Position and attitude independent control multi-rotor unmanned aerial vehicle

Abstract

The application discloses a multi-rotor unmanned aerial vehicle with independent position and attitude control, adopts a three-arm coaxial double-propeller layout, is composed of a fuselage and arms, adds a tilting mechanism between each arm and the fuselage, and designs independent position controllers and attitude controllers and corresponding control distributors. The application introduces the tilting mechanism, so that the arm can tilt around its own central axis, thereby enabling the propeller to output force and torque in any direction in the body coordinate system. The application designs independent position controllers and attitude controllers and corresponding control distributors, so that the unmanned aerial vehicle can fly in any direction at any attitude, realizes independent position and attitude control of the unmanned aerial vehicle, and has the characteristics and advantages of simultaneously tracking a given position and attitude relative to a conventional multi-rotor unmanned aerial vehicle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicle, in particular to a multi-rotor unmanned aerial vehicle with independent position and attitude control, which adopts a three-arm coaxial double-paddle layout and is composed of a fuselage and arms, a tilting mechanism is added between each arm and the fuselage, and independent position and attitude controllers and corresponding control distributors are designed, so that the unmanned aerial vehicle can fly in any attitude along any direction, independent position and attitude control is achieved, and compared with conventional multi-rotor unmanned aerial vehicles, the unmanned aerial vehicle can simultaneously track a given position and attitude. BACKGROUND

[0002] Multi-rotor unmanned aerial vehicles are widely used in aerial photography, remote sensing surveying and mapping, low-altitude reconnaissance, post-disaster rescue and other fields due to their simple mechanical structure, easy control and high maneuverability, and have become an important research direction in the field of unmanned aerial vehicles in recent years. With the increasingly wide application range of unmanned aerial vehicles, the performance requirements of unmanned aerial vehicles are also increasingly high. In some specific scenarios, such as dynamic platform landing, the unmanned aerial vehicle needs to simultaneously track a given position and attitude, while conventional multi-rotor unmanned aerial vehicles are underactuated systems and can only generate body longitudinal pull and three-axis attitude torque to drive the six-degree-of-freedom position and attitude movement of the unmanned aerial vehicle, so the position and attitude of the unmanned aerial vehicle cannot be independently controlled, and the unmanned aerial vehicle cannot simultaneously track a given position and attitude, thereby limiting the application range of the unmanned aerial vehicle. SUMMARY

[0003] The present application relates to the technical field of unmanned aerial vehicle, in particular to a multi-rotor unmanned aerial vehicle with independent position and attitude control, which adopts a three-arm coaxial double-paddle layout and is composed of a fuselage and arms, a tilting mechanism is added between each arm and the fuselage, and independent position and attitude controllers and corresponding control distributors are designed, so that the unmanned aerial vehicle can fly in any attitude along any direction, independent position and attitude control is achieved, and compared with conventional multi-rotor unmanned aerial vehicles, the unmanned aerial vehicle can simultaneously track a given position and attitude.

[0004] The technical solution adopted by the present application to solve the above technical problems is: a multi-rotor unmanned aerial vehicle with independent position and attitude control, which adopts a three-arm coaxial double-paddle layout and is composed of a fuselage and arms, a tilting mechanism is added between each arm and the fuselage, and independent position and attitude controllers and corresponding control distributors are designed.

[0005] The tilting mechanism is composed of a base, a steering engine and a coupling, the steering engine is fixedly connected with the body through the base, the output shaft of the steering engine is fixedly connected with the coupling, one end of the arm is fixedly connected with the coupling, the other end is fixedly connected with two motors, and the two propellers are fixed on the two motors respectively.

[0006] The position controller and the attitude controller are independent of each other, the position controller calculates a speed expected value according to the deviation between a position expected value and a position actual value through a position loop control law, the deviation between the speed expected value and a speed actual value is calculated into a tension expected value through a speed loop control law, the attitude controller calculates an angular velocity expected value according to the deviation between an attitude expected value and an attitude actual value through an angle loop control law, and the deviation between the angular velocity expected value and an angular velocity actual value is calculated into a torque expected value through an angular velocity loop control law.

[0007] The three-axis tension expected values of the body under the position controller and the three-axis torque expected values of the body under the attitude controller are obtained through the control distributor to obtain the propeller speed expected value and the arm tilting angle expected value.

[0008] The basic principle of the application is that the steering engine of the tilting mechanism drives the arm to tilt around its own central axis through the coupling, so that the propeller can output force and torque in any direction under the body coordinate system.

[0009] The body coordinate system is established with the gravity center of the unmanned aerial vehicle as the origin, the x-axis points to the front of the unmanned aerial vehicle, the y-axis points to the right of the unmanned aerial vehicle, and the z-axis points to the bottom of the unmanned aerial vehicle.

[0010]

[0011] Where f x ,f y ,f z is the force output by the propeller under the body coordinate system, τ x ,τ y ,τ z is the torque output by the propeller under the body coordinate system, A, B and C represent three arms, is the propeller speed on the arm, the upper and lower propellers of each arm rotate in opposite directions and have the same speed, α A ,α B ,α C is the arm tilting angle, and K is a control efficiency matrix, which is specifically represented as

[0012]

[0013] Where l is the length of the three arms, h is the distance between the intersection of the three arm central axes and the center of gravity of the drone, and the center of gravity is usually located directly below the intersection of the three arm central axes. T It is the proportionality coefficient between the square of the propeller rotational speed and the thrust. The propeller can output force f in three coordinate axes of the machine system. x f y f z and torque τ x τ y τ z This allows the output system to generate forces and torques in any direction, enabling the UAV to fly in any attitude and in any direction, thus achieving independent control of its position and attitude.

[0014] The advantages of this invention compared to existing technologies are as follows: Compared to conventional multi-rotor drones, this invention allows the drone to fly in any attitude and direction, achieving independent control of position and attitude, and simultaneously tracking a given position and attitude. Furthermore, when the arm tilt angle is fixed at 0 degrees, the drone can achieve conventional drone flight using conventional drone control methods. Attached Figure Description

[0015] Figure 1 This is a structural diagram of a multi-rotor unmanned aerial vehicle with independent position and attitude control according to the present invention;

[0016] Figure 2 This is a structural diagram of the tilting mechanism of a multi-rotor UAV with independent position and attitude control according to the present invention;

[0017] Figure 3 This is a block diagram of a control system for a multi-rotor unmanned aerial vehicle with independent position and attitude control according to the present invention. Detailed Implementation

[0018] like Figure 1 The diagram shows the structure of the drone, which adopts a three-arm coaxial dual-propeller layout and consists of a fuselage and arms, with a tilting mechanism added between each arm and the fuselage.

[0019] like Figure 2 The diagram shows the structure of the tilting mechanism. The tilting mechanism consists of a base, a servo motor, and a coupling. The servo motor's output shaft is fixedly connected to the coupling. One end of the arm is fixedly connected to the coupling, and the other end is fixedly connected to two motors (upper and lower). Two propellers are fixed to the two motors respectively. The servo motor drives the arm to tilt around its own central axis via the coupling.

[0020] like Figure 3 The diagram shows the control system block diagram of the UAV. The position controller and attitude controller are independent of each other. The position controller determines the position based on the desired value p. r The deviation from the actual position value p is used to calculate the desired velocity value v using a position loop control law. r, the speed expectation value v r The deviation of the speed expectation value v r from the speed actual value v is calculated by a speed loop control law to obtain the tension expectation value f r The deviation of the attitude expectation value Θ r from the attitude actual value Θ is calculated by an angle loop control law to obtain the angular velocity expectation value ω r The deviation of the angular velocity expectation value ω r from the angular velocity actual value ω is calculated by an angular velocity loop control law to obtain the torque expectation value τ r The tension expectation value f r under the machine body output by the position controller and the torque expectation value τ Ar under the machine body output by the attitude controller are subjected to a control distributor to obtain the propeller rotation speed expectation value and the machine arm tilting angle expectation value α Br , α Cr , α

[0021]

[0022] wherein f xr , f yr , f zr is the tension expectation value under the machine body output by the position controller, τ xr , τ yr , τ zr is the torque expectation value under the machine body output by the attitude controller, A, B, and C represent three machine arms, is the propeller rotation speed expectation value on the machine arm, the upper and lower propeller rotation speed expectation values of each machine arm are the same and opposite in direction, α Ar , α Br , α Cr is the machine arm tilting angle expectation value, K -1 is the control distribution matrix, which is obtained by inverting the control efficiency matrix K, and the control efficiency matrix K is specifically represented as

[0023]

[0024] wherein l is the machine arm length, h is the distance between the intersection point of the central axes of the three machine arms and the gravity center of the unmanned aerial vehicle, the gravity center is usually located directly below the intersection point of the central axes of the three machine arms, c T is the proportional coefficient between the square of the propeller rotation speed and the tension.

[0025] The propeller rotation speed expectation value and the machine arm tilting angle expectation value α Ar , α Br , α Cr can be further solved,

[0026]

[0027] The solved propeller speed expectation value is realized by the motor driving the propeller rotation, the arm tilt angle expectation value is realized by the tilt mechanism driving the arm tilting around its own central axis, and finally the independent control of the UAV position and attitude is realized.

[0028] In addition, when the arm tilt angle is fixed at 0 degrees, the UAV can adopt the control method of the conventional UAV to realize the flight of the conventional UAV.

Claims

1. A position and attitude independent control multi-copter drone, characterized by: The unmanned aerial vehicle adopts a three-arm coaxial double-propeller layout, is composed of a fuselage (1) and arms (2), a tilting mechanism is added between each arm (2) and the fuselage (1), independent position controllers and attitude controllers are designed, and corresponding control distributors (10) are designed; The tilting mechanism is composed of a base (3), a steering engine (4) and a coupling (5); the steering engine (4) is fixedly connected with the fuselage (1) through the base (3), the output shaft of the steering engine (4) is fixedly connected with the coupling (5), one end of the arm (2) is fixedly connected with the coupling (5), and the other end is fixedly connected with two upper and lower motors (6) and (7); two propellers (8) and (9) are respectively fixed on the two motors (6) and (7); the steering engine (4) drives the arm (2) to tilt around the central axis thereof through the coupling (5), so that the propellers (8) and (9) can output force and torque in any direction in the body coordinate system, and the expression is as follows, where f x ,f y ,f z is the force of the propeller output under the machine system, τ x ,τ y ,τ z is the torque of the propeller output under the machine system, A, B, C represents three machine arms, is the propeller rotating speed on the machine arm, the upper and lower two blades of each machine arm are opposite in direction and the same in rotating speed, α A ,α B ,α C is the machine arm tilt angle, and K is a control efficiency matrix, which is specifically represented as where l is the length of the arm, h is the distance between the intersection of the three arm center axes and the center of gravity of the drone, which is usually located directly below the intersection of the three arm center axes, c T is the proportionality coefficient between the square of the propeller rotation speed and the pulling force; The three-axis tension expected value in the body coordinate system output by the position controller and the three-axis torque expected value in the body coordinate system output by the attitude controller are obtained through the control distributor (10) to obtain the propeller speed expected value and the arm tilting angle expected value; the expression is as follows, where f xr ,f yr ,f zr is the desired value of the pull force in the body frame of the position controller, τ xr ,τ yr ,τ zr is the desired value of the moment in the body frame of the attitude controller, is the desired value of the propeller speed on the arms, the upper and lower propeller speed of each arm are the same, but the direction is opposite, α Ar ,α Br ,α Cr is the desired value of the tilt angle of the arms, K -1 is the control allocation matrix, which is obtained by inverting the control effectiveness matrix K; further, the desired values of the propeller speed ω and the tilt angle of the arms α Ar ,α Br ,α Cr , 2. The position and attitude independent control multi-rotor unmanned aerial vehicle according to claim 1, characterized in that: The position controller and the attitude controller are independent of each other; the position controller calculates a speed expected value according to the deviation between a position expected value and an actual position value through a position loop control law, calculates a tension expected value according to the deviation between the speed expected value and an actual speed value through a speed loop control law, the attitude controller calculates an angular velocity expected value according to the deviation between an attitude expected value and an actual attitude value through an angle loop control law, and calculates a torque expected value according to the deviation between the angular velocity expected value and an actual angular velocity value through an angular velocity loop control law.

3. The position and attitude independent control multi-rotor unmanned aerial vehicle according to claim 1, wherein: When the arm tilting angle of the multi-rotor unmanned aerial vehicle is fixed at 0 degrees, the unmanned aerial vehicle can adopt the control method of a conventional unmanned aerial vehicle to realize the flight of the conventional unmanned aerial vehicle.

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