Unmanned aerial vehicle and method of controlling the same

Abstract

The present application provides a kind of unmanned plane, comprising: first barometer, provides first air pressure value;Processing unit is coupled to first barometer, processing unit receives the first air pressure value provided by first barometer, and the first air pressure value of first barometer is time synchronized with the external reference air pressure value provided by external reference barometer to obtain the first air pressure value after time synchronization correction, and the first air pressure value after time synchronization correction is recalculated to generate the compensated air pressure value, processing unit carries out information fusion calculation to first air pressure value, compensated air pressure value and sensor data, to obtain target fused data, and processing unit controls the real-time height and attitude of unmanned plane according to target fused data.

Description

TECHNICAL FIELD

[0001] The present application relates to an unmanned aerial vehicle and a control method thereof. BACKGROUND

[0002] An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is a broad term for any type of aircraft that does not require a pilot on board to fly.

[0003] The unmanned aerial vehicle is usually controlled by remote control, guidance or autopilot. The unmanned aerial vehicle can be applied to scientific research, site exploration, military, leisure and entertainment, agriculture, disaster relief and other fields. Therefore, the global market for unmanned aerial vehicles has grown significantly in recent years. SUMMARY

[0004] According to an embodiment of the present application, an unmanned aerial vehicle is provided, comprising: a first barometer providing a first barometric value; a processing unit coupled to the first barometer, the processing unit receiving the first barometric value provided by the first barometer, and time synchronizing the first barometric value of the first barometer with an external reference barometric value provided by an external reference barometer to obtain a time-synchronized corrected first barometric value, and recalculating the time-synchronized corrected first barometric value to generate a compensated barometric value, the processing unit performing information fusion calculation on the first barometric value, the compensated barometric value and sensor data to obtain target fused data, and the processing unit performing real-time height and attitude control of the unmanned aerial vehicle according to the target fused data.

[0005] According to another embodiment of the present application, an unmanned aerial vehicle control method is provided for controlling an unmanned aerial vehicle comprising a first barometer, the unmanned aerial vehicle control method comprising: receiving a first barometric value provided by the first barometer; time synchronizing the first barometric value of the first barometer with an external reference barometric value provided by an external reference barometer to obtain a time-synchronized corrected first barometric value, and recalculating the time-synchronized corrected first barometric value to generate a compensated barometric value; performing information fusion calculation on the first barometric value, the compensated barometric value and sensor data to obtain target fused data; and performing real-time height and attitude control of the unmanned aerial vehicle according to the target fused data.

[0006] In order to better understand the above and other aspects of the present application, the following embodiments are described in detail below, in conjunction with the accompanying drawings: BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is a functional block diagram of an unmanned aerial vehicle according to an embodiment of the present application;

[0008] Figure 2 is a control diagram of an external control module 53 according to an embodiment of the present application;

[0009] Figure 3 is a functional block diagram of a barometer value processing module according to an embodiment of the present application;

[0010] Figure 4 is an operation diagram of a data fusion switching unit according to an embodiment of the present application;

[0011] Figure 5A and Figure 5B are two operation examples according to an embodiment of the present application;

[0012] Figure 6 is a flowchart of a UAV control method according to an embodiment of the present application.

[0013] Reference numerals:

[0014] 100: UAV;

[0015] 110: first barometer;

[0016] 130: processing unit;

[0017] 151: positioning sensor;

[0018] 153: inertial measurement element;

[0019] 155: distance sensor;

[0020] 190: communication unit;

[0021] 50: external auxiliary device;

[0022] 51: external reference barometer;

[0023] 53: external control module;

[0024] 131: barometer value processing module;

[0025] 133A, 133B: data fusion unit;

[0026] 135: data fusion switching unit;

[0027] 137: height and attitude control module;

[0028] 132: data fusion module;

[0029] 210-218: steps;

[0030] 310: data timing synchronization unit;

[0031] 320: data correction and separation unit;

[0032] 330: barometer value recalculation unit;

[0033] 340: operation unit;

[0034] 405-420: steps;

[0035] 510: bridge;

[0036] 520: control center;

[0037] 610-640: steps. DETAILED DESCRIPTION

[0038] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example implementations to those skilled in the art. The described features, structures, or characteristics can be combined in one or more implementations.

[0039] The terminology used in this specification should be interpreted in accordance with customary usage in the technical field, unless a term is otherwise defined herein. Embodiments of the application each have several innovative technical features. One or more of such innovative technical features can be employed in any combination in any embodiment of this application. The technical features of one embodiment can be combined with those of another embodiment unless the features are mutually exclusive.

[0040] The UAV calculates its current height by means of the barometer value and the GPS. When the UAV flies under a bridge for inspection, the GPS signal can be blocked by the bridge. In this case, if there is wind, the wind will cause the barometer value to change. These situations (GPS blocked by the bridge and wind causing the barometer value to change) can make it difficult for the UAV to maintain its flight height, causing flight difficulties and dangers.

[0041] Embodiments of the application propose a UAV and a control method thereof, so as to have good control over the flight and height attitude of the UAV, and to save hardware cost and software development cost while obtaining ideal control results.

[0042] Figure 1 is a functional block diagram of a UAV according to an embodiment of the application. As shown in FIG. 1, the UAV comprises a barometer 110, a GPS 120, a bridge 130, a control center 140, and a flight control system 150. Figure 1As shown, the UAV 100 according to an embodiment of the present application comprises a first barometer 110, a processing unit 130, a positioning sensor 151, an inertial measurement unit (IMU) 153, a distance sensor 155, and a communication unit 190. The UAV 100 can also wirelessly communicate with an external assistance device 50. The external assistance device 50 comprises at least one external reference barometer 51 and an external control module 53.

[0043] The first barometer 110 is configured to provide a first barometric value P1 to the processing unit 130. In the following, the first barometer 110 can also be referred to as a UAV barometer, since the first barometer 110 is located on the UAV 100.

[0044] The processing unit 130 is coupled to the first barometer 110. The processing unit 130 receives the first barometric value P1 provided by the first barometer 110, and time synchronizes the first barometric value P1 provided by the first barometer 110 with an external reference barometric value P2 provided by the external reference barometer 51 to obtain a time-synchronized corrected first barometric value P1, and recalculates the time-synchronized corrected first barometric value P1 to generate a compensated barometric value P3. The processing unit 130 performs information fusion calculation on the compensated barometric value P3 and sensor data SD to obtain target fused data. The processing unit 130 performs height and attitude control of the UAV 100 according to the target fused data.

[0045] In an embodiment, the processing unit 130 comprises a barometer value processing module 131, a first data fusion unit 133A, a second data fusion unit 133B, a data fusion switching unit 135, and a height and attitude control module 137. The processing unit 130 can be, for example but not limited to, a general purpose central processing unit (CPU), an Application Specific Integrated Circuit (ASIC), a microcontroller, a microprocessor, a processor, a digital signal processor (DSP), a digital logic circuit, a field programmable gate array (FPGA), and / or other hardware elements or circuits having computing processing functions. The first data fusion unit 133A, the second data fusion unit 133B, and the data fusion switching unit 135 can also be collectively referred to as a data fusion module 132.

[0046] The barometer count value processing module 131 time synchronizes the first barometer value P1 of the first barometer 110 with the external reference barometer value P2 provided by the external reference barometer 51, and recalculates the time synchronized corrected first barometer value P1 to generate a compensated barometer value P3.

[0047] The data fusion module 132 performs information fusion calculation on the first barometer value P1, the compensated barometer value P3, and the sensor data SD to obtain target fused data.

[0048] The first data fusion unit 133A receives the compensated barometer value P3 and the sensor data SD and performs information fusion calculation to obtain first fused data FD1.

[0049] The second data fusion unit 133B receives the first barometer value P1 of the first barometer 110 and the sensor data SD and performs information fusion calculation to obtain second fused data FD2. In an embodiment of the present disclosure, the second data fusion unit 133B can be a selective unit.

[0050] The first data fusion unit 133A and the second data fusion unit 133B, for example but not limited to, use an extended Kalman filter (EKF) for data fusion (DF). The extended Kalman filter (EKF) estimates the real-time position, velocity, and angular orientation of the UAV based on information such as IMU (e.g., gyroscope, accelerometer, or electronic compass), GPS, airspeed, and barometer.

[0051] The data fusion switching unit 135 is used to switch or select the first fused data FD1 or the second fused data FD2 to obtain target fused data, and transmit the target fused data to the height and attitude control module 137. In an embodiment of the present disclosure, the data fusion switching unit 135 can be a selective unit.

[0052] The height and attitude control module 137 controls the height and / or attitude of the UAV 100 according to the target fused data selected by the data fusion switching unit 135. Moreover, the height and attitude control module 137 can also feed back the first data fusion unit 133A and the second data fusion unit 133B of the data fusion module 132.

[0053] The positioning sensor 151 provides positioning information. For example but not limited to, the positioning sensor 151 can provide satellite positioning information and / or ultra-wideband positioning information, etc.

[0054] The inertial measurement element 153 provides inertial measurement data. For example but not limited to, the inertial measurement element 153 includes a gravity sensor, an electronic gyroscope, an electronic compass, etc.

[0055] The distance sensor 155 provides distance sensing data. For example, but not limited to, the distance sensor 155 includes a light detection and ranging (Lidar), an ultrasonic sensor, a time-of-flight (ToF) sensor, etc.

[0056] The sensor group can include any combination of the positioning sensor 151, the inertial measurement element 153, and the distance sensor 155. The data sent by the sensor group to the processing unit 130 can also be referred to as sensor data SD.

[0057] The external reference barometer 51 provides an external reference barometric value P2 to the communication unit 190. The communication unit 190 transmits the external reference barometric value P2 to the processing unit 130. If the external auxiliary device 50 includes a plurality of external reference barometers 51, a plurality of external reference barometric values P2 can be transmitted to the processing unit 130. In another embodiment, the external reference barometric value P2 can also be an average of the plurality of external reference barometers 51.

[0058] The external control module 53 is used to determine whether the external auxiliary device 50 has been fixed or is in a stable state (i.e., the external auxiliary device 50 does not have a large movement). When the external control module 53 determines that the external auxiliary device 50 has been fixed or is in a stable state, the external control module 53 outputs a notification signal to the communication unit 190 of the UAV 100. The communication unit 190 transmits the notification signal output by the external control module 53 to the processing unit 130, so that the processing unit 130 can refer to the external reference barometric value P2 of the external reference barometer 51 to perform attitude and height control.

[0059] Figure 2 is a control diagram of the external control module 53 according to an embodiment of the present application. As shown in Figure 2 The external control module 53 can obtain a height value (which can be a height above ground, a height above sea level, or a relative height of the external auxiliary device 50 relative to a known height object, etc.) of the external auxiliary device 50. The external control module 53 can be set to a full action condition or a partial action condition. In the full action condition, the external control module 53 can provide more accurate data close to the real environment for subsequent calculation, and provide more complete mutual correction capability for the factory difference of each barometer sensing value. In the partial action condition, the UAV 100 of the embodiment of the present application can be operated in a faster deployment state.

[0060] In the sensing height information step 210, an ultrasonic or optical (Lidar, infrared light, visible light, or ToF camera, etc.) device is used to sense and obtain height information.

[0061] In the extracting altitude information step 212, the altitude information is given externally or set manually.

[0062] In the obtaining altitude information step 214, the altitude information provided by the sensing altitude information step 210 or the extracting altitude information step 212 can be used.

[0063] In the determining step 216, according to the obtained altitude information, it is determined whether the external auxiliary device 50 is fixed or in a stable state. For example, if the change of the altitude information in a period of time (or between several measurements) is less than a certain value, it is determined that the external auxiliary device 50 is fixed or in a stable state. If the step 216 is yes, it means that the external auxiliary device 50 does not move greatly, and the external control module 53 outputs a notification signal to the UAV 100; and the external reference barometer 51 on the external auxiliary device 50 provides the external reference pressure value P2 for the processing unit 130 of the UAV 100 to use as a reference.

[0064] If the step 216 is no, the flow goes to step 218. In the determining step 218, it is determined that the external auxiliary device 50 can be in an unknown altitude state (but the external auxiliary device 50 can be in a fixed or stable state, and does not move greatly, such as the hovering state of the UAV).

[0065] In an embodiment of the present application, when the altitude information of the external auxiliary device 50 is known, the external auxiliary device 50 can assist the UAV 100 to set the target flight altitude and adjust the current flight altitude by increasing or decreasing the relative altitude; and when the altitude information of the external auxiliary device 50 is unknown, the external auxiliary device 50 can assist the UAV 100 to adjust the current flight altitude by increasing or decreasing the relative altitude. As for the corresponding change relationship between the altitude change and the pressure change, it can refer to the relevant local meteorological research information.

[0066] Figure 3 is a functional block diagram of the barometer count value processing module 131 according to an embodiment of the present application. As shown in Figure 3 the barometer count value processing module 131 includes a data time synchronization unit 310, a data correction and separation unit 320, a barometer count value recalculation unit 330, and an operation unit 340.

[0067] In an embodiment of the present application, the first barometer 110 provides the first pressure value P1 and the related first time mark; similarly, the external reference barometer 51 provides the external reference pressure value P2 and the related second time mark. The first and second time marks can use the real world time (but not necessarily). Alternatively, the synchronization information used to assist in marking the barometer count values can be used as the first and second time marks.

[0068] The data time synchronization unit 310 synchronizes the first barometric pressure value P1 and the external reference barometric pressure value P2 according to the time marks to obtain the time-synchronized corrected first barometric pressure value P1. For example, but not limited to, in an embodiment of the present application, when the time values of the first time mark and the second time mark are the same or differ by less than an error value, the corresponding first barometric pressure value P1 and the external reference barometric pressure value P2 are determined as barometric pressure values at the same time.

[0069] In the initial state, the data correction and separation unit 320 corrects the mutual deviation value of the first barometric pressure value P1 and the external reference barometric pressure value P2 after the synchronization arrangement, so that the first barometer 110 and the external reference barometer 51 can consistently interpret the values and barometric pressure values provided by each barometer in subsequent use. In an embodiment, the correction method is, for example, but not limited to, measuring the first barometric pressure value P1 and the external reference barometric pressure value P2 at each height to obtain the mutual deviation value of the first barometric pressure value P1 and the external reference barometric pressure value P2 at each height after the synchronization arrangement, so as to eliminate errors during operation. In the operating state, the data correction and separation unit 320 outputs the common mode barometric pressure value B_COM and the differential mode barometric pressure value B_DIFF of the target barometer (i.e., the first barometer 110) after correction.

[0070] In an embodiment of the present application, the external reference barometer 51 is corrected, for example, the external reference barometer 51 is corrected to conform to the values of the first barometer 110, and the output value of the corrected external reference barometer 51 can have "consistency" (e.g., the same or similar) in the cognition of the "height" and the "value change with the change of height" of the environment with the first barometer 110. That is, even if the barometer (e.g., the external reference barometric pressure value P2) has a measurement deviation error when it is shipped, in an embodiment of the present application, the correction can enable each barometer to have consistent interpretation of the measured barometric pressure values of each barometer in the adjacent use environment. Although the external reference barometer 51 is corrected as an example, the present application is not limited thereto, and in another embodiment, the first barometer 110 or both the first barometer 110 and the external reference barometer 51 can be corrected.

[0071] After the first barometric pressure value P1 and the external reference barometric pressure value P2 are both time-synchronized and corrected, the first barometric pressure value P1 and the external reference barometric pressure value P2 have the same or similar cognition of the barometric pressure value in space and the change of barometric pressure with height, for example, but not limited to, at the same height, the first barometric pressure value P1 and the external reference barometric pressure value P2 measure the same barometric pressure.

[0072] When the relative height of the first barometer 110 to the external reference barometer 51 is known, the data correction and separation unit 320 also performs a "mapping" to map the external reference barometric value P2 to the same height as the first barometric value P1 to obtain a mapped external reference barometric value P2 remap before calculating the common mode barometric value B COM. The mapped external reference barometric value P2 remap is used as the barometric value at the same height as the first barometric value P1. For example, if the height of the UAV 100 is H2 (the height of the external auxiliary device 50) + h (the relative height between the UAV 100 and the external auxiliary device 50), the mapped external reference barometric value P2 remap is the barometric value of the external reference barometer 51 at "H2 + h". Through the mapping, the common mode barometric value B COM can be represented as shown in equation (1-1):

[0073] B COM = (P1 + P2 remap) / 2 (1-1)

[0074] In addition, the differential mode barometric value B DIFF can be described as shown in equation (1-2):

[0075] B DIFF1 = P1 - B COM (1-2)

[0076] In an embodiment of the present application, the barometer value recalculation unit 330 eliminates or reduces the barometric value change caused by the wind. For example, in the case of no wind, the first barometric value of the first barometer 110 is P1_0, and the corrected barometric value of the external reference barometer 51 is P2 cal; in an embodiment, the positions of the first barometer 110 and the external reference barometer 51 are close, and in the presence of wind, the first barometer 110 and the external reference barometer 51 are both affected by the wind, causing the same or similar barometric value change. If the barometric value change caused by the wind is P_wind, the first barometric value of the first barometer 110 becomes P1 = P1_0 + P_wind, and the external reference barometric value of the external reference barometer 51 becomes P2 = P2 cal + P_wind. P2 can be subtracted by P2 cal to obtain P_wind; in another embodiment, the barometric value change P_wind can also be obtained using the value before correction, for example, in the case of no wind, the corrected barometric value of the external reference barometer 51 is P2_0, and the external reference barometric value of the external reference barometer 51 in the presence of wind is P2 = P2_0 + P_wind. P2 can be subtracted by P2_0 to obtain P_wind, and P1 can also be used to obtain P_wind through the same or similar algorithm. The barometer value recalculation unit 330 can then subtract the barometric value change P_wind caused by the wind as shown in equation (2):

[0077] B COM' = B COM - P_wind (2)

[0078] After the pressure value change caused by the wind is subtracted, the pressure value of the first barometer 110 is adjusted to a compensated pressure value P3 as shown in equation (3):

[0079] P3 = B_COM' + B_DIFF (3)

[0080] In one embodiment of the present application, when the relative height of the first barometer 110 and the external reference barometer 51 is unknown, the mapping is not performed, and the P2_remap of equation (1-1) can be calculated using the corrected pressure value P2_cal. In another embodiment, when the relative height of the first barometer 110 and the external reference barometer 51 is known, the mapping is not performed, and the P2_remap of equation (1-1) can be calculated using the corrected pressure value P2_cal.

[0081] In one embodiment of the present application, an example of the mapping performed by the data correction and separation unit 320 is described below, but the present application is not limited to this. For example, when the first pressure value P1 is 980 Pa and the external reference pressure value P2 is 965 Pa at the same environment and height, and when the first pressure value P1 and the external reference pressure value P2 change by the same or similar amount at the same height, the data correction and separation unit 320 can correct the external reference pressure value P2 by adding the difference between the two barometers (980 Pa - 965 Pa) to the external reference pressure value P2, and then add the difference between the first barometer 110 and the external reference barometer 51 (which can be measured in advance) to the measured value of the external reference pressure value P2 to obtain the mapped external reference pressure value P2_remap. Alternatively, the first pressure value can be measured at various heights by the UAV to establish a mapping value table, so that the UAV control mechanism of the embodiment of the present application knows the difference between the first pressure value P1 and the external reference pressure value P2 when the measurement is performed, and then compensates for the difference to correct the external reference pressure value P2, and then obtains the mapped external reference pressure value P2_remap of the external reference barometer 51 at the height of the first barometer 110 according to the mapping value table. In this case, because the corresponding relationship between each barometer at various heights and pressure values is known, the mapped data can be obtained.

[0082] In one embodiment, the height adjustment value of the UAV 100 can be obtained according to equation (4) or other height and pressure conversion formulas, so that the height and attitude control module 137 adjusts the height of the UAV.

[0083] Z2-Z1 = 18400 (1 + a*t) * log(P1 / P3) (4)

[0084] wherein Z2-Z1 represents the relative height of the first barometer 110 to the height to which the UAV 100 should be adjusted, a is a constant (for example, but not limited to, 1 / 273), and t represents the temperature in Celsius.

[0085] In another embodiment, the mapping of the table of values can also be calculated using equation (4), for example, by modifying equation (4) as follows in equation (5):

[0086] ZX-Z1= 18400(1+a*t)*log(P1 / PX) (5)

[0087] ZX is each height at which the first barometer 110 is located, and PX is the pressure value measured by the first barometer 110 at each height. When the relative height of the first barometer 110 to the external reference barometer 51 is known, the mapped external reference pressure value P2 can also be calculated by equation (5) above. Because the first pressure value P1 and the external reference pressure value P2 are calibrated, the values of the first pressure value P1 and the external reference pressure value P2 are consistent for real-world pressure and height changes.

[0088] Alternatively, if the relative height of the first barometer 110 to the external reference barometer 51 is unknown (i.e., Z2-Z1 is unknown), the height difference between the first barometer 110 and the external reference barometer 51 can be calculated by the barometer values of the first barometer 110 and the external reference barometer 51 when the heights of the first barometer 110 and the external reference barometer 51 are stable. In the absence of wind, the individual pressure values of the first barometer 110 and the external reference barometer 51 represent the individual heights. In the presence of wind, the first barometer 110 and the external reference barometer 51 are arranged in close proximity to each other so that the first barometer 110 and the external reference barometer 51 are affected by the wind as closely as possible.

[0089] In addition, if the external reference barometer 51 includes multiple reference barometers, the mapping step described above can be performed on the barometer values of each reference barometer.

[0090] In an embodiment of the present application, how to eliminate the effect of wind can be described as follows, of course, the present application is not limited thereto. The barometer is used to measure atmospheric pressure. When the barometer is shipped, the output of the barometer is a voltage value, but this output voltage value will vary with the pressure. Therefore, the barometer manufacturer will provide a table of corresponding relationship between voltage and pressure. Secondly, regarding the relationship between pressure and height, there are some research results in the field of meteorology (such as equation (3) described above). The pressure at the current average sea level is 1013.25 hundred pascal (hPa), and when the height rises, the pressure decreases, so there is a conversion table between height and pressure.

[0091] In addition, if the UAV 100 has an unusual altitude change, the additional barometric pressure difference caused by the altitude change can be presented in the parameter B_DIFF, which is then offset by the UAV 100 through the altitude adjustment.

[0092] In one embodiment, the barometer count value recalculation unit 330 can be a known atmospheric research related model, such as but not limited to, the Norwegian Cyclone Model.

[0093] The operation unit 340 is, for example but not limited to, an adder. The operation unit 340 operates (such as adds) B_COM' with the difference mode barometric pressure value B_DIFF to obtain the compensated barometric pressure value P3.

[0094] Figure 4 is a schematic diagram of the operation of the data fusion switching unit 135 according to one embodiment of the present application. The data fusion switching unit 135 is used to switch and select the first fused data FD1 and the second fused data FD2, and to transmit the selected target fused data to the altitude and attitude control module 137.

[0095] In step 405, the data fusion switching unit 135 performs manual setting, in which the user manually selects the first fused data FD1 or the second fused data FD2.

[0096] In step 407, the data fusion switching unit 135 performs automatic setting. The automatic setting (automatic switching setting) can set at least one switching condition, which includes any combination of the following (but it is understood that the present application is not limited thereto):

[0097] RF localization precision judgment: according to the radio localization precision to determine whether to perform data fusion switching. Radio localization includes satellite localization, ultra-wideband localization, or other radio localization methods. Taking satellite localization as an example, when the satellite localization fails or the localization precision is lower than a set value, one of the first fused data FD1 and the second fused data FD2 is selected, and when the satellite localization precision is higher than the set value, the other of the first fused data FD1 and the second fused data FD2 is selected. For example, when the satellite localization precision of the satellite localization information provided by the localization sensor 151 is lower than a set value, the first fused data FD2 is selected, and when the satellite localization precision is higher than the set value, the second fused data FD1 is selected.

[0098] Localization information triggering: using localization information as the basis for triggering handover. For example, when the UAV 100 is in a localization area A, one of the first fused data FD1 and the second fused data FD2 is selected, and when the UAV 100 is in a localization area B or leaves the localization area A, the other one of the first fused data FD1 and the second fused data FD2 is selected.

[0099] Sensing information triggering: using a sensor as the basis for triggering handover. When the sensing value of a distance sensor or an illumination sensor is in a range P, one of the first fused data FD1 and the second fused data FD2 is selected, and when the sensing value of the distance sensor or the illumination sensor is in another range Q or leaves the range P, the other one of the first fused data FD1 and the second fused data FD2 is selected.

[0100] In step 410, it is determined whether the current setting is manual or automatic. In an embodiment, the setting is preset to be automatic, and when the user determines that it is necessary, the setting is changed to manual or automatic.

[0101] In step 420, according to whether the current setting is manual or automatic, one of the first fused data FD1 and the second fused data FD2 is selected as the target fused data.

[0102] Figure 5A With Figure 5B are two operation examples according to an embodiment of the present application. Figure 5A The first operation example of can be applied to a case where the relative height difference between the external reference barometer 51 and the UAV 100 is known. Figure 5B The second operation example of can be applied to a case where the relative height difference between the external reference barometer 51 and the UAV 100 is unknown.

[0103] Figure 5A is one of the scenarios in which the UAV 100 of an embodiment of the present application is applied to bridge detection. The UAV 100 (with the first barometer 110 built-in or mounted thereon) in flight is kept at a specific height outside the bridge 510 and slowly moves to the underside of the bridge 510. The UAV ground control center 520 can control the UAV 100 and / or the external auxiliary device 50.

[0104] The first barometer 110 of the UAV 100 and the external reference barometer 51 of the external auxiliary device 50 are in the same or similar environment, so the first barometer 110 and the external reference barometer 51 sense similar air pressure changes. Since the relative height of the first barometer 110 and the external reference barometer 51 is known, the UAV 100 can compare the barometer values P1 and P2 of the first barometer 110 and the external reference barometer 51 to obtain the air pressure value change caused by the wind to the barometer value P1, and then recalculate to generate the compensated air pressure value P3. In this way, unnecessary height adjustment behavior of the UAV due to the change of the time-varying air pressure (wind) can be reduced or eliminated, or flight danger (such as climbing up to touch the bridge body) can be generated.

[0105] In Figure 5A , the UAV 100 uses its own GPS module time, and the external reference barometer 51 is connected to the control center 520 to use the time of the control center and is time-synchronized. When performing barometer correction and calculating the mapped external reference air pressure value P2remap, the control center 520 sends the "known relative height difference between the external reference barometer 51 and the UAV 100" to the UAV 100.

[0106] In Figure 5B , the external auxiliary device 50 is another UAV, which can be a general conventional UAV, has a satellite positioning module, and can achieve good hovering outdoors. After the external auxiliary device 50 takes off and climbs to a suitable position and hovers, the relative vertical height relationship between the UAV 100 and the external auxiliary device 50 is maintained, and the UAV 100 can refer to the barometer value of the external reference barometer 51 of the external auxiliary device 50 to perform corresponding air pressure compensation calculation, so that the UAV 100 maintains a stable physical height and reduces or eliminates unnecessary height adjustment behavior of the UAV due to the change of the time-varying air pressure (wind).

[0107] In Figure 5B , the UAV 100 uses its own GPS module time, and the external reference barometer 51 is connected to the control center 520 to use the time of the control center and is time-synchronized. When performing barometer correction and calculating the mapped external reference air pressure value P2remap, the UAV 100 refers to the external reference air pressure value P2 of the external reference barometer 51 to perform height and attitude control.

[0108] Figure 6is a flowchart of a UAV control method according to an embodiment of the present application. In step 610, a first air pressure value provided by a first air pressure gauge is received. In step 620, the first air pressure value of the first air pressure gauge is time-synchronized with an external reference air pressure value provided by an external reference air pressure gauge to obtain a time-synchronized corrected first air pressure value P1, and the time-synchronized corrected first air pressure value P1 is recalculated to generate a compensated air pressure value. In step 630, the first air pressure value, the compensated air pressure value, and sensor data are information-fused to obtain target fused data. In step 640, the UAV is controlled in real-time height and attitude according to the target fused data.

[0109] An embodiment of the present application provides a UAV and a control method for assisting the UAV to calculate a real-time height. By referring to a reference air pressure value of an external reference air pressure gauge, the UAV can maintain a relatively stable flight height in a time-varying wind environment. Thus, the usability and safety of the UAV in bridge inspection are improved.

[0110] An embodiment of the present application provides a UAV and a control method applied to a satellite positioning-free environment such as UAV bridge inspection, for reducing or eliminating the influence of time-varying air pressure (wind) on the environment, avoiding misjudgment of the real-time flight height of the UAV, avoiding incorrect height adjustment behavior, and avoiding flight danger.

[0111] An embodiment of the present application provides a low-cost UAV and a control method thereof, which solves the problem of large flight height variation of the UAV caused by poor or shielded satellite signals and time-varying air pressure (wind) in a bridge inspection scenario.

[0112] The above-described specific embodiments further illustrate the purpose, technical solutions, and advantages of the present application. It should be understood that the above-described specific embodiments are merely examples of the present application and are not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An unmanned aerial vehicle (UAV), comprising: a first barometer providing a first barometric value; a processing unit coupled to the first barometer, the processing unit receiving the first barometric value provided by the first barometer, and time synchronizing the first barometric value of the first barometer with an external reference barometric value provided by an external reference barometer to obtain a time-synchronized corrected first barometric value, and recalculating the time-synchronized corrected first barometric value to generate a compensated barometric value, the processing unit performing information fusion calculation on the first barometric value, the compensated barometric value, and sensor data to obtain target fused data, the processing unit performing real-time height and attitude control of the UAV based on the target fused data; wherein the data fusion module comprises: a first data fusion unit receiving the compensated barometric value and the sensor data and performing information fusion calculation to obtain first fused data; a second data fusion unit receiving the first barometric value of the first barometer and the sensor data and performing information fusion calculation to obtain second fused data; a data fusion switching unit for switching or selecting the first fused data or the second fused data to obtain the target fused data; wherein the sensor data is data sent by a sensor group to the processing unit.

2. The drone of claim 1, wherein, the processing unit comprises: a barometer value processing module for time synchronizing the first barometric value of the first barometer with the external reference barometric value provided by the external reference barometer, and recalculating the time-synchronized corrected first barometric value to generate the compensated barometric value; a data fusion module receiving the first barometric value, the compensated barometric value, and the sensor data and performing information fusion calculation to obtain the target fused data; and a height and attitude control module performing height and attitude control based on the target fused data, the height and attitude control module further feeding back to control the data fusion module.

3. The drone of claim 2, wherein, the data fusion switching unit is further configured to transmit the target fused data to the height and attitude control module, wherein the height and attitude control module performs height and attitude control based on the target fused data, the height and attitude control module further feeding back to control the first data fusion unit and the second data fusion unit.

4. The drone of claim 3, wherein, the barometer value processing module comprises: a data time synchronization unit synchronizing the first barometric value and the external reference barometric value according to a plurality of time markers; a data correction and separation unit outputting a common mode barometric value and a differential mode barometric value when in an operating state; a barometer value recalculation unit generating a recalculated first barometric value based on the common mode barometric value; and an operation unit obtaining the compensated barometric value based on the recalculated first barometric value and the differential mode barometric value.

5. The drone of claim 4, wherein, when in an initial state, the data correction and separation unit corrects a mutual deviation value of the synchronized first barometric value and the external reference barometric value.

6. The UAV of claim 4, wherein Before calculating the common mode pressure value, the data correction and separation unit maps the external reference pressure value to a mapped external reference pressure value as a pressure value at the same altitude as the first pressure value.

7. The drone of claim 5, wherein, In automatic setting, the at least switching condition set by the data fusion switching unit includes any combination of: wireless positioning accuracy determination, selecting the first fused data or the second fused data according to wireless positioning accuracy; positioning information triggering, selecting the first fused data or the second fused data according to positioning information; and sensing information triggering, selecting the first fused data or the second fused data according to sensing values of a distance sensor or an illuminance sensor.

8. A UAV control method for controlling a UAV comprising a first barometer, the UAV control method comprising: receiving a first pressure value provided by the first barometer; time synchronizing the first pressure value of the first barometer and an external reference pressure value provided by an external reference barometer to obtain a time synchronization corrected first pressure value, and recalculating the time synchronization corrected first pressure value to generate a compensated pressure value; performing information fusion calculation on the first pressure value, the compensated pressure value and sensor data to obtain target fused data; and controlling the UAV in real time in altitude and attitude according to the target fused data; wherein the step of obtaining the target fused data comprises: performing information fusion calculation on the compensated pressure value and the sensor data to obtain first fused data, performing information fusion calculation on the first pressure value of the first barometer and the sensor data to obtain second fused data; and switching and selecting the first fused data and the second fused data to obtain the target fused data; wherein the sensor data is data emitted by a sensor group to a processing unit. 9.The UAV control method of claim 8, wherein, The step of generating the compensated pressure value comprises: synchronizing the first pressure value and the external reference pressure value according to a plurality of time markers; outputting a common mode pressure value and a differential mode pressure value in an operating state; generating a recalculated first pressure value according to the common mode pressure value; and obtaining the compensated pressure value according to the recalculated first pressure value and the differential mode pressure value. 10.The UAV control method of claim 9, wherein, The step of generating the compensated pressure value further comprises correcting a mutual deviation value of the synchronized first pressure value and the external reference pressure value in an initial state.

11. The UAV control method according to claim 9, wherein, before calculating the common mode pressure value, mapping the external reference pressure value to a mapped external reference pressure value as a pressure value at the same altitude as the first pressure value. 12.The UAV control method of claim 10, wherein, In automatic setting, the at least switching condition set by the data fusion switching unit includes any combination of: wireless positioning accuracy determination, selecting the first fused data or the second fused data according to wireless positioning accuracy; positioning information triggering, selecting the first fused data or the second fused data according to positioning information; and sensing information triggering, selecting the first fused data or the second fused data according to sensing values of a distance sensor or an illuminance sensor. The sensing information trigger selects the first fused data or the second fused data according to the sensing value of the distance sensor or the illuminance sensor.

13. The UAV control method of claim 11, wherein, When the relative height difference between the external reference barometer and the UAV is known, the UAV recalculates the barometric value change by comparing the first barometric value with the external reference barometric value to obtain the barometric value change caused by wind to the first barometric value, and then recalculates the barometric value change to obtain the compensated barometric value. When performing barometer calibration, the control center sends the known relative height difference between the external reference barometer and the UAV to the UAV. 14.The UAV control method of claim 11, wherein, When performing barometric compensation, When the relative height difference between the external reference barometer and the UAV is unknown, When the external auxiliary device with the external reference barometer takes off and climbs to a predetermined position, the external auxiliary device hovers to maintain a relative vertical height relationship between the UAV and the external auxiliary device, and the UAV performs barometric compensation by referring to the external reference barometric value of the external reference barometer of the external auxiliary device.

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