JP6999290B2 - Flight equipment, flight methods and flight programs - Google Patents

Description

The present invention relates to flight devices, flight methods and flight programs.

Conventionally, the use of small unmanned aerial vehicles (also called "drones") has been proposed. A technique for collecting video information using such a drone has been proposed (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-27331

By the way, if the motor that drives the drone is out of order due to a failure or the like, there is a danger of it crashing. Even if the motor itself is not defective, if the propeller connected to the motor is damaged or the center of gravity of the drone is off, there is still a danger of a crash. If the motor stops, the propeller is completely damaged, or the center of gravity shifts significantly, the possibility of a crash increases. It needs to be detected early.

The present invention is an attempt to solve such a problem, and an object of the present invention is to provide a flight device, a flight method, and a flight program capable of detecting a defect at an early stage by monitoring the condition of a motor.

The first invention is a flight device capable of autonomous flight, which has a plurality of motors connected to a propeller for obtaining thrust, and the motors are brushless DC motors (brushless direct) controlled by vector control. A motor information acquisition means for acquiring motor information including the angular speed of the rotor of each motor acquired in the vector control process and the voltage supplied to each motor, and the motor information. Based on this, it is a flight device having a motor state determining means for determining the state of each of the motors.

According to the configuration of the first invention, the flight apparatus can determine the state of each motor by the motor state determination means. Then, since the motor state determination means determines the state of the motor based on the angular velocity of the rotor, it is necessary to determine the abnormality of the motor at a stage before a fatal state such as a motor failure and stop. Can be done. That is, by monitoring the condition of the motor, it is possible to detect a defect at an early stage.

According to the second aspect of the present invention, in the configuration of the first invention, the motor state determining means is configured to determine that a malfunction has occurred in the motor when the angular velocity with respect to the voltage is not within the allowable range. It is a flight device.

In the third invention, in the configuration of the first invention or the second invention, when it is determined by the motor state determining means that the motor is not defective, the thrust generated by each motor is within the permissible range. It is a flight device having a thrust determination means for determining whether or not it is inside.

The fourth invention is a flight method carried out by a flight device capable of autonomous flight by obtaining thrust by a brushless direct rotor motor controlled by vector control, and is acquired in the process of vector control. Motor information acquisition step for acquiring motor information including the angular speed of the rotor of each motor and the voltage supplied to each motor, and motor state determination for determining the state of each motor based on the motor information. A flight method that includes steps.

A fifth aspect of the invention is to obtain a computer for controlling a flight device capable of autonomous flight by obtaining thrust by a brushless direct rotor motor controlled by vector control, each of which is acquired in the process of vector control. Motor information acquisition means for acquiring motor information including the angular speed of the rotor of the motor and the voltage supplied to each motor, and motor state determination means for determining the state of each motor based on the motor information. It is a flight program to function as.

According to the present invention, by monitoring the condition of the motor, it is possible to detect a defect at an early stage.

It is a schematic diagram which shows the flight apparatus and the base station which concerns on embodiment of this invention. It is a schematic diagram which shows the functional block of a flight apparatus. It is a schematic diagram which shows the structure of a motor. It is a schematic diagram which shows the structure of a motor and the like. It is a flowchart which shows the operation of a flight apparatus.

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

As shown in FIG. 1, the flight system of the present embodiment includes a flight device 1 (hereinafter referred to as "unmanned aerial vehicle 1") and a base station 100 capable of communicating with the unmanned aerial vehicle 1. The base station 100 is a personal computer and also includes a charging device (not shown) for the unmanned aerial vehicle 1.

The unmanned aerial vehicle 1 starts flying according to an instruction from the base station 100, and is charged at the base station 100.

The unmanned aerial vehicle 1 has a housing 2. A computer for controlling each part of the unmanned aircraft 1, an autonomous flight device, a wireless communication device, a positioning device using a GPS (Global Positioning System), an inertial sensor, a pressure sensor, a battery, and the like are arranged in the housing 2. Further, a camera 14 is arranged in the housing 2 via a fixing device 12. The camera 14 is a visible light camera or a near-infrared camera, but may be a switchable hybrid camera. The fixing device 12 is a three-axis fixing device (so-called gimbal) capable of minimizing blurring of an image captured by the camera 14 and controlling the optical axis of the camera 14 in an arbitrary direction.

A round bar-shaped arm 4 is connected to the housing 2. A motor 6 is connected to each arm 4, and a propeller 8 is connected to each motor 6. The motor 6 is an outer rotor type brushless DC motor (brushless direct current motor). The brushless DC motor of the unmanned machine 1 has a configuration in which a permanent magnet is arranged on a rotor (rotor) and a winding (coil) is arranged on a stator (stator).

The unmanned aerial vehicle 1 sequentially switches the direction of the magnetic flux by controlling the direction of the current supplied to the winding of the stator (referred to as "commutation"). A rotating magnetic field is formed by sequentially switching the direction of the magnetic flux. As a result, the permanent magnets arranged on the rotor and the stator are repeatedly attracted and repelled, and the rotor is configured to rotate. The timing of commutation is controlled by vector control. Vector control will be described later.

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

FIG. 2 is a diagram showing a functional configuration of the unmanned aerial vehicle 1. The unmanned machine 1 includes a CPU (Central Processing Unit) 50, a storage unit 52, a wireless communication unit 54, a GPS (Global Positioning System) unit 56, an inertial sensor unit 58, a motor control unit 60, an image processing unit 64, and a power supply unit. Has 70.

The unmanned aerial vehicle 1 can communicate with the base station 100 by the wireless communication unit 54. The unmanned aerial vehicle 1 receives an instruction such as starting from the base station 100 by the wireless communication unit 54.

The unmanned aerial vehicle 1 can measure the position of the unmanned aerial vehicle 1 itself by the GPS unit 56 and the inertial sensor unit 58. The GPS unit 56 basically receives radio waves from three or more GPS satellites and measures the position of the unmanned aerial vehicle 1. The inertial sensor unit 58 measures the position of the unmanned aerial vehicle 1 by integrating the movement of the unmanned aerial vehicle 1 from the starting point by, for example, an acceleration sensor and a gyro sensor.

The unmanned aerial vehicle 1 controls the rotation of each motor 6 connected to each propeller 8 by the motor control unit 60.

The image processing unit 64 allows the unmanned aerial vehicle 1 to operate the camera 14 to acquire an external image.

The power supply unit 70 is, for example, a replaceable rechargeable battery, and is adapted to supply electric power to each unit of the unmanned aerial vehicle 1.

3 and 4 are diagrams showing the configuration of each motor 6. The motor 6 includes a motor control unit 60 and a motor main body unit 62. The motor main body 62 includes a plurality of stators (stator) to which multi-phase electric power is supplied, and a rotor (rotor) that rotates by receiving a magnetic action from these stators. In the motor control unit 60, for example, information regarding the start and stop of the motor body unit 62 and information regarding the rotation speed of the motor body unit 62 are input. The motor control unit 60 is composed of a group of transistors that switch under the control of a CPU (not shown), and energizes the stator of the motor body unit 62 to drive the motor body unit 62.

FIG. 4B is a conceptual diagram for explaining vector control. In FIG. 4B, the three stators U, V and W are arranged at equal intervals of 120 degrees. At the center of the three stators, NS two-pole permanent magnets are arranged. The magnetic flux direction of the permanent magnet is the d-axis, and the direction perpendicular to it is the q-axis. In vector control, the d-axis current and the q-axis direction are controlled individually. In actual control, the d-axis current and q-axis current are not obtained directly from the three-phase current values, but first phase conversion is performed to the α-axis that is the same as the U-phase and the β-axis that is perpendicular to it, and then the d-axis current. And the q-axis current is calculated. The motor 6 of the present embodiment is an outer rotor type, unlike the conceptual diagram of FIG. 4B, and the number of salient poles (number of stators) is, for example, 12, and is three-phase (that is, 4). One salient pole constitutes one phase).

The outline of the basic flow of vector control will be described with reference to FIG. 4A. First, the voltage of the shunt resistor is measured by an AD converter and converted into a three-phase current value (Iu, Iv, Iw). Next, the three-phase current value is converted into a two-phase current value, that is, a d-axis current value (Id) and a q-axis current value (Iq). Next, the d-axis induced voltage Ed is used to calculate the angular velocity ω of the rotor and the electric angle θ of the rotor. Next, the current command value (Idref, Iqref) is calculated from the target velocity ωref and the actual velocity ω by PI control (Proportional-Integral-Differential). Next, the output voltage (Vd, Vq) is calculated from the current command values (Idref, Iqref) and the actual current values (Id, Iq) by PI control. Then, the output voltage (Vd, Vq) is converted into a three-phase (U, V, W) voltage (PWM pulse width). The angular velocity ω of the rotor is controlled by this three-phase voltage. Here, if the load torque T is constant, the angular velocity ω of the rotor is proportional to the output voltage (and the three-phase voltage). However, when the propeller is connected to the rotor, the load torque T increases as the rotation speed of the propeller increases.

In the above basic flow, the d-axis induced voltage Ed is calculated by Equation 1: Ed = Vd-R × Id + ωest × Lq × Iq (Ed: d-axis induced voltage, Vd: d-axis applied voltage, R: rotor coil). Resistance, Id: d-axis current, Iq: q-axis current, ωest: estimated speed, Lq: q-axis rotor coil inductance). Ed is calculated from the previously measured ωest0 and the current Vd, Id, and Iq by Equation 1. Using the deviation between the calculated Ed and the target value (Ed = 0), the manipulated variable of ω (R_Ed_Pi) is obtained from PI control. From the manipulated variable of ω (R_Ed_Pi), the new estimated speed is calculated by Equation 2: ωest = ωcom + (R_Ed_Pi), and the new estimated position is calculated by Equation 3: θ _n = θ _n-1 + Ts × ωest (ωest: estimated speed, ωcom: target speed, R_Ed_Pi: ω operation amount, Ts: control cycle, θ: rotor electric angle).

In the present embodiment, the state of the motor 6 itself is first determined based on the angular velocity ω of the rotor calculated in the process of the above-mentioned vector control, and then the abnormality of the environment including the possibility of damage of the propeller 8 is determined. It is designed to judge the presence or absence.

Returning to FIG. 2, in the storage unit 52 of the unmanned machine 1, various data and programs necessary for autonomous movement such as data indicating a movement plan for autonomous movement from the starting point to the target position, topography and shape of the planned work area. In addition to the information indicating the position of the structure and the structure, the following programs are stored.

The storage unit 52 stores a flight control program, a drive control program, a motor information acquisition program, a motor state determination program, a thrust determination program, and a corresponding program. The CPU 50 and the flight control program are examples of flight control means. The CPU 50 and the drive control program are examples of drive control means. The CPU 50 and the motor information acquisition program are examples of motor information acquisition means. The CPU 50 and the motor state determination program are examples of the motor state determination means. The CPU 50 and the thrust determination program are examples of thrust determination means. The CPU 50 and the corresponding program are examples of the corresponding means.

The unmanned aerial vehicle 1 controls the autonomous flight of the unmanned aerial vehicle 1 by a flight control program. Specifically, when the unmanned aerial vehicle 1 deviates from the planned flight path or the flight attitude is disturbed, the output of each motor 6 is adjusted to maintain a predetermined flight path and altitude. ing. The flight path is received from the base station 100. The unmanned aerial vehicle 1 also controls the drive of the motor 6 by the flight control program.

The unmanned aerial vehicle 1 acquires the output voltage (Vd, Vq) and the angular velocity ω of the rotor from each motor 6 by the motor information acquisition program. In addition, instead of the output voltage (Vd, Vq), a three-phase voltage may be acquired and used for the following processing. The output voltage (Vd, Vq) and the three-phase voltage are examples of the voltage supplied to the motor.

The unmanned aerial vehicle 1 determines the state of each motor 6, that is, whether or not each motor 6 is operating normally by the motor state determination program. Specifically, the unmanned aerial vehicle 1 determines whether or not the angular velocity ω with respect to the output voltage is within the permissible range, and if it is not within the permissible range, it is determined that the corresponding motor 6 has a problem. Since the propeller 8 is connected to the motor 6, the angular velocity ω is defined by the output voltage and the load torque T that varies depending on the rotation speed of the propeller 8. Since the rotation speed of the propeller 8 is defined by the angular velocity ω, the variables are the angular velocity ω and the output voltage.

The storage unit 52 of the unmanned aerial vehicle 1 stores data indicating the relationship between the angular velocity ω and the output voltage when the motor 6 is operating normally. Assuming that the permissible range (error range) is ± 5%, the unmanned machine 1 is when the angular velocity ω shown in the motor information deviates by ± 5% or more from the angular velocity ω1 determined for the output voltage. Determines that the motor 6 has a problem. In the present specification, the angular velocity of the motor 6 within the allowable range is referred to as "normal speed" (state in which a defect has not occurred), and the angular velocity of the motor 6 outside the allowable range is referred to as "abnormal speed" (state in which a defect has occurred). .. The unmanned aerial vehicle 1 determines whether each motor 6 has a normal speed or an abnormal speed.

The unmanned aerial vehicle 1 determines that no problem has occurred in the motor 6 itself when the state of any of the motors 6 is at a normal speed, but there are cases where a problem has occurred in a part other than the motor 6. For example, if the propeller 8 is damaged or the position of the center of gravity of the unmanned aerial vehicle 1 is deviated from the initial setting, there is a problem in parts other than the motor 6 (hereinafter, also referred to as "environmental abnormality"). It is.). In a state where there is an abnormality in the environment, the thrust is insufficient even if the motor 6 itself does not have a problem. The unmanned aerial vehicle 1 increases the rotation speed of the target motor 6 by a flight control program in order to make up for the abnormal condition in the environment.

When it is determined that the state of any of the motors 6 is the normal speed, the unmanned aerial vehicle 1 determines whether or not there is an abnormality in the thrust. Specifically, the unmanned machine 1 determines whether or not the rotation speed (angular velocity) of each motor 6 is within an allowable range with respect to the rotation speed (angular velocity) of the other motor 6 by a thrust determination program. As described above, there is a relationship that the original thrust of the motor 6 is not exerted when there is an abnormality in the environment. Therefore, determining whether or not there is an abnormality in the thrust is in a state where there is an abnormality in the environment. It is synonymous with determining whether or not there is.

As described above, even if each motor 6 is in a normal speed state, if there is an abnormality in the environment, the original thrust is not generated. Therefore, the unmanned aircraft 1 has a desired thrust according to the flight control program. Increase the number of revolutions (increase the angular velocity) in order to obtain. In other words, if the rotation speed (angular velocity) of the motor 6 affected by the environmental abnormality is set to the same rotation speed (angular velocity) as the motor 6 not affected by the environmental abnormality, the thrust will be insufficient and unmanned. Machine 1 is designed to increase the number of revolutions (angular velocity).

Then, the unmanned machine 1 compares the rotation speed (angular velocity) of each motor 6 with the rotation speed (angular velocity) of the other motor 6 by a thrust determination program, and determines whether or not the difference is within the allowable range.

The following is an example of judgment by the thrust judgment program. When the drone 1 moves forward, the thrusts of the two rear motors 6 are greater than the thrusts of the two front motors 6. The thrusts of the two front motors 6 are equal, and the thrusts of the two rear motors 6 are equal. Of the two front (or rear) motors 6, for example, if the propeller 8 connected to one motor 6 is damaged and the propeller 8 connected to the other motor 6 is not damaged, it is unmanned. The aircraft 1 uses a flight control program to make the number of revolutions of the motor 6 connected to the damaged propeller 8 higher than the number of revolutions of the other motor 6 so that the two motors 6 in the front (or rear) can rotate. Make the thrusts equal. Then, the unmanned aerial vehicle 1 compares the rotation speeds (angular velocities) of the two front (or rear) motors 6 by a thrust determination program, and determines whether or not the difference is within the permissible range (within the error range). .. The rotation speed (angular velocity) within the permissible range is, for example, within 5%. The unmanned aerial vehicle 1 determines that the thrust is abnormal when the rotation speed (angular velocity) of one motor 6 is 5% or more higher than the rotation speed (angular velocity) of the other motor 6.

Further, when the unmanned aerial vehicle 1 is stopped in the air (hovering), if the center of gravity of the unmanned aerial vehicle 1 is at the center, the thrusts of the four motors 6 are equal. However, for example, if the propeller 8 connected to one motor 6 is damaged, the original thrust of the motor 6 is not generated. Therefore, in order to obtain the same thrust as the other motors 6, the unmanned machine 1 is used. Increase the number of revolutions (angular velocity) by the flight control program. Then, the unmanned machine 1 compares the rotation speed (angular velocity) of one motor 6 with the rotation speed (angular velocity) of the other motor 6 by a thrust determination program, and determines whether or not the difference is within the allowable range. to decide. The rotation speed (angular velocity) within the allowable range is, for example, less than 5%. The unmanned machine 1 determines that the thrust is abnormal when the rotation speed (angular velocity) of one motor 6 is 5% or more higher than the average value of the rotation speed (angular velocity) of the other motor 6. Alternatively, the unmanned aerial vehicle 1 compares the rotation speed (angular velocity) of one motor 6 with the rotation speed (angular velocity) of the other three motors 6 and determines whether or not the difference is within the allowable range. May be good. Even in this case, the rotation speed (angular velocity) within the permissible range is, for example, within 5%. The unmanned machine 1 determines that the thrust is abnormal when the rotation speed (angular velocity) of one motor 6 is 5% or more higher than the average value of the rotation speed (angular velocity) of the other three motors 6.

The unmanned aerial vehicle 1 implements a predetermined response when a malfunction occurs in any of the motors 6 according to the response program, or when the thrust generated by any of the motors 6 is not within the allowable range. The predetermined response is, for example, a return to the base station 100.

Hereinafter, the operation of the unmanned aerial vehicle 1 will be described with reference to the flowchart of FIG. When the unmanned aircraft 1 receives a start instruction from the base station 100, it starts flying (step ST1), and acquires output voltage information and angular velocity information indicating the voltage continuously supplied to each motor 6 (step ST2). For the motor 6, it is determined whether or not the angular velocity is within the allowable range (step ST3). Step ST2 is an example of a motor information acquisition step, and step ST3 is an example of a motor state determination step. If the angular velocity is not within the permissible range, it is determined that the corresponding motor 6 has a problem (step ST4), and the motor returns to the base station (step ST5).

If it is determined in step ST3 that the angular velocity is within the permissible range, the unmanned aerial vehicle 1 determines whether or not the thrust is within the permissible range (step ST6), and if the thrust is not within the permissible range, the propeller 8 or the like. It is determined that an abnormality has occurred in the environment, such as a problem in the base station (step ST7), and the vehicle returns to the base station (step ST5). Step ST6 is an example of a thrust determination step, and step ST5 is an example of a corresponding step.

The present invention is not limited to each of the above-described embodiments, and modifications, improvements, and the like to the extent that the object of the present invention can be achieved are included in the present invention.

1 Flight device 2 Housing 6 Motor 8 Propeller

Claims (4)

It is a flight device capable of autonomous flight,
Has multiple motors connected to the propeller for thrust,
The motor is a brushless direct current motor controlled by vector control.
A motor information acquisition means for acquiring motor information including the angular velocity of the rotor of each motor acquired in the vector control process and the voltage supplied to each motor.
It has a motor state determining means for determining whether or not each of the motors is operating normally based on the motor information, and further.
The flight control program controls the autonomous flight and adjusts the output of each motor when the flight device deviates from the planned flight path or the flight attitude is disturbed, and the flight path and altitude specified in advance. When it is determined by the motor state determining means that the motor is not defective, the rotation speed (angular speed) of each of the motors is the rotation speed of the other motors. It has a thrust determining means for determining whether or not the thrust generated by each of the motors is within the allowable range by determining whether or not the (angular speed) is within the allowable range.
Flight equipment. The motor state determining means is configured to determine that a malfunction has occurred in the motor when the angular velocity with respect to the voltage is not within the allowable range.
The flight device according to claim 1. It is a flight method carried out by a flight device capable of autonomous flight by obtaining thrust by multiple brushless direct current motors controlled by vector control.
A motor information acquisition step for acquiring motor information including the angular velocity of the rotor of each motor acquired in the vector control process and the voltage supplied to each motor.
Based on the motor information, a motor state determination step for determining whether or not each motor is operating normally, and a motor state determination step.
The flight control program controls the autonomous flight and adjusts the output of each motor when the flight device deviates from the planned flight path or the flight attitude is disturbed, and the flight path and altitude specified in advance. When it is determined in the motor state determination step that there is no problem with the motor, the rotation speed (angular speed) of each of the motors is the rotation speed of the other motors. A thrust determination step for determining whether or not the thrust generated by each of the motors is within the allowable range by determining whether or not the (angular speed) is within the allowable range.
Flight methods including. A computer that controls a flight device capable of autonomous flight by obtaining thrust by multiple brushless direct current motors controlled by vector control.
A motor information acquisition means for acquiring motor information including the angular velocity of the rotor of each motor acquired in the vector control process and the voltage supplied to each motor.
Motor state determination means for determining whether or not each motor is operating normally based on the motor information,
In addition, the flight control program controls the autonomous flight, and when the flight device deviates from the planned flight path or the flight attitude is disturbed, the output of each of the motors is adjusted to adjust the output of the predetermined flight path. And, in a state where the altitude is maintained, when the motor state determination means determines that the motor has no problem, the rotation speed (angle speed) of each of the motors is the same as that of the other motors. A thrust determination means for determining whether or not the thrust generated by each of the motors is within the allowable range by determining whether or not the rotation speed (angle speed) is within the allowable range.
A flight program to function as.

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