Micro unmanned aerial vehicle

Abstract

The application provides a nano unmanned aerial vehicle, comprising: a flight control board, comprising a motor through hole; a driving unit fixed at the motor through hole, used for providing driving force; a management chip arranged on the flight control board, used for controlling the driving unit; and an environment sensing unit arranged on the flight control board, used for sensing environment information. According to the example embodiment of the application, by fusing multiple sensors, the environment sensing capability of the nano unmanned aerial vehicle is enhanced, so that the autonomous flight and active obstacle avoidance of the nano unmanned aerial vehicle are realized, and the nano unmanned aerial vehicle is more autonomous and intelligent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of unmanned aerial vehicle technology, in particular, to a nano unmanned aerial vehicle. BACKGROUND

[0002] Multi-rotor unmanned aerial vehicle as a relatively simple and flexible unmanned aerial vehicle has a wide range of applications in production and life. With the rapid development of personal portable mobile electronic devices in recent years, new production, packaging, manufacturing process iteration, various sensors and microprocessors and other electronic components develop towards low power consumption, miniaturization and low cost, which provides a technical premise for the design and production of nano unmanned aerial vehicles, and gives birth to a series of miniaturized unmanned aerial vehicle projects.

[0003] AutoQuad is a soft firmware open source but hardware closed source project, which started in 2011, aiming to provide stable, dynamic flight and automatic driving function flight control board. The hardware of AutoQuad flight control board adopts 32-bit MCU and carefully selected IMU sensor, and at the beginning of the project, AutoQuad 5 flight control board is used to realize the AutoQuad 5 flight control board of constant gain navigation filter on the development board of STM32 microprocessor chip. In 2012, the project launched a new generation of AutoQuad 6.4, AutoQuad 6.5 and electronic speed controller ECS32 1.5, ECS32 2.1, and completed the design of new generation nano unmanned aerial vehicle flight control board AutoQuad M4 in July 2014, and launched AutoQuad M4 V2 in 2015. AutoQuad M4 aims to provide a high expandability multi-rotor system flight control board with a pocket size (for example, the diagonal length is 8cm) to a heavy payload of up to 16 brushless motors realized by expansion board.

[0004] Crazyflie is an open source project of both software and hardware. The project started the development of Crazyflie quadcopter in late 2009. Crazyflie 1.0, weighing about 19g and motor to motor length about 90mm, making it the smallest quadcopter in the world at that time. Nano quadcopter Crazyflie 2.0 greatly changed the design of PCB board and also increased the support for a variety of external expansion boards, with a total weight of about 27g and three-dimensional size of 92x92x29mm, providing 7min of endurance. Crazyflie 2.1 maintains the same weight and three-dimensional appearance, providing backward compatibility with Crazyflie 2.0, slightly improving the radio performance and external antenna, upgrading the imu sensor, and keeping the same performance as Crazyflie 2.0.

[0005] PX4 is an independent software and hardware open source project, which aims to provide a low-cost high-performance high-end autopilot for academic, hobby and industrial groups. The PX4 project is open source under the BSD license. The project originated from the Pixhawk project of the Computer Vision and Geometry Laboratory of ETH Zurich, and was supported by the Autonomous Systems Laboratory and the Automatic Control Laboratory.

[0006] Pixhawk is the reference hardware platform of PX4, which runs PX4 on NuttX OS. The latest released flight control system Pixhawk 5X core flight control module weighs only 23g, and the three-dimensional size is 38.8x 31.8x 14.6mm. The total board weighs 51g, and the total board three-dimensional size is 52.4x 103.4x 16.7mm. Pixhawk 5X is based on Pixhawk Autopilot FMUv5X standard, Autopilot bus standard and connector standard, pre-installed with the latest PX4 Autopilot firmware, uses a high-performance microprocessor of STM32F7, and uses triple redundancy, temperature control, isolated sensor domain and other designs to bring high performance and high reliability.

[0007] The inventors found that the above projects played an important role in promoting the development of nano unmanned aerial vehicle technology, but were limited by the initiation time of the project and the technical conditions at that time, the open source policy and the demand for external scalability. There are some deficiencies in size, power consumption, integration and high integration. At the same time, the above projects only focus on the modular solution of the unmanned aerial vehicle flight control system, and do not consider the design of enhanced unmanned aerial vehicle autonomous ability such as autonomous positioning, autonomous flight and safety obstacle avoidance. SUMMARY

[0008] The present application proposes a new nano unmanned aerial vehicle to solve at least one of the above problems.

[0009] According to an aspect of the present application, a nano unmanned aerial vehicle is provided, comprising: a flight control board comprising a motor through hole; a driving unit fixed at the motor through hole for providing driving force; a management chip disposed on the flight control board for controlling the driving unit; and an environment perception unit disposed on the flight control board for sensing environmental information.

[0010] According to some embodiments, the management chip comprises a micro-control sub-chip, a wireless communication and energy management sub-chip, wherein the micro-control sub-chip is electrically connected to the driving unit through a MOS tube, and controls the on-off of the MOS tube by using a pulse width modulation signal to realize the control of the driving unit; the wireless communication and energy management sub-chip is electrically connected to the micro-control sub-chip through serial communication mode, and provides enablement through IO port.

[0011] According to some embodiments, the nano-type unmanned aerial vehicle further comprises an inertial measurement unit and / or a barometer, wherein the management chip, the inertial measurement unit and / or the barometer are prepared on the flight control board through dense wiring, and the inertial measurement unit and / or the barometer are respectively electrically connected with the micro-control sub-chip through an I2C bus.

[0012] According to some embodiments, the flight control board has an axisymmetric cross-shaped structure, and the driving units are fixed at the end points of the flight control board.

[0013] According to some embodiments, the environment perception unit is arranged on the flight control board through an expansion board pin.

[0014] According to some embodiments, the environment perception unit comprises a horizontal distance sensing sub-unit for measuring the distance of obstacles in the horizontal direction, a vertical distance sensing sub-unit for measuring the flight height of the nano-type unmanned aerial vehicle, and an optical flow sensing sub-unit for measuring the flight speed of the nano-type unmanned aerial vehicle.

[0015] According to some embodiments, the environment perception unit further comprises an optical flow mother board arranged on the flight control board through an expansion board pin, the horizontal distance sensing sub-unit is connected with the optical flow mother board in a pluggable manner, and the vertical distance sensing sub-unit and the optical flow sensing sub-unit are respectively welded on the optical flow mother board.

[0016] According to some embodiments, the environment perception unit further comprises a sensor management sub-unit, the sensor management sub-unit is electrically connected with the micro-control sub-chip through an I2C bus, and the sensor management sub-unit is respectively electrically connected with the horizontal distance sensing sub-unit and the vertical distance sensing sub-unit through an IO port, wherein the micro-control sub-chip enables the horizontal distance sensing sub-unit and the vertical distance sensing sub-unit through the sensor management sub-unit to obtain distance data.

[0017] According to some embodiments, the driving unit comprises a motor base fixed at the motor through hole, a motor installed on the motor base, and a rotor installed on the motor.

[0018] According to some embodiments, the micro-control sub-chip 7 and the wireless communication and energy management sub-chip are packaged in WLCSP.

[0019] According to some embodiments, the nano-type unmanned aerial vehicle further comprises a power supply unit and a colored indicator light, wherein a positive electrode of the colored indicator light is electrically connected to a positive electrode of the power supply unit, a negative electrode of the colored indicator light and an IO port of the micro-control sub-chip are electrically connected, and the micro-control sub-chip causes the colored indicator light to emit light by controlling the IO port to be grounded.

[0020] According to the example embodiments of the present application, by fusing multiple sensors, the environmental perception capability of the nano-type unmanned aerial vehicle is enhanced, so as to realize autonomous flight and active obstacle avoidance of the nano-type unmanned aerial vehicle, and make the nano-type unmanned aerial vehicle more autonomous and intelligent.

[0021] According to some other embodiments of the present application, by adopting a modular design, the driving unit and the environmental perception unit are cascaded together in the form of independent subsystems, which provides a more flexible system configuration mode, reduces the production and transportation costs, and improves the maintainability, assembly and disassembly convenience and maintenance cost of the unmanned aerial vehicle system. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced as follows.

[0023] Figure 1a A top view of a layout mode of a nano-type unmanned aerial vehicle according to an example embodiment of the present application is shown.

[0024] Figure 1b A side view of a layout mode of a nano-type unmanned aerial vehicle according to an example embodiment of the present application is shown.

[0025] Figure 1c Another top view of a layout mode of a nano-type unmanned aerial vehicle according to an example embodiment of the present application is shown.

[0026] Figure 1d A highly schematic view of a layout mode of a nano-type unmanned aerial vehicle according to an example embodiment of the present application is shown.

[0027] Figure 1e A schematic view of an inter-axis distance (motor-motor diagonal distance) of a layout mode of a nano-type unmanned aerial vehicle according to an example embodiment of the present application is shown.

[0028] Figure 2 A physical diagram of a minimum aerial vehicle (without battery) according to an example embodiment of the present application is shown.

[0029] Figure 3 A physical diagram of an environmental perception unit according to an example embodiment of the present application is shown.

[0030] Figure 4Fig. 1 shows a perspective view of a nano-type unmanned aerial vehicle according to an example embodiment of the present application.

[0031] Figure 5 Fig. 2 shows a structural schematic diagram of a nano-type unmanned aerial vehicle according to an example embodiment of the present application.

[0032] Figure 6a Fig. 3 shows a structural schematic diagram of a flight control board of a nano-type unmanned aerial vehicle according to an example embodiment of the present application.

[0033] Figure 6b Fig. 4 shows a structural schematic diagram of a flight control board of a nano-type unmanned aerial vehicle according to an example embodiment of the present application.

[0034] Figure 7 Fig. 5 shows an assembly diagram of an environment perception unit of a nano-type unmanned aerial vehicle according to an example embodiment of the present application. DETAILED DESCRIPTION

[0035] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments may, however, be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the description.

[0036] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the techniques described can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, methods, devices, implementations, materials, and so forth have not been described in detail in order to avoid obscuring aspects of the disclosure.

[0037] The flow diagrams shown in the figures are merely examples and are not necessarily to be construed as having any dependencies, or any order, unless explicitly stated that certain blocks are to be performed before other blocks. For example, blocks can be performed in an order different than that shown in the figures, and / or blocks can be skipped or performed in parallel. In some embodiments, one or more blocks can be performed before, after, or in parallel with other blocks.

[0038] The terms "first", "second", and the like in the description and in the claims of the present application and in the above drawings are used for distinguishing between similar objects and are not necessarily used to describe a particular sequential or chronological order. Also, the terms "comprises", "comprising", "includes", "including", or the like are used herein to generally mean comprising, consisting of or consisting in. For example, a process, method, article, or apparatus that comprises a list of steps or elements is not necessarily limited to the listed steps or elements, but can include additional steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

[0039] With the rapid development of personal portable mobile electronic devices, new production, packaging, manufacturing processes, and the development of various sensors and microprocessors and other electronic components towards low power consumption, miniaturization and low cost, providing technical premise for the design and production of nano unmanned aerial vehicles, promoting the development of miniaturized unmanned aerial vehicles. However, the prior art only focuses on the modular solution of the unmanned aerial vehicle flight control system, and does not consider the design of enhanced unmanned aerial vehicle autonomous capabilities such as autonomous positioning, autonomous flight and safety obstacle avoidance.

[0040] Nano unmanned aerial vehicle generally refers to an unmanned aerial vehicle with a weight of less than 50g and a size of less than 15cm. Figure 1a A top view of a layout of a nano unmanned aerial vehicle according to an example embodiment of the present application is shown, Figure 1b A side view of a layout of a nano unmanned aerial vehicle according to an example embodiment of the present application is shown, Figure 1c Another top view of a layout of a nano unmanned aerial vehicle according to an example embodiment of the present application is shown, Figure 1d A highly schematic view of a layout of a nano unmanned aerial vehicle according to an example embodiment of the present application is shown, Figure 1e A schematic view of the inter-axis distance (motor-motor diagonal distance) of a layout of a nano unmanned aerial vehicle according to an example embodiment of the present application is shown. As Figures 1a-1e The nano unmanned aerial vehicle shown is a four-rotor layout in a multi-rotor unmanned aerial vehicle, with a frame axis distance of 70mm and a height of 35.6mm. As Figures 1a-1e The nano unmanned aerial vehicle shown adopts an integrated design, directly using a flight control board as the core of the unmanned aerial vehicle system as a support structure, and adopting a split design on the functional subsystems. The environmental perception unit is mounted to the flight control board in the form of an expansion board, improving the flexibility and expandability of the overall system. As Figures 1a-1e The nano unmanned aerial vehicle shown also includes a hollow cup brushless motor, a three-bladed rotor, a motor base, and a lithium battery 6.

[0041] According to the embodiments of the present application, a nano unmanned aerial vehicle with autonomous flight and five-direction obstacle avoidance capability is proposed for the constraints of low power consumption, low cost and small size of the nano unmanned aerial vehicle, which includes management chip, inertial measurement unit, barometer, color indicator and other modules, which are printed on the same flight control board through reasonable wiring, and the driving unit (for example, including motor base, motor and rotor) and lithium battery are fixed on the flight control board through point gluing, sealing and other methods, thereby composing the smallest aircraft.

[0042] Figure 2 A physical diagram of a smallest aircraft (without battery) according to an example embodiment of the present application is shown as Figure 2 The smallest aircraft shown adopts a highly integrated one-piece molding scheme, and the electronic components such as management chip, inertial measurement unit and barometer are printed on the same PCB board, and the motor through hole for inserting the motor is reserved in the four corner extension frame area of the PCB board, and the motor is aligned with the motor base through the motor through hole, thereby improving the position accuracy of the motor installation. At the same time, the PCB board is used as a structure support. Figure 2 The smallest aircraft shown has a weight of 25g, a maximum design power consumption of 4.6W, a full body height of 35.6mm, a maximum envelope size of 100mm (rotor edge-rotor edge distance), and an inter-axis distance of 70mm (motor-motor diagonal distance).

[0043] According to some embodiments, Figure 2 The smallest aircraft shown communicates with the terminal device through Bluetooth, accesses the wired / wireless controller, and realizes manual control of the flight of the nano unmanned aerial vehicle by setting the control key mapping, so that the smallest aircraft can be used for debugging, testing the hardware and software system, human control in complex environment, realization of high maneuverability trajectory and data acquisition.

[0044] According to some embodiments of the present application, the environment perception unit includes a horizontal distance sensing subunit for measuring the distance of obstacles in the horizontal direction, a vertical distance sensing subunit for measuring the flight height of the nano unmanned aerial vehicle, and an optical flow sensing subunit for measuring the flight speed of the nano unmanned aerial vehicle.

[0045] The body plane of the nano unmanned aerial vehicle is set as XY plane, the Z axis is perpendicular to the body and points to the space, the X positive direction is the forward direction of the unmanned aerial vehicle, and the Y positive direction is the right direction of the unmanned aerial vehicle. According to some embodiments, the X and Y direction data output by the optical flow sensing subunit and the Z direction height information output by the vertical distance sensor are used to establish the ground world coordinate system of the nano unmanned aerial vehicle, thereby realizing autonomous positioning and stable hovering of the nano unmanned aerial vehicle. And through the flight trajectory of the pre-defined specific coordinate point to another coordinate point, with the help of the horizontal distance sensing subunit, the autonomous flight of completely five-direction dynamic obstacle avoidance is realized. Figure 3An environment perception unit physical diagram according to an example embodiment of the present application is shown. According to other embodiments, the environment perception unit is arranged on the flight control board through the expansion board pin on the basis of the minimum aircraft, and functions such as autonomous positioning, stable hovering, point-to-point autonomous flight and five-way obstacle avoidance are realized, so that the micro unmanned aircraft is more autonomous and intelligent, such as Figure 4 A micro unmanned aircraft physical diagram according to an example embodiment of the present application is shown.

[0046] The specific embodiments according to the present application will be described in detail below with reference to the accompanying drawings.

[0047] Figure 5 A structural schematic diagram of a micro unmanned aircraft according to an example embodiment of the present application is shown, Figure 6a A structural schematic diagram of a flight control board of a micro unmanned aircraft according to an example embodiment of the present application is shown from one angle, Figure 6b A structural schematic diagram of a flight control board of a micro unmanned aircraft according to an example embodiment of the present application is shown from another angle, Figure 7 An environment perception unit assembly diagram of a micro unmanned aircraft according to an example embodiment of the present application is shown.

[0048] The specific embodiments according to the present application will be described in detail below with reference to the accompanying drawings. Figures 5-7 , a micro unmanned aircraft according to an example embodiment of the present application will be described in detail.

[0049] According to an embodiment of the present application, a micro unmanned aircraft is provided, which includes a flight control board (such as Figure 5 the flight control board 1 shown), a driving unit and a management chip. The flight control board 1, the driving unit and the management chip constitute a flight control system of the micro unmanned aircraft.

[0050] The flight control board 1 provides hardware implementation of all basic functions of the micro unmanned aircraft, is a basic support of the micro unmanned aircraft, provides stress support for external components such as the motor 3 and the lithium battery 6 and bears internal stress in the flight process. At the same time, it also provides physical connection and electrical interface for peripheral expansion hardware such as the environment perception expansion board. The micro unmanned aircraft realizes basic external communication, pose perception, power management and power control by integrating various electrical components on the flight control board 1, thereby providing an abstract interface for application development.

[0051] According to some embodiments of the present application, the flight control board 1 adopts an integrated molding scheme and uses a glass cloth copper-clad plate as a substrate to reduce the weight of the micro unmanned aircraft. For example, a glass cloth copper-clad plate with a bending strength greater than 300Mpa, 1.8mm and 8 layers of FR-4 is used as a substrate to meet the stress support required by the micro unmanned aircraft.

[0052] According to some embodiments, motor through holes 12 are reserved in advance during the preparation of flight control board 1. Flight control board 1 has an axisymmetric cross-shaped structure, and the drive unit is fixed at the end points of flight control board 1, that is, at the four ends of the "+" shape.

[0053] like Figure 5 As shown, according to some embodiments, the drive unit is used to provide driving force. It includes a motor base 4, a motor 3 (e.g., a hollow cup brushed motor), and a rotor 5 (e.g., a three-bladed rotor). The motor base 4 is fixed at the motor through hole 12, the motor 3 is mounted on the motor base 4, and the rotor 5 is mounted on the motor 3. The specific assembly process of the drive unit is as described in steps S101 to S107.

[0054] Step S101: Align the motor base 4 with the motor through hole 12;

[0055] Step S103: Fix the motor 3 onto the motor base 4

[0056] Step S105: Fix the motor 3, motor base 4, and flight control board 1 by applying adhesive.

[0057] Step S107: Insert the motor 3 shaft into the mortise of the three-bladed rotor 5.

[0058] According to some embodiments, in order to meet the electrical connection requirements of the flight control board 1, structures such as deck expansion interface pin mounting holes and motor power supply holes are machined on the flight control board 1.

[0059] According to some embodiments of this application, a management chip is disposed on the flight control board 1 for controlling the drive unit. According to some embodiments, the management chip includes a microcontroller sub-chip 7 and a wireless communication and power management sub-chip 8. The microcontroller sub-chip 7 is electrically connected to the drive unit via a MOSFET and uses a pulse width modulation signal to control the on / off state of the MOSFET, thereby controlling the motor speed in the drive unit. The wireless communication and power management sub-chip 8 is electrically connected to the microcontroller sub-chip 7 via serial communication and provides enable functionality through an I / O port.

[0060] According to other embodiments, the nano-unmanned aerial vehicle also includes an inertial measurement unit (e.g., a MEMS inertial measurement unit) 9 and / or a barometer 10, wherein the management chip, the inertial measurement unit 9 and / or the barometer 10 are fabricated on the flight control board 1 by dense wiring, wherein the inertial measurement unit 9 and / or the barometer 10 are electrically connected to the microcontroller subchip 7 via an I2C bus, respectively.

[0061] According to some embodiments, the micro-control sub-chip 7 adopts a 32-bit chip based on ARM Cortex-M0, for example, a chip of STM32F405 series, which has a main frequency of 168 MHz, 196 KB RAM and 1 MB Flash, and many interfaces to meet the operation requirements of the pico unmanned aerial vehicle system. The micro-control sub-chip 7 adopts WLCSP packaging to reduce the chip mass and volume and improve the overall integration of the unmanned aerial vehicle. For example, the size of the packaged chip is 4.223x3.969 mm.

[0062] According to some embodiments, the wireless communication and energy management sub-chip 8 adopts a chip nRF51822, which has a main frequency of 16 MHz, 16 KB RAM and 256 KB Flash, and supports Bluetooth and 2.4 GHz mode. The wireless communication and energy management sub-chip 8 adopts WLCSP packaging to reduce the chip mass and volume. For example, the size of the packaged chip is 3.83x3.83 mm.

[0063] According to some embodiments, the wireless communication and energy management sub-chip 8 is electrically connected with the micro-control sub-chip 7 through serial communication mode (for example, UART serial communication mode) and controls the enablement of other modules through IO port. The radio signal is connected to a radio frequency power amplifier, for example, a BAL-NRF02D3, through a differential signal, and the signal is transmitted through an antenna.

[0064] According to some embodiments, the inertial measurement unit 9 is a 6-axis inertial sensor, for example, a sensor BMI088, which has a 16-bit high-precision 3-axis acceleration sensor and a 16-bit high-precision 3-axis angular velocity sensor, and the chip size is 4.5x3 mm.

[0065] According to some embodiments, the pico unmanned aerial vehicle is connected in a paired mode with a supported device (for example, a computer or a mobile terminal) supporting a Bluetooth communication protocol (for example, a BLE communication protocol), to realize the real-time transmission of data including raw sensor data of the inertial measurement unit 9, pose estimation data of the pico unmanned aerial vehicle, local relative coordinates and speed of the pico unmanned aerial vehicle, and advanced flight control commands, and to send the entire flight plan to the pico unmanned aerial vehicle through the paired supported device or ground station system.

[0066] According to some embodiments, the barometer 10 adopts a sensor BMP388, which has a range of 300-1250 hPa and a size of 2x2 mm.

[0067] According to some embodiments, the inertial measurement unit 9 and / or the barometer 10 are respectively electrically connected with the micro-control sub-chip 7 through I2C bus.

[0068] According to some embodiments, the nano-type unmanned aerial vehicle further comprises a power supply unit and a colored indicator light (e.g., a mini colored LED) 11, wherein the positive pole of the colored indicator light 11 is electrically connected to the positive pole of the power supply unit, the negative pole of the colored indicator light 11 and the IO port of the micro control sub-chip 7 are electrically connected, and the micro control sub-chip 7 causes the colored indicator light 11 to emit light by controlling the IO port to be grounded.

[0069] For example, as Figure 5 The power supply unit is a lithium battery 6.

[0070] According to some embodiments, the management chip, the inertial measurement unit 9, the barometer 10, and the colored indicator light 11 are printed on the same PCB board, for example, the same 8-layer PCB board, by dense wiring.

[0071] According to some embodiments, the flight control board of the nano-type unmanned aerial vehicle further comprises an expansion board interface (e.g., a double 7-pin row needle with a pitch of 1.27 mm), and the expansion board is connected to the flight control board through the expansion board needle. The expansion board interface comprises an SPI interface (e.g., 1), an I2C interface (e.g., 1), a UART interface (e.g., 2), a power supply and a ground, a main controller IO port (e.g., 4), and / or a power management IO port (e.g., 3).

[0072] According to some embodiments, the motor speed is 73,000 RPM, and the diameter is 6 mm; the outer diameter of the rotor is 30 mm; and the motor base is used to fix the motor, provide support for the unmanned aerial vehicle, and ensure that the environment perception expansion board has sufficient ground clearance.

[0073] According to some embodiments,

[0074] According to some embodiments, the motor base is manufactured by 3D printing, and the material is ABS. The motor base comprises support pieces (e.g., 4) mounted on the motor. According to the embodiments of the present application, the total length of the motor base is 19 cm, the diameter is 9 cm, and the center hole is 6 cm.

[0075] According to Figure 5 As shown in the nano-type unmanned aerial vehicle, the wireless communication and power management chip 8 and the micro control sub-chip 7 are the core, and are connected to the 6-axis inertial measurement unit 9 and the EEPROM through the I2C bus, control the hollow cup motor through the pulse width modulation signal, and are connected to the colored LED through the IO port. The OW / GPIO / SPI / I2C / PMW signals of the wireless communication and power management chip 8 and the micro control sub-chip 7 are led out to the expansion board interface.

[0076] According to the embodiments of the present application, the modules such as the management chip, the inertial measurement unit, the barometer, the color LED indicator light, etc. are prepared on the same flight control board through wiring printing, and the driving units (for example, including the motor base, the motor, and each pair of the forward and reverse rotors) and the lithium battery are fixed on the basis of the flight control board through the means such as dispensing and sealing, so as to constitute the minimum aircraft. The minimum aircraft realizes the communication with the ground station through Bluetooth (for example, Bluetooth BLE mode), so as to realize the manual control flight of the unmanned aircraft by the ground station. Or through the client software, the wireless or wired controller is accessed, the control key mapping is set, the flight of the minimum aircraft is manually controlled, and the complete manual flight control capability is obtained. The minimum aircraft can be applied to the occasions such as debugging, testing the software and hardware system, artificial control in complex environment, realization of high maneuverability trajectory, and data acquisition.

[0077] According to some embodiments of the present application, the environment perception unit is arranged on the flight control board 1 through the expansion board pin, and is used for sensing the environmental information. The environment perception unit includes a horizontal distance sensing subunit, a vertical distance sensing subunit, and an optical flow sensing subunit. The horizontal distance sensing subunit is used for measuring the distance of the obstacle in the horizontal direction, the vertical distance sensing subunit is used for measuring the flight height of the nano unmanned aircraft, and the optical flow sensing subunit is used for measuring the flight speed of the nano unmanned aircraft.

[0078] According to some embodiments, the environment perception unit further includes an optical flow mother board, and the horizontal distance sensing subunit, the vertical distance sensing subunit, and the optical flow sensing subunit are connected with the optical flow mother board in a pluggable manner. According to another embodiment, the horizontal distance sensing subunit is connected with the optical flow mother board in a pluggable manner, and the vertical distance sensing subunit and the optical flow sensing subunit are respectively welded on the optical flow mother board.

[0079] According to the embodiments of the present application, the optical flow mother board is arranged below the flight control board through the expansion board pin.

[0080] According to another embodiment, the environment perception unit further includes a sensor management subunit, the sensor management subunit is electrically connected with the micro control sub-chip 7 through an I2C bus, and the sensor management subunit is electrically connected with the horizontal distance sensing subunit and the vertical distance sensing subunit through an IO port. The micro control sub-chip 7 realizes the enablement of the horizontal distance sensing subunit and the vertical distance sensing subunit through the sensor management subunit, so as to obtain the distance data.

[0081] As shown in Figure 5 , the environment perception unit is an environment perception expansion board 2 in Figure 5 . As shown in Figure 7As shown, the environmental sensing expansion board 2 includes four identical horizontal distance sensor sub-boards 13 (e.g., including four horizontal sensing sub-units 18) and an optical flow motherboard 14 (e.g., including one vertical sensing sub-unit 16 and one optical flow sensing sub-unit 17). The assembly of the environmental sensing expansion board 2 is completed by vertically inserting and soldering the horizontal distance sensor sub-units 13 onto the optical flow motherboard 14.

[0082] According to some embodiments, the horizontal sensing subunit 18 and the vertical sensing subunit 16 are ToF distance sensors.

[0083] like Figure 5 As shown, the environmental perception expansion board 2 is connected to the flight control board 1 through the reserved left and right dual 7pin expansion board pins 15. By connecting the environmental perception expansion board 2 into the smallest aircraft, the construction of a nano-sized unmanned aerial vehicle with autonomous flight and active obstacle avoidance capabilities in five directions (forward, backward, left, right, and down) is completed.

[0084] According to some embodiments, the sensors on the environmental perception expansion board 2 are mounted on the same I2C bus of the microcontroller sub-chip 7. The horizontal sensing sub-unit 18 and the vertical sensing sub-unit 16 are controlled by the enable signal of the sensor management chip, and the initialization process is loaded in sequence to complete the address change. Dynamic obstacle avoidance or power saving is achieved by turning the horizontal sensing sub-unit 18 or the vertical sensing sub-unit 16 on or off.

[0085] The entire nano-sized unmanned aerial vehicle (UAV) system can connect to a ground station system via Bluetooth, enabling fully autonomous flight of the UAV. For example... Figure 5 As shown, the fuselage plane of the nano-sized unmanned aerial vehicle is set as the XY plane, the Z-axis is perpendicular to the fuselage and points to space, the positive X-direction is the forward direction of the unmanned aerial vehicle, and the positive Y-direction is the rightward direction of the unmanned aerial vehicle.

[0086] The take-off and landing mode of the UAV scheduled flight trajectory is written into the flight control firmware in the ground station system by means of Bluetooth or a wired debugging device, etc. The nano UAV measures the real-time flight height by using the vertical distance sensing subunit 16 on the optical flow motherboard 14. The optical flow sensing subunit 14 on the optical flow motherboard 14 measures the component velocities in the X-axis direction and the Y-axis direction of the real-time flight. The local world coordinate system is established by reading the X and Y direction data output by the optical flow sensing subunit and the Z-axis height data output by the vertically downward vertical distance sensing subunit, so as to realize the autonomous positioning, stable hovering or flight from a specific coordinate point to another coordinate point of the nano UAV. With the aid of the obstacle distance data of the front, rear, left and right four horizontal distance sensing subunits, and according to the preset alert threshold, when the real-time measured obstacle distance is less than the alert threshold, autonomous maneuvering is taken to avoid the obstacle, so as to realize the completely independent obstacle avoidance flight in the whole process without any external information input or human intervention.

[0087] According to some embodiments, the flight control firmware runs on the micro control sub-chip 7.

[0088] According to the embodiments of the present application, the size and weight of the nano UAV are reduced by adopting a highly integrated design; the environmental perception capability is enhanced by fusing more sensors, so that the nano UAV can realize autonomous flight and five-way active obstacle avoidance function. By adopting a modular design, the management chip, the inertial measurement unit and the environmental perception unit are cascaded together in the form of independent subsystems, which provides more flexible UAV system configuration, reduces the production and transportation costs, improves the maintainability of the UAV, the convenience of assembly and disassembly, and reduces the maintenance cost. At the same time, the design and development of the low-cost nano UAV system are realized by using civilian-level and low-cost electronic components, which provides a reference example for further promoting the lightweight, miniaturization and intelligentization of the nano UAV.

[0089] Those skilled in the art can understand that the above modules can be distributed in the device according to the description of the embodiments, and can also be changed in one or more devices different from the embodiments. The modules of the above embodiments can be combined into one module, or further split into multiple sub-modules.

[0090] The embodiments of the present application are described in detail above, and the principles and implementation modes of the present application are described by applying specific examples. The above embodiment descriptions are only used to help understand the method of the present application and its core idea. Meanwhile, the changes or deformations made by those skilled in the art according to the idea of the present application, based on the specific implementation modes and application scope of the present application, all belong to the scope of protection of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A nano unmanned aerial vehicle, comprising: a flight control board including a motor through hole; a driving unit fixed at the motor through hole for providing driving force; a management chip disposed on the flight control board for controlling the driving unit; and an environment sensing unit disposed on the flight control board for sensing environment information; wherein the flight control board has an axisymmetric cross-shaped structure, the driving unit and the environment sensing unit are cascaded together in a design mode of independent subsystems, and the environment sensing unit is disposed on the flight control board through an expansion board pin; the driving unit is fixed at the motor through hole reserved at an end point of the flight control board; the environment sensing unit includes a horizontal distance sensing subunit, a vertical distance sensing subunit, an optical flow sensing subunit, an optical flow motherboard, and a sensor management subunit, wherein the optical flow motherboard is disposed on the flight control board through an expansion board pin, the horizontal distance sensing subunit is connected to the optical flow motherboard in a pluggable manner, and the vertical distance sensing subunit and the optical flow sensing subunit are respectively welded on the optical flow motherboard; the management chip includes a micro control subchip, the sensor management subunit is electrically connected to the micro control subchip through an I2C bus, the sensor management subunit is electrically connected to the horizontal distance sensing subunit and the vertical distance sensing subunit through IO ports, and the micro control subchip enables the horizontal distance sensing subunit and the vertical distance sensing subunit through the sensor management subunit to obtain distance data; after the takeoff and landing mode of the predetermined flight trajectory of the unmanned aerial vehicle is written into the flight control firmware through a Bluetooth or wired debugging device in a ground station system, the XY plane of the nano unmanned aerial vehicle body is set as the XY plane, the Z axis is vertically directed to space, the X positive direction is the forward direction of the unmanned aerial vehicle, and the Y positive direction is the right direction of the unmanned aerial vehicle, the vertical distance sensing subunit on the optical flow motherboard of the nano unmanned aerial vehicle is used to measure the real-time flight height, the optical flow sensing subunit on the optical flow motherboard with a vertical downward direction is used to measure the component velocities of the X axis direction and the Y axis direction of the real-time flight, a local world coordinate system is established by reading the X and Y direction data output by the optical flow sensing subunit and the Z axis height data output by the vertical distance sensing subunit with a vertical downward direction, to realize the autonomous positioning, stable hovering, or flight from a specific coordinate point to another coordinate point of the predetermined trajectory of the nano unmanned aerial vehicle, and the obstacle distance data of the front, rear, left, and right horizontal distance sensing subunits are used to realize the completely independent and autonomous obstacle avoidance flight in the whole process without any external information input or human intervention. the management chip further includes a wireless communication and energy management subchip, wherein 2. The nanocraft of claim 1, wherein, the micro control subchip is electrically connected to the driving unit through a MOS tube, and controls the on-off of the MOS tube by using a pulse width modulation signal to realize the control of the driving unit. ​ The wireless communication and energy management sub-chip is electrically connected with the micro control sub-chip through serial communication mode, and provides enable through an IO port.

3. The nanocraft of claim 2, wherein, The micro unmanned aerial vehicle further comprises an inertial measurement unit and / or a barometer, wherein the management chip, the inertial measurement unit and / or the barometer are prepared on the flight control board through dense wiring, wherein, The inertial measurement unit and / or the barometer are respectively electrically connected with the micro control sub-chip through I2C bus.

4. The nanocraft of claim 1, wherein, The horizontal distance sensing sub-unit is used for measuring the distance of an obstacle in the horizontal direction. The vertical distance sensing sub-unit is used for measuring the flight height of the micro unmanned aerial vehicle. The optical flow sensing sub-unit is used for measuring the flight speed of the micro unmanned aerial vehicle.

5. The nanocraft of claim 1, wherein, The driving unit comprises: A motor base fixed at the motor through hole; A motor installed on the motor base; and A rotor installed on the motor.

6. The nanocraft of claim 2, wherein, The micro control sub-chip and the wireless communication and energy management sub-chip adopt WLCSP packaging.

7. The nanocraft of claim 3, wherein, Further comprising a power supply unit and a color indicating lamp, wherein the positive electrode of the color indicating lamp is electrically connected with the positive electrode of the power supply unit, the negative electrode of the color indicating lamp and the IO port of the micro control sub-chip are electrically connected, The micro control sub-chip controls the IO port to be grounded to make the color indicating lamp emit light.

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