Unmanned Aerial Vehicle Immunity Test Equipment

Abstract

There is no established immunity test method for unmanned aerial vehicles. Because unmanned aerial vehicles fly and move, it is difficult to conduct immunity tests under actual operating conditions. [Solution] The immunity test device and test method disclosed herein utilize a test environment used for general electronic devices, etc., to enable testing of unmanned aerial vehicles in conditions close to their actual operation. A simulated signal is used to perform immunity testing in a simulated flight state equivalent to an actual operating state, with the unmanned aerial vehicle remaining at a fixed position in a certain space. A GTEM cell can be used as a shielding structure to house the unmanned aerial vehicle. An evaluation configuration is also proposed for analyzing parts of the unmanned aerial vehicle that are vulnerable to electromagnetic interference and identifying parts that cause malfunctions.

Description

[Technical field]

[0001] The present invention relates to an apparatus for testing the electromagnetic immunity of unmanned aerial vehicles. [Background technology]

[0002] An unmanned aerial vehicle (UAV) is an aircraft that cannot carry people due to its structure, such as airplanes, rotorcraft, gliders, and airships, and can be flown by remote control or automatic pilot. Initially, its use was limited to military and observational purposes, but with the recent emergence of civilian drones, it has spread to a wide range of industrial fields, such as aerial photography, agriculture, inspection, logistics, crime prevention, civil engineering, and construction.

[0003] As unmanned aerial vehicles such as drones come to be widely used near human living spaces, they will be exposed to various electromagnetic wave environments and will be affected by electromagnetic interference. Electromagnetic interference includes natural sources such as lightning strikes and cosmic rays, as well as artificial phenomena emitted from communication devices and devices that use electromagnetic waves, and even those generated intentionally with malicious intent. If an unmanned aerial vehicle becomes uncontrollable and falls due to electromagnetic interference, it can immediately lead to a serious accident. Therefore, it is important to evaluate the immunity of unmanned aerial vehicles to electromagnetic waves.

[0004] For general electrical and electronic equipment, the levels of electromagnetic interference and test methods are stipulated in international standards according to various radio wave environments and types of electromagnetic interference. The interference level is the magnitude of electromagnetic interference measured using a prescribed method according to the type of noise. The equipment being measured must be resistant to electromagnetic waves that exceed this interference level. Immunity testing does not measure the immunity level of individual equipment, but rather classifies the target equipment according to its function and performance, determines the interference level that each equipment group must clear, and judges whether it passes or fails against that level. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] IEC 61000-4-20 Ed. 3.0:2022 (b), Testing and measurement techniques - Transverse electromagnetic (TEM) waveguide emission and immunity testing standard Summary of the Invention [Problem to be solved by the invention]

[0006] However, no established method has yet been established for immunity testing of unmanned aerial vehicles, and there have been obstacles to conducting appropriate testing due to the unique moving attributes of unmanned aerial vehicles. Below, we will explain the issues in immunity testing using drones as a representative example of unmanned aerial vehicles.

[0007] FIG. 1 is a block diagram showing the configuration and functions of the electronic devices of a drone, which is a typical unmanned aerial vehicle. The drone 10 is driven by a battery 15, and a voltage converter 14 supplies the necessary stabilized power supply voltage to each part. The entire drone is controlled by a flight controller (FCU: Flight Control Unit) 12. The drone grasps its position information by a signal received by an antenna 11 from a Global Positioning System (GPS). A remote controller receiver 17 and a telemetry transmitter 16 exchange control information, status information, and the like via an antenna 19. The FCU 12 drives a plurality of motors 18 for flight via a speed controller 13.

[0008] Fig. 2 is a schematic diagram showing the configuration and function of the mechanical aspects of the drone. In the drone 10, motors 18-1 to 18-4 for obtaining power for flight are fixed to a frame 21. On a board 22 in the center of the frame 21, each block as the electronic device shown in Fig. 1 is mounted. In Fig. 2, the arrangement of each block on the board is different from the actual one, and details such as wiring between each block are omitted.

[0009] In the worst case, an unmanned aerial vehicle such as a drone may crash if it is struck by lightning, for example. The FCU 12 of the drone 10 described above is equipped with many sensors, and attitude control may become impossible due to malfunction of the sensor body or communication error of the sensor signal. In addition, various factors such as a voltage supply stop due to a malfunction of the voltage converter 14, heat damage to the drivers of the motors 18-1 to 18-4, and a short circuit of the coil windings may cause the motors to stop and cause a crash. Even if it does not result in a crash, if the GPS signal cannot be received, the vehicle will become uncontrollable and enter a dangerous state. It is very important to evaluate the resistance of unmanned aerial vehicles to electromagnetic waves and perform immunity tests.

[0010] However, immunity test methods for unmanned aerial vehicles are still being formulated, and no established ones have been established. Because unmanned aerial vehicles have evolved from military and observation applications, immunity test methods and immunity levels have not been made public. Unmanned aerial vehicles can move anywhere, just like automobiles, and are exposed to a variety of electromagnetic phenomena. However, there are no EMC regulations established for civilian automobiles, trains, or ships.

[0011] Since unmanned aircraft are inherently flying and mobile, it is difficult to keep them in a fixed shielded test environment for immunity testing in actual operating conditions. Due to the inherent mobility of unmanned aircraft, it is practically difficult to conduct immunity testing. Even if a fixed shielded space for testing can be prepared, for example, a drone requires an expensive radio repeater to re-radiate GPS signals into that space. Unmanned aircraft are rapidly spreading to civilian applications, and at the same time, they are increasingly being used in close proximity to living spaces. There was an urgent need to establish an immunity test method for unmanned aircraft.

[0012] The present invention has been made in consideration of such problems, and its purpose is to propose an immunity test method and test device for unmanned aerial vehicles that can utilize the test environment for conventional electronic devices, etc. [Means for solving the problem]

[0013] One embodiment of the present invention is an immunity testing apparatus comprising an electromagnetically shielded structure that houses a target unmanned aerial vehicle inside, a test signal source that generates interfering electromagnetic waves for the unmanned aerial vehicle, a simulated signal transmitter that generates a simulated signal including information for identifying a virtual position of the unmanned aerial vehicle, and a control unit that generates the information, and based on the virtual position, determines whether or not a malfunction occurs due to the interfering electromagnetic waves in a simulated flight state equivalent to the unmanned aerial vehicle being stopped or moving in a predetermined direction and at a predetermined speed. Effect of the Invention

[0014] As described above, a novel immunity test apparatus for unmanned aerial vehicles is provided. [Brief description of the drawings]

[0015] [Figure 1] This is a block diagram showing the configuration and functions of the side of the electronic devices of the drone. [Diagram 2]FIG. 1 is a schematic diagram showing the configuration and function of the mechanical aspects of a drone. [Diagram 3] A diagram showing the configuration of an immunity test device for an unmanned aerial vehicle disclosed herein. [Figure 4] FIG. 2 is a diagram for explaining a simulated GPS signal of the immunity test apparatus of the present disclosure. [Diagram 5] 4A and 4B are diagrams for explaining state information and control information of the immunity test apparatus of the present disclosure. [Figure 6] 13A and 13B are diagrams showing the results of fault determination by the immunity test apparatus of the present disclosure. [Figure 7] 1 is a diagram showing the configuration of an immunity test device for parts of an unmanned aerial vehicle. [Figure 8] This is a diagram showing the FCU immunity test equipment from the viewpoint of physical configuration. [Figure 9] FIG. 1 shows the state of an actual immunity test for an FCU. [Figure 10] This is a diagram comparing immunity tests of the entire drone and its parts. [Figure 11] Another diagram comparing immunity testing of the whole drone and parts of it. [Figure 12] This is a diagram showing electrical signals observed during an ESC immunity test. [Figure 13] FIG. 2 is another diagram of electrical signals observed during immunity testing of the ESC. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The immunity test device and test method disclosed herein utilize a test environment used for general electronic devices and the like to enable testing of unmanned aerial vehicles in conditions close to their actual operation. A simulated signal is used to perform immunity testing on the unmanned aerial vehicle in a simulated flight state equivalent to the actual operation state. For example, in the case of a drone, a simulated GPS signal is used. A GTEM cell (Gigahertz TEM cell) can be used as the immunity test environment. In addition, an evaluation configuration is proposed for analyzing parts of the unmanned aerial vehicle that are vulnerable to electromagnetic interference and identifying parts that cause malfunctions.

[0017] [Immunity test equipment] FIG. 3 is a diagram showing the configuration of an immunity test device for unmanned aerial vehicles according to the present disclosure. The immunity test device 100 is composed of a GTEM cell 101 that contains an unmanned aerial vehicle (UAV) to be tested, and a test control and monitor unit 105. The GTEM cell 101 is, for example, specified in Non-Patent Document 1, and has a structure in which electromagnetic waves are generated inside and is entirely shielded. The vertical cross section of the GTEM cell has a tapered shape, and a coaxial connector is attached to the tip of the taper. A test signal 121, which is an interfering electromagnetic wave, is emitted from a septum 103, which is a flat conductor in the center. The opposite side of the tip of the taper is not narrowed and is terminated by a terminator 102 and a radio wave absorber (not shown). Since the GTEM cell 101 is an electromagnetically shielded structure, no other anechoic chamber or the like is required for the immunity test.

[0018] A UAV 10 to be tested is placed in the GTEM cell 101, and in the following description, a drone 10 is used as an example of the UAV. The drone 10 is installed at a predetermined position (within the range of heights x to y from the bottom) relative to the septum 103 as specified in Non-Patent Document 1.

[0019] It is also possible to replace the GTEM cell 101 with another shield structure, place the drone 10 inside this structure, and use a means for emitting test electromagnetic waves such as an antenna. Specifically, as in vehicle immunity testing, a strip line or an antenna may be placed inside an anechoic chamber to radiate test electromagnetic waves to the drone.

[0020] In addition to the test signal 121 being input via the coaxial cable, the inside and outside of the GTEM cell 101 are coupled by antennas 116 and 117. A simulated GPS signal 118, which will be described later, is provided to the drone 10 by the antenna 116, and a signal 119 containing control information and status information is sent to and received from the drone 10 by the antenna 117.

[0021] The test control and monitoring unit 105 includes a test signal generator 111 that generates a test signal 121, and a high-frequency amplifier 110 that amplifies the test signal to a predetermined level. The test signal control unit 112 controls the test signal generator 111 and the high-frequency amplifier 110 and monitors their states. The simulated GPS signal control unit 113 controls the simulated GPS signal transmitter 114 and the drone control transceiver 115. In FIG. 3, the test signal control unit 112 and the simulated GPS signal control unit 113 are shown as separate units, but they may be integrated into one control unit. Any of the control units may be implemented by a computer including a processor, and may also include an input device and a display device.

[0022] [Simulated GPS signal] In the immunity test device 100 of the present disclosure, a simulated GPS signal is generated to set the drone 10 in a simulated flight state equivalent to a real flight state, thereby making it possible to keep the drone within a shielded structure in which it can be stored. When the propeller (rotor) 23 of a drone as shown in FIG. 2 is removed, the drone does not move and is held stationary at a fixed position. In the limited space of the GTEM cell 101 in FIG. 3, the motor can perform an operation corresponding to the simulated flight state according to the position information obtained from the simulated GPS signal and the control information obtained from the control transceiver 115. The simulated GPS signal that enables the immunity test of the drone will be further described.

[0023] FIG. 4 is a diagram for explaining a simulated GPS signal in the immunity test device of the present disclosure. FIG. 4(a) is a schematic diagram of an actual GPS signal received by a drone. The GPS device 303 receives GPS signals 301a-1, 301b-1, and 301c-1 from three satellites 300a to 300c, respectively. Each satellite transmits a GPS signal including time information synchronized with the time on the ground. The GPS device can determine position information 302-1 from the time difference of the time information by using each time information from three or more GPS signals from different satellites, and identify the position of the GPS device on the ground.

[0024] When the GPS device 303 moves a certain distance in a certain direction, new location information 302-2 updated from GPS signals 301a-2, 301b-2, and 301c-2 can be obtained at the location after the movement. If the updated location information 302-2 is the same as the previous location information 302-1, the GPS device is determined to be stopped. The stopped state includes a state in which the GPS device is hovering in the sky and a state in which it is landed on the ground. The principle of specifying a location using GPS signals may use time for the time information or may use the difference in time information, as long as three or more signals including synchronized time information from different transmission sources are obtained. In addition, the principle is not limited to the GPS system, and may be used to specify the location of an unmanned aerial vehicle in systems using other similar satellite signals or systems using radio waves from ground transmission facilities.

[0025] The GPS device recognizes its moving state based on GPS signals 301a-1, 301b-1, and 301c-1 when deriving the above-mentioned position information 302-1, and GPS signals 301a-2, 301b-2, and 301c-2 when deriving the position information 302-2. Therefore, if the GPS device can receive these GPS signals continuously or intermittently, it is in a state equivalent to the GPS device being in motion.

[0026] FIG. 4(b) shows a state in which a simulated GPS signal 118 is sent from the simulated GPS signal transmitter 114 into the GTEM cell in the immunity test device 100 of the present disclosure. The drone 10 to be tested can receive the simulated GPS signal 118 via the GPS antenna 11, so that a simulated flight state can be realized. The baseband signal of the simulated GPS signal 118 is generated by the simulated GPS signal control unit 113. The simulated GPS signal control unit 113 creates a baseband signal structure of the GPS signal including synchronized time information. The simulated GPS transmitter generates three wireless GPS signals with a carrier of a predetermined frequency for the baseband signal, combines them, and sends them from the antenna 116. The target drone 10 in the GTEM cell receives the simulated GPS signal 118 with the propeller removed, so that a simulated flight state equivalent to flying in reality can be achieved, and an immunity test can be performed in the same state as the actual flight environment. The simulated flight state includes a state equivalent to moving in a predetermined direction at a predetermined speed, or a state equivalent to stopping at a predetermined position. A stationary state corresponds to, for example, a state in which the drone is hovering.

[0027] The simulated GPS signal 118 described above is a simulated signal that includes information for identifying the virtual location of the test drone 10 when it is received. The drone 10 determines its current virtual location based on the simulated signal, and can achieve a simulated flight state or stationary state based on this virtual location and control information from a remote control transmitter, which will be described later.

[0028] The simulated GPS signal, which allows the target drone to virtually recognize whether it is moving or stationary, is preferably updated continuously with time information in the same way as a real GPS signal, and should be updated at time intervals shorter than the update time of the drone's position information according to the position, moving speed, moving direction, etc. set for the test drone.

[0029] GPS signals perform positioning using signals from three or more different satellites. Therefore, the simulated signal includes three or more signals each including time information synchronized with each other, and the virtual position of the drone under test is determined based on the time difference between the time information of the three or more signals. An example of an unmanned aerial vehicle that can be tested by the immunity test apparatus 100 of the present disclosure is a drone.

[0030] To carry out an immunity test, a test signal 121 of a predetermined level must be provided to the target drone 10 to determine whether or not a malfunction or fault has occurred. This determination can be made by receiving status information generated in the drone 10 (described later) with a telemetry receiver and monitoring it in the simulated GPS signal control unit 113.

[0031] FIG. 5 is a diagram for explaining the transmission and reception of state information and control information in the immunity test device of the present disclosure. As shown in FIG. 1, the target drone 10 transmits downstream state information 122 generated by the drone from the telemetry transmitter 16. The telemetry receiver 115a of the test control and monitor unit 105, which faces the telemetry transmitter 16, receives the downstream state information 122. In addition, in order to control the movement and stopping operation of the drone, the remote control transmitter (RC transmitter) 115b of the test control and monitor unit 105 transmits upstream control information 123 to the drone under test. The RC receiver 17 of the drone 10, which faces the RC transmitter 115b, receives the upstream control information 123. By transmitting and receiving the downstream state information 122 and the upstream control information 123, it is possible to check for malfunctions and failures that have occurred in the drone.

[0032] In this way, in the immunity test device 100, the simulated GPS signal control unit 113 can receive downstream status information 122, i.e., status information of the unmanned aerial vehicle, using the telemetry receiver 115a, and transmit upstream control information 123, i.e., control information for the unmanned aerial vehicle, from the RC transmitter 115b.

[0033] Here, the control information for the unmanned aerial vehicle is, from the viewpoint of immunity testing, control information for setting the unmanned aerial vehicle to be tested to a stopped state or a simulated flight state. More specifically, when the drone is stopped, information on the stopping position is included. When the drone is in a simulated flight state, information on the movement target position, information on the movement speed, etc. are included.

[0034] The status information of the unmanned aerial vehicle includes information on the current position related to the flight status, information on the movement speed, information on the movement direction, information on the flight altitude, etc. It also includes information related to the obstacle class described below. Here, it should be noted that the above-mentioned current position information during the test is obtained based on the simulated GPS signal generated by the simulated GPS signal control unit 113.

[0035] In the following description, the drone under test is assumed to be set in a simulated flight state by control information from the RC transmitter 115b. However, if the drone can operate with an autopilot program, the drone can autonomously maintain the simulated flight state together with the activation of the autopilot program by simply receiving the simulated GPS signal 118.

[0036] The fault classes in Table 1 below are defined for malfunctions and abnormal operations that occur during drone immunity testing. Fault class 1 is a state in which a phenomenon called "lost synchronism" occurs in one of the four motors. Details will be described later, but this is a phenomenon in which the motor control pulse signal and the motor rotation become out of sync, and the motor that has lost synchronism will produce abnormal noise. Fault class 2 is an error in the GPS and inertial measurement unit (IMU), and is output as fault information from the FCU12 shown in Figure 2. Specifically, there are errors in which the received GPS signal is cut off, making the current position unknown, and errors in which the attitude that was maintained horizontal tilts to the left or right, causing abnormal attitude control. Fault class 3 indicates that at least one of the multiple motors has stopped, making it impossible to maintain normal flight, and is a serious fault that can lead to a crash. For fault classes 1 and 3, the motor status can be visually confirmed through a window inside the GTEM cell, or a camera can be installed inside to check it with a camera. TIFF0007678915000002.tif31148 EXAMPLES

[0037] The following describes a more specific configuration example of the immunity test device 100 shown in Fig. 3. The drone to be tested was configured using the following available products for each block shown in Fig. 2. TIFF0007678915000003.tif52156 A software radio (Hack RF One) was used to generate the simulated GPS signal. The software radio corresponds to the simulated GPS signal transmitter 114 of the immunity test device 100 in Fig. 3. The baseband signal generated by the simulated GPS signal control unit 113 was modulated by the simulated GPS signal transmitter 114 to generate the simulated GPS signal 118.

[0038] To obtain the status information 122 of the drone 10 under test, a telemetry device using the 2.45 GHz band and a full-featured ground station application (Mission Planner) for the open source autopilot project were used, which corresponds to the telemetry transmitter 16 of the drone 10 and the telemetry receiver 115a of the test device.

[0039] The following three types of modulation methods were adopted for a frequency-swept RF signal as the test signal 121, which is an electromagnetic interference wave for evaluating immunity resistance. (1) 1kHz, 80% AM modulation (e.g., as specified in IEC 61000-4-39) (2) Pulse modulated wave (repetition period 20 ms, pulse width 2 ms) (3) Pulse modulated wave (repetition period 2 ms, pulse width 1 ms) The test signal 121 with the above-mentioned modulation was changed in 0.1 MHz steps from 0.1 MHz to 80 MHz and in 1 MHz steps from 0.1 MHz to 80 MHz. The dwell time at one frequency was 3 seconds. The electric field strength at the drone installation position in the GTEM cell during the test was 100 V / m, which is the maximum electric field strength of the test facility.

[0040] FIG. 6 shows an example of fault class determination results using the immunity test device of the present disclosure. The horizontal axis shows the frequency of the test signal, and the vertical axis shows the fault class that was confirmed to have occurred. Each plot point indicates that a state of each fault class occurred in the drone. Faults were detected at each point: test signal 1 (plot ◯), test signal 2 (pulse width 2 ms) (plot △), and test signal 2 (pulse width 1 ms) (plot □). ​​A motor stop of fault class 3 was also confirmed near 200 MHz. Errors in the GPS and inertial measurement unit of fault class 2 were also confirmed over a wide range of frequencies.

[0041] The immunity test device 100 shown in FIG. 6 can perform immunity testing on a drone while it is stationary at a fixed position by using the GTEM cell 101, which is an existing test environment similar to that of general electronic devices. This state of the drone under test is a simulated flight state equivalent to an unmanned aerial vehicle being stopped or moving in a specified direction and at a specified speed, and immunity testing of the drone can be performed in a state equivalent to an actual operating state. However, immunity testing can be performed on a drone set in a simulated flight state with a simulated GPS signal in a shielded environment or within a shielded structure that can accommodate the drone to be tested. The configuration is not limited to the GTEM cell of FIG. 3. The GTEM cell 101 of FIG. 3 can be replaced with a shielded room (electromagnetic anechoic chamber), and the transmission of the test signal can be replaced with a single antenna. For example, a strip line, a biconical antenna, a log periodic antenna, etc. used in immunity testing of vehicles can be used as the antenna.

[0042] Therefore, the immunity testing apparatus disclosed herein comprises an electromagnetically shielded structure 101 that houses the target unmanned aerial vehicle 10 therein, a test signal source 111 that generates interfering electromagnetic waves for the unmanned aerial vehicle, a simulated signal transmitter 114 that generates a simulated signal including information for identifying a virtual position of the unmanned aerial vehicle, and a control unit 113 that generates the information, and can be implemented to determine whether or not a malfunction occurs due to the interfering electromagnetic waves based on the virtual position in a simulated flight state equivalent to the unmanned aerial vehicle being stopped or moving in a predetermined direction and at a predetermined speed.

[0043] The immunity test of the unmanned aerial vehicle disclosed herein is characterized in that a simulated signal capable of deriving virtual position information similar to that obtained in a real flight state is given to the unmanned aerial vehicle to place the unmanned aerial vehicle in a "simulated flight state". In the immunity test device 100 of FIG. 3 described above, the unmanned aerial vehicle is a drone that operates by GPS, but it may also operate using other satellite positioning systems. The unmanned aerial vehicle to be tested may be of a system that can identify its position based on time information contained in radio waves from a terrestrial base station other than a satellite.

[0044] As shown in Fig. 6, the immunity test device 100 in Fig. 3 can perform some pass / fail judgment on whether or not abnormal operation occurs for a drone set in a simulated flight state using a simulated GPS signal. Although the immunity test device in Fig. 3 can perform immunity testing on the entire drone, it cannot determine which parts of the drone are vulnerable. Therefore, next, we propose a test device that can identify parts of an unmanned aerial vehicle that have immunity vulnerabilities.

[0045] [Immunity test equipment for unmanned aerial vehicle parts] FIG. 7 is a diagram showing the configuration of an immunity test device for parts of an unmanned aerial vehicle. In contrast to the test device 100 for the entire unmanned aerial vehicle using the GTEM cell shown in FIG. 3, in the test device 200 of FIG. 7, all elements are housed in an anechoic chamber 206. FIG. 7 also uses a drone 10 as an example of an unmanned aerial vehicle for explanation. A part 10-1 (EUT: Equipment Under Test) of the drone 10 for evaluating immunity resistance is housed in a TEM cell 201 via an extension wiring 204. In this example, the part 10-1 of the drone to be tested is the FCU 12 of the drone in FIG. 2.

[0046] The TEM (Transverse Electromagnetic) cell has a structure in which a coaxial cable is expanded and the central conductor is a septum 203. Both ends of the TEM cell 201 are tapered, and a coaxial connector is attached to the end. A disturbance electromagnetic wave test signal 121 is input from one end of the coaxial cable, and the other end is terminated by a terminator 202. The entire cell is shielded, and the electromagnetic field generated within the cell is confined within the cell and radiated only to the FCU 12.

[0047] The main body of the drone excluding the FCU 12 is outside the TEM cell 201, and includes a test control and monitor unit 205 similar to that shown in Fig. 3. A simulated GPS signal 118 is provided to the main body of the drone 10 from an antenna 116. The configurations of the test signal generator 111, test signal control unit 112, simulated GPS signal control unit 113, simulated GPS signal transmitter 114, and control transceiver 115 are the same as those of the immunity test apparatus 100 in Fig. 3.

[0048] FIG. 8 is a diagram showing an immunity test device for an FCU of a drone from the viewpoint of a physical configuration. In the immunity test device of FIG. 7, a state in which an immunity test is performed on the FCU 12 as a part of the drone is shown. The FCU 12 housed in the TEM cell is connected to the main body of the drone 10 via an extension wiring 204, and is functionally capable of normal operation. Although the extension wiring 204 is shown as a single wiring in FIG. 7, it may be a plurality of wirings. In the TEM cell 201, a test signal 121 can be emitted only to the FCU 12 to be tested as a part of the drone. The drone 10 is set in a simulated flight state by the simulated GPS signal control unit 113 and the simulated GPS signal 118 from the simulated GPS signal transmitter 114. The test signal 121 is selectively given only to the target FCU 12 in the TEM cell, and the drone can perform an immunity test in the same state as the actual operating environment. The target drone 10 in the anechoic chamber 206 receives a simulated GPS signal 118 with its propellers removed, and remains in a fixed position, creating a simulated flight state equivalent to flying in reality.

[0049] Figure 9 shows the actual immunity test state for the FCU. On the left side of the photo, a window is open so that the inside of the TEM cell can be seen, and the FCU is visible. During actual testing, the window is closed. On the right side of the TEM cell, a drone is shown with each block except the FCU mounted on a frame. In the drone block diagram shown in Figure 2, parts other than antennas 11 and 19 can be placed away from the drone body inside the TEM cell by extension wiring 204 or extension transmission lines. It is possible to individually and selectively evaluate the immunity resistance of each part (block) inside the drone.

[0050] The immunity test apparatus for the unmanned aerial vehicle parts shown in Fig. 7 must be entirely performed inside an anechoic chamber 206. This is because the simulated GPS signal 118 from the simulated GPS signal transmitter 114 causes malfunctions in drones other than the test subject. EXAMPLES

[0051] In Fig. 8, an example was described in which immunity testing was performed on only the FCU of a drone using immunity testing device 200 for parts of an unmanned aerial vehicle. Similarly, testing can also be performed on only the speed controller (ESC), which is another part of the drone, or on only the voltage converter (BEC). Therefore, the results of the immunity test of the entire drone using the GTEM cell in Fig. 3 were compared with the test results of each part using the TEM cell in Fig. 7.

[0052] Figure 10 is a diagram comparing immunity tests of the entire drone and its parts. The horizontal axis shows the frequency of the test signal, and the vertical axis shows the three fault classes. When the above-mentioned AM modulated wave was used as the test signal, the diagram shows the results of a whole drone test using the GTEM cell in Figure 3 and a test of three drone parts using the TEM cell in Figure 7. The plot ◯ indicates a whole drone (UAV) test using the GTEM cell. For the TEM cell tests, the plot △ indicates a part test on the FCU, the plot □ indicates a part test on the ESC, and the plot ● indicates a part test on the voltage converter (BEC).

[0053] Comparing the UAV plot ◯ with the BEC plot ●, it can be seen that malfunctions of fault class 1 and fault class 3 occurred at the same frequency, and it can be inferred that the cause of these malfunctions is the BEC. Furthermore, comparing the UAV plot ◯ with the FCU plot △, it can be seen that a malfunction of fault class 2 occurred, and it can be inferred that the cause of the malfunction is the FCU.

[0054] Figure 11 is another diagram comparing immunity tests of the entire drone and its parts. The horizontal axis shows the frequency of the test signal, and the vertical axis shows the three fault classes. When the above-mentioned pulse modulated wave was used as the test signal, the results of the entire drone test using the GTEM cell in Figure 3 and the test of three parts of the drone using the TEM cell in Figure 7 are shown. The plot ◯ indicates the whole drone (UAV) test using the GTEM cell. For the TEM cell test, the plot △ indicates the part test for the FCU, the plot □ indicates the part test for the ESC, and the plot ● indicates the part test for the BEC.

[0055] Comparing the UAV plot ◯ and the ESC plot □, fault class 1 malfunctions occurred at close frequencies, and it can be inferred that the cause of fault class 1 is the ESC. Fault class 2 occurred at the UAV plot ◯ and the FCU plot △ at the same frequency, and it can be inferred that the cause of fault class 1 is the FCU. Fault class 3 occurred at the UAV plot ◯ and the BEC plot ● at the same frequency, and it can be inferred that the cause of fault class 1 is the BEC.

[0056] From Fig. 10 and Fig. 11, a clear correspondence can be confirmed between the occurrence of a fault in the overall test of the drone in the GTEM cell and the occurrence of a fault in a part of the drone in the TEM cell. In other words, it can be seen that the part causing the fault in the drone can be identified by the immunity test apparatus 200 using the TEM cell shown in Fig. 7. In Fig. 10 and Fig. 11, fault class 1, which indicates a loss of synchronism of the motor, has occurred, and a fault in the ESC shown in plot □ has also been confirmed. Therefore, the electrical signals around the ESC 13 were observed when the ESC was tested using the immunity test apparatus 200 using the TEM cell shown in Fig. 7.

[0057] FIG. 12 shows electrical signals observed during an immunity test of the ESC. In the test device configuration shown in FIG. 8, only the ESC 13 is placed in the TEM cell via the extension wiring 204. In this state, differential voltage probes were connected to two locations in the drone: between the FCU 12 and the ESC 13 (waveform A: between ESC-FCU) and between the ESC 13 and the motor (waveform B: between ESC-motor), and measurements were taken. FIG. 12 shows two observed waveforms superimposed for one phenomenon when an AM modulated wave was used as the test signal. In the waveform B between the ESC 13 and the motor, a PWM signal for driving the motor is visible, and the motor completely stops in 0.46 s. After the motor stops, the waveform B between the ESC 13 and the motor becomes a minute noise, and the amplitude waveform of the AM modulated wave combined as waveform A is visible. It is believed that a high level of electromagnetic interference was irradiated to the ESC 13, which controls the speed of the motor, causing a fault class 3 in which the motor stops.

[0058] FIG. 13 is another diagram showing electrical signals observed during an immunity test of the ESC. As in the case of FIG. 12, only the ESC 13 is placed in the TEM cell via the extension wiring 204. In this state, signals appearing at two points in the drone, between the FCU 12 and the ESC 13 (waveform A: between ESC-FCU) and between the ESC 13 and the motor (waveform B: between ESC-motor), were measured. FIG. 13 shows a case where a pulse modulated wave was used as the test signal. It shows a repetitive phenomenon with a period shorter than the observation time in FIG. 12, and in the waveform B between the ESC 13 and the motor, a PWM signal (period 2 msec) for driving the motor is visible. The original PWM signal is also visible in the waveform A between the FCU 12 and the ESC 13. Here, an irregular noise waveform indicated as "out of step" is generated in the waveform B. This noise waveform indicates that an abnormality has occurred in the rotation of the motor, and out of step corresponding to fault class 1 has occurred. It is considered that the pulse of the interfering electromagnetic wave has caused an irregular abnormality in the rotation operation of the motor.

[0059] As shown in Figures 12 and 13, the immunity test device 200 for the parts of the unmanned aerial vehicle shown in Figure 7 made it possible to identify the part causing the disturbance, and also observed the abnormal signal waveform corresponding to the disturbance. With the immunity test device 200 in Figure 7, a simulated signal is applied to the target unmanned aerial vehicle in a normal anechoic chamber, placing it in a "simulated flight state," and it is possible to test the immunity resistance of specific parts of the unmanned aerial vehicle.

[0060] The immunity test device disclosed herein can perform immunity resistance tests on an unmanned aerial vehicle while the vehicle remains stationary at a fixed position in a certain space, under conditions almost equivalent to flight conditions in a real operating environment. Immunity tests on unmanned aerial vehicles can be performed using existing simple equipment configurations, such as a GTEM cell or a combination of a normal anechoic chamber and a TEM cell, and repeater equipment for positioning signals such as GPS signals is not required. [Industrial Applicability]

[0061] The present invention can be used for immunity testing of unmanned aerial vehicles. [Explanation of symbols]

[0062] 10. Drone 11 GPS antenna 12 Flight Controller (FCU) 13 Speed ​​controller (ESC) 18, 18-1~18-4 Motor 100, 200 Immunity Test Equipment 101 GTEM Cell 103, 203 septum 111 Test Signal Generator 113 Simulated GPS signal control unit 114 Simulated GPS signal transmitter 115 Control Transmitter / Receiver 201 TEM Cell

Claims

1. An immunity test apparatus comprising: an electromagnetically shielded anechoic chamber for housing the target unmanned aerial vehicle therein; A test signal source that generates electromagnetic interference waves for the unmanned aerial vehicle; a simulated signal transmitter for generating a simulated signal including information for identifying a virtual location of the unmanned aerial vehicle; A control unit that generates the information; Equipped with Based on the virtual position, the presence or absence of a fault caused by the electromagnetic interference is determined in a simulated flight state equivalent to the unmanned aerial vehicle being stationary or moving in a predetermined direction and at a predetermined speed; A part of the unmanned aerial vehicle is stored inside a TEM cell, and another part of the unmanned aerial vehicle is stored in the anechoic chamber, and the simulation signal is applied to the other part. Test equipment.

2. The test apparatus of claim 1 , wherein the control unit is further configured to transmit control information for setting the unmanned aerial vehicle to the stopped state or the simulated flight state, and to receive status information of the unmanned aerial vehicle.

3. 2. The test apparatus according to claim 1, wherein the simulation signal includes three or more signals each including time information synchronized with each other, and the virtual position is determined based on a time difference between the time information of the three or more signals.

4. 2. The test apparatus of claim 1, wherein the simulation signal corresponds to a signal obtained by multiplexing radio waves from a transmission source including a satellite or a base station.

5. The test device of claim 1 , wherein the unmanned aerial vehicle is a drone, and the simulated signal corresponds to a signal obtained by combining positioning signals from different satellites.

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