A pan-tilt device for installing microwave radar and its control system

Abstract

This invention provides a gimbal device and its control system for mounting microwave radar on a drone. The device includes a gimbal box, a gimbal cover, an upper arm, a lower arm, an upper arm cover plate, a first three-phase brushless DC motor, and a second three-phase brushless DC motor. One end of the lower arm is connected to the gimbal box via the first three-phase brushless DC motor, and the other end is connected to the upper arm via the second three-phase brushless DC motor. The first three-phase brushless DC motor is fixedly connected to the lower arm, and its rotating shaft is connected to the gimbal box. The second three-phase brushless DC motor is fixedly connected to the upper arm, and its rotating shaft is connected to the lower arm. The top of the upper arm is connected to the drone chassis. This invention provides a horizontal and pitch adjustment support device and system, which, through coordinated structural, hardware circuit, and software program control, achieves the functions of maintaining the radar incident angle of the drone's flight attitude and data transmission.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic control, and relates to a pan / tilt platform for an unmanned aerial vehicle, and in particular to a pan / tilt platform device for installing a microwave radar and a control system thereof. Background Art

[0002] Microwave radar has the advantages of high resolution, strong penetration and low power consumption. It can obtain soil information, especially covering soil information, and realize all-weather and all-day monitoring of soil information. UAV microwave remote sensing has the advantages of convenient transportation, high flexibility, short operation cycle and high data resolution. It effectively overcomes the shortcomings of satellite remote sensing technology such as being greatly affected by weather, low temporal and spatial resolution, and being limited by transit cycle. It has become a new means to achieve rapid and accurate perception of soil information on a large scale of farmland. However, the incident angle, irradiation area, width of drone-borne radar data, resolution and overlap of multispectral data are greatly affected by the drone's flight attitude, flight stability and ground slope. It is necessary to have a special pan-tilt mounted microwave radar to realize microwave radar attitude maintenance, data transmission and other functions.

[0003] The existing airborne gimbal devices have complex structures, many non-standard parts, high processing costs, and the product appearance cannot meet the requirements of industrial production. The existence of friction between the gimbal structures requires the motor to provide greater power for relative movement, and it is relatively difficult to adjust the center of gravity during operation. The gimbal will shake violently, which will cause the microwave radar equipment on board to be unstable and affect the transmission of microwave radar data. At the same time, during the operation of the drone, the shaking and tilting of the drone will have a serious impact on data transmission and reception. In view of the above problems, there is an urgent need for an airborne gimbal structure with simple structure, convenient adjustment, and stable performance. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art and solve the problems that the posture of the UAV body is unstable and the data is greatly affected by terrain changes, the purpose of the present invention is to provide a pan-tilt device for installing a microwave radar and its control system, which monitors the radar pitch angle in real time through a posture acquisition module and adjusts the radar pitch angle in real time through a motor drive circuit, thereby solving the technical problems of unstable pan-tilt and poor detection effect.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A pan-tilt device for installing a microwave radar, the pan-tilt device is fixed directly below the drone, and includes an upper arm, a lower arm, a pan-tilt box, a shock absorbing unit, a data transmission unit, and a posture adjustment unit, and the microwave radar is fixed below the pan-tilt box;

[0007] The shock absorbing unit is connected to the upper arm and the UAV chassis mounting frame to achieve a shock absorbing function;

[0008] The data transmission unit includes a PTZ main control board, which transmits the data collected by the microwave radar to the computer in real time;

[0009] The attitude adjustment unit includes a three-phase DC brushless motor 1 and a three-phase DC brushless motor 2. The three-phase DC brushless motor 1 is fixed on the lower arm, the rotation axis is in the Y direction, and is connected to the gimbal box. The three-phase DC brushless motor 2 is fixed at the bottom end of the upper arm, the rotation axis is in the X direction, and is connected to the lower arm. Through the relative movement between the upper arm and the lower arm and between the lower arm and the gimbal box, the microwave radar maintains an incident angle of 45° with the ground during the flight of the UAV.

[0010] In one embodiment, the upper arm is in an inverted L-shape, and the horizontal arm at the top is used to connect to the shock absorbing unit, and the lower arm is in a horizontally placed L-shape, with the outer side of one arm connected to the rotating shaft of the three-phase DC brushless motor 2, and the inner side of the other arm fixing the three-phase DC brushless motor 1.

[0011] In one embodiment, the shock absorbing unit includes an upper shock absorbing plate, a lower shock absorbing plate and a plurality of shock absorbing columns, wherein the plurality of shock absorbing columns are connected between the upper shock absorbing plate and the lower shock absorbing plate, the upper shock absorbing plate is fixedly connected to the drone chassis mounting frame, and the lower shock absorbing plate is fixedly connected to the upper arm. The upper shock absorbing plate is fixed to the lower shock absorbing plate through four shock absorbing columns; the upper shock absorbing plate and the lower shock absorbing plate are made of carbon fiber plates, and the four shock absorbing columns are made of rubber.

[0012] In one embodiment, the gimbal box is in the shape of a rectangular parallelepiped and is hollow inside, and the gimbal main control board is fixed inside the gimbal box.

[0013] The present invention also provides a control system for the pan-tilt device for installing a microwave radar, comprising a posture acquisition module, a wireless transmission module, a power module and a DC voltage stabilization module; the pan-tilt main control board comprises an MCU processing circuit, a motor drive circuit and a serial port and communication circuit;

[0014] The attitude acquisition module is used to measure the pitch angle and linear acceleration of the microwave radar;

[0015] The wireless transmission module is used to transmit the data collected by the microwave radar to the pan-tilt main control board, and the pan-tilt main control board transmits the data to the computer end;

[0016] The power supply module and the DC voltage stabilization module are used to provide a stable DC voltage for the PTZ main control board;

[0017] The MCU processing circuit is connected to the posture acquisition module, receives its measurement data, and outputs control pulses;

[0018] The motor driving circuit is used to control the rotation angle of the pan-tilt device according to the control pulse, complete the horizontal and pitch adjustment of the microwave radar, and realize the radar's attitude holding function;

[0019] The serial port download circuit and communication circuit are used for burning programs and providing a power supply interface.

[0020] In one embodiment, the posture acquisition module is installed on the gimbal main control board, and the motor drive circuit controls the rotation angles of three-phase DC brushless motor 1 and three-phase DC brushless motor 2 according to the control pulse, thereby realizing the posture maintenance function of the gimbal device through the relative movement between the upper arm and the lower arm and between the lower arm and the gimbal box.

[0021] In one embodiment, the gimbal main control board uses a timer to periodically obtain the pitch angle measured by the attitude acquisition module; when the deviation between the current pitch angle and the set 45° pitch angle exceeds a preset value, the attitude acquisition module converts the pitch angle of the microwave radar during the flight of the UAV into an electrical signal and sends it to the MCU processing circuit; the MCU processing circuit sends instructions to the motor drive circuit in the form of a control pulse based on the electrical signal; the motor drive circuit sends a PWM signal to the drive chips of the three-phase DC brushless motor 1 and the three-phase DC brushless motor 2 to adjust the angle.

[0022] In one embodiment, the serial port download circuit and the communication circuit are multiplexed circuits, and the written program is burned into the MCU processing circuit through the USB interface during the debugging of the MCU processing circuit.

[0023] In one embodiment, the program is an attitude adjustment program and a ground slope calculation program; the attitude adjustment program first obtains the pitch angle of the microwave radar in the current state, calculates the deviation angle between the pitch angle of 45°, and then adjusts the motor angle through the motor drive circuit to achieve the attitude stabilization function; the ground slope settlement program first determines that there is a slope on the ground at this time through the time of microwave return, calculates the ground slope at this time through the flight speed of the drone and the time difference of microwave return, compares it with the current gimbal pitch angle, calculates the angle that the gimbal should be adjusted, and realizes the ground slope adaptive adjustment function.

[0024] In one embodiment, the wireless transmission module transmits the data of the microwave radar to the gimbal main control board. The gimbal main control board calculates the ground slope through the microwave return time and adjusts the motor angle to keep the microwave radar at a 45° depression angle with the ground. At this time, the gimbal will re-enter a new self-stabilizing state.

[0025] In one embodiment, the present invention further includes an indicator light circuit, which is used to display whether the SD card is normally connected to the card slot; the card slot is located below the pan-tilt main control board, and its notch is flush with the edge of the pan-tilt main control board.

[0026] In one embodiment, the DC voltage module is installed on the gimbal main control board. The drone provides a 12V DC voltage to the gimbal through a voltage divider board, and a DC-DC adjustable step-down module is used to provide a stable 10V DC voltage to the gimbal main control board; the adjustable step-down DC-DC module uses an LM2596S step-down chip, and the output ripple is small.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention mainly realizes the horizontal and pitch adjustment of the microwave radar through the upper arm, the lower arm and two three-phase DC brushless motors, and combines the control system of the pan-tilt device to realize the function of posture maintenance, thereby effectively improving the detection effect.

[0029] (2) The present invention can autonomously adjust the angle of the pan / tilt head and then re-enter a new self-stabilizing state, and can adapt to plains, hills and mountains, which greatly enhances the practicality of the present invention.

[0030] (3) The shock absorbing unit designed in the present invention can reduce the vibration transmitted from the UAV to the gimbal, thus providing a better working environment for the microwave radar.

[0031] (4) The present invention can realize the function of real-time data transmission, and the computer terminal can obtain and process information in a timely manner and understand the detection results of the microwave radar in a timely manner.

[0032] (5) The present invention has a simple structure, high installation efficiency, low operation and maintenance costs, small friction resistance between structures, relatively simple center of gravity adjustment, and more stable radar.

[0033] (6) The line noise designed by the present invention is small, the system has strong anti-interference ability, and the cross interference between signals is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the pan-tilt device of the present invention.

[0035] Figure 2 This is the MCU processing circuit diagram of the present invention.

[0036] Figure 3 4 is a reset circuit diagram of the control circuit of the present invention.

[0037] Figure 4 This is a voltage stabilizing circuit diagram of the present invention.

[0038] Figure 5-7 This is a motor driving circuit diagram of the present invention.

[0039] Figure 8-9 This is the serial port downloading circuit diagram of the present invention.

[0040] Fig.10 This is a communication circuit diagram of the present invention.

[0041] Fig.11 It is the circuit diagram of the indicator light of the present invention.

[0042] Fig.12 It is the work flow chart of the present invention.

[0043] Fig.13 This is a structural block diagram of the control system of the present invention.

[0044] Explanation of the accompanying drawings: 1—upper shock absorbing plate; 2—shock absorbing column; 3—lower shock absorbing plate; 4—upper arm; 5—upper arm cover; 6—three-phase DC brushless motor one; 7—pan head cover; 8—three-phase DC brushless motor two; 9—pan head box; 10—lower arm. DETAILED DESCRIPTION

[0045] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0046] The present invention discloses a pan-tilt device for installing a microwave radar. The pan-tilt device is fixed directly below an unmanned aerial vehicle (UAV) and has functions of shock absorption, attitude holding, data transmission and autonomous adjustment. During the flight of the UAV, the shock absorption unit can effectively alleviate the influence of the vibration of the UAV body on the pan-tilt device. The pan-tilt device maintains a 45° depression angle between the microwave radar and the ground, can autonomously adjust the pan-tilt angle, and transmits the data collected by the microwave radar to a computer in real time.

[0047] A specific mechanical structure reference of the pan-tilt device Figure 1 As shown, it includes an upper arm 4 and a lower arm 10. The top of the upper arm 4 is used to connect to the drone, and the bottom is fixed with a three-phase DC brushless motor 28. The rotation axis of the three-phase DC brushless motor 28 is connected to the lower arm 10. The lower arm 10 is fixed with a three-phase DC brushless motor 16. The rotation axis of the three-phase DC brushless motor 16 is connected to the pan-tilt box 9. The pan-tilt box 9 is used to carry the pan-tilt main control board, and the data transmission function can be realized through the pan-tilt main control board. The rotation axis of the three-phase DC brushless motor 28 is in the X direction, and the rotation axis of the three-phase DC brushless motor 16 is in the Y direction. Through the relative movement between the upper arm 4 and the lower arm 10 and between the lower arm 10 and the pan-tilt box 9, the attitude holding function of the radar can be realized.

[0048] In one embodiment, the upper arm 1 is in an inverted L-shape, and the horizontal arm at the top can be used to connect to the chassis of the drone, and the lower arm 10 is in a horizontally placed L-shape, with the outer side of one arm connected to the rotating shaft of the three-phase DC brushless motor 2 8, and the inner side of the other arm fixed with the three-phase DC brushless motor 1 6.

[0049] In the present invention, the microwave radar is fixedly mounted on the bottom surface of the pan-tilt box 9, with the transmitting end facing downward. In one embodiment, the pan-tilt box 9 is in the shape of a rectangular parallelepiped, hollow inside, and equipped with a pan-tilt cover 7 that can be opened as needed on the top, and the pan-tilt main control board can be fixed inside the pan-tilt box 9 by screws.

[0050] For example, a line placement groove and an upper arm cover plate 5 may be provided on the outer side of the upper arm 4 , and the upper arm cover plate 5 is used to cover important lines located in the line placement groove to prevent the lines from being damaged due to environmental factors.

[0051] Furthermore, the present invention also provides a control system for the pan-tilt device, including a posture acquisition module, a wireless transmission module, a DC voltage module and a pan-tilt main control board; wherein the pan-tilt main control board includes an MCU processing circuit, a motor drive circuit, and a serial port and communication circuit. The main functions and principles of each part are as follows:

[0052] Attitude acquisition module, used to measure the pitch angle and linear acceleration of microwave radar;

[0053] The wireless transmission module transmits the data collected by the microwave radar to the gimbal, and the gimbal transmits the data to the computer;

[0054] DC voltage regulator module, used to provide stable DC voltage for the PTZ main control board;

[0055] The MCU processing circuit is connected to the attitude acquisition module, receives its measurement data, and outputs control pulses.

[0056] The motor drive circuit is used to control the rotation angle of the pan-tilt device according to the control pulse, complete the horizontal and pitch adjustment of the microwave radar, and realize the radar's attitude maintenance function.

[0057] Serial port download circuit and communication circuit are used to burn programs and provide power interface.

[0058] Specifically, the attitude acquisition module of the present invention adopts MPU-6050, which can be installed on the main control board of the pan-tilt platform and communicate with the main control board of the pan-tilt platform through IIC and other methods. The main control board of the pan-tilt platform uses a timer to periodically obtain the pitch angle measured by the angle sensor. MPU6050 is very sensitive to the angle and linear acceleration of the carrier's movement, and can detect the attitude and state changes of the carrier without external signals. By using the fixed axis and precession of MPU6050, a constant reference can be established during the flight of the drone, thereby measuring the pitch angle and linear acceleration of the radar.

[0059] like Figure 2As shown, the MCU processing circuit includes a processor U1 and peripheral circuits, and the peripheral circuits include an oscillation circuit, a reset circuit, and a voltage stabilization circuit. The processor U1 is an ATSAM3X8E series chip, and its main function is to receive the measurement data input by the angle sensor through the I / O interface and output control pulses to the motor drive circuit. Figure 2 In the circuit shown, the PC26 pin of the processor U1 is connected to the PA29 pin, and the PA28 pin is connected to the PC29 pin; the GND pin, the GND1 pin, the GND2 pin, the GND3 pin, the GND4 pin, the GNDUTM1 pin, the GNDBU pin, the GNDANA pin, and the JTAGSEL pin are all connected to the GNDTST pin and connected to GND through a resistor R1, VBG is connected to GND through a resistor R4, and the resistor R4 is connected in parallel with a capacitor C6; the VDDBU pin, the VDDIO1 pin, the VDDIO2 pin, the VDDIO3 pin, the VDDIO4 pin, and the VDDIN pin are all connected to VCC 3.3, VDDANA is connected to VCC3.3 through an inductor L1, and VDDUTM1 is connected to VCC 3.3 through an inductor L2; the VDDOUT pin is connected to the VDDCORE1 pin, the VDDCOREE2 pin, the VDDCORE3 pin, the VDDCORE4 pin, and the VDDCORE5 pin, and the VDDOUT pin is connected to VCC through a resistor R18 3.3; the VDDPLL pin is connected to the VDDOUT pin through the inductor L3 and then to VCC 3.3 through the resistor R18; the parallel capacitor C20 and capacitor C23 connected to the VDDANA pin are connected in parallel with the parallel capacitor C21 and capacitor C22 connected to the VDDUTM1 pin, and are connected to the VDDPLL pin through the parallel capacitor C24 and capacitor C25; the FWUP pin outputs 3.3V through the resistor R11, PC0 is connected to the MOS tube source, the MOS tube gate is connected to the MOS tube drain through the resistor R8 and outputs 3.3V, one end of RESET CMD is connected to one end of the NRSTB pin, outputs 3.3V through the resistor R13, and this end is connected to GND through the resistor R14; the LED pin is connected to GND through the resistor R22 and the light-emitting diode D3, connected to VCC3.3, connected to the RXL pin through the resistor R24 ​​and the light-emitting diode D3, connected to VCC3.3, connected to the TXL pin through the resistor R25 and the light-emitting diode D4.

[0060] The function of the oscillator circuit is to generate AC oscillation as the signal source of the processor U1. Figure 2 In the circuit shown, the oscillation circuit is connected between the XTAL-OUT pin and the XTAL-IN pin of the processor U1, the XTAL-OUT pin and the XTAL-IN pin are connected through the crystal oscillator Y1, and the crystal oscillator is connected to GND.

[0061] The reset circuit function is to restore the MCU processing circuit to the initial state. Figure 3 In the circuit shown, the reset circuit is connected to the 3.3V voltage terminal of the processor U1, one end of KEY1 is connected to the 3.3V voltage terminal through a resistor R23, and one end is connected to GND through a capacitor C26, and the capacitor C26 is connected in parallel with a switch K2; one end of KEY2 is connected to the 3.3V voltage terminal through a resistor R26, and one end is connected to GND through a capacitor C35, and the capacitor C35 is connected in parallel with a switch K3; one end of KEY3 is connected to the 3.3V voltage terminal through a resistor R27, and one end is connected to GND through a capacitor C38, and the capacitor C38 is connected in parallel with a switch K4.

[0062] The voltage regulator circuit provides a stable 3.3V voltage to the MCU processing circuit. Figure 4 In the circuit shown, the voltage stabilizing circuit includes two U6AMS1117 chips, capacitor C27, capacitor C28, capacitor C29, capacitor C30, capacitor C31, capacitor C32, capacitor C33, and capacitor C34; one end of capacitor C28 is connected to the 5.0V terminal voltage and connected to the IN pin, and the other end is connected to GND, capacitor C28 is connected in parallel with capacitor C27, one end of capacitor C29 is connected to the OUT pin to output a 3.3V voltage, and one end is connected to GND, capacitor C29 is connected in parallel with capacitor C30, and the ADJ pin is connected to GND; one end of capacitor C32 is connected to the 5.0V terminal voltage and connected to the IN pin, and one end is connected to GND, capacitor C32 is connected in parallel with capacitor C31, one end of capacitor C33 is connected to the OUT pin to output a 3.3V voltage, and one end is connected to GND, capacitor C33 is connected in parallel with capacitor C34, and the ADJ pin is connected to GND.

[0063] The motor drive circuit controls the rotation angles of the three-phase DC brushless motor 1 6 and the three-phase DC brushless motor 2 4 according to the control pulse, and then realizes the attitude holding function of the radar through the relative movement between the upper arm 1 and the lower arm 8 and between the lower arm 8 and the pan-tilt box 7.

[0064] like Figure 5 , Figure 6 and Figure 7 As shown, the motor driving circuit includes a driving chip U2, a driving chip U3 and a microcontroller U4.

[0065] The driving chips U2 and U3 are both DRV8313 series chips, which are dedicated driving chips for three-phase brushless DC motor one and three-phase brushless DC motor two respectively; the driving chip U2 is connected to the PD3 pin, PD5 pin, PD6 pin, of the microcontroller U4 through the IN1 pin, IN2 pin and IN3 pin respectively, the CP1 pin of the driving chip U2 is connected to the CP2 pin through the capacitor C1, and the VCP pin is connected to the VM pin through the capacitor C2; the PGND1 pin, PGND2 pin and PGND3 pin are connected to GND; the EN1 pin, EN2 pin and EN3 pin are connected to the V3P3OUT pin, and the V3P3OUT pin is connected to GND through the resistor R5 and the capacitor C7; the RESET pin is connected to the SLEEP pin, and the SIEEP pin is connected to GND through the capacitor C7; the three-phase brushless DC motor is connected to the OUT1 pin, OUT2 pin and OUT3 pin of the driving chip U2 through the socket, and the three-phase brushless DC motor is connected in parallel with three capacitors, namely, capacitor C3, capacitor C4 and capacitor C5.

[0066] The driving chip U3 is connected to the PB1 pin, PB2 pin and PB3 pin of the microcontroller U4 through the IN1 pin, IN2 pin and IN3 pin respectively, the CP1 pin and CP2 pin of the driving chip U3 are connected through the capacitor C9, and the VCP pin and VM pin are connected through the capacitor C11; the PGND1 pin, PGND2 pin and PGND3 pin are connected to GND; the EN1 pin, EN2 pin and EN3 pin are connected to the V3P3OUT pin, and the V3P3OUT pin is connected to GND through the resistor R7 and the capacitor C16; the RESET pin is connected to the SLEEP pin, and the SIEEP pin is connected to GND through the capacitor C16; the three-phase brushless DC motor is connected to the OUT1 pin, OUT2 pin and OUT3 pin of the driving chip U3 through the socket, and the three-phase brushless DC motor is connected in parallel with three capacitors: capacitor C12, capacitor C13 and capacitor C14.

[0067] The peripheral circuit of microcontroller U4 includes an oscillation circuit, a reset circuit, and an ISP module. Microcontroller U4 is an ATMEGA328P-AU series chip. Microcontroller U4 receives the control pulse of processor U1, and then sends a PWM signal to driver chips U2 and U3; driver chips U2 and U3 amplify the pulse signal and transmit it to three-phase DC brushless motor 16 and three-phase DC brushless motor 24. Figure 5 , Figure 6 and Figure 7 In the circuit shown, LED1 is connected to GND through resistor R21 and light-emitting diode D2. The MISO pin of the ISP module is connected to the PB4 pin of chip U4, the SCK pin is connected to the PB5 pin of chip U4, the MOSI pin is connected to the PB5 pin of chip U4, the VCC pin is connected to the V5.0 pin, and the RESET pin is connected to RESET 1.

[0068] The oscillation circuit is connected between the PB6 pin and the PB7 pin of the microcontroller U4. The PB6 pin and the PB7 pin are connected through a crystal oscillator Y2. The crystal oscillator Y2 is connected in parallel with a resistor R20. The crystal oscillator is connected to GND.

[0069] The reset circuit includes capacitor C19 and resistor R15. DTR is connected to the RESET pin through capacitor C19, and the 5.0V terminal voltage is connected to the RESET pin through resistor R15 and RESET 1.

[0070] The serial port download circuit and the communication circuit of the present invention are multiplexed circuits, and the written program is burned into the MCU processing circuit through the USB interface during the debugging of the MCU processing circuit. The program is a posture adjustment program, which mainly plays the role of stabilizing the radar, first obtains the pitch angle of the radar in the current state, analyzes the deviation angle between the pitch angle of 45°, and then adjusts the motor angle through the motor drive circuit to achieve the function of posture stabilization.

[0071] refer to Figure 8 , Fig. 9 and Fig.10 The serial port download circuit includes three standard interfaces USB-Micro, USB-A, and USB-type-c, and a microcontroller U2; the microcontroller U2 model is Atmega16, and the microcontroller U2 is used to receive signals from the processor U1; the three standard interfaces USB-Micro, USB-A, and USB-type-c provide three power interfaces.

[0072] The communication circuit includes a standard interface USB-A and a conversion chip CH340; CH340 is a USB bus conversion chip used to realize the function of USB to serial port; the standard interface USB-A is a data communication interface.

[0073] exist Figure 8 In the circuit shown, the standard interface USB1 is a USB-Micro interface, and its VCC pin is grounded through capacitor C5; the standard interface USB2 is a USB-A interface, and its VCC pin is grounded through capacitor C6; the standard interface USB3 is a USB-type-c interface, and its VCC pin is connected to V5.0 through resistor R5.

[0074] exist Fig. 9In the circuit shown, the microcontroller U2 is an Atmega16U2 series chip, and its peripheral circuits include an oscillation circuit and a voltage stabilizing circuit; the UGND pin and PAD pin of the microcontroller are connected to GND; the 5.0V terminal voltage is connected to the PD5 pin of the microcontroller U2 through a resistor R2 and a light emitting diode D1, and the 5.0V terminal voltage is connected to the PD4 pin of the microcontroller U2 through a resistor R3 and a light emitting diode D2; RESET CMD is connected to pin PC6 through a resistor R4, V5.0 is connected to the RESET pin through a resistor R6, and the UCAP pin is connected to GND through a capacitor C9.

[0075] The oscillation circuit is connected between the XTAL1 pin and the XTAL2 pin, the XTAL1 pin and the XTAL2 pin are connected through the crystal oscillator Y1, the crystal oscillator Y1 is connected in parallel with the resistor R1, and the crystal oscillator is connected to GND; the voltage stabilization circuit includes a chip U1AMS1117, capacitor C1, capacitor C2, capacitor C3, and capacitor C4; one end of capacitor C2 is connected to the 5.0V terminal voltage and connected to the IN pin, and the other end is connected to GND, capacitor C2 is connected in parallel with capacitor C1, one end of capacitor C3 is connected to the OUT pin to output a 3.3V voltage, and one end is connected to GND, capacitor C3 is connected in parallel with capacitor C4, and the ADJ pin is connected to GND; the communication circuit includes a standard interface USB-A and an adapter chip CH340.

[0076] exist Fig.10 In the circuit shown, the peripheral circuit of the adapter chip CH340 includes capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, and crystal oscillator Y1; the V3 pin of the adapter chip CH340 is connected to GND through capacitor C3; the VCC pin is connected to the power supply, and the VCC pin is grounded through capacitor C1; the XI pin and the XO pin are connected through the crystal oscillator Y1, and the crystal oscillator Y1 is connected in parallel with a series circuit of capacitor C4 and capacitor C5, and the crystal oscillator is connected to GND.

[0077] Furthermore, the present invention may also include an indicator light circuit, which is used to display whether the SD card is normally connected to the card slot; the card slot is located below the gimbal main control board, and its slot is flush with the edge of the gimbal main control board; in one embodiment of the present invention, the indicator light circuit is used to indicate whether the SD card is normally connected to the card slot, and when the SD card is normally inserted, the indicator light is green; otherwise, it is red.

[0078] Specific as Fig.11 As shown, the indicator light circuit includes LED-RGB, resistor R16, resistor R17, and resistor R19. Line 1 is connected to the PC23 pin of the processor U1 through resistor R16, line 2 inputs a 5.0V voltage, line 3 is connected to the PC21 pin of the processor U1 through resistor R17, and line 4 is connected to the PC22 pin of the processor U1 through resistor R19.

[0079] The workflow of the present invention is as follows: Fig.12 As shown, according to the present invention, after the MCU processing circuit is powered on, the system is first initialized to put the gimbal box in a 45° depression angle working state; when the gimbal achieves attitude stability, the attitude acquisition module converts the pitch angle of the microwave radar during the flight of the UAV into an electrical signal and sends it to the MCU processing circuit; the MCU processing circuit outputs a correction angle after processing the obtained information and sends an instruction to the motor drive circuit; the two three-phase DC brushless motors in the motor drive circuit adjust the angle, and the gimbal maintains a stable 45° depression angle; but when the main controller determines that there is a slope on the ground through the microwave return time, the main controller will calculate the ground slope, and then the controller controls the motor rotation by outputting a PWM signal, and the UAV gimbal will enter a new self-stabilizing state.

[0080] During the debugging of the MCU processing circuit, the written program is burned into the MCU processing circuit through the USB interface. During the operation of the device, the radar receives the echo signal and transmits the signal wirelessly to the gimbal main control board, and the gimbal transmits the signal to the computer.

[0081] The working principle of the present invention is as follows: Fig.13 As shown, MPU-6050 is used as the feedback element of the angle information of the present invention. By judging the angle information, the main control module controls the three-phase DC brushless motor to drag the pan-tilt box to rotate, and realizes the posture stabilization function. The MPU6050 module is integrated with a digital motion processor (DMP). The original data of the sensor can be directly output as quaternion through DMP, and the Euler angle can be calculated through the rotation matrix transformation of the quaternion. This process can reduce the workload of the processor and avoid cumbersome data fusion, with less calculation amount, and more convenient for intuitive feeling and output control; the finally solved Euler angle communicates data with the processor U1 on the main control board through the IIC mode; the processor U1 sends instructions to the microcontroller U4 according to the information obtained, and the microcontroller U4 sends PWM signals to the drive chips U2 and U3. The drive chips U2 and U3 process the received pulse signals, and the amplified signals drive the three-box DC brushless motor one and the three-box DC brushless motor two to rotate, and control the two brushless DC motors to adjust the angle, thereby realizing the posture holding function of the pan-tilt device, with high control accuracy and stability. When the main controller determines that there is a slope on the ground through the microwave return time, the main controller will first calculate the ground slope angle, and then the controller will output a PWM signal through the motor drive circuit to control the motor rotation. At this time, the drone gimbal will enter a new self-stabilizing state.

[0082] The written program is burned into the MCU processing circuit through the serial port download circuit. During the operation of the device, the microwave radar will wirelessly transmit the received echo signal to the pan-tilt main control board, and the pan-tilt will transmit the signal to the computer, thereby realizing the function of real-time data transmission. The computer can timely analyze the obtained signal and understand the information on the ground and soil.

[0083] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A control system for a pan-tilt device for installing a microwave radar, the pan-tilt device being fixed directly below an unmanned aerial vehicle, comprising an upper arm (4), a lower arm (10), a pan-tilt box (9), a shock absorbing unit, a data transmission unit and a posture adjustment unit, wherein the microwave radar is fixed below the pan-tilt box (9); The shock absorbing unit is connected to the upper arm (4) and the drone chassis mounting frame to achieve a shock absorbing function; The data transmission unit includes a PTZ main control board, which transmits the data collected by the microwave radar to the computer in real time; The attitude adjustment unit comprises a three-phase DC brushless motor 1 (6) and a three-phase DC brushless motor 2 (8); the three-phase DC brushless motor 1 (6) is fixed on the lower arm (10), the rotation axis is in the Y direction, and is connected to the gimbal box (9); the three-phase DC brushless motor 2 (8) is fixed on the bottom end of the upper arm (4), the rotation axis is in the X direction, and is connected to the lower arm (10); through the relative movement between the upper arm (4) and the lower arm (10) and between the lower arm (10) and the gimbal box (9), the microwave radar maintains an incident angle of 45° with the ground during the flight of the unmanned aerial vehicle; It is characterized in that The control system includes a posture acquisition module, a wireless transmission module, a power module and a DC voltage stabilization module; the pan / tilt main control board includes an MCU processing circuit, a motor drive circuit, and a serial port and communication circuit; The attitude acquisition module is used to measure the pitch angle and linear acceleration of the microwave radar; The wireless transmission module is used to transmit the data collected by the microwave radar to the pan-tilt main control board, and the pan-tilt main control board transmits the data to the computer end; The power supply module and the DC voltage stabilization module are used to provide a stable DC voltage for the PTZ main control board; The MCU processing circuit is connected to the posture acquisition module, receives its measurement data, and outputs control pulses; The motor driving circuit is used to control the rotation angle of the pan-tilt device according to the control pulse, complete the horizontal and pitch adjustment of the microwave radar, and realize the radar's attitude holding function; The serial port and communication circuit are used to burn programs and provide a power supply interface; The program includes an attitude adjustment program and a ground slope calculation program; the attitude adjustment program first obtains the pitch angle of the microwave radar in the current state, calculates the deviation angle from the 45° pitch angle, and then adjusts the motor angle through the motor drive circuit to achieve the attitude stabilization function; the ground slope settlement program first determines whether there is a slope on the ground at this time through the time of microwave return, calculates the ground slope at this time through the flight speed of the drone and the time difference of microwave return, compares it with the current gimbal pitch angle, calculates the angle that the gimbal should be adjusted, and realizes the ground slope adaptive adjustment function.

2. The control system for the pan / tilt device for installing microwave radar according to claim 1, characterized in that: The upper arm (4) is in an inverted L-shape, and the horizontal arm at the top is used to connect to the shock absorbing unit. The lower arm (10) is in a horizontally placed L-shape, and the outer side of one arm is connected to the rotating shaft of the three-phase DC brushless motor 2 (8), and the inner side of the other arm fixes the three-phase DC brushless motor 1 (6).

3. The control system for a pan / tilt device for installing a microwave radar according to claim 1 or 2, characterized in that: The shock absorbing unit comprises an upper shock absorbing plate (1), a lower shock absorbing plate (3) and a plurality of shock absorbing columns (2); the plurality of shock absorbing columns (2) are connected between the upper shock absorbing plate (1) and the lower shock absorbing plate (3); the upper shock absorbing plate (1) is fixedly connected to the drone chassis mounting frame; the lower shock absorbing plate (3) is fixedly connected to the upper arm (4); and the upper shock absorbing plate (1) is fixed to the lower shock absorbing plate (3) via four shock absorbing columns (2).

4. The control system for a pan / tilt device for installing a microwave radar according to claim 1, characterized in that: The pan / tilt box (9) is in the shape of a rectangular parallelepiped and is hollow inside. The pan / tilt main control panel is fixed inside the pan / tilt box (9).

5. The control system for the pan-tilt device for installing microwave radar according to claim 1, characterized in that: The posture acquisition module is installed on the pan-tilt main control board, and the motor drive circuit controls the rotation angles of the three-phase DC brushless motor 1 (6) and the three-phase DC brushless motor 2 (8) according to the control pulse, thereby realizing the posture holding function of the pan-tilt device through the relative movement between the upper arm (4) and the lower arm (10) and between the lower arm (10) and the pan-tilt box (9).

6. The control system for a pan / tilt device for installing a microwave radar according to claim 1, characterized in that: The gimbal main control board uses a timer to periodically obtain the pitch angle measured by the attitude acquisition module; when the deviation between the current pitch angle and the set 45° pitch angle exceeds a preset value, the attitude acquisition module converts the pitch angle of the microwave radar during the flight of the unmanned aerial vehicle into an electrical signal and sends it to the MCU processing circuit; the MCU processing circuit sends instructions to the motor drive circuit in the form of control pulses according to the electrical signal; the motor drive circuit sends PWM signals to the drive chips of the three-phase DC brushless motor 1 (6) and the three-phase DC brushless motor 2 (8) to adjust the angle.

7. The control system for the pan-tilt device for installing microwave radar according to claim 1, characterized in that: The serial port download circuit and the communication circuit are multiplexed circuits. During the debugging of the MCU processing circuit, the written program is burned into the MCU processing circuit through the USB interface.

8. The control system for the pan-tilt device for installing microwave radar according to claim 1, characterized in that: The wireless transmission module transmits the data of the microwave radar to the gimbal main control board, which calculates the ground slope through the microwave return time and adjusts the motor angle to keep the microwave radar at a 45° depression angle with the ground. At this time, the gimbal will re-enter a new self-stabilizing state.

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