Unmanned aerial vehicle flight controller and working method thereof

Abstract

The invention discloses an unmanned aerial vehicle flight controller and a working method thereof, the controller comprises an MCU and a Beidou board card, the MCU collects static pressure sensor data through an I2C1 interface, collects dynamic pressure sensor data through an I2C2 interface, collects three-axis gyroscope data through an SPI1 interface, and collects three-axis accelerometer data through an SPI3 interface; two paths of TTL UART (Transistor-Transistor-Transistor Asynchronous Receiver / Transmitter) of an OEM serial port of the Beidou board card are accessed to an MCU (Microprogrammed Control Unit), one path of TTL UART information is used for sending positioning and speed measuring information to a navigation computer to carry out combined navigation filtering with a three-axis gyroscope, three-axis accelerometer data, static pressure data and dynamic pressure data, and the other path of TTL UART information is used for receiving differential data sent by a data chain and is used for RTK differential positioning of the board card. The controller provided by the invention realizes full isolation of a power supply and a transmission signal, and internally integrates the functions of flight control, inertial navigation, embedded atmosphere data acquisition, flight parameter recording and the like.

Description

Technical Field

[0001] The invention belongs to the field of aerospace technology, and in particular relates to a domestically produced unmanned aerial vehicle flight controller. Background Art

[0002] The flight controller is the core control unit of the aircraft. Its main tasks include collecting and receiving data from internal and external sensors, converting specific flight control algorithms into control signals required by the electronic speed governor, thereby changing and controlling the attitude (pitch / roll / heading), geographic location and altitude of the drone.

[0003] First, focusing on navigation, existing drones mainly rely on Beidou navigation modules to achieve navigation functions. However, in actual application scenarios, relying solely on this single navigation method is prone to heading deviation problems. This heading deviation not only affects the flight accuracy of the drone, but may also cause it to fail to accurately reach the target location, making it impossible for the drone to fly according to the scheduled route.

[0004] Secondly, the complex electromagnetic environment poses a severe challenge to the line system of the drone. In the internal environment of a heavy-loaded drone, a complex electromagnetic environment will be generated because of the need to use high-power motors or other high-power devices. The input power supply will experience surges due to the effect of the magnetic field. If the surge voltage exceeds the rated voltage of the equipment, the service life of the equipment will be shortened. In severe cases, the equipment will be directly scrapped. In a complex electromagnetic environment, communication signals will be distorted and packet loss will occur. If the magnetic field environment is strong, the induced current on the communication line will exceed the rated current of the chip, and in severe cases, the chip will burn out. When a drone flies in such an environment, its lines are susceptible to electromagnetic interference, which can cause line failures, affecting normal operation and the stability of data transmission.

[0005] Finally, from the perspective of localization, the current existing flight controllers rely heavily on imported components for the selection of their internal core components. For example, key components such as MCU processors, IMU inertial measurement units, power modules, barometer modules, and storage modules are mainly imported. This high degree of reliance on imported components makes drone production face many potential risks and challenges. Once restricted by the import and export policies of components, the production cycle of a single machine will be difficult to be effectively guaranteed, which will lead to delays and confusion in the entire production plan. More importantly, this situation will greatly accelerate the iteration cycle of product research and development, disrupting the company's originally orderly research and development process, making it difficult to carry out technological innovation and product optimization according to the established rhythm, and limiting my country's technological innovation and industrial upgrading in this field. Summary of the invention

[0006] The first problem that the present invention aims to solve is that the existing UAVs rely solely on Beidou navigation modules for navigation, and suffer from heading deviation;

[0007] The second problem to be solved by the present invention is the line fault problem caused by the complex electromagnetic environment;

[0008] The final problem to be solved by the present invention is the problem that all products cannot be localized;

[0009] In response to the above-mentioned defects, the present invention provides a UAV flight controller, which has powerful data acquisition capabilities, can collect a variety of different types of data, and perform combined navigation filtering through advanced algorithms; the flight controller also has an isolation filtering function; the flight controller is also fully localized.

[0010] Technical solution:

[0011] A UAV flight controller comprises a microcontroller unit (MCU) and a Beidou board. The MCU collects static pressure sensor data through an I2C1 interface, collects dynamic pressure sensor data through an I2C2 interface, collects three-axis gyroscope data through an SPI1 interface, and collects three-axis accelerometer data through an SPI3 interface. Two TTL UARTs of the OEM serial port of the Beidou board are connected to the MCU, wherein one TTL UART information sends positioning and speed measurement information to the MCU for combined navigation filtering with the three-axis gyroscope, three-axis accelerometer data, static pressure, and dynamic pressure data, and another TTL UART information receives differential data sent by a data link for RTK differential positioning of the board.

[0012] Preferably, the MCU collects the Beidou board positioning and speed measurement information through the TTL USART2 interface, and sends the differential RTCM3.2 data (differential data based on the RTCM3.2 communication protocol) received from the data link from the USART3 interface to the Beidou board through the TTL USART6 interface for RTK differential positioning.

[0013] Preferably, the MCU collects data from an external magnetic sensor through the I2C3 interface, and the magnetic sensor is used to monitor the steering angle of the wind vane. (Because the wind vane changes its position with the wind direction, the angle change of the wind vane relative to a fixed reference point is measured) After the angle information is collected by the magnetic sensor, it is sent to the processor through the I2C_3 interface. The received data may contain noise or errors, and the "Kalman filtering" technology is used to filter these data to obtain more accurate flight attitude information.

[0014] Preferably, the three-axis gyroscope adopts the MGZ2067HC chip, and the chip's SPI clock line SCLK, data input line MOSI, data output line MISO pin and chip select signal CS are respectively connected to the MCU's PA5, PA6, PA7 and PB12 pins, and data exchange with the MCU is achieved through the SPI interface.

[0015] Preferably, the three-axis accelerometer adopts the MAX535LCA chip, and the chip's SPI clock line SCLK, data input line DI, data output line DO pins and chip select signal CS are respectively connected to the MCU's PA5, PA6, PA7 and PB12 pins, and data exchange with the MCU is achieved through the SPI interface.

[0016] Preferably, the static pressure sensor adopts the XGZP6858D110KPA chip, and the dynamic pressure sensor adopts the XGZP6899D chip. The SDA pin and SCL pin of the two chips are connected to the I2C, data line SDA and clock line SCL of the MCU.

[0017] As a preferred embodiment, according to the dynamic pressure measurement value P 总 and static pressure measurement value P 静 At this time, the space speed V is: The three-axis gyroscope measures the aircraft attitude at this time; the three-axis accelerometer measures the aircraft acceleration at this time; the airspeed, aircraft attitude and aircraft acceleration information collected by the above three sensors are calibrated with the inertial navigation information obtained by the Beidou board through Kalman filtering to eliminate attitude errors, speed and position errors.

[0018] Preferably, the flight controller also includes a spike and surge suppression circuit. After the input power enters the controller, it passes through the spike and surge suppression circuit (filtering out the part with a larger voltage amplitude, and then passing through the anti-reverse connection circuit to prevent the power supply from being reversed and effectively intercepting the backflow current); the power after the spike and surge suppression process is transmitted to the JLD50V2A-ZKP2A filter chip to suppress common-mode, differential-mode and high-frequency interference signals; the filtered power is transmitted to the isolated DCDC module, including URB2412YMD-10WR3 and URB2405YMD-6WR3 chips Among them, the URB2405YMD-6WR3 chip steps down the input power supply to 5V, and the 5V power supply is used as the primary power supply for the ADC, RPM, and PWM isolation chips; the URB2412YMD-10WR3 chip outputs a stepped-down 12V isolated power supply, and the 12V power supply is transmitted to the BD4644I power management chip, and the BD4644I chip steps down the 12V power supply to 5V and 3.3V; the stepped-down power supply of the BD4644I chip is supplied to the Beidou inertial navigation, sensor, MCU chip, and the secondary power supply of the ADC, RPM, and PWM isolation chips.

[0019] Preferably, the flight controller also includes a digital isolator, which uses a pai160E61 chip. The pai160E61 chip is used to isolate the PWM signal emitted by the microcontroller, the RPM speed signal transmitted from the external device to the flight controller, and the IO port signal of the microcontroller.

[0020] The present invention also discloses a working method of a UAV flight controller. Based on the above-mentioned flight controller, the carrier angular velocity and acceleration obtained by the three-axis gyroscope and the three-axis accelerometer are converted into an attitude angle represented by a quaternion and sent to an MCU. The MCU obtains a quaternion vector by solving the quaternion equation, and obtains the attitude angle, velocity and displacement of the carrier through an integration link; the attitude angle, velocity and displacement are fused with the velocity and three-dimensional position information provided by the Beidou board and input into a Kalman filtering module, and an optimal estimate of the carrier motion parameters is output.

[0021] The beneficial effects of the present invention are:

[0022] (1) The invention discloses a domestic UAV flight controller with powerful data collection capabilities, capable of collecting multiple different types of data and performing combined navigation filtering through advanced algorithms. In this way, the heading of the UAV can be accurately corrected, effectively solving the heading deviation problem and ensuring that the UAV always maintains an accurate route during flight.

[0023] (2) The present invention discloses a domestic UAV flight controller with isolation and filtering functions. When faced with a complex electromagnetic environment, it can effectively isolate and filter external interference signals to ensure the stable operation of the line system, thereby solving the line problems caused by the electromagnetic environment and improving the reliability and adaptability of the UAV in complex environments. The entire board realizes the isolation of the inside and outside of the device, effectively isolates the interference signals and noise transmitted from external devices, and has a strong anti-electromagnetic interference capability.

[0024] (3) The domestically produced UAV flight controller disclosed in the present invention has achieved full domestic production. From core components to overall design, all technologies and products independently developed and produced in China are adopted, which not only reduces production costs and improves the market competitiveness of products, but also provides strong support for the independent development and safety of my country's UAV industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below.

[0026] Figure 1 It is a product composition block diagram of an embodiment of the present invention;

[0027] Figure 2is a product hardware block diagram of an embodiment of the present invention;

[0028] Figure 3 is a schematic diagram of a MEMS gyroscope circuit according to an embodiment of the present invention;

[0029] Figure 4 is a schematic diagram of a MEMS accelerometer circuit according to an embodiment of the present invention;

[0030] Figure 5 It is a circuit schematic diagram of a domestic static pressure sensor according to an embodiment of the present invention;

[0031] Figure 6 is a power supply structure block diagram of an embodiment of the present invention;

[0032] Figure 7 It is a schematic diagram of a spike and surge suppression circuit according to an embodiment of the present invention;

[0033] Figure 8 is a schematic diagram of an EMC filter circuit according to an embodiment of the present invention;

[0034] Fig. 9 This is a circuit schematic diagram of a Goldensun isolated DCDC module (10WR3) according to an embodiment of the present invention;

[0035] Fig.10 This is a circuit schematic diagram of a Goldensun isolated DCDC module (6WR3) according to an embodiment of the present invention;

[0036] Fig.11 This is a schematic circuit diagram of a DCDC power module of Xi'an Guangqin Electronic Technology Co., Ltd. according to an embodiment of the present invention;

[0037] Fig.12 It is a circuit schematic diagram of an isolated RS422 serial port chip (CA-IS3096W chip) according to an embodiment of the present invention;

[0038] Fig.13 This is a circuit schematic diagram of an isolation 485 chip (CA-IS3098W chip) according to an embodiment of the present invention;

[0039] Fig.14 This is a circuit schematic diagram of an isolated CAN chip (CA-IS3050W chip) according to an embodiment of the present invention;

[0040] Fig.15 It is a circuit schematic diagram of a digital isolator (pai160E61 chip) according to an embodiment of the present invention;

[0041] Fig.16 This is a circuit schematic diagram of an isolation amplifier (NSI1311-DSWVR chip) according to an embodiment of the present invention;

[0042] Fig.17 is a navigation solution principle diagram of an embodiment of the present invention;

[0043] Fig.18 It is a block diagram of the system error compensation principle of an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The embodiments of the present invention provide a method for making the purpose, technical solution and advantages of the present invention more clear, and the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] Example 1

[0046] like Figure 1 to Figure 2 As shown, a domestically produced UAV controller provided by an embodiment of the present invention includes a microcontroller unit MCU, an IMU, a sensor and a Beidou board.

[0047] The IMU in this embodiment mainly includes an inertial navigation unit composed of a three-axis gyroscope, a three-axis accelerometer, and a three-axis magnetometer. The sensor part adopts a self-developed high-precision inertial navigation unit and a 24-bits ADC high-precision dynamic pressure and static pressure sensor. The internal processor has low power consumption, and the output heading angle has no drift. At the same time, it provides calibrated three-axis acceleration, angular velocity, and magnetic field strength. The Beidou receiver realizes the positioning and orientation function. Various sensor data fusion is realized through Kalman filter estimation, and the UAV flight controller completes the monitoring and adjustment of the real-time status of the aircraft based on these data.

[0048] MCU realizes connection with external devices through I / O interface. Specifically, MCU collects static pressure sensor data through I2C1 interface, dynamic pressure sensor data through I2C2 interface, three-axis gyroscope data through SPI1 interface, and three-axis accelerometer data through SPI3 interface. MCU collects Beidou board positioning and speed measurement information through TTL USART2 interface, and sends differential RTCM3.2 data received from the data link from USART3 interface to Beidou board through TTL USART6 interface for RTK differential positioning.

[0049] The three-axis gyroscope uses a high-precision domestically produced MGZ2067HC chip, such as Figure 3 As shown, the chip's SPI clock line SCLK, data input line MISI, data output line MOSO pin and chip select signal CS are respectively connected to the MCU's PA5, PA6, PA7 and PB12 pins, and data exchange with the MCU is achieved through the SPI interface.

[0050] The three-axis accelerometer uses the high-precision domestically produced MAX535LCA chip, such as Figure 4 As shown in the figure, the SPI clock line SPI_SCLK pin, data input line SPI_DI pin, data output line SPI_DO pin and chip select signal SPI_CS pin of the chip are connected to the PA5, PA6, PA7 and PB12 pins of the MCU respectively, and data exchange with the MCU is realized through the SPI interface. The power pins (DVCC, AVCC, VIO, etc.) of the MAX535LCA chip are connected to the corresponding power supply. The DVCC and AVCC pins are usually connected to the 3.3V power supply, and the VIO pin may be connected to different voltage sources according to the specific application. The chip also has multiple capacitors (C7, C8, C9, C10) for filtering and smoothing the power supply to remove high-frequency and low-frequency noise.

[0051] The static pressure sensor uses the high-precision domestically produced XGZP6858D110KPA chip, such as Figure 5 As shown, the dynamic pressure sensor uses a high-precision domestically produced XGZP6899D chip. The SDA pins and SCL pins of the two chips are connected to the MCU's I2C (static pressure sensor connected to I2C1, dynamic pressure sensor connected to I2C2) data line SDA (PB6) and clock line SCL (PB7). The dynamic pressure sensor measures the total pressure (Ptotal) when the airflow velocity is 0, and the static pressure sensor measures the static pressure (Pstatic) including the airflow velocity. At this time, the airspeed (V) and the pressure value have the following relationship:

[0052] (ρ represents air density)

[0053] like Figure 6 As shown, it is a power supply structure block diagram of this embodiment.

[0054] After the input power enters the device, it passes through the spike and surge suppression circuit to filter out the part with larger voltage amplitude, and then passes through the anti-reverse connection circuit to prevent the power supply from being reversed and effectively intercept the backflow current. The processed power is transmitted to the JLD50V2A-ZKP2A filter chip, which can effectively suppress common-mode interference signals, differential-mode interference signals, and high-frequency interference signals after processing. The filtered power is transmitted to the URB2412YMD-10WR3 and URB2405YMD-6WR3 chips, where the URB2405YMD-6WR3 chip steps down the input power to 5V, which is the primary test power supply for the ADC, RPM, and PWM isolation chips. The URB2412YMD-10WR3 chip outputs a stepped-down 12V isolated power supply, which is then transmitted to the BD4644I power management chip. The BD4644I chip steps down the 12V power supply to 5V or 3.3V. The stepped-down power supply from the BD4644I chip is then supplied to the secondary side power supply of the Beidou inertial navigation, sensor, MCU chip, and ADC, RPM, and PWM isolation chip.

[0055] Specifically,

[0056] The power supply in this embodiment is powered by a model aircraft lithium battery, which has the advantages of large capacity, small size, and large instantaneous current. The input power needs to go through the following Figure 7 The spike and surge suppression circuit shown in the figure can prevent the power supply entering the device from reverse connection, lightning strike, surge and spike removal. Figure 7The power conversion circuit shown is used to convert the input voltage (9-38V) into a stable output voltage. The two ends of the bidirectional transient suppression diode D4 at the input end are connected to the metal oxide varistor MOV1 to protect the circuit from voltage spikes and provide overvoltage protection. The two ends of MOV1 are connected in parallel with the input filter capacitor C2 (2.2nF / 50V) to smooth the input voltage and reduce noise; one end of C2 is connected to the inductor L1 for energy storage and current smoothing. The other end of L1 is connected to a bidirectional transient suppression diode D5 (model SMBJ36CA), and then connected to the feedback resistors R5 (10kΩ) and R9 (36kΩ). The midpoint of R5 and R9 is connected to MOSFET Q1. Q1 is a switching element that controls the on and off of the current. The feedback resistors R5 and R9 are used to detect the output voltage and adjust the switching frequency of the MOSFET to maintain a stable output voltage. The drain of Q1 is connected to C4 and C3 (both 22uF / 50V) in parallel, which are mainly used for filtering and smoothing voltage. They can also be used for energy storage. When the circuit needs to provide current quickly, the stored charge is released. Finally, the pulse current generated by the MOSFET switch is converted into a DC current output through the output rectifier diode D1. Working principle: Energy conversion is achieved through the switching action of MOSFET: when Q1 is turned on, the current stores energy through L1, and when Q1 is turned off, L1 releases energy and is output after rectification by D1. The output voltage is kept stable through feedback control: The voltage divider network composed of R5 and R6 detects the output voltage, and adjusts the switching frequency of Q1 through the feedback mechanism to ensure that the output voltage is stable at the set value.

[0057] After the spike and surge suppression circuit is processed, the power is transmitted to Figure 8 The EMC filter circuit shown in the figure performs filtering and primary isolation. Input protection and filtering are achieved through input filter capacitor C5 and voltage regulator diode D6; the switch element Q2 controls the on and off of the current, and the gate of Q2 is connected to resistor R10, which is used to set the gate drive signal of the MOSFET to ensure its normal operation. The drain of Q2 is connected to the VIN+ pin of U1. U1 is an output rectifier, which converts the pulse current generated by the MOSFET switch into a DC current. The VOUT+ pin of U1 is connected to a series of resistors R7, R4, R5, and R6 through D2 to achieve voltage division or current limiting. Working principle: The input voltage provides a stable 5.1V reference voltage through the voltage regulator diode D8, and C5 filters out high-frequency noise in the input voltage. When Q2 is turned on, the current stores energy through L1; when Q2 is turned off, L1 releases energy and is output after rectification through U1.

[0058] After passing through the EMC filter circuit, the power is transmitted to Figures 9 to 11Jinshengyang isolated DCDC modules URB2412YMD-10WR3, URB2403YMD-6WR3, URB2405YMD-6WR3, Xi'an Guangqin Electronic Technology Co., Ltd. DCDC power module BD4644TI, for secondary power isolation and voltage conversion. Specifically,

[0059] like Figure 6 , Fig.10 As shown, the URB2405YMD-6WR3 chip steps down the input power supply to 5V, and the 5V power supply is the primary test power supply of the ADC, RPM, and PWM isolation chips.

[0060] like Figure 6 The URB2412YMD-10WR3 chip shown in the figure outputs a stepped-down 12V isolated power supply, which is transmitted to the BD4644I power management chip. The BD4644I chip steps down the 12V power supply to 5V and 3.3V. The stepped-down power supply from the BD4644I chip will be used to supply the secondary side power supply for Beidou inertial navigation, sensors, MCU chips, and ADC, RPM, and PWM isolation chips.

[0061] like Fig. 9 As shown, the power after the EMC filter circuit is transmitted to the DCDC power module. The input filter capacitors C7, C9, C10, and C11 are connected in parallel and connected between the VIN and GND pins of the power management chip U2. U2 uses the Golden Sun isolation DCDC module URB2412YMD-10WR3, which is responsible for converting the input voltage into a stable output voltage. The output voltage is +12VDC and the maximum current is 8.33A. That is, when the load does not exceed the maximum current of 8.33A, the output voltage will remain at 12VDC.

[0062] like Figure 6 , Fig.11 As shown in the figure, the power management chip BD4644TI steps down the 12V power supply and divides it into 4 power supplies. The names of the 4 power supply networks are +5V_2, +5V, +3.3V, and +3.3V_BD500S.

[0063] +5V_2 power supply is output to the secondary power supply of the ADC isolation chip, and the ADC isolation chip is NSI1311-DSWVR. +5V power supply is output to the three-axis accelerometer MAX535LCA, gyroscope MGZ206HC, and Beidou inertial navigation BD500S. +3.3V power supply is output to the processor GD32F470IIH6, PWM isolation chip pai160E61 secondary power supply, RPM isolation chip pai160E61 secondary power supply, RS422 serial port chip CA-IS3096W, RS232 serial port chip SIT3232EEUE, RS485 serial port chip CA-IS3098W, and CAN transceiver chip CA-IS3050W. 3.3V_BD500S power supply is output to Beidou inertial navigation BD500S. The +5V_2 power supply is transmitted to the isolated power supply IB0503XT-1WR3, and then isolated and stepped down again to step down the 5V power supply to 3.3V. The stepped-down 3.3V power supply is then output to the magnetic sensor isolation chip CA-IS3021S.

[0064] The UAV flight controller in this embodiment also includes a communication module, including a serial port RS422, a serial port RS485 and a CAN port. The serial port RS422 for communicating with external devices uses a CA-IS3096W chip, the serial port RS485 for communicating with external devices uses a CA-IS3098W chip, and the CAN for communicating with external devices uses a CA-IS3050W chip.

[0065] like Fig.12 As shown, the serial port RS422 (U34) uses CA-IS3096W. The chip has its own LDO inside, which can achieve isolation between external communication devices, and each RS422 communication port inside the product is isolated. The antenna interface of U34 is used for wireless communication, the Beidou board is used for satellite positioning, the CAN, RS485, RS422 and other interfaces are used to communicate with other devices, and the isolation interface is used to protect the system from external interference. Pins A, B, Z, and Y of U34 are RS422 interfaces, RS422_1_RX_P, RS422_1_RX_N: are the positive and negative ends of receiving data, and RS422_1_TX_P, RS422_1_TX_N are the positive and negative ends of sending data. Fig.13 As shown, the RS485 (U50) CA-IS3098W chip has its own LDO, which can achieve isolation between external communication devices, and each RS485 communication port inside the product is isolated. Fig.14 As shown, the CAN (U55) CA-IS3050W chip has its own LDO, which can achieve isolation between external communication devices, and each RS485 communication port inside the product is isolated.

[0066] It should be noted that the present embodiment is not limited to the specific configuration of two 422 channels and one 232 channel mentioned above. In fact, two 422 channels and one 232 channel only constitute a part of its basic functional architecture. In the actual application of the flight controller, the serial port configuration is more diverse. In addition to multiple 422 and 232 channels, it is also equipped with various types of serial ports such as CAN and 485. These rich and diverse serial port settings are mainly to achieve effective expansion of other types of optional modules, so as to meet the functional requirements in different application scenarios and improve the overall performance and flexibility of the flight controller.

[0067] The signal port of the processor passes through Fig.15 The pai160E61 chip shown isolates the processor signal and performs level conversion on the signal.

[0068] The external voltage signal passes through Fig.16 The NSI1311-DSWVR chip shown isolates the voltage signal and performs logic conversion on the voltage to a level recognizable by the processor.

[0069] After the isolation treatment of the above-mentioned fixed chip, the internal and external access devices of the product have been isolated, the internal devices of the product have been protected, and the high-frequency electromagnetic interference has been greatly weakened, reducing the impact of environmental factors on the product.

[0070] The present invention has built a domestic UAV controller that integrates deep power isolation, signal transmission protection, multiple sensor redundancy, and highly integrated electronic components. The controller integrates flight control, inertial navigation, embedded atmospheric data acquisition, flight parameter recording and other functions. It is designed for long-duration, integrated inspection and strike missions, and has enhanced anti-interference and electromagnetic compatibility designs. Currently, a 100% domestic solution has been achieved.

[0071] Example 2

[0072] like Figure 17 to Figure 18 As shown, an embodiment of the present invention discloses a working method of a UAV flight controller. Based on the UAV flight controller disclosed in Example 1, the carrier angular velocity and acceleration obtained by the three-axis gyroscope and the three-axis accelerometer are converted into an attitude angle represented by a quaternion and sent to the MCU. The MCU obtains the quaternion vector by solving the quaternion equation, and obtains the attitude angle, velocity and displacement of the carrier through an integration link; the attitude angle, velocity and displacement are fused with the velocity and three-dimensional position information provided by the Beidou module and input into the Kalman filter module to output the optimal estimate of the carrier motion parameters.

[0073] Among them, static pressure and dynamic pressure can be used to calculate altitude and airspeed. Static pressure is obtained by collecting atmospheric pressure, and the pressure generated by air flow is collected as dynamic pressure. These values ​​are transmitted to the flight control for flight control, and can also be used for combined navigation (including altitude and speed).

[0074] The working method specifically includes two stages:

[0075] Initial alignment phase: After error compensation is performed on the accelerometer (used to capture acceleration information) and gyroscope (used to accurately collect angular velocity) in the IMU module to complete the initial alignment, the inertial navigation enters the navigation phase.

[0076] Among them, the error compensation is: through Kalman filtering, the information of airborne inertial navigation, Beidou and the information of this inertial navigation (other sensor data) are integrated to obtain the optimal speed, position and attitude errors of the system, and compensate them. Specifically: the system inputs acceleration data, obtains speed data through integral calculation, and further integrates to obtain position data; the system inputs Beidou positioning data and angular velocity, and the angular velocity is integrated to obtain attitude angle data, and the acceleration, speed, position data and Beidou positioning and attitude angle data are input into Kalman filtering. After filtering, accurate acceleration, speed, position, Beidou positioning and attitude angle data are obtained and compared with the input data to obtain acceleration error, speed error, position error and attitude angle error.

[0077] Navigation phase: After receiving GPS information, the combined navigation mode is implemented and the relevant optimal parameters are output. Figure 2 As shown in the figure, the acceleration information measured by the gage and the angular rate information measured by the gyroscope are used to obtain the attitude angle, position and speed of the carrier after navigation solution. After Kalman filtering information fusion with the airborne Beidou information, the error divergence of the attitude angle, speed and position is suppressed to obtain the optimal attitude angle, speed and position.

[0078] It should be noted that by multiplying the two data collected by the accelerometer and gyroscope with the time interval, the speed and attitude angle can be derived; further, by multiplying the speed by the time again, the position change can be obtained. This process reflects the core principle of integral operation. However, a significant drawback of this calculation method is that it will include the error of the device itself in the calculation, resulting in the error accumulating and becoming quite significant over time.

[0079] To overcome this limitation, we introduce satellite navigation systems such as GPS or BeiDou to obtain the current absolute position or velocity information of the aircraft. To overcome this limitation, we introduce satellite navigation systems such as GPS or BeiDou to obtain the current absolute position or velocity information of the aircraft. These satellite signals can be regarded as reference standards without error accumulation due to their high precision. Using this absolute position or velocity information, we can accurately correct the data calculated by the IMU, thereby significantly improving the navigation accuracy. It is worth noting that the IMU is good at reflecting the dynamic changes of the aircraft in a short period of time due to its high output frequency, but it is prone to error accumulation, especially drift, when running for a long time, which will affect the accuracy of the final result. In contrast, although GPS can provide long-term stable information, it cannot meet the monitoring needs of short-term dynamic changes. Therefore, the combined navigation system achieves complementarity by cleverly combining the advantages of IMU and GPS.

[0080] In this fusion process, the Kalman filter algorithm plays a key role. The Kalman filter can dynamically adjust the weight distribution between the IMU and GPS data according to the Kalman gain (K), that is, to determine which sensor data should be more relied on at a specific moment. Through continuous iterative operations, the algorithm can guide the mutual correction between the IMU and GPS data, gradually eliminate errors, and finally converge to the optimal solution. In other words, GPS data, with its high-precision characteristics, gradually corrects the errors caused by the IMU due to time accumulation. After this fine-tuning process, we can finally obtain accurate attitude, speed and position information to meet the needs of high-precision navigation.

[0081] In summary, in this embodiment, through the organic combination of IMU and GPS, assisted by the precise control of the Kalman filter algorithm, it can not only overcome the limitations of a single sensor, but also make full use of the advantages of each component to ensure that a high navigation performance can be maintained even in complex environments, providing a reliable and accurate navigation solution for the aircraft.

[0082] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A UAV flight controller, characterized in that: It includes a microcontroller unit MCU and a Beidou board. The MCU collects static pressure sensor data through the I2C1 interface, dynamic pressure sensor data through the I2C2 interface, three-axis gyroscope data through the SPI1 interface, and three-axis accelerometer data through the SPI3 interface. The OEM serial port 2-way TTL UART of the Beidou board is connected to the MCU, of which 1-way TTL UART information sends the positioning and speed measurement information to the MCU for combined navigation filtering with the three-axis gyroscope, three-axis accelerometer data, static pressure and dynamic pressure data. The other 1-way TTL UART information receives the differential data sent by the data link, which is used for the RTK differential positioning of the board.

2. The flight controller according to claim 1, characterized in that: The MCU collects the positioning and speed measurement information of the Beidou board through the TTL USART2 interface, and sends the differential RTCM3.2 data from the data link received from the USART3 interface to the Beidou board through the TTL USART6 interface for RTK differential positioning.

3. The flight controller according to claim 1, characterized in that: The MCU collects data from an external magnetic sensor through an I2C3 interface, and the magnetic sensor is used to monitor the steering angle of the wind vane.

4. The flight controller according to claim 1, characterized in that: Three-axis gyroscope MGZ2067HC chip, the chip's SPI clock line SCLK, data input line MOSI, data output line MISO pin and chip select signal CS are connected to the MCU's PA5, PA6, PA7 and PB12 pins respectively, and data exchange with the MCU is realized through the SPI interface.

5. The flight controller according to claim 1, characterized in that: The three-axis accelerometer uses The MAX535LCA chip, the chip's SPI clock line SCLK, data input line DI, data output line DO pins and chip select signal CS are connected to the MCU's PA5, PA6, PA7 and PB12 pins respectively, and data exchange with the MCU is achieved through the SPI interface.

6. The flight controller according to claim 1, characterized in that: Static pressure sensor uses The XGZP6858D110KPA chip and the dynamic pressure sensor use the XGZP6899D chip. The SDA pin and SCL pin of the two chips are connected to the I2C, data line SDA and clock line SCL of the MCU.

7. The flight controller according to claim 1 or 6, characterized in that: According to the dynamic pressure measurement value P 总 and static pressure measurement value P 静 At this time, the space speed V is: The three-axis gyroscope measures the aircraft attitude at this time; The three-axis accelerometer measures the aircraft acceleration at this time; the airspeed, aircraft attitude and aircraft acceleration information collected by the above three sensors are calibrated with the inertial navigation information obtained by the Beidou board through Kalman filtering to eliminate attitude errors, speed and position errors.

8. The flight controller according to claim 7, characterized in that: The flight controller also includes a spike and surge suppression circuit. After the input power enters the controller, it passes through the spike and surge suppression circuit; the power after the spike and surge suppression process is transmitted to the JLD50V2A-ZKP2A filter chip to suppress common mode, differential mode and high-frequency interference signals; the power after the filtering process is transmitted to the isolated DCDC module, including URB2412YMD-10WR3 and URB2405YMD-6WR3 chips, where The URB2405YMD-6WR3 chip steps down the input power supply to 5V, and the 5V power supply is used as the primary power supply for the ADC, RPM, and PWM isolation chips. The URB2412YMD-10WR3 chip outputs a stepped-down 12V isolated power supply, which is transmitted to the BD4644I power management chip. The BD4644I chip steps down the 12V power supply to 5V and 3.3V. The stepped-down power supply from the BD4644I chip is supplied to the secondary power supply of the Beidou inertial navigation, sensor, MCU chip, and ADC, RPM, and PWM isolation chips.

9. The flight controller according to claim 1, characterized in that: The flight controller also includes a digital isolator, which uses a pai160E61 chip. The pai160E61 chip is used to isolate the PWM signal sent by the microcontroller, the RPM speed signal transmitted from the external device to the flight control, and the IO port signal of the microcontroller.

10. A method for operating a drone flight controller, characterized in that: Based on the UAV flight controller as described in any one of claims 1 to 9, the carrier angular velocity and acceleration obtained by the three-axis gyroscope and the three-axis accelerometer are converted into attitude angles represented by quaternions and sent to the MCU. The MCU obtains the quaternion vector by solving the quaternion equation, and obtains the attitude angle, velocity and displacement of the carrier through an integration step; the attitude angle, velocity and displacement are fused with the velocity and three-dimensional position information provided by the Beidou board and input into the Kalman filtering module to output the optimal estimate of the carrier motion parameters.

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