WO2020013264A1

WO2020013264A1 - Flight vehicle

Info

Publication number: WO2020013264A1
Application number: PCT/JP2019/027453
Authority: WO
Inventors: 千大和氣; 洋柳下
Original assignee: 株式会社ナイルワークス
Priority date: 2018-07-11
Filing date: 2019-07-11
Publication date: 2020-01-16
Also published as: JP6811976B2; JPWO2020013264A1

Abstract

[Problem] To obtain a flight vehicle in which it is possible to detect looseness and play of fuselage structure components, and take evasive action when looseness or play is detected, and to avoid in advance defects occurring due to the reduction of various types of control precision. [Solution] A flight vehicle having a fuselage and a plurality of propeller drive motors 102-1a to 102-4b that are mounted on the fuselage and separately rotationally drive a plurality of propellers, the fuselage having a frame obtained by joining a plurality of support arms that support the plurality of propeller drive motors 102-1a to 102-4b, wherein a loosening sensor 530, which detects looseness or play of structure components of the fuselage including the frame, is attached to the fuselage, and the aerial vehicle takes evasive action when the loosening sensor 530 has outputted an abnormality signal.

Description

Flying object

(4) The present invention relates to an air vehicle represented by a drone.

飛行 Applications of flying vehicles having a plurality of propellers called drones, particularly unmanned flying vehicles, in the industrial field are increasing. Agricultural drones that spray chemicals such as pesticides and liquid fertilizer on fields are one of the applied fields. In the following description, "drone" refers to a flying object.

An industrial drone is a large drone having a relatively large-diameter propeller capable of generating a thrust capable of withstanding the load of the load, for loading a load such as a drug, as seen in, for example, an agricultural drone. Is used. A drone having a large-diameter propeller has a large body vibration caused by the rotation of the propeller. An aircraft such as an agricultural drone is equipped with various sensors for performing various controls such as automatic driving control, attitude control, speed control, and flying height control for flying according to a predetermined route.

(4) When the body of the drone vibrates due to the rotation of the propeller, the sensors also vibrate with the body, and the accuracy of each sensor's detection data decreases, and the accuracy of the various controls decreases.

As one of the sensors, there is a GPS sensor for the drone itself to detect its own position. In an industrial drone, in order to detect a position with higher accuracy, for example, a GPS sensor including, for example, an RTK antenna and an RTK-GPS (Real Time Kinematic Global Positioning System) module is often configured. In RTK-GPS, radio waves in a short wavelength band are used to increase the resolution. Therefore, when the RTK antenna vibrates together with the airframe, the position detection accuracy is significantly reduced.

６ A 6-axis gyro sensor is used for controlling the attitude and flight direction of the drone. The six-axis gyro sensor is used to measure the acceleration of the drone in three orthogonal directions, and to calculate the velocity by integrating the acceleration. Further, the six-axis gyro sensor is also used for measuring an angular velocity around the above three axes. When the six-axis gyro sensor vibrates together with the airframe, the accuracy of acceleration measurement decreases, and the accuracy of attitude control and flight direction control decreases.

Industrial drones are designed with a fuselage structure that makes it difficult for the aircraft to vibrate.However, as the number of operations increases, rattling occurs in the aircraft, and the accuracy of various controls decreases with this. .

Patent Document 1 discloses an invention in which an unmanned aerial vehicle detects an abnormality and land the aerial vehicle. The invention described in Patent Document 1 detects rotation speeds of a plurality of motors driving a plurality of rotors and currents flowing through the respective motors, and based on the relationship between the rotation speeds and the currents, each motor or a motor corresponding thereto is abnormal. It is to determine whether or not.

The invention described in Patent Document 1 detects abnormality of each motor driving a plurality of propellers and abnormality of each propeller, but does not detect vibration of the body of the flying body. Therefore, the invention described in Patent Literature 1 does not consider reduction in detection accuracy of various sensors and reduction in various control accuracy due to vibration of the body.

JP 2007-210111 A

The present invention relates to an air vehicle capable of detecting looseness or rattling of an airframe structural component, performing an evacuation action when detecting loosening or rattling, and previously avoiding a problem caused by a decrease in various control accuracy. The purpose is to obtain.

The present invention
An airframe, a plurality of propeller drive motors mounted on the airframe and individually driving a plurality of propellers, and the airframe is coupled with a plurality of support arms supporting the plurality of propeller drive motors. A flying object having a frame comprising
A relaxation sensor that detects looseness and rattling of structural parts of the body including the frame is attached to the body,
When the relaxation sensor outputs an abnormal signal, the most important feature is to perform an evacuation action.

According to the present invention, since the relaxation sensor outputs an abnormal signal when detecting the looseness or rattling of the body structural parts including the frame, it is possible to take appropriate measures based on the output of the abnormal signal, and to detect the relaxation sensor. It is possible to avoid a decrease in various control accuracy due to a decrease in accuracy.

It is a perspective view showing an example of a flight object concerning the present invention. FIG. 3 is a plan view of the embodiment. It is a front view of the said example. It is a right view of the said Example. FIG. 4 is a bottom view of the embodiment. FIG. 3 is a plan view showing the embodiment with a propeller removed. FIG. 2 is a front view showing the embodiment with a propeller removed. FIG. 3 is a right side view showing the embodiment with a propeller removed. It is a perspective view which expands and shows the principal part of the said Example. It is a mimetic diagram showing roughly the example in the case of using the flying object concerning the present invention for agriculture. FIG. 3 is a block diagram illustrating an example of a control system of the flying object according to the present invention.

Hereinafter, an embodiment of a flying object (hereinafter, referred to as “drone”) according to the present invention will be described with reference to the drawings. The drawings are all examples, and the configuration of the flying object according to the present invention is not limited to the configuration of the embodiment. In this specification, a drone refers to an entire flying object having a plurality of rotary wings or flying means regardless of a power system or a steering system. As the power system, there are a system using electric power and a system using a prime mover such as an internal combustion engine. The control method includes a wireless or wired control method, an autonomous flight type, and a manual control type.

[Configuration of the entire drone]
In FIG. 1 to FIG. 5, the drone includes four upper and lower propellers 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-4a, 101-a. 4b. These propellers are means for flying the drone, and are provided with four sets of two-stage propellers, for a total of eight aircraft, in consideration of the balance of flight stability, aircraft size, and battery consumption. . The rotation centers of the four sets of propellers are located at corners of the rectangle in plan view. The propellers 101-2a and 101-4a are on the front side in the traveling direction of the drone.

Each of the above-mentioned propellers is a propeller drive motor (hereinafter sometimes simply referred to as “motor”) 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 102-4a, 102-4b. Are individually driven to rotate. A pair of upper and lower propellers, for example, 101-1a and 101-1b, are coaxial with each other for flight stability of the drone, and are in opposite directions by motors 102-1a and 102-1b. Is driven to rotate. The upper and lower propellers of each set are driven to rotate in opposite directions to generate a downward flow, thereby generating a thrust in a direction to raise the drone. Other sets of upper and lower propellers are similarly configured and similarly generate thrust.

The illustrated embodiment is an agricultural drone provided with four medicine nozzles 103-1, 103-2, 103-3, 103-4 for spraying medicine downward. As used herein, agents generally refer to liquids or powders that are sprayed on the field, such as pesticides, herbicides, liquid manures, pesticides, seeds, and water.

The drone has a medicine tank 104 for containing the medicine to be sprayed. The medicine tank 104 is provided at a position close to the center of gravity of the drone and lower than the center of gravity from the viewpoint of weight balance. A pump 106 is mounted below the medicine tank 104, and the pump 106 is connected to a medicine hose 105. The drug hose 105 extends linearly at a lower portion on the front side in the traveling direction of the drone and substantially over the entire width of the drone. Four drug nozzles 103-1, 103-2, 103-3, and 103-4 are arranged at regular intervals in the length direction of the drug hose 105. By operating the pump 106, the medicine in the medicine tank 104 is discharged from each medicine nozzle and is sprayed on the field.

[Frame configuration]
Next, the configuration of the frame of the drone and the configuration of the body 50 according to the embodiment will be described in detail with reference to FIGS. 6 to 9. In this specification, the "fuselage" is a portion on which control parts for controlling the operation of the drone, a battery or a sensor serving as a driving power source, and the like are mounted, and corresponds to a fuselage of a helicopter or an airplane. The entire drone, including its fuselage, frame, propeller, and propeller drive motor, is called the "airframe." The frame of the drone is composed of a plurality of support arms integrally connected to each other and supporting the plurality of propeller drive motors. The frame composed of a plurality of support arms is composed of a pair of frames that are integrally connected at predetermined intervals in the vertical direction.

The plurality of support arms forming the upper frame include one first support arm 10 that supports a propeller drive motor at each end, and two

second support arms

11 and 12 that extend from the first support arm 10. Having. The

second support arms

11 and 12 extend obliquely symmetrically from the middle of the length direction of the first support arm 10 and extend in a direction in which the distal ends spread out from each other.

２The

second support arms

11 and 12 are connected by a reinforcing beam 13 in the middle of the length direction. The reinforcing beam 13 is parallel to the first supporting arm 10, and is formed in a trapezoidal shape in plan view by the first supporting arm 10, the second supporting

arms

11, 12, and the reinforcing beam 13, and is close to a so-called truss structure. It has a structure. Since the frame has a structure close to the truss structure, the mechanical strength can be increased while having a relatively simple configuration. The first support arm 10, the

second support arms

11, 12 and the reinforcing beam 13 are connected via an appropriate connection member so as to be located on the same plane.

モーター Motors 102-2a and 102-4a are supported at both ends of the first support arm 10, respectively. Propellers 101-2a and 101-4a are respectively attached to the rotation output shafts of the motors 102-2a and 102-4a, and the propellers are individually driven to rotate by the motors. Motors 102-1a and 102-3a different from the above-mentioned motors are supported at the respective distal ends of the

second support arms

11 and 12. Propellers 101-1a and 101-3a are attached to the rotation output shafts of the motors 102-1a and 103-3a, respectively, and the propellers are individually rotated by the motors.

The lower frame has almost the same structure as the upper frame. The lower frame has one first support arm 20 that supports a propeller drive motor at each end, and two

second support arms

21 and 22 extending from the first support arm 20. The

second support arms

21 and 22 extend obliquely symmetrically from the middle in the length direction of the first support arm 20 and extend in a direction in which the distal ends are widened. The first support arm 20 and the

second support arms

21 and 22 are coupled via an appropriate coupling member so as to be located on the same plane.

(4) The upper and lower frames are connected under an appropriate number of columns so as to be parallel to each other. The upper and lower pairs of the

second support arms

11 and 21 and another pair of the

second support arms

12 and 22 are connected by pillars 30 at an intermediate portion in the longitudinal direction. The upper and lower pair of

first support arms

10 and 20 are respectively provided with columns 31 near the joint with the upper

second support arms

11 and 21 and near the joint with the lower

second support arms

12 and 22. , 31. Each support arm and each column are connected by interposing an appropriate connecting member.

(4) The pair of

pillars

30, 30 are connected to each other by reinforcing beams 23 at positions lower in the vertical direction. The reinforcing beam 23 is a reinforcing beam for the lower frame composed of the first support arm 20 and the

second support arms

21 and 22, and also functions as a reinforcing beam for the entire upper and lower frames. The reinforcing beam 13 is parallel to the first supporting arm 10, and is formed in a trapezoidal shape in plan view by the first supporting arm 10, the second supporting

arms

11, 12, and the reinforcing beam 13, and is close to a so-called truss structure. It has a structure.

The

first support arms

10, 20, the

second support arms

11, 12, 21, 22, the reinforcing

beams

13, 23, and the

columns

30, 31, which connect the upper and lower frames, which constitute the upper and lower frames, are pipe-shaped members. is there. Further, the above-mentioned members constituting the frame, at least the first support arm, the second support arm, and the material of the reinforcing beam are made of a heat conductive material, for example, an aluminum alloy or a carbon fiber composite material. Examples of the carbon fiber composite include carbon fiber reinforced plastic (CFRP) and carbon fiber reinforced carbon composite. Since the material of the members constituting the frame is made of an aluminum alloy or a carbon fiber composite material and is a pipe-shaped member, the weight of the frame can be reduced while having the necessary strength for the frame. Further, as will be described in detail later, the heat radiation effect can be enhanced.

[Propeller guard]
The propellers 101-1a and 101-1b supported by the distal ends of the pair of upper and lower

second support arms

11 and 21 are surrounded by the propeller guard 41 and rotate in the propeller guard 41. The propeller guard 41 includes a pair of upper and lower annular frames, a columnar interposed member that connects these frames in parallel at a fixed interval, a hub at the center of the upper and lower frames, and upper and lower frames. And a plurality of spokes for coupling with the hub. The upper and lower hubs are coupled to the distal ends of the

second support arms

11 and 21 with their centers aligned with the rotation centers of the propellers 101-1a and 101-1b.

プロ The propellers 101-2a and 101-2b supported at the right ends when viewed from the front of the pair of upper and lower

first support arms

10 and 20 are surrounded by the propeller guard 42 and rotate in the propeller guard 42.

プロ The propellers 101-3 a and 101-3 b supported by the distal ends of the pair of upper and lower

second support arms

12 and 22 are surrounded by the propeller guard 43 and rotate in the propeller guard 43.

(4) The propellers 101-4a and 101-4b supported at the left ends when viewed from the front of the pair of upper and lower

first support arms

10 and 20 are surrounded by the propeller guard 44 and rotate in the propeller guard 44.

Each of the propeller guards 42, 43, and 44 has the same configuration as the propeller guard 41. That is, each of the propeller guards 42, 43, and 44 includes a pair of upper and lower annular frames, a plurality of columnar intervening members that connect these frames in parallel, a hub at the center of the upper and lower frames, And a plurality of spokes for connecting the frame and the hub. The upper and lower hubs of the propeller guard 42 are coupled to the right end when viewed from the front of the

first support arms

10 and 20. The upper and lower hubs of the propeller guard 43 are connected to the distal ends of the

second support arms

12 and 22. The upper and lower hubs of the propeller guard 44 are connected to the left end when viewed from the front of the

first support arms

10 and 20.

The distance between the propellers 101-1a and 101-1b located on the right rear of the drone and the propellers 101-2a and 101-2b located on the right front is small, and the annular frame forming these

propeller guards

41 and 42 is In contact. The distance between the propellers 101-3a and 101-3b located on the left rear of the drone and the propellers 101-4a and 101-4b located on the left front is also small, and the annular frame forming these

propeller guards

43 and 44 is In contact.

枠 It is preferable that the frame, hub, and spokes constituting the propeller guards 41, 42, 43, 44 are made of a heat conductive material. It is desirable that at least the spokes arranged in a lattice on the upper and lower surfaces of the propeller guards 41, 42, 43, 44 are made of a heat conductive material.

間隔 The distance between the propellers located on the left and right is wider than the distance between the propellers located before and after the drone. That is, the distance between the propellers 101-4a and 101-4b and the propellers 101-2a and 101-2b and the distance between the propellers 101-3a and 101-3b and the propellers 101-1a and 101-1b are located on the left and right sides of the drone. It is getting wider. These propeller guards 44 and 42 and 43, 41 are spaced apart from each other.

[body]
In plan view, the lines connecting the rotation centers of the four sets of propellers 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, and 101-4a, 101-4b are horizontally long. It is a rectangle. There is a space between the left and right propeller guards 43 and 44 arranged in front and rear and the right propeller guards 41 and 42 arranged in front and back, and this space supports built-in components such as a power supply battery, a control circuit, and a motor drive circuit. Body 50 is disposed.

The body 50 has a flat dish-shaped bottom plate 51 and a cover 52 placed on the bottom plate 51. The bottom plate 51 and the cover 52 are made of a heat conductor such as an aluminum alloy or a carbon fiber composite material. The internal space surrounded by the bottom plate 51 and the cover 52 serves as a component mounting part for incorporating built-in components such as a power supply battery, a motor drive circuit, and a control circuit. The body 50 is long in the front-rear direction, and has a semicircular planar shape at the front end in the traveling direction.

The body 50 is disposed in a space formed between the left and right propellers and the left and right propeller guards 41, 42 and 43, 44 and between the upper and lower reinforcing

beams

13, 23. The bottom plate 51 of the body 50 is coupled to the lower reinforcing beam 23 via a coupling member at the bottom surface. The coupling member is a plate-shaped member made of a material having good heat conductivity, and holds the reinforcing beam 23 over substantially half a circumference, and is fastened in a state where both side edges are in surface contact with the bottom surface of the bottom plate 51.

カバー The cover 52 constituting the body 50 is connected to the upper reinforcing beam 13 via a connecting member 59. The coupling member 59 is also a plate-shaped member made of a material having good heat conductivity, and is wound around the reinforcement beam 13 over substantially half a circumference, and is fastened in a state where both side edges are in surface contact with the upper surface of the cover 52.

FIG. 9 shows an outline of a component arrangement in a component mounting portion in the body 50. A space 56 about half of the rear side (obliquely lower right side in FIG. 9) in the body 50 is close to the upper and lower reinforcing

beams

13 and 23 and has a high cooling effect. This space 56 is vertically divided into layers, and a battery mounting space 153 is provided in an upper layer portion. The battery mounting space 153 includes a battery receiving member 152 and two battery fasteners 154 so that two secondary batteries, that is, rechargeable batteries 55 can be arranged in parallel.

During operation of the flying vehicle, two batteries 55 are loaded in the battery mounting space 153. One battery is the main battery and is used during normal operation, and the other battery is a spare battery. If the storage capacity of the main battery decreases while the main battery is in use, or if the main battery malfunctions, continue the flight to switch to the spare battery and perform the evacuation behavior described later. Let me take. In this way, by attaching the two batteries 55, the power supply system is provided with so-called redundancy, and appropriate processing is performed when a power supply trouble occurs, thereby avoiding a fatal trouble. can do.

FIG. 9 shows a state in which only one battery 55 is loaded. The battery 55 is also one of the heat-generating components, and is designed so that the battery 55 is loaded into the space 56 having a high cooling effect and the temperature of the battery 55 is suppressed from rising. The battery 55 itself is a component having high mechanical strength and rigidity, and the strength and rigidity of the body 50 can be increased by tightly mounting the battery 55 with the battery fastener 154. The battery 55, the battery mounting space 153, the battery receiving member 152, and the battery fastener 154 also contribute as members for securing the strength of the frame.

約 About half of the rear side of the cover 52 is a lid that can be opened and closed so that the battery 55 can be attached to and detached from the battery mounting space 153. The reinforcing beam 13 of the upper frame is provided at a position shifted forward of the reinforcing beam 23 of the lower frame in order to allow the lid to be opened and closed.

(4) In the space 56, a mounting board for a heat-generating component is disposed in a layer below the battery mounting space 153 in surface contact with the bottom plate 51. A rotational speed control component (ESC: Electronic Speed Control) of the motor and a step-down distribution machine are mounted on the mounting board. The step-down distribution machine steps down the DC power supplied from the battery 55 to a voltage suitable for the drive voltage of the motor and the drive voltage of the control circuit and distributes the voltage. The ESC and the step-down electric generator generate high heat.

適宜 An appropriate number of circuit boards 58 are arranged on the bottom plate 51 of the body 50 in front of the space 56. A control circuit such as a flight controller, a circuit for processing signals from various sensors, a communication circuit, and the like are mounted on these circuit boards 58.

(6) A six-axis gyro sensor, which is a means for measuring the acceleration of the drone and calculating the speed by integrating the acceleration, is arranged on the back surface, that is, the lower surface side of the battery receiving member 152 constituting the battery mounting space 153. The six-axis gyro sensor has an acceleration sensor that detects accelerations in three axes directions orthogonal to each other, and an angular velocity sensor that detects angular velocities of rotation around the three axes, for example, pitching, rolling, and yawing. ing.

The position of the center of gravity of the drone when two batteries 55 are loaded in the battery mounting space 153 is in a planar direction, that is, between the two batteries 55 when the drone is viewed from above, and the heavy battery 55 is loaded. By doing so, it is at a relatively lower position in the vertical direction. On the other hand, the rotation center P of the attitude control of the drone by the rotation control of the four sets of motors is, as viewed from the plane, the intersection of the lines connecting the centers of the diagonal motors as shown in FIG. , As shown in FIG. 3, at the center of the distance between the upper and lower motors.

The horizontal line of the lift generated by the rotation of the four sets of motors, that is, the horizontal line including the rotation center P of the attitude control, is above the position of the center of gravity of the drone. In other words, by arranging the battery 55 which is a fixed weight, the center of gravity of the drone is located below the rotation center P.

By setting the positional relationship between the position of the center of gravity of the drone and the horizontal line for generating lift as described above, the stability of the posture of the drone and the energy saving required for the posture control can be achieved.

薬剤 A medicine tank 104 is arranged below the body 50 with a space 70 between the medicine tank 104 and the lower surface of the body 50. The medicine tank 104 stores the medicine to be sprayed. Since the medicine is sprayed while flying over the field, the medicine tank 104 is a variable weight material. The drug tank 104, which is a variable weight object, is disposed further below the center of gravity of the drone, and is designed to reduce the influence of weight fluctuation on the attitude control of the drone.

[GPS sensor]

GPS sensors

60, 60 are attached to the two

second support arms

11, 12 constituting the upper frame, facing upward. The

GPS sensors

60, 60 are composed of, for example, an RTK antenna and an RTK-GPS (Real Time Kinematic-Global Positioning System) module. The

GPS sensors

60, 60 measure the absolute position of the drone, determine whether the measured position is, for example, a position according to a program, and rotate each of the drive motors to a correct position if the position is shifted. Control.

When the

GPS sensors

60, 60 vibrate, the accuracy of the drone's absolute position measurement decreases, and the accuracy of the position control also decreases. Therefore, in the illustrated embodiment, the

GPS sensors

60, 60 are located at the positions farthest from the respective drive motors so that the second support arms 11 are not affected by the vibration of the respective drive motors serving as vibration sources. , 12 are installed substantially at the center in the length direction.

The installation positions of the

GPS sensors

60 and 60 are located between the front and rear propeller guards 41 and 42 and between the propeller guards 43 and 44, respectively, when viewed from the plane. The

second support arms

11, 12 are located near the

columns

30, 30, which connect the upper and lower frames of the

GPS sensors

60, 60, to positions where the

second support arms

11, 12 are less likely to vibrate. Therefore, the

GPS sensors

60, 60 are hardly affected by the vibrations of the drive motors, and can measure the position of the drone with high accuracy.

[Frame cooling effect]
According to the configuration of the flying object and its frame described above, the following cooling effects can be obtained.

内蔵 Built-in components including heat-generating components, such as a motor rotation control component and a distribution machine, are mounted on the body 50. The bottom plate 51 and the cover 52 constituting the body 50 are made of a heat conductive material, and the heat generated from the heat-generating components is transmitted to the body 50 and dissipated. Therefore, the body 50 is a main part for dissipating the heat generated by the heat-generating components.

Furthermore, the bottom plate 51 of the body 50 is connected to the reinforcing beams 23 of the lower frame made of a heat conductive material, and the reinforcing beams 23 are further connected to the

second support arms

21 and 22. The cover 52 of the body 50 is also connected to the reinforcing beam 13 of the upper frame made of a heat conductive material, and the reinforcing beam 13 is connected to the

second support arms

11 and 12. As described above, the heat generated in the built-in components is easily transmitted from the body 50 to the frame. Even if the heat dissipation by the body 50 is insufficient, the frame compensates for the heat dissipation.

The body 50 is surrounded by a pair of front and rear propellers located on the left and right sides. When each propeller is rotationally driven, a downward flow of air is generated along the left and right sides of the body 50. The downward flow of the air flows at a relatively high speed in a substantially triangular space viewed from the plane direction defined by the left and right side surfaces of the body 50 and the front and rear propeller guards. In this embodiment, four propellers each have a two-stage configuration with upper and lower portions, and it is known that the downflow is more concentrated and a stronger downflow occurs than the one-stage configuration of the propeller.

As described above, in the present embodiment, both sides of the body 50 and a part of the frame are located in the flow path of the downward flow generated by the two-stage propeller intensively and at a high speed. More specifically, a downward flow flows along both side surfaces of the body 50, and both ends of the

first support arms

10 and 20, substantially the entirety of the

second support arms

11, 12, 21 and 22, and the reinforcing

beams

13 and 23. Are traversing the downflow channel. Therefore, the heat transmitted to the body 50 and the frame from the body 50 is effectively dissipated, and the temperature rise of the built-in components is suppressed.

[Drone use example]
FIG. 10 schematically shows an overall conceptual diagram of a system using an embodiment of the drone 100 according to the present invention for spraying medicine. The pilot 401 can transmit a command to the drone 100 by an operation of the user 402, and can display information received from the drone 100, for example, information such as a position, a medicine amount, a battery remaining amount, and a camera image. . The pilot 401 may be realized by a portable information device such as a general tablet terminal that runs a computer program.

The drone 100 according to the present embodiment is controlled so as to perform an autonomous flight, but it is preferable that a manual operation can be performed at the time of basic operations such as takeoff and return, and in an emergency. In addition to the portable information device, an emergency operation device having a function dedicated to emergency stop may be used. It is desirable that the emergency operating device is a dedicated device equipped with a large emergency stop button and the like so that an emergency operation can be quickly performed. 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 field or a field to which the drone 100 is to apply the medicine. Actually, the terrain of the field 403 is complicated, and there is a case where a topographic map cannot be obtained in advance, or a case where the topographic map and the situation of the site are different. Usually, the field 403 is adjacent to houses, hospitals, schools, other crop fields, roads, railways, and the like. Further, an obstacle such as a building or an electric wire may exist in the field 403.

The base station 404 is a device that provides a master device function or the like of Wi-Fi communication, and also functions as an RTK-GPS base station, and desirably provides an accurate position of the drone 100. The master device function of Wi-Fi communication and the RTK-GPS base station may be independent devices. The farming cloud 405 is typically a group of computers and related software operated on a cloud service, and is desirably wirelessly connected to the controller 401 via 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. The farming cloud 405 can provide the stored topographical information of the field 403 to the drone 100, and in addition, accumulates the history of the flight and photographed images of the drone 100 and may perform various analysis processes. .

Normally, the drone 100 takes off from the departure / departure point 406 outside the field 403 and returns to the departure / departure point 406 after spraying the medicine on the field 403 or when it becomes necessary to replenish or charge the medicine. The flight route (also referred to as the intrusion route) from the departure / arrival point 406 to the target field 403 may be stored in advance in the farming cloud 405 or the like, or may be input before the user 402 starts takeoff. .

[Drone control system]
FIG. 11 is a block diagram showing a control function of the embodiment of the medicine spraying drone according to the present invention. The flight controller 501 is a component that controls the entire drone, and may specifically be an embedded computer including a CPU, a memory, related software, and the like. The flight controller 501 controls the motors 102-1a and 102-1b via control means such as ESC (Electronic Speed Control) based on input information received from the pilot 401 and input information obtained from various sensors described below. , 102-2a, 102-2b, 102-3a, 102-3b, 102-4a, and 102-4b to control the rotation speed of the drone 100.

The actual rotation speed of each motor is fed back to the flight controller 501 so that it can be monitored whether normal rotation is being performed. An optical sensor or the like may be provided on the propeller so that the rotation speed of the propeller is fed back to the flight controller 501.

The software used by the flight controller 501 is desirably 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. It is desirable to protect by encryption, checksum, electronic signature, virus check software, etc. so that rewriting by unauthorized software is not performed.

Part of the calculation processing used by the flight controller 501 for control may be executed on the pilot 401, on the farming cloud 405, or by another computer existing in another place. The flight controller 501 is a highly important part that forms the core of the drone, and it is desirable that some or all of its components be duplicated.

The battery 55 is a means for supplying power to the flight controller 501 and other components of the drone, and is preferably a rechargeable battery. The battery 55 is connected to the flight controller 501 via a fuse or a power supply unit including a circuit breaker or the like. It is desirable that the battery 55 be a smart battery having a function of transmitting the internal state, that is, the amount of stored power, the accumulated use time, and the like to the flight controller 501 in addition to the power supply function.

The flight controller 501 communicates with the pilot 401 via the Wi-Fi slave unit function 503 and further via the base station 404, receives necessary commands from the pilot 401, and receives necessary information from the pilot 401. Can be sent to The communication should be encrypted so as to prevent eavesdropping, impersonation, hijacking of devices, and other illegal acts.

It is desirable that the base station 404 has a function of an RTK-GPS base station in addition to a communication function by Wi-Fi. 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 the GPS module. Further, in order to cope with a failure of a specific GPS satellite, it is preferable that each redundant GPS module 504 is controlled to use another satellite.

The 6-axis gyro sensor 505 is a means for measuring the acceleration of the drone body in three orthogonal directions orthogonal to each other, a means for calculating the velocity by integrating the acceleration, and a means for detecting the angular velocity of rotation about the three axes. . The geomagnetic sensor 506 is means for measuring the direction of the drone body by measuring geomagnetism. The air pressure sensor 507 is a means for measuring the air pressure, and can also indirectly measure the altitude of the drone. The laser sensor 508 is a means for measuring the distance between the drone aircraft and the surface of the earth using reflection of laser light, and it is preferable to use an infrared (IR) laser. The sonar 509 is a unit that measures the distance between the drone body and the ground surface using reflection of sound waves such as ultrasonic waves.

These sensors may be selected according to the cost objectives and performance requirements of the drone. In addition, a gyro sensor (angular velocity sensor) for measuring the inclination of the aircraft, a wind sensor for measuring wind power, and the like may be added. Also, it is desirable that these sensors are duplicated or multiplexed. When there are a plurality of sensors for the same purpose, the flight controller 501 may use only one of them, and may switch to an alternative sensor when it fails. Alternatively, a plurality of sensors may be used simultaneously, and if the respective measurement results do not match, it may be determined that a failure has occurred.

The flow rate sensor 510 is a means for measuring the flow rate of the medicine, and is desirably provided at a plurality of locations 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 multispectral camera 512 is a unit that captures the image of the field 403 and acquires data for image analysis. The obstacle detection camera 513 is a camera for detecting a drone obstacle, and is mounted separately from the multispectral camera 512 because the image characteristics and the lens direction are different from those of 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, particularly 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 or a cover for internal maintenance is open. The drug inlet sensor 517 is a sensor that detects that the inlet of the drug tank 104 is open.

センサー These sensors may be selected according to the cost targets and performance requirements of the drone, and may be duplicated or multiplexed. Further, a sensor may be provided at the external base station 404, the pilot 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 to transmit information about the wind and the wind direction to the drone 100 via Wi-Fi communication.

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

The LED 107 is display means for notifying the drone operator of the status of the drone. A display means such as a liquid crystal display may be used instead of or in addition to the LED. The buzzer 518 is an output unit for notifying a drone state, particularly an error state, by an audio signal. The Wi-Fi slave device function 519 is an optional component for communicating with an external computer or the like for transferring software, for example, separately from the controller 401.

Instead of or in addition to the Wi-Fi slave 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. May be used. The speaker 520 is an output unit that notifies a drone state, particularly an error state, by using a recorded human voice or a synthesized voice. Depending on the weather conditions, the visual display of the drone 100 during flight may be difficult to see, and in such a case, voice communication of the situation is effective. The warning light 521 is a display means such as a strobe light for notifying a drone state, particularly 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.

[Relaxation sensor]
Next, the characteristic components of the present invention will be described. As shown in FIG. 11, in addition to the various sensors described above, a relaxation sensor 530 is provided, and a detection signal of the relaxation sensor 530 is input to the flight controller 501. The relaxation sensor 530 is a sensor that detects looseness or rattling of a structural component of a body mainly composed of a frame having the

first support arms

10 and 20 and the

second support arms

11, 12, 21 and 22. is there. Further, as described later, the relaxation sensor 530 may be arranged inside the accommodation space of the substrate of the drone body.

マイクロ As the relaxation sensor 530, for example, a microphone can be used. There is a difference in the sound or noise emitted when the propeller is driven to rotate between a normal condition where there is no looseness or rattling of the structural components of the aircraft and a case where there is loosening or rattling. Occurs. The difference between the sound or noise in the normal state and the abnormal state is mainly a difference in frequency or an abnormal sound generated only in the abnormal state. Therefore, a microphone for detecting the noise of the drone is attached to the drone, and the detection signal converted into electroacoustic by the microphone is processed to detect an abnormality.

フィルタ The output signal of the microphone is filtered for each frequency band, and if an abnormality is found in a specific frequency band, it can be determined that the body is loose or rattling. Alternatively, when an abnormal signal that does not appear in a normal state is detected in comparison with a detection signal in a normal state, it can be determined that the machine body is loosened or rattled. The method of determining looseness and rattling of the body based on the output signal of the microphone is not limited to these methods, and other methods may be used.

In particular, the relaxation sensor 530 using a microphone also serves as a sensor (hereinafter, also referred to as an “existing sensor” for convenience) used for flight control of the drone, such as an acceleration sensor, a 6-axis gyro sensor 505, and an angular velocity sensor described later. It has a higher sampling frequency as compared with the case where a relaxation sensor is configured by using the above-described method.

サンプリング The sampling frequency of the existing sensor depends on the control cycle of the drone aircraft, and is, for example, about 100 Hz. On the other hand, the frequency band of the vibration that increases due to the aged deterioration of the drone is a high frequency band of 1 kHz to 2 kHz. The vibration in this frequency band is caused, for example, by a gel washer such as a silicon washer or a bush between frames or fixing a substrate becoming loose. Further, the vibration in this frequency band is a vibration that affects the elements on the substrate, and is a vibration that has a high possibility of causing a failure such as breakage of defective soldering.

The sensor generally uses a frequency that is sufficiently lower than the Nyquist frequency and about one third of the sampling frequency as a detectable range. Therefore, it is difficult to detect the above-mentioned vibration in the frequency band by the existing sensor. In addition, if the sampling frequency of the existing sensor is set to be high, the control cycle of the drone body will be changed, which has a great influence on other configurations. Therefore, by separately providing a microphone driven at a higher sampling frequency than the existing sensor, vibration in a high frequency band can be measured independently of the control cycle of the drone body.

The sampling frequency of the microphone may be a frequency capable of sufficiently measuring at least a frequency of 1 kHz to 2 kHz, for example, 6 kHz or more, and may be a microphone capable of collecting sound in an audible region.

Note that the relaxation sensor 530 may be configured by combining a plurality of sensors that detect vibrations in different frequency bands.

The microphone is located inside the drone fuselage, especially inside the accommodation space for the substrate. Further, the microphone is connected to a recording medium different from a recording area in which data of the existing sensor is recorded, and sound collection data by the microphone is stored in the recording medium. According to the configuration in which the microphone is arranged inside the accommodation space of the substrate, the microphone can be prevented from being stained with dust or water, as compared with the configuration in which the microphone is exposed outside the body. In addition, the microphone can be isolated from the sound from the outside of the drone, so that the collection of noise generated outside the drone can be prevented.

場合 If the drone's body is loose, the output signal of the acceleration sensor attached to the drone will be abnormal. Therefore, an acceleration sensor may be used as the relaxation sensor 530. The acceleration sensor may be mounted as a dedicated device for detecting the relaxation of the body, or the six-axis gyro sensor 505 may also be used as the relaxation sensor 530. When the six-axis gyro sensor 505 is also used as the relaxation sensor 530, not only the acceleration sensor of the six-axis gyro sensor 505 but also the angular velocity sensor can be used as the relaxation sensor 530.

(4) The attachment position of the relaxation sensor 530 is arbitrary, but it is desirable that the attachment position be a position where the looseness and rattling of the body can be effectively detected. In the drone body according to the above-described embodiment, the frames having the first and second support arms form a vertical pair, and the upper and lower frames are connected by columns. The upper and lower pairs of frames each have a reinforcing beam to form a trapezoidal three-dimensional space. The relaxation sensor 530 is arranged inside the trapezoidal three-dimensional space. More specifically, a body 50 is arranged in the trapezoidal three-dimensional space, and a relaxation sensor 530 is arranged in the body 50.

When the 6-axis gyro sensor 505 also serves as the relaxation sensor 530, the 6-axis gyro sensor 505 is disposed in the body 50 as described above. In the body 50, a component mounting portion for mounting components including vibration suppressing components such as the battery 55, the battery receiving member 152, and the battery fastener 154 is arranged. The component mounting portion is vertically layered, and the six-axis sensor is arranged in a layer below the layer on which the vibration suppressing component is mounted. Therefore, when the six-axis gyro sensor 505 also functions as the relaxation sensor, the relaxation sensor is disposed in the body 50 and below the mounting portion of the vibration suppression component.

[Evacuation behavior]
If the structural components of the body of the drone having the frame become loose or rattle, the body generates abnormal noise. The abnormal noise is a sound in a frequency band different from a normal state, or a sound generated suddenly or irregularly. The abnormal sound is detected by the relaxation sensor 530 (see FIG. 11) including the microphone, the acceleration sensor, and the like, and an abnormal signal is output. When an abnormality detection signal is input from the relaxation sensor 530, the flight controller 501 controls the rotation of each of the propeller drive motors 102-1a to 102-4b via the ESC to cause the drone to perform an evacuation action.

The evacuation action is any of emergency return, emergency landing, and emergency stop, and the flight controller 501 causes any of the above-described evacuation actions according to the degree of abnormal noise, that is, the strength of the abnormality detection signal of the relaxation sensor 530. Emergency return is performed if the noise is relatively slight, emergency landing is performed if the noise is moderate, and emergency stop is performed if the noise is strong. The emergency return is, for example, returning to the original position from which the aircraft has taken off and landing. Emergency landing is landing on the spot. Emergency stop means stopping all propeller drive motors and crashing on the spot. It is safer to crash the drone than to lose control.

As one of the evacuation actions, hovering may be performed once, and when the abnormality detection signal from the relaxation sensor 530 disappears during hovering, the hovering may be returned to a normal operation state. When an abnormality detection signal is output from the relaxation sensor 530 during hovering, one of emergency return, emergency landing, and emergency stop is performed according to the intensity of the abnormality detection signal.

フライト When the evacuation action is taken, the flight controller 501 stops the pump 106 to stop spraying the medicine. Further, the flight controller 501 may activate the LED 107 and the warning light 521 to visually display the emergency, and may activate the buzzer 518 and the speaker 520 to acoustically display the emergency.

As described above, according to the embodiment of the flying body according to the present invention, when the structural members of the airframe are loosened or rattled, the relaxed sensor detects the loosened or rattled and outputs an abnormal signal. Since the drone performs the evacuation action by the output of the abnormal signal, it is possible to avoid in advance the problems caused by the deterioration of various control accuracy due to the looseness and rattling of the body structural parts. The faults include departure from the planned flight path, variations in flight altitude, variations in attitude control and speed control, and in some cases, collisions with obstacles, but according to the present embodiment. Thus, such a problem can be avoided.

As described above, the agricultural chemical spraying drone has been described as an example of the present embodiment, but the technical idea of the present invention is not limited to this, and can be applied to drones in general.

10 First Support Arm 11 Second Support Arm 12 Second Support Arm 13 Reinforcement Beam 20 First Support Arm 21 Second Support Arm 22 Second Support Arm 23 Reinforcement Beam 50 Body 51 Bottom Plate 60 GPS Sensor 153 Battery Mounting Space 530 Relaxation Sensor

Claims

An airframe having an airframe, and a plurality of propeller drive motors mounted on the airframe and individually driving a plurality of propellers, wherein the airframe has a frame supporting the plurality of propeller drive motors. hand,
A relaxation sensor that detects looseness and rattling of structural parts of the body including the frame is attached to the body,
A flying object that performs an evacuation action when the relaxation sensor outputs an abnormal signal.
The flying object according to claim 1, wherein the relaxation sensor is a microphone, and performs an evacuation action when the microphone detects abnormal noise.
The flying object according to claim 2, wherein the abnormal noise is a sound in a frequency band different from a sound in a frequency band generated in a normal state.
The flying object according to claim 1, wherein the relaxation sensor is an acceleration sensor, and performs an evacuation action when the acceleration sensor detects abnormal acceleration.
The aircraft according to claim 4, wherein the acceleration sensor is also used as a six-axis sensor for controlling the attitude of the aircraft.
The frame includes one first support arm, and two second support arms that extend obliquely symmetrically from the middle of the length of the first support arm, and both ends of the first support arm. The flying object according to any one of claims 1 to 5, wherein the propeller drive motor is supported by a portion and a tip portion of the second support arm, respectively.
7. The flying object according to claim 6, wherein the two second support arms extend from the first support arm in a direction in which respective tip portions spread.
8. The flying object according to claim 6, wherein the frame has a reinforcing beam that connects the two second support arms at an intermediate position in a length direction. 9.
The first support arm, the second support arm, and the frame having the reinforcing beam are vertically arranged, and the upper and lower frames are connected by columns, and the first support arm, the second support arm, The flying object according to claim 8, wherein a trapezoidal three-dimensional space is formed by the reinforcing beams, and the relaxation sensor is disposed in the three-dimensional space.
The propellers are arranged at a total of four places in front, rear, left and right in a plan view, and the left and right propeller intervals are wider than the front and rear propeller intervals, and a component mounting unit for mounting a component including a vibration suppression component between the left and right propellers. The flying object according to any one of claims 1 to 9, wherein is disposed.
11. The flying object according to claim 10, wherein the component mounting portion is vertically layered, and the relaxation sensor is disposed in a layer below the layer on which the vibration suppression component is mounted.
The flying object according to any one of claims 1 to 11, wherein the evacuation action is one of an emergency return, an emergency landing, and an emergency stop.