Compact unmanned aerial vehicle flight control board core component layout and efficient connection method

Abstract

This invention discloses a compact UAV flight control board core component layout and efficient connection method, belonging to the field of UAV flight control design technology. The layout scheme centers on the main control module, achieving a radial and compact arrangement of various functional modules on a flight control board body with an area not exceeding 50cm²: sensor modules surround the main control module with a spacing not exceeding 5mm, power management and communication modules are diagonally distributed at the edges, and interface expansion modules are dispersed in the remaining edge areas. Independent digital and analog ground copper foils are provided, using single-point grounding. The connection method utilizes surface mount technology for direct soldering of core chips. The power link employs a tree topology and array filtering, while the signal link optimizes impedance matching and wiring. Connection detection and thermal adhesive reinforcement ensure reliability. This invention significantly reduces the size and weight of the flight control board, effectively reduces signal interference and transmission loss, improves connection stability and flight control accuracy, and is suitable for the needs of miniaturized UAVs.

Description

Technical Field

[0001] This invention relates to the field of UAV flight control circuit design technology, specifically to a compact UAV flight control board core component layout and efficient connection method. Background Technology

[0002] As the "brain" of a drone, the drone flight control board integrates multiple core functional modules such as main control, sensors, power management, and communication. The rationality of its component layout and the reliability of its connection directly determine the drone's flight performance, stability, and service life.

[0003] Existing UAV flight control boards suffer from two major problems: First, their layout is loose. To avoid signal interference between modules, components are typically distributed, resulting in a large flight control board that is difficult to install in miniaturized and lightweight UAVs, while also increasing the overall weight and wind resistance of the UAV. Second, their connection efficiency is low. In traditional connection methods, sensors and main control modules are often connected via long ribbon cables, resulting in messy power supply wiring. This not only increases signal transmission loss and delay but also makes the connections prone to loosening due to vibration, temperature and humidity changes, leading to flight malfunctions. In addition, unreasonable grounding design further exacerbates crosstalk between digital and analog signals, leading to a decrease in sensor data acquisition accuracy and affecting the control accuracy of the flight control system.

[0004] Therefore, designing a compact, low-interference, and stable drone flight control board layout and connection method has become an urgent problem to be solved in the current development of drone technology. Summary of the Invention

[0005] The purpose of this invention To address the shortcomings of existing technologies, this invention provides a compact layout and efficient connection method for core components of a UAV flight control board. While miniaturizing the flight control board, it ensures the stability of connections between modules and the efficiency of signal transmission, reduces signal interference, and improves the flight performance of the UAV. Technical solution

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A layout of core components for a compact UAV flight control board

[0007] The flight control board includes a main control module, a sensor module, a power management module, a communication module, and an interface expansion module. These modules are arranged in a compact, radial layout centered on the main control module, as detailed below: Main control module layout: The main control module is centrally located at the geometric center of the flight control board, forming the layout baseline for the entire flight control board. The main control module uses a high-performance MCU chip, with dedicated solder pads reserved around it for direct connection to sensor modules, shortening the signal transmission path.

[0008] Sensor module layout: The sensor modules are arranged around the main control module, with a distance of no more than 5mm between them to minimize signal transmission delay. The sensor modules include a gyroscope, accelerometer, magnetometer, and barometer. The gyroscope and accelerometer are integrated into the same MEMS chip, which is directly mounted on the peripheral pads of the main control module. The magnetometer and barometer are respectively located on both sides of the MEMS chip, with a distance of 3mm-4mm between them to avoid magnetic field and air pressure interference between the sensors.

[0009] Power Management Module Layout: The power management module is located on one edge of the flight controller board, with its power output facing inwards to facilitate the extension of power supply links to various functional modules. The power management module includes a step-down chip, filter capacitors, and power distribution terminals. The step-down chip is located near the power input interface of the flight controller board, and the filter capacitors are arranged in an array around the step-down chip.

[0010] Communication module layout: The communication module is located on the opposite edge of the flight controller board, diagonally opposite the power management module, to reduce interference between power signals and communication signals. The communication module includes a wireless communication chip and an antenna interface. The antenna interface is located in a corner of the flight controller board to ensure that signal transmission is not obstructed by other components.

[0011] Interface expansion module layout: The interface expansion modules are distributed in the remaining edge area of ​​the flight control board body, including motor control interface, GPS interface, debugging interface, etc. The distance between each interface and the adjacent functional module is not less than 2mm to meet electrical safety requirements.

[0012] The area of ​​the flight control board body does not exceed 50cm², the projection overlap rate of each core component on the flight control board body is 0, and the minimum electrical safety distance between components complies with the IPC-2221 standard. To further reduce signal interference, the flight control board body is provided with two independent grounding copper strips: one is a digital ground copper strip, covering the area where the main control module, communication module, and interface expansion module are located; the other is an analog ground copper strip, covering the area where the sensor module is located. The two grounding copper strips are connected to the grounding terminal of the flight control board body through a single-point grounding method to avoid crosstalk between digital and analog signals. A method for efficient connection of a compact UAV flight control board based on the above layout

[0013] Includes the following steps: Functional module pre-connection: Surface mount technology (SMT) is used to solder the MEMS chips from the sensor module to the peripheral pads of the main control module, achieving direct electrical connection between the gyroscope, accelerometer, and main control module. The soldering temperature is controlled at 230℃-250℃, and the soldering time is 3s-5s, ensuring that the bonding strength between the pads and chip pins is not less than 5N. The magnetometer and barometer are connected to their corresponding interfaces on the main control module via flexible ribbon cables, with the cable length controlled within 5mm to reduce signal transmission loss. After soldering, ultrasonic testing is used to check the bonding strength between the pads and chip pins to ensure reliable connection.

[0014] Power supply link construction: The input pins of the step-down chip of the power management module are directly connected to the power input interface of the flight controller board through a copper trace with a line width of not less than 2mm to reduce the impedance of the power supply link; the output of the step-down chip is connected to the power bus of the flight controller board through a metallized via. The power bus adopts a tree topology structure, extending to each functional module. A filter capacitor is set every 10mm along the extension path to filter out ripple interference in the power signal and ensure stable power supply to each module.

[0015] Signal link optimization: The wireless communication chip of the communication module is connected to the UART interface of the main control module via impedance matching lines. The characteristic impedance of the matching lines is controlled at 50Ω±10%, using a serpentine routing method with a line width of 0.8mm-1.2mm, a line spacing of 1.5 times the line width, and a bending angle of 45° or 135° to avoid 90° right-angle bends and reduce signal reflection. During the routing process, the signal paths of the power bus and sensor modules are avoided to reduce cross-interference. The interface pins of the interface expansion module are connected in series to the I / O interface of the main control module in a daisy-chain manner, simplifying the wiring structure and improving connection efficiency.

[0016] Grounding system setup: A digital ground plane and an analog ground plane are set on the inner layer of the flight control board. The thickness of both the digital ground plane and the analog ground plane is not less than 0.2mm. An insulating layer with a thickness of not less than 0.1mm and a dielectric constant of 3.5-4.5 is set between the two ground planes to avoid mutual interference. The digital ground plane is connected to the grounding pins of the main control module and the communication module through vias, and the analog ground plane is connected to the grounding pins of the sensor module through vias. The two ground planes are connected at a single point on the edge of the flight control board through a 0Ω resistor to ensure the integrity of the grounding system and block crosstalk paths.

[0017] Connection testing and reinforcement: A multi-channel resistance tester is used to test the continuity of each connection point. The test voltage is 1V-3V and the test current does not exceed 1mA to ensure that the contact resistance is less than 10mΩ. For vulnerable connection parts such as flexible ribbon cables and impedance matching lines, silicone thermal conductive adhesive is used for fixation. The thermal conductivity of the thermal conductive adhesive is not less than 2.0W / (m·K), and the coverage area does not exceed 50% of the total area of ​​the connection part. This achieves the reinforcement effect while ensuring heat dissipation performance. The curing time of the thermal conductive adhesive is controlled within 24h-48h to ensure full curing. Beneficial effects

[0018] Compared with the prior art, the present invention has the following beneficial effects: Compact size and highly adaptable: Through a radial compact layout centered on the main control module, the flight control board body area is controlled within 50cm², which significantly reduces the size and weight of the flight control board, making it better suited for the installation needs of miniaturized and lightweight drones and expanding the application range of the flight control board.

[0019] Low signal interference and high transmission efficiency: The distance between the sensor module and the main control module is no more than 5mm, and the connection method of direct soldering or short ribbon cable is adopted, which shortens the signal transmission path and reduces transmission delay and loss; the independent digital ground and analog ground design and single-point grounding method effectively avoid crosstalk between digital signals and analog signals, and improve the accuracy of sensor data acquisition and flight control system control; the diagonal distribution of the communication module and power management module and the optimized wiring method further reduce cross interference and ensure stable transmission of communication signals.

[0020] Stable connection and high reliability: The surface mount technology is used to directly connect the core chip. Combined with flexible ribbon cable reinforcement and thermal adhesive fixation, the vibration resistance of the connection parts is improved and the risk of failure due to loosening is reduced. The array of filter capacitors in the power link filters out power ripple, ensuring stable power supply to each module and further improving the reliability and service life of the flight control board.

[0021] Standardized layout, easy to manufacture: The layout of each module is clear, the spacing between components meets electrical safety standards, the wiring rules are clear, which facilitates the use of automated equipment for production and assembly, improves production efficiency and reduces production costs. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to specific embodiments. Example 1: A layout of core components for a compact UAV flight control board

[0023] In this embodiment, the flight control board body adopts a 4-layer PCB board with a size of 50mm×100mm (area 50cm²), is made of FR-4, and has a thickness of 1.6mm.

[0024] Main control module: The STM32H743VIT6 chip is selected as the main control MCU, which is centrally located at the geometric center of the PCB board. Eight pads with a spacing of 1.27mm are reserved around it for connecting MEMS chips.

[0025] Sensor module: The MEMS chip used is the MPU6050 (integrating a gyroscope and accelerometer), which is soldered to the peripheral pads of the main control module using SMT technology, with a distance of 3mm from the STM32H743VIT6 chip; the magnetometer is the HMC5883L, and the barometer is the BMP280, which are respectively set on the left and right sides of the MPU6050 chip, with a distance of 3.5mm from the MPU6050. The HMC5883L and BMP280 are connected to the I2C interface of the STM32H743VIT6 through a 4mm long flexible ribbon cable.

[0026] Power management module: Located on the left edge of the PCB board, the step-down chip is MP2307 (output voltage 3.3V), near the power input interface (XT30 interface) in the upper left corner of the PCB board. The input pin of the step-down chip is connected to the XT30 interface through a 2.5mm copper trace. The filter capacitor is a 0.1μF ceramic capacitor, a total of 8, arranged in a 2×4 array around the MP2307. The connection length between each capacitor pin and the MP2307 output pin is 2.5mm. The power distribution terminal is a PH2.0 terminal, located on the right side of the step-down chip.

[0027] Communication module: Located on the right edge of the PCB board, diagonally opposite the power management module. The wireless communication chip is NRF24L01, and the antenna interface is IPEX connector, located in the lower right corner of the PCB board. The NRF24L01 and the UART interface of STM32H743VIT6 are connected through differential signal lines with a length difference of 0.3mm. The wiring avoids the left power bus.

[0028] Interface expansion module: The motor control interface (ESC interface, 6 in total) is located on the upper edge of the PCB board, the GPS interface (TTL interface) is located on the lower left edge of the PCB board, and the debugging interface (USB-TTL interface) is located on the lower right edge of the PCB board. The distance between each interface and the adjacent module is 2.5mm.

[0029] Two grounding copper strips are installed on the PCB: a digital ground copper strip covering the main control module, communication module, and interface expansion module area, with a width of 5mm; and an analog ground copper strip covering the sensor module area, with a width of 3mm. The two copper strips are connected at a single point in the lower left corner of the PCB through a 0Ω resistor, and the grounding terminal is located next to the XT30 interface. The minimum electrical safety distance between all components is 0.3mm, conforming to the IPC-2221 standard. Example 2: A method for efficient connection of a compact UAV flight control board

[0030] Based on the layout of Embodiment 1, the connection method includes the following steps: Functional module pre-connection: The MPU6050 chip was mounted onto the peripheral pads of the STM32H743VIT6 using a fully automated pick-and-place machine. Reflow soldering was then performed with the following temperature profile: preheating zone 150℃-180℃ (10s), heating zone 180℃-230℃ (5s), soldering zone 240℃ (4s), and cooling zone to room temperature. The HMC5883L and BMP280 were connected to the I2C interfaces (PB8, PB9) of the STM32H743VIT6 via 4mm long FFC flexible cables (1.0mm pitch), with both ends of the cable secured by thermoforming. After soldering, the bonding strength of the MPU6050 pads was tested using an ultrasonic tester, and the measured strength was 6.2N, meeting the requirements.

[0031] Power supply link construction: The input pin (Vin) of MP2307 is connected to the positive terminal of the XT30 interface through a 2.5mm wide copper trace with a thickness of 0.03mm; the output pin (Vout) of MP2307 is connected to the 3.3V power bus on the inner layer of the PCB board through four metallized vias (0.8mm in diameter). The power bus adopts a tree topology, extending to the main control module, sensor module, communication module and interface expansion module respectively. A 0.1μF filter capacitor is soldered every 10mm along the extension path, for a total of 12 filter capacitors.

[0032] Signal link optimization: The TX and RX pins of the NRF24L01 are connected to the UART2 interface (PA2, PA3) of the STM32H743VIT6 via impedance matching lines. The matching lines use serpentine routing with a line width of 1.0mm, a line spacing of 1.5mm, and a bending angle of 45°. The characteristic impedance was measured to be 52Ω, which meets the requirements. The 6 pins of the motor control interface are connected in series in a daisy chain to the TIM1-TIM3 interface of the STM32H743VIT6. The routing avoids the power bus and sensor module area.

[0033] Grounding system setup: Digital ground plane and analog ground plane are set on the inner layers of the PCB board (layer 2 and layer 3), each with a thickness of 0.25mm, and a 0.12mm thick FR-4 insulating layer (dielectric constant 4.0) is set in between. The digital ground plane is connected to the grounding pins of STM32H743VIT6, NRF24L01 and each interface through 8 vias. The analog ground plane is connected to the grounding pins of MPU6050, HMC5883L and BMP280 through 4 vias. The two ground planes are connected at the lower left corner of the PCB board through a 0Ω / 1206 resistor, and the grounding terminal is connected to the negative terminal of the XT30 interface.

[0034] Connection testing and reinforcement: Each connection point was tested using an AGILENT 34401A multi-channel resistance tester. The test voltage was 2V and the test current was 0.5mA. The contact resistance of each connection point was measured to be between 3-8mΩ, which meets the requirements. Silicone thermally conductive adhesive (model TC-5021, thermal conductivity 2.2W / (m·K)) was applied to the connection between the HMC5883L and BMP280 flexible ribbon cables and the PCB board, covering an area of ​​40% of the connection area. The adhesive was cured at 25℃ for 36 hours to complete the reinforcement.

[0035] The performance of the flight control board assembled in this embodiment was tested: the flight control board weighs 8.5g, which is 35% lighter than the traditional flight control board with the same function; the sensor data transmission delay is 0.8ms, which is 62% lower than the traditional layout; it works continuously for 24 hours under a vibration environment of 1500rpm without any loose connections or faults, and its operation is stable.

Claims

1. A layout of core components for a compact UAV flight control board, characterized in that, The system includes a flight control board body, which integrates a main control module, a sensor module, a power management module, a communication module, and an interface expansion module. The layout of each module satisfies the following conditions: The main control module is centrally located at the geometric center of the flight control board body, forming a layout reference; the sensor modules are arranged around the main control module, with a distance of no more than 5mm from the main control module; the power management module is located on one edge of the flight control board body, with its power output terminal facing the interior of the flight control board body; the communication module is located on the other edge of the flight control board body, with its signal transmission terminal close to the main control module; the interface expansion modules are distributed in the remaining edge areas of the flight control board body, with a distance of no less than 2mm from adjacent functional modules; The area of ​​the flight control board body does not exceed 50cm², the projection overlap rate of each core component on the flight control board body is 0, and the minimum electrical safety distance between components complies with the IPC-2221 standard.

2. The core component layout of the compact UAV flight control board according to claim 1, characterized in that, The sensor module includes a gyroscope, an accelerometer, a magnetometer, and a barometer. The gyroscope and accelerometer are integrated into the same MEMS chip. The MEMS chip is directly connected to the main control module's I2C interface via a microstrip line, and the characteristic impedance of the microstrip line is controlled at 50Ω±10%. The magnetometer and barometer are respectively located on both sides of the MEMS chip, with a distance of 3mm-4mm between them.

3. The core component layout of the compact UAV flight control board according to claim 1, characterized in that, The power management module includes a step-down chip, filter capacitors, and power distribution terminals. The input pins of the step-down chip are directly connected to the power input interface of the flight controller board via copper foil, and the line width of the copper foil is not less than 2mm. The filter capacitors are arranged in an array around the step-down chip, and the connection length between the pin of each filter capacitor and the output pin of the step-down chip does not exceed 3mm.

4. The core component layout of the compact UAV flight control board according to claim 1, characterized in that, The communication module includes a wireless communication chip and an antenna interface. The signal pins of the wireless communication chip are connected to the UART interface of the main control module via differential signal lines, and the length difference of the differential signal lines does not exceed 0.5mm. The antenna interface is located in a corner of the flight control board, and the connection between it and the wireless communication chip avoids the area where the sensor module is located.

5. The core component layout of the compact UAV flight control board according to claim 1, characterized in that, The flight control board body is provided with at least two grounding copper strips. One is a digital grounding copper strip, covering the area where the main control module, communication module and interface expansion module are located; the other is an analog grounding copper strip, covering the area where the sensor module is located. The two grounding copper strips are connected to the grounding terminal of the flight control board body through a single-point grounding method.

6. A method for efficiently connecting a compact UAV flight control board based on the layout described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Functional Module Pre-connection: The MEMS chip in the sensor module is soldered to the peripheral pads of the main control module using surface mount technology to achieve direct electrical connection between the gyroscope, accelerometer and main control module; the magnetometer and barometer are connected to the corresponding interfaces of the main control module through flexible ribbon cables, with the ribbon cable length controlled within 5mm; S2. Power Link Construction: The output terminal of the step-down chip of the power management module is connected to the power bus of the flight control board through metallized vias. The power bus adopts a tree topology structure, extending to each functional module. A filter capacitor is set every 10mm along the extension path. S3. Signal Link Optimization: Connect the wireless communication chip of the communication module to the UART interface of the main control module through an impedance matching line. The matching line adopts a serpentine wiring method, avoiding the power bus and the signal path of the sensor module during the wiring process; connect the interface pins of the interface expansion module in series to the I / O interface of the main control module through a daisy chain. S4. Grounding System Setup: Set up a digital ground plane and an analog ground plane on the inner layer of the flight controller board. The digital ground plane is connected to the grounding pins of the main control module and the communication module through vias; the analog ground plane is connected to the grounding pins of the sensor module through vias; the two ground planes are connected at a single point on the edge of the flight controller board through a 0Ω resistor. S5. Connection Inspection and Reinforcement: Conduct continuity tests on each connection point to ensure that the contact resistance is less than 10mΩ; use thermally conductive adhesive to fix vulnerable connection parts such as flexible ribbon cables and impedance matching lines, and the coverage area of ​​the thermally conductive adhesive shall not exceed 50% of the total area of ​​the connection part.

7. The efficient connection method for a compact UAV flight control board according to claim 6, characterized in that, In step S1, the surface mount technology soldering temperature is controlled at 230℃-250℃, and the soldering time is 3s-5s. After soldering, the bonding strength between the pad and the chip pin is tested by ultrasonic testing, and the bonding strength is not less than 5N.

8. The efficient connection method for a compact UAV flight control board according to claim 6, characterized in that, In step S3, the serpentine wiring has a line width of 0.8mm-1.2mm, a line spacing of 1.5 times the line width, and a bending angle of 45° or 135° to avoid 90° right-angle bends.

9. The efficient connection method for a compact UAV flight control board according to claim 6, characterized in that, In step S4, the thickness of both the digital ground plane and the analog ground plane is not less than 0.2 mm, and an insulating layer with a thickness of not less than 0.1 mm is provided between the two ground planes. The dielectric constant of the insulating layer is 3.5-4.

5.

10. The efficient connection method for a compact UAV flight control board according to claim 6, characterized in that, In step S5, the conductivity test is performed using a multi-channel resistance tester with a test voltage of 1V-3V and a test current not exceeding 1mA. The thermally conductive adhesive is a silicone thermally conductive adhesive with a thermal conductivity of not less than 2.0W / (m·K) and a curing time of 24h-48h.