Dual-redundancy height source measurement system of unmanned aerial vehicle and control method of dual-redundancy height source measurement system

Abstract

The invention relates to the technical field of unmanned aerial vehicle control, in particular to an unmanned aerial vehicle dual-redundancy height source measurement system and a control method thereof, and the method is based on a barometer measurement system and a Beidou measurement system. The two measuring systems have an instruction switching function, and when the barometer measuring system fails and cannot acquire accurate height data, the Beidou measuring system is automatically switched to acquire the flight height of the unmanned aerial vehicle for controlling the unmanned aerial vehicle. If the data of the two systems are abnormal, the flight control system of the unmanned aerial vehicle adopts the last frame of effective height data to control the aircraft, and if one of the height data returns to normal, the flight control system of the unmanned aerial vehicle automatically selects the effective height data as a height data source. Based on two height measurement systems with different working principles and a switching strategy, the unmanned aerial vehicle can work normally after a fault occurs in height measurement, and the flight reliability and safety of the unmanned aerial vehicle can be obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle control, and in particular to an unmanned aerial vehicle dual-redundancy height source measurement system and a control method thereof. Background Art

[0002] The altitude measurement system is a key component of drone navigation and flight control. During the entire flight control process of the drone, the altitude data of the drone needs to be collected as information input, and the control amount of the drone is calculated through the corresponding control algorithm to achieve the purpose of controlling the flight of the drone. Therefore, the accuracy of the measurement system data is crucial to the safe flight of the drone.

[0003] Existing drones usually use a barometer installed on the drone as a source of altitude information. The accuracy of this method is easily affected by static pressure errors, resulting in reduced altitude measurement accuracy. In addition, the barometer is not suitable for situations where the altitude changes very quickly when measuring altitude. In addition, drones also use the Global Positioning System (GPS) or the Beidou Positioning System. The drone determines its precise location, including longitude, latitude and altitude, by receiving signals from multiple satellites. The altitude information provided by the satellite is very accurate, but the satellite cannot be used normally to obtain drone altitude data in an obstructed environment. Summary of the invention

[0004] In order to solve the deficiencies in the above-mentioned background technology, the present invention provides a UAV dual-redundancy altitude source measurement system and a control method thereof. The method is based on two sets of altitude measurement systems with different working principles and a switching strategy, so as to achieve the purpose of enabling the UAV to work normally after a failure in altitude measurement, thereby significantly improving the flight reliability and safety of the UAV.

[0005] The first object of the present invention is to provide a dual-redundancy height source measurement control method for an unmanned aerial vehicle, comprising:

[0006] The altitude data of the drone is measured simultaneously through the barometer measurement system and the Beidou measurement system;

[0007] When the barometer measurement system and the Beidou measurement system are both normal, the UAV flight control system uses the altitude data of the barometer measurement system for UAV control;

[0008] The barometer measurement system and the Beidou measurement system have a command switching function;

[0009] When the barometer measurement system fails and cannot collect accurate altitude data, it automatically switches to the Beidou measurement system to collect the flight altitude of the drone for drone control;

[0010] When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data to control the aircraft;

[0011] When both the altitude data of the barometer measurement system and the altitude data of the Beidou measurement system are abnormal, if one of the altitude data in the barometer measurement system and the Beidou measurement system returns to normal, the UAV flight control system automatically selects the altitude data as the altitude data source to control the UAV.

[0012] Preferably, when both the barometer measurement system and the Beidou measurement system are normal, the Beidou measurement system is set as a backup system, and the data collected by it is in a monitoring state.

[0013] Preferably, the barometer measurement system fault judgment process is as follows:

[0014] When the airspeed is greater than the threshold value υ, and the barometer data changes within the range of ±b, it is determined that the barometer altitude measurement system is faulty;

[0015] Or if the receiving of air pressure data fails within the threshold time t1 seconds, it is determined that the barometer altitude measurement system is faulty;

[0016] Or if the received barometer altitude data is greater than h meters for n consecutive frames, it is determined that the barometer altitude measurement system is faulty;

[0017] Or according to the state equation and measurement equation of the pressure altitude measurement system, the residual χ 2 The test method is to use the residual r of the system state equation k Calculation, when the residual is 0, it can be proved that the system has no fault. When the residual is not 0, it is determined that the barometer height measurement system has a fault.

[0018] Preferably, when the barometer measurement system fails, the UAV flight control system abandons the current mission, disconnects the altitude holding mode, and maintains direct flight;

[0019] The Kalman filtering algorithm is used to fuse the altitude data before the failure of the barometer measurement system and the altitude data measured by the Beidou measurement system. After switching to the Beidou measurement system, the altitude data of the Beidou measurement system is transmitted to the UAV flight control system as the data source of altitude data.

[0020] Preferably, the Beidou measurement system fault judgment process is as follows:

[0021] The altitude data measured by the Beidou system is monitored within the threshold time t3. If the Beidou satellite positioning UTC time is not updated within time t3, or if the reception of satellite positioning data fails within time t4, or if the UAV flight control system displays the satellite status word as "no positioning", it is determined that the Beidou measurement system is faulty.

[0022] Preferably, when both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data to control the aircraft, including:

[0023] When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data as the altitude data source, and the UAV flight control system disconnects the altitude hold mode, maintains direct flight, and returns to the base for disposal.

[0024] The second object of the present invention is to provide a dual-redundancy height source measurement system for an unmanned aerial vehicle, comprising:

[0025] Dual-system measurement module, used to measure the altitude data of the drone simultaneously through the barometer measurement system and the Beidou measurement system;

[0026] A measurement judgment module is used when the barometer measurement system and the Beidou measurement system are both normal, when the barometer measurement system fails and cannot collect accurate altitude data, when both the barometer measurement system and the Beidou measurement system fail, and when the altitude data of the barometer measurement system and the altitude data of the Beidou measurement system are both abnormal;

[0027] The flight control module is used for when the barometer measurement system and the Beidou measurement system are both normal, the unmanned aerial vehicle flight control system uses the altitude data of the barometer measurement system for unmanned aerial vehicle control; the barometer measurement system and the Beidou measurement system have a command switching function; when the barometer measurement system fails and cannot collect accurate altitude data, it automatically switches to the Beidou measurement system to collect the flight altitude of the unmanned aerial vehicle for unmanned aerial vehicle control; when both the barometer measurement system and the Beidou measurement system fail, the unmanned aerial vehicle flight control system uses the last frame of valid altitude data to control the aircraft; when both the altitude data of the barometer measurement system and the Beidou measurement system are abnormal, if one of the altitude data in the barometer measurement system and the Beidou measurement system returns to normal, the unmanned aerial vehicle flight control system automatically selects the altitude data as the altitude data source to control the unmanned aerial vehicle.

[0028] The present invention has at least the following beneficial effects:

[0029] The present invention provides a dual-redundancy height source measurement system for an unmanned aerial vehicle and a control method thereof. The method adopts a dual-redundancy height source measurement system model, can improve the success rate of the unmanned aerial vehicle in completing tasks, and has high reliability and safety. The dual-redundancy height source measurement system switching method of the present invention is simple, so that the unmanned aerial vehicle can adapt to different environments, expand the operation range of the unmanned aerial vehicle, support the completion of complex tasks, and can also be promoted and used in different unmanned aerial vehicle systems. The present invention adopts a dual-redundancy height source measurement system, can detect faults and isolate them, reduce the risk of overall system failure, reduce maintenance costs, and improve the performance of the flight control system in combination with multiple sensor data fusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a valid judgment process for barometer data.

[0031] Figure 2 It is an effective judgment process for satellite positioning data.

[0032] Figure 3 Switching process for height data source. DETAILED DESCRIPTION

[0033] In order to illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description in conjunction with embodiments.

[0034] The present invention includes two parts: dual-redundancy height source measurement system model construction and dual-redundancy height source measurement system switching method. The dual-redundancy height source measurement system consists of a barometer measurement system and a Beidou measurement system. The effective judgment of the barometer and Beidou data can be found in Figures 1-2 As shown, the automatic switching method of the height data source can be found in Figure 3 shown.

[0035] The barometer measurement system generally transmits the atmospheric pressure signal to the flight control computer through the pitot tube. The flight control computer uses a high-precision piezoelectric sensor to convert the atmospheric pressure signal into a voltage signal. The built-in A / D conversion module collects the voltage signal in real time and calculates the current UAV altitude based on the preset nonlinear calibration formula.

[0036] The Beidou measurement system receives signals from multiple satellites and uses the principle of triangulation to calculate the position of the UAV. It then calculates the current altitude of the UAV using the longitude, latitude, distance and other information of the UAV's position combined with known geoid data.

[0037] The system consists of a barometer measurement system and a BeiDou measurement system. When both measurement systems are normal, the measured altitude data will be transmitted to the UAV flight control system. The UAV flight control system will give priority to using the altitude data measured by the barometer for UAV control. The two measurement systems have a command switching function. When the barometer measurement system fails and cannot collect accurate altitude data, it will automatically switch to the BeiDou measurement system to collect the UAV's flight altitude for UAV control. If the data of both systems are abnormal, the UAV flight control system uses the last frame of valid altitude data to control the aircraft. If one of the altitude data returns to normal, the UAV flight control system automatically selects the valid altitude data as the altitude data source.

[0038] In order to achieve the above object, the present invention provides a dual-redundancy altitude source measurement control method for an unmanned aerial vehicle, comprising a barometer measurement system and a Beidou measurement system;

[0039] The altitude data of the drone is measured simultaneously through the barometer measurement system and the Beidou measurement system;

[0040] When the barometer measurement system and the Beidou measurement system are both normal, the UAV flight control system uses the altitude data of the barometer measurement system for UAV control;

[0041] The barometer measurement system and the Beidou measurement system have a command switching function;

[0042] When the barometer measurement system fails and cannot collect accurate altitude data, it automatically switches to the Beidou measurement system to collect the flight altitude of the drone for drone control;

[0043] When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data to control the aircraft;

[0044] When both the altitude data of the barometer measurement system and the altitude data of the Beidou measurement system are abnormal, if one of the altitude data in the barometer measurement system and the Beidou measurement system returns to normal, the UAV flight control system automatically selects the altitude data as the altitude data source to control the UAV.

[0045] Among them, when the barometer measurement system and the Beidou measurement system are both normal, the Beidou measurement system is set as a backup system, and the data it collects is in a monitoring state.

[0046] When the barometer measurement system fails, the UAV flight control system abandons the current mission, disconnects the altitude hold mode, and maintains direct flight;

[0047] The Kalman filtering algorithm is used to fuse the altitude data before the failure of the barometer measurement system and the altitude data measured by the Beidou measurement system. After switching to the Beidou measurement system, the altitude data of the Beidou measurement system is transmitted to the UAV flight control system as the data source of altitude data.

[0048] When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data to control the aircraft, including:

[0049] When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data as the altitude data source, and the UAV flight control system disconnects the altitude hold mode, maintains direct flight, and returns to the base for disposal.

[0050] According to the present invention, the process of judging whether there is a fault in the barometer measurement system is as follows:

[0051] When the airspeed is greater than the threshold value υ, and the barometer data changes within the range of ±b, it is determined that the barometer altitude measurement system is faulty;

[0052] Or if the receiving of air pressure data fails within the threshold time t1 seconds, it is determined that the barometer altitude measurement system is faulty;

[0053] Or if the received barometer altitude data is greater than h meters for n consecutive frames, it is determined that the barometer altitude measurement system is faulty;

[0054] Or according to the state equation and measurement equation of the pressure altitude measurement system, the residual χ 2 The test method is to use the residual r of the system state equation k Calculation, when the residual is 0, it can be proved that the system has no fault. When the residual is not 0, it is determined that the barometer height measurement system has a fault.

[0055] According to the present invention, the Beidou measurement system has a fault judgment process as follows:

[0056] The altitude data measured by the Beidou system is monitored within the threshold time t3. If the Beidou satellite positioning UTC time is not updated within time t3, or if the reception of satellite positioning data fails within time t4, or if the UAV flight control system displays the satellite status word as "no positioning", it is determined that the Beidou measurement system is faulty.

[0057] In order to illustrate the dual-redundancy height source measurement control method for an unmanned aerial vehicle provided by the present invention, it is described in conjunction with the accompanying drawings.

[0058] Step 1: After the drone is powered on, the drone flight control system automatically sets the barometer measurement system as the main measurement system, and the altitude data collected by it is used for drone control, and sets the Beidou measurement system as the backup system, and the data collected by it is in monitoring status.

[0059] Step 2: See Figure 1 As shown, the altitude data measured by the barometer is monitored. ① When the airspeed is greater than 54km / h, the barometer data changes within the range of ±50 meters (combined with the barometer altitude measurement error), the barometer altitude measurement system is determined to be faulty; ② Within 20 seconds, if the pressure data reception fails, the barometer altitude measurement system is determined to be faulty; ③ If the received barometer altitude data is greater than 9000 meters for 20 consecutive frames (determined according to the platform capability), the barometer altitude measurement system is determined to be faulty; ④ The system state equation can be defined according to the barometer altitude measurement parameters as:

[0060] X=[xve]

[0061] In the formula, x is the vertical height; v is the vertical velocity; and e is the absolute error of the barometric altimeter measurement. By discretizing the system equation, the overall state variable X can be obtained: (k) The system state at time k can be expressed by a linear stochastic differential equation:

[0062] X (k) =A (k) X (k-1) +W (k)

[0063] Where, X (k) is the state of the pressure altitude measurement system at time k; A (k) is the state transfer matrix of the pressure altitude measurement system at time k; W (k) is the system noise of the pressure altitude measurement system at time k.

[0064] The altitude value measured by the barometric altimeter is expressed in h q Indicates that the altitude h measured by Beidou b As an observation value, the relationship between it and the state variable at time k is:

[0065]

[0066] Using the residual χ 2 Test method, for the residual of the system state equation:

[0067]

[0068] In the formula, Z k is the measured value; H k is the measurement array; V (k) To measure noise; is the state one-step estimate; Φ k / k-1 is the one-step transfer matrix; is the estimated value of the previous state. k}, when E{r k}=0, the system has no fault, E{r k}≠0, the system fails, and it is determined that the barometer altitude measurement system fails.

[0069] It should be noted that there are four criteria for determining barometer data failure, and the occurrence of any one of them will determine that the barometer data is invalid.

[0070] Step 3: After the barometer altitude measurement system fails, the UAV flight control system abandons the current task, disconnects the altitude hold mode, and maintains direct flight. The Kalman filter method is used to fuse the effective value of the pressure altitude measurement system before the failure and the altitude observation value measured by the Beidou measurement system receiver. Based on the state equation and measurement equation of the pressure altitude measurement system, the one-step state vector estimate based on time update is obtained:

[0071]

[0072] Where, X (k|k-1) is the optimal filtering value of the system state at time k-1; X (k|k-1) The state X at time k is used at time k-1 (k-1|k-1) Predicted results; P (k|k-1) The state P at time k is used as the state P at time k-1 (k-1|k-1) Predicted results; P (k|k-1) For X (k|k-1) The corresponding error variance matrix; P (k-1|k-1) For X (k-1|k-1) The corresponding error variance matrix; Q is the process excitation noise covariance.

[0073] Based on the altitude observation value measured by the Beidou measurement system receiver at time k and the effective value of the barometric altimeter at time k-1, the system state update equation can be obtained as follows:

[0074]

[0075] In the formula, K (k) is the Kalman gain of the system at time k; P (k|k-1) is the prior estimated covariance of the system at time k; P (k|k)is the posterior estimated covariance of the system at time k. The system state update equation shows that after the failure of the barometer altitude measurement system, the Kalman filter algorithm is used to fuse the effective value of the altitude measurement system and the observation value of the Beidou measurement system to avoid adverse transients when the aircraft switches to the Beidou measurement system. After switching to the Beidou measurement system, the Beidou measurement system altitude data is transmitted to the UAV flight control system as the altitude data source.

[0076] Step 4, see Figure 2 As shown, the altitude data measured by the Beidou system is monitored within 10 seconds of the threshold moment. If the Beidou satellite positioning UTC time is not updated within 10 seconds, or the reception of satellite positioning data fails within 10 seconds, or the UAV flight control system displays the satellite status word as "not positioned", it is determined that the Beidou measurement system is faulty.

[0077] Step 5: If both the barometer altitude measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data as the altitude data source, and the UAV flight control system disconnects the altitude hold mode, maintains direct flight, and returns to the base.

[0078] Step 6: When both the satellite altitude data and the pressure altitude data are abnormal, if one of the altitude data returns to normal, the UAV flight control system automatically selects the valid altitude data as the altitude control data source.

[0079] This enables dual-redundancy altitude source switching to control the UAV.

[0080] It should be noted that the data obtained by the barometer measurement system when measuring altitude is air pressure data, while the data obtained by the Beidou measurement system when measuring altitude is satellite data.

[0081] See also Figure 3 As shown, the height data source switching process includes:

[0082] When both the air pressure data and satellite data are normal, the air pressure data is used as the altitude data source;

[0083] When there is a failure in the air pressure data, satellite data is used as the altitude data source;

[0084] When both the air pressure data and the satellite data fail, the last frame of valid data from the barometer is kept as the current altitude data source.

[0085] The present invention provides a dual-redundancy height source measurement system for an unmanned aerial vehicle, comprising:

[0086] Dual-system measurement module, used to measure the altitude data of the drone simultaneously through the barometer measurement system and the Beidou measurement system;

[0087] A measurement judgment module is used when the barometer measurement system and the Beidou measurement system are both normal, when the barometer measurement system fails and cannot collect accurate altitude data, when both the barometer measurement system and the Beidou measurement system fail, and when the altitude data of the barometer measurement system and the altitude data of the Beidou measurement system are both abnormal;

[0088] The flight control module is used for when the barometer measurement system and the Beidou measurement system are both normal, the unmanned aerial vehicle flight control system uses the altitude data of the barometer measurement system for unmanned aerial vehicle control; the barometer measurement system and the Beidou measurement system have a command switching function; when the barometer measurement system fails and cannot collect accurate altitude data, it automatically switches to the Beidou measurement system to collect the flight altitude of the unmanned aerial vehicle for unmanned aerial vehicle control; when both the barometer measurement system and the Beidou measurement system fail, the unmanned aerial vehicle flight control system uses the last frame of valid altitude data to control the aircraft; when both the altitude data of the barometer measurement system and the Beidou measurement system are abnormal, if one of the altitude data in the barometer measurement system and the Beidou measurement system returns to normal, the unmanned aerial vehicle flight control system automatically selects the altitude data as the altitude data source to control the unmanned aerial vehicle.

Claims

1. A dual-redundancy height source measurement control method for an unmanned aerial vehicle, characterized in that: include: The altitude data of the drone is measured simultaneously through the barometer measurement system and the Beidou measurement system; When the barometer measurement system and the Beidou measurement system are both normal, the UAV flight control system uses the altitude data of the barometer measurement system for UAV control; The barometer measurement system and the Beidou measurement system have a command switching function; When the barometer measurement system fails and cannot collect accurate altitude data, it automatically switches to the Beidou measurement system to collect the flight altitude of the drone for drone control; When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data to control the aircraft; When both the altitude data of the barometer measurement system and the altitude data of the Beidou measurement system are abnormal, if one of the altitude data in the barometer measurement system and the Beidou measurement system returns to normal, the UAV flight control system automatically selects the altitude data as the altitude data source to control the UAV.

2. The UAV dual-redundancy height source measurement control method according to claim 1 is characterized in that: When both the barometer measurement system and the Beidou measurement system are normal, the Beidou measurement system is set as the backup system and its collected data is in monitoring status.

3. The UAV dual-redundancy height source measurement control method according to claim 2 is characterized in that: The barometer measurement system fault judgment process is as follows: When the airspeed is greater than the threshold value υ, and the barometer data changes within the range of ±b, it is determined that the barometer altitude measurement system is faulty; Or if the receiving of air pressure data fails within the threshold time t1 seconds, it is determined that the barometer altitude measurement system is faulty; Or if the received barometer altitude data is greater than h meters for n consecutive frames, it is determined that the barometer altitude measurement system is faulty; Or according to the state equation and measurement equation of the pressure altitude measurement system, the residual χ 2 The test method is to use the residual r of the system state equation k Calculation, when the residual is 0, it can be proved that the system has no fault. When the residual is not 0, it is determined that the barometer height measurement system has a fault.

4. The UAV dual-redundancy height source measurement control method according to claim 1 is characterized in that: When the barometer measurement system fails, the UAV flight control system abandons the current mission, disconnects the altitude hold mode, and maintains direct flight; The Kalman filtering algorithm is used to fuse the altitude data before the failure of the barometer measurement system and the altitude data measured by the Beidou measurement system. After switching to the Beidou measurement system, the altitude data of the Beidou measurement system is transmitted to the UAV flight control system as the data source of altitude data.

5. The UAV dual-redundancy height source measurement control method according to claim 1 is characterized in that: The Beidou measurement system fault diagnosis process is as follows: The altitude data measured by the Beidou system is monitored within the threshold time t3. If the Beidou satellite positioning UTC time is not updated within the time t3, or the reception of satellite positioning data fails within the time t4, or the UAV flight control system displays the satellite status word as "no positioning", it is determined that the Beidou measurement system is faulty.

6. The UAV dual-redundancy height source measurement control method according to claim 1 is characterized in that: When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data to control the aircraft, including: When both the barometer measurement system and the Beidou measurement system fail, the UAV flight control system uses the last frame of valid altitude data as the altitude data source, and the UAV flight control system disconnects the altitude hold mode, maintains direct flight, and returns to the base for disposal.

7. A UAV dual-redundancy height source measurement system, characterized in that: include: Dual-system measurement module, used to measure the altitude data of the drone simultaneously through the barometer measurement system and the Beidou measurement system; A measurement judgment module is used when the barometer measurement system and the Beidou measurement system are both normal, when the barometer measurement system fails and cannot collect accurate altitude data, when both the barometer measurement system and the Beidou measurement system fail, and when the altitude data of the barometer measurement system and the altitude data of the Beidou measurement system are both abnormal; The flight control module is used for when the barometer measurement system and the Beidou measurement system are both normal, the unmanned aerial vehicle flight control system uses the altitude data of the barometer measurement system for unmanned aerial vehicle control; the barometer measurement system and the Beidou measurement system have a command switching function; when the barometer measurement system fails and cannot collect accurate altitude data, it automatically switches to the Beidou measurement system to collect the flight altitude of the unmanned aerial vehicle for unmanned aerial vehicle control; when both the barometer measurement system and the Beidou measurement system fail, the unmanned aerial vehicle flight control system uses the last frame of valid altitude data to control the aircraft; when both the altitude data of the barometer measurement system and the Beidou measurement system are abnormal, if one of the altitude data in the barometer measurement system and the Beidou measurement system returns to normal, the unmanned aerial vehicle flight control system automatically selects the altitude data as the altitude data source to control the unmanned aerial vehicle.

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