotor blades by a fixed ratio (step S5).

The operating state measuring unit 241 measures the actual rotation speed of the motor again (step S6), and the determining unit 242 determines whether or not the rotary blade is over-rotating (step S7). When it is determined that the rotor blades are not over-rotating, the flight control unit 23 performs the normal feedback operation while keeping the command value of the motor rotation speed reduced by a fixed ratio (step S8).

When it is determined that the rotor blades are over-rotating even after the preliminary evacuation action, the flight control unit 23 rotates the controllable rotor blades to generate downward lift force on the drone 100 (step S10). According to this configuration, the drone 100 can reach the ground faster.

Further, the flight control unit 23 may particularly rotate the motor corresponding to the rotor blade that is set with the over-rotating rotor blade to generate the downward lift force on the drone 100. The flight control unit 23 rotates the rotor blades that are set with the over-rotating rotor blades so that lift force in the descending direction is generated.

According to this configuration, the set rotor blades generate a reverse lift force with respect to the rotor blades that are over-rotating, so that the drone 100 is prevented from running out of control or unintentionally continuously rising. be able to.

In the present description, the drone having the rotary blades is described as an example, but the technical idea of the present invention is not limited to this, and is also applied to a drone that generates lift by jet injection instead of the rotary blades. It is possible. In this case, the operating state detection unit detects whether the operating state of the jet injection mechanism is above a predetermined level. Further, the determination unit compares the difference between the measured value of the operating state of the jet injection mechanism and the command value from the flight control unit, and if this difference is greater than or equal to a predetermined value, it means that the jet injection mechanism is operating too much. To detect.

Further, in the present description, the agricultural drug spray drone has been described as an example, but the technical idea of the present invention is not limited to this, and is applicable to drones in general. It is especially useful for autonomous flying drones.

(Technically remarkable effect of the present invention)
In the drone according to the present invention, it is possible to provide a drone (unmanned air vehicle) that can maintain high safety even during autonomous flight.

Claims (7)

Multiple rotors,
A plurality of motors respectively driving the rotary blades,
A flight controller for operating the motor,
An operating state detection unit that determines the operating state of the motor,
A drone comprising
Each of the plurality of rotor blades and the plurality of motors forms a pair, and the plurality of rotor blade sets each including the pair are arranged above and below each other,
The flight control unit, when the operating state of the rotary blade is determined to be abnormal by the operating state detection unit , stops the motor that drives the rotary blade determined to be abnormal, and the abnormality The rotation of the other rotor blades of the rotor blade set having the rotor blades determined to be continued,
Included in a rotor blade set different from the rotor blade set having the rotor blade determined to be abnormal, one of the rotor blades arranged above and below is stopped, and rotation of the other rotor blade is continued,
Drone.
Comprising four sets of the rotary blades,
When the operating state of the rotor is determined to be abnormal by the operating state detection unit, the flight control unit stops the motor that drives the rotor determined to be abnormal, and determines that the abnormality. Of the other three rotor blades different from the rotor blade set having the above-mentioned rotor blades, one of the motors driving the plurality of rotor blades arranged above and below is stopped, and the remaining four rotor blades Keep the motor running,
The drone according to claim 1.
The flight control unit, when the operating state detection unit determines that the operating state of the upper rotor blades of the rotor blade set is abnormal, stops the motor that drives the upper rotor blades of each rotor blade set, respectively. And continue the rotation of each motor that drives the remaining lower rotor blades,
The drone according to claim 1 or claim 2.
The flight control unit, when the operating state of the lower rotor of the rotor set is determined to be abnormal by the operating state detection unit, a motor for driving the lower rotor of each rotor set. Stop each, and continue the rotation of each motor that drives the remaining upper rotor blades,
The drone according to claim 1 or claim 2.
The drone according to claim 1, wherein the operating state detection unit determines that the operating state is abnormal when detecting the excessive rotation of the rotary blade.
Multiple rotors,
A plurality of motors respectively driving the rotary blades,
Is a drone control method comprising a plurality of rotor blade sets each of which is a pair, and the pairs are arranged one above the other,
A flight control step of operating each of the plurality of rotors by the plurality of motors ,
An operating state detection step of determining the operating state of the rotor ,
When it is determined that the operating state of the rotor is abnormal , the motor that drives the rotor determined to be abnormal is stopped, and the rotor having the rotor determined to be abnormal. Continuing the rotation of the other rotor blades of the set,
A step of stopping one of the plurality of rotor blades arranged above and below included in a rotor blade set different from the rotor blade having the rotor blade determined to be abnormal and continuing the rotation of the other rotor blade. When,
Controlling drone, including.

Multiple rotors,
A plurality of motors that respectively drive the rotor blades,
Is a drone control program comprising a plurality of rotor blade sets each of which is a pair, and the pairs are arranged one above the other,
Flight control commands for respectively operating the plurality of rotors by the plurality of motors ,
An operating state detection command for determining the operating state of the rotor ,
When it is determined that the operating state of the rotor is abnormal , the motor that drives the rotor determined to be abnormal is stopped, and the rotor having the rotor determined to be abnormal. An instruction to continue the rotation of the other rotor blades of the set,
An instruction to stop one of the plurality of rotor blades arranged above and below included in a rotor blade set different from the rotor blade set having the rotor blade determined to be abnormal and continue the rotation of the other rotor blade. When,
Drone control program that causes a computer to execute.

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