CN102426458A - Ground control system applicable to rotor-wing unmanned aerial vehicle - Google Patents

Abstract

The invention discloses a ground control system suitable for a rotor drone. The ground control system comprises a PC (4), a real-time attitude controller (2), an SPI communication collector (3) and a driver (1). On the one hand, the driver (1) receives the motion command Din output by the real-time attitude controller (2), and on the other hand, according to the motion command Din, respectively outputs the motor control signal D2 to drive the motor (12) to move, and the A-th servo signal DA to drive A steering gear (13) moves, B steering gear signal DB drives B steering gear (14) moves, C steering gear signal DC drives C steering gear (15) moves, D steering gear signal DD drives D rudder The machine (16) moves; the SPI communication collector (3) collects the parameter information D1 measured by the inertial measurement unit (11) on the rotor UAV on the one hand, and outputs the linear acceleration signals of the three degrees of freedom of the rotor UAV on the other hand α and angular velocity signal ω are sent to the real-time attitude controller (2); the PC (4) communicates with the real-time attitude controller (2) through the TCP/IP protocol, providing a friendly man-machine interface for the operator.

Description

A Ground Control System for Rotary Wing Unmanned Aerial Vehicles

technical field

The invention relates to a ground control system suitable for a rotary-wing unmanned aerial vehicle. The ground control system is connected with an actuator and a sensor on the rotary-wing unmanned aerial vehicle in a wired manner.

Background technique

Rotor UAV has the characteristics of flexible use, low cost, and zero casualties, and has been widely used in both modern military and civilian applications. Rotary-wing UAVs have special functions of vertical take-off and landing and hovering, but compared with fixed-wing UAVs, their stability and wind resistance are weaker, and autonomous control is more complicated. At present, there are three main ground control methods for rotor UAVs: manual remote control, autonomous/semi-autonomous control, and a combination of over-the-horizon remote control and autonomous control.

The autonomous/semi-autonomous type is used for rotor UAVs operating outside the line of sight (long distance) under the supervision of ground flight controllers. The machine control system is demanding and difficult.

The general method for designing a ground control system for a rotor UAV is as follows: first, establish a dynamic model of a small rotor UAV based on the Newtonian mechanics model, then design a flight attitude controller for the rotor UAV based on this model, and finally based on a certain flight The state is introduced into the corresponding control algorithm. However, due to the structural characteristics of the rotor UAV itself, such as small size, high self-coupling, strong nonlinearity, etc., it is difficult to determine the dynamic model of the small rotor UAV, which leads to the control parameters of the rotor UAV. Uncertainty.

Contents of the invention

The purpose of the present invention is to provide a ground control system for a miniature rotor drone with an unconventional layout. The ground control system realizes power supply to the rotor drone, collection of attitude data, control signals and feedback by means of wires transmission of signals. The ground control system designed by the present invention saves the complicated steps of establishing the dynamic model of the small rotor UAV, and realizes data reception, attitude calculation, filtering, and PID control through the real-time attitude controller without establishing the UAV model , and can be debugged online and obtain ideal PID control parameters, successfully enabling the rotor UAV to achieve the hovering task.

The first aspect of the ground control system of the present invention receives the three-axis acceleration information α _X , α _Y , α _Z and the angular velocity information ω _X , ω _Y , ω _Z output by the IMU (inertial measurement unit) in the rotor drone; the second On the one hand, carry out power control to the motor 12 in the miniature rotor drone by real-time attitude controller 2; In the third aspect, a plurality of steering gears (A steering gear 13, B steering gear 13, B steering gear) in the miniature rotor drone are controlled by real-time attitude controller 2. Machine 14, C steering gear 15, D steering gear 16) are controlled, thereby realize under the situation of not setting up UAV model, successfully make rotor UAV realize hovering task. A steering gear 13 cooperates with C steering gear 15 to realize the pitching motion of the miniature rotor drone; B steering gear 14 and D steering gear 16 cooperate to realize the rolling motion of the miniature rotor drone; A steering gear 13, B steering gear 14 , C steering gear 15 and D steering gear 16 cooperate to realize the yaw motion of the miniature rotor UAV.

The present invention is used for the advantage of the ground control system of miniature rotor unmanned aerial vehicle:

① The power supply excitation and receiving control signals are interacted through wired methods, which avoids the unreliability of wireless transmission.

②The combination of PC, control chip and processor chip can realize a ground control system of a micro-rotor UAV with an unconventional layout at low cost.

③ Eliminate high-frequency vibration through the Butterworth filter, reducing the interference of the strong vibration caused by the motor rotation on the control system

④ On-line debugging of the control parameters of the PID controller shortens the debugging cycle and improves the debugging efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the signal control of the ground control system of the present invention applicable to the rotor UAV.

Fig. 2 is a structural block diagram of the real-time attitude controller part of the present invention.

Fig. 2A is a signal flow chart of the PID controller in the real-time attitude controller of the present invention.

Fig. 3 is a schematic diagram of the interface of the PC in the ground control system of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Referring to FIG. 1 , a ground control system applicable to a rotor UAV of the present invention includes a PC 4 , a real-time attitude controller 2 , an SPI communication collector 3 and a driver 1 . On the one hand, the driver 1 receives the motion command Din output by the real-time attitude controller 2, and on the other hand, according to the motion command Din, respectively outputs the motor control signal D2 to drive the motor 12 to move, the A-th steering gear signal DA to drive the A steering gear 13 to move, The B steering gear signal DB drives the B steering gear 14 to move, the C steering gear signal DC drives the C steering gear 15 to move, and the D steering gear signal DD drives the D steering gear 16 to move; the SPI communication collector 3 collects on the one hand The parameter information D1 measured by the inertial measurement unit (IMU) 11 on the rotor UAV, on the other hand, outputs the linear acceleration signal α(α _X , α _Y , α _Z ) of the three degrees of freedom (three axes) of the rotor UAV. ) and angular velocity signals ω (ω _X , ω _Y , ω _Z ) to the real-time attitude controller 2; the PC 4 communicates with the real-time attitude controller 2 through the TCP/IP protocol, providing a friendly man-machine interface for the operator.

The ground control system of the present invention is respectively connected with the IMU (inertial measurement unit), motor 12, A steering gear 13, B steering gear 14, C steering gear 15 and D steering gear 16 on the rotor UAV in a wired manner. The power supply for the rotor drone is also wired. The wired connection between the ground control system and the rotor UAV can avoid the unreliability of wireless transmission and improve the reliability and stability of the ground control system.

In the present invention, the first aspect of the ground control system receives the three-axis acceleration information α _X , α _Y , α _Z and the angular velocity information ω _X , ω _Y , x _Z output by the IMU (inertial measurement unit) in the rotor drone; The second aspect carries out power control to the motor 12 in the miniature rotor unmanned aerial vehicle by real-time attitude controller 2; In the third aspect, a plurality of steering gears (A steering gear 13, A steering gear 13, B steering gear 14, C steering gear 15, D steering gear 16) are controlled, thereby realize under the situation of not setting up UAV model, successfully make rotor UAV realize hovering task. α _X represents the X-axis acceleration information output by the inertial measurement unit, α _Y represents the Y-axis acceleration information output by the inertial measurement unit, α _Z represents the Z-axis acceleration information output by the inertial measurement unit, and ω _X represents the X-axis angular velocity output by the inertial measurement unit information, ω _Y represents the Y-axis angular velocity information output by the inertial measurement unit, and ω _Z represents the Z-axis angular velocity information output by the inertial measurement unit.

In the present invention, the ground control system makes the attitude realized by the micro-rotor UAV include pitching motion, rolling motion, etc. Turning motion and yaw motion, that is, A steering gear 13 and C steering gear 15 cooperate to realize the pitching motion of the micro-rotor UAV; B steering gear 14 and D steering gear 16 cooperate to realize the rolling motion of the micro-rotor UAV; The steering gear 13, the B steering gear 14, the C steering gear 15 and the D steering gear 16 cooperate to realize the yaw motion of the miniature rotor UAV.

The ground control system designed by the present invention is except the PC machine 4, and the real-time controller 2 selects the model of Freescale to be the MPC8270 real-time control chip. The information collection and driving of the rotor UAV is realized in an FPGA processor, and the FPGA processor uses the XC5VLX50T chip of Xilinx.

The functions realized by each module in the ground control system of the present invention will be described in detail below:

(1) PC

In the present invention, the PC 4 communicates with the real-time attitude controller 2 through the TCP/IP protocol, providing a friendly man-machine interface for the operator (see FIG. 3). The operator adjusts the control parameters of the rotor drone through the man-machine interface, and displays the flying attitude of the rotor drone in real time.

Interface description in Figure 3: roll attitude (Td) respectively represents the PID control parameters of the roll angle part of the PID attitude loop; pitch attitude (Kp), pitch attitude (Ti), and pitch attitude (Td) respectively represent the pitch angle of the PID attitude loop Part of the PID control parameters; roll velocity (Kp), roll velocity (Ti), and roll velocity (Td) represent the PID control parameters of the roll angular velocity part of the attitude velocity loop respectively; pitch velocity (Kp), pitch velocity (Ti ), pitch velocity (Td) represent the PID control parameters of the pitch rate of the attitude velocity loop; yaw_attitude velocity (Kp), yaw_attitude velocity (Ti), yaw_attitude velocity (Td) respectively represent the The PID control parameters of the yaw rate. Output(X) represents the control quantity output by the pitch loop PID control module, Output(Y) represents the control quantity output by the roll loop PID control module, and Output(Z) represents the control quantity output by the yaw loop PID control module. δp(X) represents the duty cycle of the PWM wave controlling the deflection of the steering gear A and C (roll angle); δq(Y) represents the duty cycle of the PWM wave controlling the deflection of the steering gear B and D (pitch angle); δr(Z) controls the duty cycle of the PWM wave deflected by A steering gear, B steering gear, C steering gear, and D steering gear (yaw angle). Indicates that Gravity+Drag(gf) indicates the duty cycle of the PWM wave driving the UAV motor. Boolean represents the switching between manual operation and automatic operation. Click the Stop button to stop the program.

A PC is a modern intelligent electronic device that can automatically and quickly perform a large number of numerical calculations and various information processing according to pre-stored programs. The minimum configuration is CPU 2GHz, memory 2GB, hard disk 20GB; the installation operating system is windows 2000/2003/XP; and Labview 2010 software is installed.

(2) Real-time attitude controller

Referring to FIG. 2 , the real-time attitude controller 2 is divided into a calibration module 21 , a Butterworth filter module 22 , an attitude calculation module 25 , a PID controller 23 and a data acquisition engine module 24 according to the realized functions.

(1) Calibration module 21

In the present invention, the calibration module 21 converts the information collected by the IMU on the rotor drone into readable and processable acceleration information and angular velocity information by collecting, reorganizing, and adjusting the data information at the FPGA end.

Since the information collected from the IMU (inertial measurement unit) 11 in the rotor drone is read out in the form of a data packet D1, the data packet D1 contains acceleration information and angular velocity information.

In the present invention, the acceleration information output by the X-axis, Y-axis and Z-axis of the IMU is respectively denoted as α _X , α _Y , α _Z ; the angular velocity information output by the X-axis, Y-axis and Z-axis of the IMU is respectively denoted as ω _X , ω _Y , ω _Z . The initial acceleration information and angular velocity information generated by the IMU are expressed in the form of 14-bit two’s complement, so the calibration module first converts the two’s complement data into decimal, and then multiplies the calibration coefficient to obtain the actual acceleration information and angular velocity information. For example: if the output of the accelerometer is 00 0000 0000 0001, then converted to decimal is 1, then the acceleration is 1×2.522mg (calibration coefficient) = 0.002522g, if the output of the accelerometer is 11 11111111 1111, then converted to decimal is -1, the acceleration is (-1)×2.522mg＝0.002522g; if the output of the gyroscope is 00 0000 0000 0001, then converted to decimal is 1, then the output of the gyroscope is 1×0.07306°/s＝0.07306° /s, if the output of the gyroscope is 11 1111 1111 1111, then converted to decimal is -1, then the output of the gyroscope is (-1)×0.07306°/s (calibration coefficient)=-0.07306°/s.

(2) Butterworth filter module 22

In the present invention, the Butterworth filter module 22 filters out the burrs and high-frequency jitter of the collected data through the Butterworth filter in the Labview signal processing development kit.

In the present invention, since the motor 12 in the rotor drone rotates violently, the noise of the data is very large, so a filter needs to be added to eliminate the high-frequency noise. There is a ready-made Butterworth filter in the Labview software development kit. You only need to pass the collected and calibrated acceleration and angular velocity information through this filter, and you can eliminate unnecessary high-frequency noise by setting a high cut-off frequency.

(3) Attitude calculation module 25

In the present invention, the attitude calculation module 25 calculates the roll angle θ, pitch angle φ, roll velocity ω _X , pitch angular velocity ω _Y , and yaw angular velocity ω _Z of the drone according to the acceleration information and angular velocity information generated by the IMU.

同理可得 $1\begin{array}{c}{f}_y=-g_y=-g\cos \mathrm{\θ}\sin \mathrm{\φ}\\ f_z=-g_z=-g\cos \mathrm{\θ}\cos \mathrm{\φ}\end{array}\⇒\mathrm{\φ}{\text{=tan}}^{-1}\frac{f_y}{f_z}.$ The premise of the design of the ground control system of the present invention is that all state quantities are accurately read with a sufficiently high frequency, and become the feedback signals of the ground control system. The accelerometer of the IMU is used to give the specific force of the rotor UAV on a certain axis in the body coordinate system as f=ag, where a represents the actual acceleration, and g represents the gravitational acceleration on the X axis; If there is no disturbance in the X-axis direction of the body coordinate system, and the rotor UAV is basically in a balanced state, the value of the actual acceleration a _x on the X-axis can be ignored: then

Empathy $1\begin{array}{c}{f}_{\mathrm{the\; y}}=-g_{\mathrm{the\; y}}=-g\cos \mathrm{\θ}\sin \mathrm{\φ}\\ f_z=-g_z=-g\cos \mathrm{\θ}\cos \mathrm{\φ}\end{array}\⇒\mathrm{\φ}{\text{=tan}}^{-1}\frac{f_{\mathrm{the\; y}}}{f_z}.$

(4) PID control module 23

Referring to shown in Fig. 2A, in the present invention, PID control module 23 according to the roll angle θ of the unmanned rotor aircraft of solution, pitch angle phi, roll angular velocity ω _X , pitch angular velocity ω _Y , yaw angular velocity ω _Z , output The control information of the servo to control the hovering of the drone.

For the micro-rotor UAV with a single rotor + aerodynamic surface structure, because it is a new type of aircraft with an unconventional layout, for this new controlled object at home and abroad, practical and effective PID is often used in the initial stage of scientific research. Therefore, also in order to design a controller that is simple, intuitive and convenient for debugging, the present invention selects an error-based PID controller. PID is a linear controller, which constitutes deviation control according to the deviation error(t) between the given value and the actual output value, and its control law is: $u\left(t\right)=k_p[\mathrm{error}\left(t\right)+\frac{1}{T_I}{\∫}_0^t\mathrm{error}\left(t\right)\mathrm{dt}+\frac{T_{\mathrm{D.}}\mathrm{error}\left(t\right)}{\mathrm{dt}}],$ Among them, u(t) represents the control quantity output by the PID control module, k _p represents the proportional gain of the PID control module, error(t) represents the deviation between the given value and the actual output value, T _I represents the integral time constant, and T _D represents Derivative time constant, t represents the sampling time.

The speed of the rotorcraft is mainly caused by the change of attitude, so a classic loop control system is designed, the inner loop is the attitude angle rate control loop, and the outer loop is the attitude angle control loop.

When collecting information, the IMU measures the angular velocity and acceleration of the rotor UAV in the body coordinate system, and generates a control system feedback signal; the controller 2 receives the feedback signal from the IMU and calculates and processes the corresponding steering gear and motor control quantities; The output of the control amount given by the driver 1 of a steering gear and a motor is used to stabilize the flight attitude of the rotor drone.

In Fig. 2A, φ _c represents the set pitch angle (in the hovering state, φ _c =0); θ _c represents the set roll angle (in the hovering state, θ _c =0); δ _r represents the set deflection angle Pitch angular velocity (in the hovering state, δ _r =0); δ _p represents the set roll angular velocity; δ _q represents the set pitch angular velocity.

(5) Data acquisition engine module 24

The data acquisition engine module 24 reads out all the sensors of the IMU collected through the first-in-first-out queue FIFO.

In the present invention, the real-time controller 2 selects the model of Freescale as MPC8270 real-time control chip.

(3) SPI communication collector

In the present invention, the SPI communication collector 3 performs data and command interaction with the inertial measurement unit (IMU) on the rotor drone through the SPI interface, and is used to collect the linear acceleration signals and the linear acceleration signals of three degrees of freedom on the rotor drone induced by the IMU. angular velocity signal.

Read and write operations of the SPI interface: The SPI interface used by ADIS16350 (IMU) is a 4-wire system: chip select line (CS), clock line (SCLK), data input line (DIN), and data output line (DOUT). The chip select line is used to enable the SPI interface to enable normal communication. When it is high, the output signal line is always in a high-impedance state without being affected by the clock line and the data input line. It takes 16 clock cycles to transmit a complete data frame. Since the SPI interface is a full-duplex mode, it can both receive and send during a frame of data transmission. In this way, the read operation of the next frame of data can be set in the current frame of data, and the register read by the previous frame of read operation can be received at the same time.

The 16-bit data format when reading the register content is as follows: the first bit is 0 (used to distinguish from the write register), the second bit is 0, the third to ninth bits are the address of the target register, and the last eight bits have no effect on the data of this frame. Since the 16 bits of each register are composed of two independent 8 bits, and the address of each 8 bits is different, so when reading the contents of the register, the address of the third to ninth target register can be high 8 The bit address can also be the lower 8-bit address, and the effects of the two operations are exactly the same. The 16-bit content of the target register to be read this time can be obtained in the next frame data after the data transmission of this frame is completed. In this way, after each read operation is completed, the desired content cannot be obtained until the next data frame operation. Therefore, a single read process requires two data frames, but if it is a continuous read operation, only one additional frame is required. data frame. For example, to read n pieces of data, only n+1 read operations are required.

Access data output registers: ADIS16350 (IMU) output register list is as follows:

In the present invention, the program of the SPI communication collector 3 first adopts Labview 2010 programming to obtain, and then converts into a data stream file and burns it in the FPGA chip through a compiler.

(4) Driver 1

In the present invention, the driver 1 uses software programming to realize the generation of PWM waves with arbitrary duty ratios on the FPGA chip, and then drives the deflection of one motor and four steering gears of the micro-rotor drone.

In the present invention, the SPI communication collector 3 and the driver 1 are selected and obtained by using Labview 2010 programming in the same FPGA chip. The FPGA chip uses Xilinx's XC5VLX50T chip.

Claims (4)

1. A ground control system applicable to rotor drones, characterized in that: the ground control system comprises a PC (4), a real-time attitude controller (2), an SPI communication collector (3) and a driver (1) ; On the one hand, the driver (1) receives the motion command Din output by the real-time attitude controller (2), and on the other hand, according to the motion command Din, respectively outputs the motor control signal D2 to drive the motor (12) to move, and the A-th servo signal DA to drive A steering gear (13) moves, B steering gear signal DB drives B steering gear (14) moves, C steering gear signal DC drives C steering gear (15) moves, D steering gear signal DD drives D rudder Machine (16) motion; On the one hand, the SPI communication collector (3) collects the parameter information D1 measured by the inertial measurement unit (11) on the rotor drone, and on the other hand outputs the linear acceleration signal α and angular velocity signal ω of the three degrees of freedom of the rotor drone to Real-time attitude controller (2); The PC (4) communicates with the real-time attitude controller (2) through the TCP/IP protocol, providing a friendly man-machine interface for the operator. 2. the ground control system that is applicable to rotor UAV according to claim 1, is characterized in that: described real-time attitude controller (2) comprises calibration module (21), Butterworth filter module (22), Attitude calculation module (25), PID controller (23) and data acquisition engine module (24); The calibration module (21) converts the collected IMU information into readable and processable acceleration information and angular velocity information by collecting, reorganizing, and adjusting the data information at the FPGA end. The Butterworth filter module (22) filters out the burrs and high-frequency jitter of the collected data through the Butterworth filter in the Labview signal processing development kit. The attitude calculation module (25) calculates the roll angle θ of the drone according to the acceleration information and the angular velocity information generated by the IMU, the pitch angle φ, the roll velocity ω _X , the pitch angular velocity ω _Y , and the yaw angular velocity ω _Z . The PID control module (23) outputs the control information of the steering gear to control the unmanned vehicle according to the calculated roll angle θ of the rotor drone, the pitch angle φ, the roll angular velocity ω _X , the pitch angular velocity ω _Y , and the yaw angular velocity ω _Z . machine hovering. The data acquisition engine module (24) reads out all the sensors of the collected IMU through the first-in-first-out queue FIFO. 3. the ground control system applicable to rotor drones according to claim 1, characterized in that: the read and write operation of the SPI interface in the described SPI communication collector (3) is a 4-wire system with the SPI interface that ADIS16350 uses : Chip select line (CS), clock line (SCLK), data input line (DIN), data output line (DOUT). 4. the ground control system that is applicable to rotor UAV according to claim 1, is characterized in that: described driver (1) adopts the mode of software programming, realizes the generation of arbitrary duty ratio PWM wave on FPGA chip, Then drive the deflection of one motor and four steering gears of the micro-rotor UAV.

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