Flight controller and flight control method

Abstract

The present disclosure relates to a flight controller, and the purpose of the disclosure is to provide a flight controller capable of controlling a small unmanned aerial vehicle so that the flight speed becomes zero just as the aerial vehicle arrives at a target position. A flight controller according to the present disclosure is configured to perform: a reception process for receiving position information and speed information from a small unmanned aerial vehicle; an acceptance process for accepting a target position to which to fly the small unmanned aerial vehicle and the flight time required for the small unmanned aerial vehicle to reach the target position; an acceleration calculation process for calculating an acceleration for the speed of the small unmanned aerial vehicle to become zero just as the aerial vehicle arrives at the target position, on the basis of the target position, the flight time, the position information, and the speed information; and a notification process for notifying the small unmanned aerial vehicle of the calculated acceleration.

Description

Flight controller and flight control method

[0001] The present disclosure relates to flight control technology for small unmanned aerial vehicles.

[0002] A technology for inspecting structures using a small unmanned aerial vehicle such as a drone has been disclosed. The small unmanned aerial vehicle is instructed to a target position by a flight controller operated by a pilot, and flies to the target position (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-176822

[0004] In the above-mentioned flight control, a flight controller that receives a target position calculates the acceleration of a small unmanned aerial vehicle and controls the small unmanned aerial vehicle to fly at that acceleration. However, conventional flight controllers were unable to calculate an acceleration that would cause the flight speed of the small unmanned aerial vehicle to become zero as soon as it arrived at the target position. As a result, the small unmanned aerial vehicle was unable to stop at the target position and there was a possibility of it colliding with other aerial objects or other small unmanned aerial vehicles.

[0005] In order to solve the above-mentioned problems, the first objective of the present disclosure is to provide a flight controller that can control a small unmanned aerial vehicle so that its flight speed becomes zero as soon as it arrives at a target position.

[0006] A second object of the present disclosure is to provide a flight control method that can control a small unmanned aerial vehicle so that its flight speed becomes zero as soon as it arrives at a target position.

[0007] A first aspect of the present disclosure is a flight controller that controls a small unmanned aerial vehicle, and is preferably configured to execute the following: a receiving process that receives position information and speed information from the small unmanned aerial vehicle; a receiving process that receives a target position to fly the small unmanned aerial vehicle and a flight time of the small unmanned aerial vehicle until it reaches the target position; an acceleration calculation process that calculates an acceleration at which the speed of the small unmanned aerial vehicle becomes 0 upon arrival at the target position based on the target position, the flight time, the position information, and the speed information; and a notification process that notifies the small unmanned aerial vehicle of the acceleration.

[0008] A second aspect of the present disclosure is a flight control method for a small unmanned aerial vehicle, preferably including the following steps: a flight controller executes a receiving process to receive position information and speed information from the small unmanned aerial vehicle; executes a receiving process to receive a target position to fly the small unmanned aerial vehicle and a flight time for the small unmanned aerial vehicle to reach the target position; executes an acceleration calculation process to calculate an acceleration at which the speed of the small unmanned aerial vehicle will become 0 upon arrival at the target position based on the target position, the flight time, the position information, and the speed information; executes a notification process to notify the small unmanned aerial vehicle of the acceleration; and the small unmanned aerial vehicle flies based on the acceleration.

[0009] According to the first and second aspects of the present disclosure, a flight controller and a flight control method can be provided that can control a small unmanned aerial vehicle so that its flight speed becomes zero as soon as it arrives at a target position.

[0010] 1 is a configuration example of a flight control system according to embodiment 1 of the present disclosure. FIG. 2 is a diagram illustrating a method for calculating acceleration by a controller according to embodiment 1 of the present disclosure. FIG. 3 is a diagram illustrating a method for calculating acceleration by a controller according to embodiment 1 of the present disclosure. FIG. 4 is a diagram illustrating an acceleration calculation process performed by a controller according to embodiment 1 of the present disclosure. FIG. 5 is a diagram illustrating a conventional flight control system according to a comparative example of the present disclosure. FIG. 6 is a diagram plotting equation (17) showing the magnitude of a velocity vector v(t) in the prior art according to a comparative example of the present disclosure. FIG. 7 is a block diagram illustrating a configuration example of a controller according to embodiment 1 of the present disclosure. FIG. 8 is a block diagram illustrating a configuration example of an aircraft according to embodiment 1 of the present disclosure. FIG. 9 is a flowchart illustrating processing performed by a controller according to embodiment 1 of the present disclosure. FIG. 10 is a flowchart illustrating processing performed by a conventional controller according to a comparative example of the present disclosure. FIG. 11 is a flowchart illustrating processing performed by an aircraft according to embodiment 1 of the present disclosure.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The same or corresponding components will be denoted by the same reference numerals, and repeated description may be omitted.

[0012] 1 illustrates a configuration example of a flight control system 100 according to a first embodiment of the present disclosure. The flight control system 100 includes a small unmanned aerial vehicle (hereinafter referred to as an aerial vehicle) 110 and a flight controller (hereinafter referred to as a controller) 130.

[0013] The controller 130 executes a process (hereinafter referred to as a receiving process) to receive position information and velocity information from the flying object 110. Furthermore, the controller 130 executes a process (hereinafter referred to as a receiving process) to receive from the pilot 60 a target position for the flying object 110 and a flight time for the flying object 110 to reach the target position. Based on the received target position and flight time, and the position information and velocity information of the flying object 110, the controller 130 executes a process (hereinafter referred to as an acceleration calculation process) to calculate an acceleration at which the velocity of the flying object 110 becomes zero upon arrival at the target position. Furthermore, the controller 130 executes a process (hereinafter referred to as a notification process) to notify the flying object 110 of a control signal 30 including the acceleration calculation result.

[0014] The flying object 110 receives a control signal 30 from the controller 130. The flying object 110 flies from a position indicated by point A to a target position indicated by point B based on the acceleration included in the control signal 30. As a result, the flying object 110 comes to a stop upon reaching the target position.

[0015] 2 and 3 are diagrams illustrating a method for calculating acceleration by the controller 130 according to the first embodiment of the present disclosure. As shown in FIG. 2 , the position of the aircraft 110 at time t=0 is the origin position, indicated by point A. The target position of the aircraft 110 received by the controller 130 from the pilot 60 is indicated by point B. Furthermore, the vector of the target position starting from the origin position is represented by position vector l(τ). Note that τ is the flight time received by the controller 130 from the pilot 60.

[0016] In the following, the acceleration to be applied to the flying object 110 is calculated as a function of time t so that the flying object 110 flying from the origin position to the target position stops as soon as it arrives at the target position.

[0017] As an example, assume that the velocity vector v(t) of the air vehicle 110 at time t is expressed as a quadratic function of time t as follows:

[0018]

[0019] On the other hand, the acceleration vector a(t) of the flying object 110 at time t is obtained as the time derivative of the velocity vector v(t) as follows:

[0020]

[0021] Here, in order to find the condition under which the velocity vector v(t) becomes 0 at time t=τ, the following is defined.

[0022]

[0023] Next, the position vector l(t) at time t is obtained as the integral of the velocity vector v(t) as follows:

[0024]

[0025] Therefore, the position vector l(t) at time t=τ is obtained as follows:

[0026]

[0027] On the other hand, the magnitude of the velocity vector v(t) at time t=τ can be obtained from equations (1) and (3) as follows:

[0028]

[0029] Using the above relationship, the coefficients of the quadratic function are obtained as follows:

[0030]

[0031]

[0032] Therefore, the velocity vector v(t) of the flying vehicle 110 at time t is obtained as follows:

[0033]

[0034] From this, the magnitude of the velocity vector v(t) is obtained as follows:

[0035]

[0036] 3 plots equation (10) as a function of time t. It is clear that the magnitude of the velocity vector v(t) becomes zero at time t=τ.

[0037] From the above, the acceleration to be applied to the flying object 110 so that the flying object 110 flying from the starting position to the target position stops as soon as it arrives at the target position can be calculated as follows.

[0038]

[0039] Note that the above description has been given of a method for calculating the acceleration vector a(t) using an example in which the velocity vector v(t) is expressed as a quadratic function with respect to time t. However, the velocity vector v(t) is not limited to the above example, as long as it is calculated to simultaneously satisfy the condition that the integral value from 0 to τ is l(τ), as in Equation (4), and the condition that the absolute value of v(τ) is 0, as in Equation (6). The acceleration to be applied to the aircraft 110 can be calculated by calculating the acceleration vector a(t) through the time differentiation of the calculated velocity vector v(t).

[0040] 4 is a diagram illustrating the acceleration calculation process executed by the controller 130 according to the first embodiment of the present disclosure. In the acceleration calculation process, the controller 130 sets the position indicated by the position information received from the flying object 110 as the starting position. Furthermore, the controller 130 sets the velocity vector indicated by the velocity information received from the flying object 110 as v(0). Furthermore, the controller 130 determines the position vector l(τ) based on the target position and flight time τ received from the pilot 60. Furthermore, the controller 130 calculates the acceleration vector expressed by the following equation and notifies the flying object 110.

[0041]

[0042] It should be noted that Equation (13) is the acceleration vector to be applied to the aircraft 110 flying from the starting position indicated by point A. The controller 130 repeatedly executes the reception process until the aircraft 110 reaches the target position. Furthermore, each time the reception process is executed, the controller 130 also executes the acceleration calculation process and the notification process. This allows the controller 130 to calculate the acceleration each time based on the position information and speed information of the aircraft 110 that are updated each time the reception process is executed, and ultimately controls the aircraft 110 to stop as soon as it reaches the target position.

[0043] Comparative Example To illustrate the effects of the present disclosure, a flight control method in the prior art will be described as a comparative example using Figures 5 and 6. Figure 5 is a diagram showing a conventional flight control system 200 according to a comparative example of the present disclosure. This example shows a small unmanned aerial vehicle (hereinafter referred to as the aircraft) 210 flying from a starting position indicated by point A to a target position indicated by point B where a structure 240 to be inspected is located. Like the controller 130 of the present disclosure, the conventional controller 230 also calculates the acceleration of the aircraft 210 based on the target position and flight time τ input by the pilot 60.

[0044] However, the conventional technology does not impose a condition that the velocity of the aircraft 110 becomes 0 immediately upon arrival at the target position. That is, in the conventional technology, since it is sufficient for the aircraft 110 to reach the target position indicated by the position vector l(τ) after the flight time τ has elapsed, the following condition is imposed on the velocity vector v(t) at time t:

[0045]

[0046]

[0047] Therefore, the velocity vector v(t) in the prior art is calculated as follows:

[0048]

[0049] The magnitude of the velocity vector v(t) is obtained as follows:

[0050]

[0051] Furthermore, the acceleration vector a(t) in the prior art is calculated as follows: Note that the calculated acceleration is different from that of the present disclosure in that it is a constant value with respect to time t.

[0052]

[0053] FIG. 6 is a plot of Equation (17) showing the magnitude of the velocity vector v(t) in the conventional technology according to a comparative example of the present disclosure. The results are shown by the dashed line. As described above, since the acceleration vector a(t) in the conventional technology is a constant with respect to time, the magnitude of the velocity vector v(t) changes linearly with respect to time t. In this case, the velocity vector v(t) of the flying object 210 does not become zero at time t=τ when the flying object 210 arrives at the target position. In other words, the flying object 210 does not come to a stop at the target position.

[0054] Meanwhile, the solid line is a plot of Equation (10) as a function of time t, showing the magnitude of the velocity vector v(t) in the present disclosure. As described in FIG. 3, in the present disclosure, the velocity vector v(t) of the air vehicle 110 can be set to 0 at time t = τ.

[0055] Below, configuration examples of the controller 130 and the flying vehicle 110 of the present disclosure and flowcharts executed by them will be described. Note that after each figure explaining the present disclosure, configuration examples of the controller 230 and the flying vehicle 210 in a conventional flight control system 200 and flowcharts executed by them may be described as comparative examples. In the explanation of the comparative examples, differences from the present disclosure will be explained.

[0056] 7 is a block diagram showing an example configuration of the controller 130 according to the first embodiment of the present disclosure. The operation content acquisition unit 31 executes the above-described reception process and notifies the information processing unit 32 of the received target position and flight time.

[0057] The communication unit 38 executes the above-described reception process and notifies the information processing unit 32 of the received position information and speed information of the flying object 110. The information processing unit 32 notifies the acceleration calculation unit 33 of the target position and flight time information, as well as the position information and speed information of the flying object 110. The acceleration calculation unit 33 executes acceleration calculation processing based on this information. The acceleration calculation unit 33 further notifies the information processing unit 32 of the calculation result.

[0058] The information processing unit 32 notifies the communication unit 38 of the determined acceleration information for the flying object 110. The communication unit 38 executes the notification process described above.

[0059] The guidance position storage unit 36 ​​stores the target position. The position information storage unit 37 stores the position information received from the flying object 110. The input / output interface 35 communicates with other devices.

[0060] 8 is a block diagram showing an example configuration of a conventional controller 230 according to a comparative example of the present disclosure. The same reference numerals are used to designate components that are the same as or correspond to those in FIG. 7. In the conventional controller 230, the acceleration calculated by the acceleration calculation unit 33 is a constant acceleration with respect to time, as expressed by, for example, Equation (18).

[0061] 9 is a block diagram showing an example configuration of an aircraft 110 according to the first embodiment of the present disclosure. The first communication unit 18 receives a control signal 30 from the controller 130 and notifies the information processing unit 12. The information processing unit 12 acquires acceleration information from the signal. The information processing unit 12 then notifies the flight control unit 13 of the acceleration information. Based on the acceleration information, the flight control unit 13 applies acceleration by driving multiple motors 14, each connected to a rotor. The guidance position memory unit 20 stores the acceleration information.

[0062] The information processing unit 12 also transmits the position information of the aircraft calculated by the position measuring device 15 to the controller 130 via the first communication unit 18. The position measuring device 15 calculates the position information and speed information of the aircraft based on the GPS acquisition unit 16 and the gyro sensor 17. The GPS acquisition unit 16 acquires radio waves from GPS satellites. The gyro sensor 17 measures the aircraft's direction.

[0063] 10 is a flowchart illustrating processing executed by the controller 130 according to the first embodiment of the present disclosure. First, the processing is started. Next, it is determined whether the target position and flight time have been accepted (step S01). If not accepted, the process returns to step S01. On the other hand, if accepted, the process executes a reception process, and the received position information and velocity information of the flying object 110 are stored in the position information storage unit 37 (step S02). Next, it is determined whether the flying object 110 has arrived at the target position based on the accepted position information (step S03).

[0064] If arrival is not confirmed, an acceleration calculation process is executed based on the position information and velocity information received in step S02 (step S04). Furthermore, a notification process is executed (step S05). On the other hand, if arrival is confirmed in step S03, the flying object 110 is notified that control has been completed (step S06). Finally, the process ends.

[0065] FIG. 11 is a flowchart showing processing executed by a conventional controller 230 according to a comparative example of the present disclosure. Steps S11 to S13 are common to steps S01 to S03 described in FIG. 10 , and therefore will not be described again. If arrival is not confirmed in step S13, the conventional controller 230 also calculates acceleration based on the position information and velocity information received in step S12 (step S14). However, the acceleration here is a constant acceleration over time, as expressed by, for example, Equation (18). Note that steps S15 and S16 are common to steps S05 and S06 described in FIG. 10 , and therefore will not be described again.

[0066] 12 is a flowchart illustrating processing executed by the aircraft 110 according to the first embodiment of the present disclosure. First, the processing is started. Next, the position of the aircraft is measured by the GPS acquisition unit 16 (step S21). Next, the orientation of the aircraft is measured by the gyro sensor 17 (step S22). Next, the speed is measured (step S23). Next, the position information and speed information of the aircraft calculated by the position measurement device 15 are transmitted to the controller 130 (step S24).

[0067] Next, it is determined whether or not a control signal 30 has been received from the controller 130 (step S25). If reception is confirmed, the acceleration information contained in the signal is stored in the guidance position storage unit 20 (step S26). Furthermore, flight is performed based on the acceleration information (step S27). Note that if reception is not confirmed in step S25, the latest acceleration information stored in the guidance position storage unit 20 is obtained (step S28), and then the process proceeds to step S27.

[0068] Next, it is determined whether or not the target position has been reached (step S29). If it is determined that the target position has been reached, a notification of arrival is sent to the controller 130 (step S30), and the process ends. On the other hand, if it is determined that the target position has not been reached, the process returns to the start.

[0069] The processes performed by the aircraft 110 and the controller 130 may be executed by a program using a computer equipped with a CPU and memory and storing a program in the memory. Alternatively, the processes may be executed by a program using an integrated circuit such as an FPGA (Field Programmable Gate Array). The program may be provided by being recorded on a storage medium or via a network.

[0070] As described above, the present disclosure provides a flight controller and a flight control method that can control a small unmanned aerial vehicle so that its flight speed becomes zero as soon as it arrives at a target position.

[0071] In the above description, the controller 130 has been described as receiving the target position and flight time for flying the aircraft 110 from the pilot 60 in the reception process. However, these may be received from another device instead of the pilot 60. This allows the aircraft 110 to be automatically piloted.

[0072] As described above, the controller 130 repeatedly executes the reception process until the flying object 110 reaches the target position. Furthermore, it has been described that the acceleration calculation process and the notification process are also executed each time the reception process is executed. However, the number of times and timing at which the controller 130 executes these processes may be freely determined.

[0073] For example, the receiving process, the accepting process, the acceleration calculation process, and the notification process may be executed only once until the flying object 110 reaches the target position. In this case, the acceleration to be applied by the flying object 110 can be determined as a function of time by calculating the acceleration based on Equation (11) in the acceleration calculation process. Furthermore, by notifying data linking time information and acceleration information in the notification process, the flying object 110 can change its acceleration based on the data. Using this method reduces the burden on both the controller 130 and the flying object 110 related to the calculation and notification of acceleration. Note that the formula used in the acceleration calculation process is not limited to Equation (11). In other words, as described above, it is sufficient that the velocity vector v(t) satisfies the condition that the integral value from 0 to τ is l(τ), as in Equation (4), and the condition that the absolute value of v(τ) is 0, as in Equation (6). The acceleration to be applied to the flying object 110 can be calculated by calculating the acceleration vector a(t) by differentiating the calculated velocity vector v(t) with respect to time.

[0074] In the above description, the reception process executed by the controller 130 receives from the pilot 60 the flight time for flying the aircraft 110. However, the flight time may be determined by the controller 130. That is, the controller 130 may further execute a determination process for determining the flight time based on the position information and velocity information of the aircraft 110, and the flight time received in the reception process may be the flight time determined in the determination process. This allows the controller 130 to automatically determine the flight time even when the reception process is frequently executed and the flight time τ must also be frequently updated in accordance with updates to the position information.

[0075] The present disclosure is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the present disclosure. Furthermore, the embodiments may be implemented in appropriate combinations, and in such cases, the combined effects can be obtained.

[0076] 12 Information processing unit, 13 Flight control unit, 14 Motor, 15 Position measuring device, 16 GPS acquisition unit, 17 Gyro sensor, 18 First communication unit, 20 Guidance position memory unit, 30 Control signal, 31 Operation content acquisition unit, 32 Information processing unit, 33 Acceleration calculation unit, 35 Input / output interface, 36 Guidance position memory unit, 37 Position information memory unit, 38 Communication unit, 60 Pilot, 100 Flight control system, 110 Small unmanned aerial vehicle, 130 Flight controller, 130 Controller, 200 Flight control system, 210 Small unmanned aerial vehicle, 230 Controller, 240 Structure

Claims

1. A flight controller that controls a small unmanned aerial vehicle, configured to execute the following: a receiving process that receives position information and speed information from the small unmanned aerial vehicle; a receiving process that receives a target position to fly the small unmanned aerial vehicle and the flight time of the small unmanned aerial vehicle until it reaches the target position; an acceleration calculation process that calculates an acceleration at which the speed of the small unmanned aerial vehicle becomes 0 upon arriving at the target position based on the target position, the flight time, the position information, and the speed information; and a notification process that notifies the small unmanned aerial vehicle of the acceleration.

2. A flight controller as described in claim 1, further comprising a determination process for determining the flight time based on the position information, and the flight time accepted in the acceptance process is the flight time determined in the determination process.

3. A flight controller as described in claim 1 or 2, wherein the acceleration calculation process further includes: a process of setting the position indicated by the position information as a starting position; a process of setting the velocity vector indicated by the velocity information as the velocity vector v(0) of the small unmanned aerial vehicle at the starting position; a process of setting the velocity vector of the small unmanned aerial vehicle at time t as v(t); a process of setting the flight time as τ; a process of setting the position vector of the target position starting from the starting position as l(τ); a process of calculating v(t) as a function of time t for the velocity vector v(t) such that the integral value from 0 to τ of the time t is l(τ) and the absolute value of v(τ) is 0; and a process of calculating the acceleration as a function of time t by time differentiation of the calculated velocity vector v(t); and wherein the notification process notifies data linking the information on time t and the information on acceleration.

4. A flight controller as described in any one of claims 1 to 3, wherein in the acceleration calculation process, the position indicated by the position information is set to the starting position, the velocity vector indicated by the velocity information is set to the velocity vector v(0) of the small unmanned aerial vehicle at the starting position, the velocity vector of the small unmanned aerial vehicle at time t is set to v(t), the flight time is set to τ, and the position vector of the target position starting from the starting position is set to l(τ), and the acceleration of the small unmanned aerial vehicle during the time from when it flies from the starting position to when it reaches the target position is calculated as a function of the time t based on the following formula, and in the notification process, data linking the information on the time t and the information on the acceleration is notified.

5. A flight control device as described in claim 1 or 2, wherein the reception process is repeatedly executed until the small unmanned aerial vehicle reaches the target position, the acceleration calculation process and the notification process are executed each time the reception process is executed, and in the acceleration calculation process, the position indicated by the position information is set to a starting position, the velocity vector indicated by the velocity information is set to the velocity vector v(0) of the small unmanned aerial vehicle at the starting position, the flight time is set to τ, and the position vector of the target position starting from the starting position is set to l(τ), and the acceleration is calculated based on the following formula:

6. A flight control method for a small unmanned aerial vehicle, comprising: a flight control device executing a receiving process to receive position information and speed information from the small unmanned aerial vehicle; executing a receiving process to receive a target position to fly the small unmanned aerial vehicle and a flight time of the small unmanned aerial vehicle until it reaches the target position; executing an acceleration calculation process to calculate an acceleration at which the speed of the small unmanned aerial vehicle becomes 0 upon arriving at the target position based on the target position, the flight time, the position information, and the speed information; executing a notification process to notify the small unmanned aerial vehicle of the acceleration; and the small unmanned aerial vehicle flying based on the acceleration.

7. A flight control method as described in claim 6, further comprising executing a determination process for determining the flight time based on the position information, wherein the flight time accepted in the acceptance process is the flight time determined in the determination process.

8. A flight control method as described in claim 6 or 7, wherein the reception process is repeatedly executed until the small unmanned aerial vehicle reaches the target position, the acceleration calculation process and the notification process are executed each time the reception process is executed, and in the acceleration calculation process, the position indicated by the position information is set to a starting position, the velocity vector indicated by the velocity information is set to the velocity vector v(0) of the small unmanned aerial vehicle at the starting position, the flight time is set to τ, the position vector of the target position starting from the starting position is set to l(τ), and the acceleration is calculated based on the following formula:

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