Rocket crossing machine with automatic adjustment of full rudder surface and control method thereof

Abstract

The application provides a rocket crossing machine with automatic adjustment of full rudder surfaces and a control method thereof. The rocket crossing machine is in a four-rotor configuration, comprising a columnar machine body, four machine arms arranged in a cross shape, four rotor power units, four full-actuated rudder surfaces, four rudder machines, an inertial measurement unit and a flight control computer. Each machine arm serves as a rudder shaft of a corresponding full-actuated rudder surface, and the four full-actuated rudder surfaces are one-to-one corresponding and installed on the four machine arms and located in the rotor slipstream influence area. Each rotor power unit is fixedly connected with a corresponding full-actuated rudder surface and synchronously deflects with the full-actuated rudder surface around the machine arm. The airfoil of each full-actuated rudder surface is a symmetrical airfoil. The flight control computer calculates the real-time attitude of the machine body according to the inertial measurement unit data. The application takes into account the hovering and forward flight working conditions, significantly improves the flight stability and aerodynamic efficiency of the rocket crossing machine, and has simple structure, fast response and high control precision.

Description

Technical Field

[0001] This invention belongs to the field of aircraft control technology, and in particular relates to a rocket racing drone with automatic adjustment of all control surfaces and its control method. Background Technology

[0002] Racing drones (also known as FPV racing drones) are small unmanned aerial vehicles (UAVs) controlled from a first-person perspective, characterized by high speed and high maneuverability. Their mainstream configuration is a quadcopter layout, where lift and attitude control are achieved through the different rotational speeds of the four rotors. In recent years, a type of racing drone with a rocket-like shape (hereinafter referred to as "rocket racing drone") has gradually emerged. Its fuselage is cylindrical and rocket-shaped, and it is parked in a vertical or near-vertical posture with the nose pointing upwards. It boasts strong visual impact and a small takeoff and landing footprint, showing promise for applications in racing performances and low-altitude reconnaissance.

[0003] Existing rocket racing drones are essentially quadcopter drones, with their attitude control relying entirely on the rotational speed adjustment of their four rotors. However, relying solely on rotor speed for attitude control has inherent limitations: firstly, the rotor attitude control torque and lift are coupled, requiring the sacrifice of some lift for large attitude corrections, making it difficult to balance maneuverability and stability; secondly, in high-speed forward flight conditions, the fuselage is susceptible to additional aerodynamic torques due to asymmetric aerodynamic flow, and adjusting rotor speed alone would significantly increase energy consumption and reduce aerodynamic efficiency, and rotor speed adjustment has response bandwidth and saturation limitations. Therefore, existing rocket racing drones still have considerable room for improvement in flight stability, aerodynamic efficiency, and maneuverability.

[0004] In existing technologies, there are schemes for attitude control using aerodynamic control surfaces on aircraft. For example, Chinese Patent CN204452929U discloses a tilt-fuselage hybrid multi-mode aircraft with control surfaces, which has four sets of rotors and control surfaces mounted on two fixed wings. Pitch, roll, and yaw control are achieved by controlling the rotation of the control surfaces via servos. However, in this scheme, the control surfaces are mounted on fixed wings, and the installation positions of the fuselage, motors, and propellers are relatively fixed. There is no linkage between the control surfaces and rotors, and it is designed for tilt-fuselage hybrid multi-mode aircraft, not quadcopter racing drones.

[0005] For example, Chinese patent CN110104177B discloses an all-moving control surface for a flapping rotor aircraft, which achieves forward flight, side flight, and turning control of the flapping rotor aircraft through large control surfaces, small control surfaces, and servo motors. However, in this solution, the control surfaces are mounted on the flapping rotor aircraft through independent control arms, resulting in a complex structure, and it does not involve the linkage and coordination between the control surfaces and the rotor.

[0006] For example, Chinese patent CN119611832B discloses a fully driven coaxial rotor UAV based on control surface, which achieves full drive control through two coaxial power units in conjunction with control surfaces. However, this solution is designed for a coaxial rotor configuration, where the movement between the control surfaces and the rotor is independent, and the control axis and the arm are not integrated.

[0007] In summary, none of the existing technologies address how to achieve integrated control arm and control shaft when introducing aerodynamic control surfaces into a quadcopter flight configuration, how to achieve a linkage mechanism for the rotor power unit to deflect synchronously with the control surfaces, and how to achieve active trim of the entire aircraft under the premise that control surface angle control and rotor speed control are independent of each other.

[0008] Therefore, how to provide a technical solution that can automatically adjust all-moving control surfaces on a quadcopter rocket racing drone, make the arms also serve as control axes, make the rotor deflect synchronously with the control surfaces, make the control surfaces and rotor work together in a coordinated manner, and make the control surface angle control and rotor speed control independent of each other, while maintaining the overall aircraft balance, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0009] Objective: To address the problem in existing quadcopter rocket racing drones that rely solely on rotor speed for attitude control, resulting in a trade-off between stability and aerodynamic efficiency, this invention provides a rocket racing drone with automatically adjustable control surfaces and its control method. This invention features four fully movable control surfaces on the four cross-shaped arms of the quadcopter rocket racing drone. Each arm also serves as the control shaft for the corresponding fully movable control surface, achieving integrated control of the arm and control shaft. The rotor power unit is fixedly connected to the fully movable control surfaces and deflects synchronously around the arm with the control surfaces. The four fully movable control surfaces are located within the slipstream influence zone of their respective rotors, employing the NACA0012 airfoil, with a deflection angle limited to ±15°. The inertial measurement unit and the flight control computer form a closed loop. The flight control computer independently controls the rotor speed and control surface deflection angle through independent speed control channels and control surface control channels. The rotor and control surface work together in a coordinated manner, but the two control channels are independent of each other, so that the net external force and net external torque on the fuselage tend to be balanced at the same time, thereby improving flight stability and aerodynamic efficiency while maintaining overall aircraft trim.

[0010] The rocket racing drone includes a cylindrical fuselage, four arms, four fully movable control surfaces, four rotor power units, four control surface drive mechanisms, an inertial measurement unit, and a flight control computer.

[0011] The four arms are symmetrically mounted in a cross shape on the columnar fuselage, and each arm also serves as the rudder shaft (rotation shaft) of the corresponding all-moving rudder surface.

[0012] The four fully movable control surfaces are installed on the four arms in a one-to-one correspondence. Each fully movable control surface can deflect independently around the corresponding arm. The airfoil of each fully movable control surface is a symmetrical airfoil (such as the NACA0012 airfoil), and the deflection angle of each fully movable control surface relative to the neutral position does not exceed ±15°.

[0013] The four rotor power units are respectively installed at the ends of the four arms. Each rotor power unit includes a brushless motor and a rotor driven by the brushless motor. The four rotor power units together provide the lift and basic attitude control torque required for the rocket racing machine to fly.

[0014] Each rotor power unit is rigidly fixed to its corresponding all-moving control surface. When the all-moving control surface deflects around the arm, the rotor power unit deflects synchronously with the all-moving control surface.

[0015] The four control surface drive mechanisms are connected to the four all-moving control surfaces in a one-to-one correspondence, and are used to drive the corresponding all-moving control surfaces and rotor power units to deflect synchronously around the arm.

[0016] The inertial measurement unit is installed inside the cylindrical fuselage and is used to measure the triaxial angular velocity and triaxial acceleration of the cylindrical fuselage in real time.

[0017] The flight control computer is housed inside the cylindrical fuselage and is electrically connected to the inertial measurement unit, the brushless motors of the four rotor power units, and the four control surface drive mechanisms.

[0018] The flight control computer is used to calculate the real-time attitude of the cylindrical fuselage based on the three-axis angular velocity and three-axis acceleration. Based on the deviation between the real-time attitude and the desired attitude, it independently generates speed commands for the four brushless motors through the speed control channel and independently generates deflection commands for the four all-moving control surfaces through the rudder angle control channel.

[0019] The rotor of the rotor power unit works in conjunction with the corresponding all-moving control surface, and the speed control channel and the control angle control channel are independent of each other.

[0020] The flight control computer coordinates the rotational speed of the four rotor power units and the deflection angle of the four all-moving control surfaces to simultaneously balance the net external force and net external torque on the cylindrical fuselage, thereby achieving stable flight of the rocket racing drone while maintaining overall aircraft trim.

[0021] The four all-moving control surfaces are respectively installed on the four arms of the aircraft and located within the downwash slipstream influence zone of the corresponding rotor power unit. This allows each all-moving control surface to obtain effective aerodynamic force by utilizing the downwash slipstream generated by the corresponding rotor in hovering and low-speed states, and to generate aerodynamic force by utilizing the incoming flow in forward high-speed states.

[0022] The four control surface drive mechanisms are driven by servo motors, rocker arms, or direct drive motors.

[0023] The servo motor is fixedly connected to a connecting rod at one end of the rocker arm, and the other end of the rocker arm is hinged to the rudder shaft. The servo motor drives the rocker arm to rotate, and the rocker arm drives the rudder shaft to rotate.

[0024] The direct drive motor's output shaft is fixedly connected to the rudder shaft, directly driving the rudder shaft to rotate.

[0025] The four control surface drive mechanisms are connected to the control shafts of the corresponding fully moving control surfaces via output shafts, forming a closed-loop position servo control.

[0026] The inertial measurement unit includes a three-axis MEMS gyroscope and a three-axis MEMS accelerometer; the flight control computer uses a complementary filtering algorithm or an extended Kalman filtering algorithm to fuse the three-axis angular velocity and three-axis acceleration to obtain the pitch angle, roll angle and yaw angle of the cylindrical fuselage.

[0027] The flight control computer includes a cascaded PID controller and a control distributor;

[0028] The cascaded PID controller calculates the three-axis control torque based on the deviations between the pitch angle, roll angle, and yaw angle and the desired attitude.

[0029] The control distributor distributes the three-axis control torque into independent rotor speed distribution and control surface angle distribution. The rotor speed distribution is output as speed commands for four brushless motors via the speed control channel, and the control surface angle distribution is output as deflection angle commands for four all-moving control surfaces via the control angle control channel.

[0030] The control distributor limits the distribution of control surface angles to ensure that the absolute value of the deflection angle command for each all-moving control surface does not exceed 15°. When the absolute value of the deviation is less than a preset trim threshold, the flight control computer keeps the current deflection angle of the four all-moving control surfaces unchanged. The deviation is the difference between the pitch angle, roll angle, and yaw angle and the corresponding desired attitude. The preset trim threshold ranges from 1° to 5°, preferably 2°.

[0031] The flight control computer generates pitch or yaw torque through differential deflection of two of the four all-moving control surfaces (during attitude adjustment, the two diagonally opposite all-moving control surfaces are equivalent to two cross-shaped vertical or horizontal all-moving control surfaces), and generates roll torque through differential deflection of two adjacent all-moving control surfaces. These torques are then superimposed with the basic attitude control torque generated by the four rotor power units to achieve three-axis attitude control.

[0032] The rocket racing drone also includes a first-person perspective camera and an image transmission module. The first-person perspective camera is located at the head of the cylindrical fuselage, and the image transmission module is used to transmit real-time images to the ground control terminal. The cylindrical fuselage is rocket-shaped, and the tail of the cylindrical fuselage is provided with a tail support structure for vertical parking.

[0033] The four rotor power units provide the main lift, and the four all-moving control surfaces gradually take on the main attitude control torque as the rocket racing drone's forward speed increases, thereby reducing the attitude correction burden of the rotor power units, reducing energy consumption, and improving aerodynamic efficiency.

[0034] This invention also provides a control method for automatically adjusting all control surfaces, applied to the aforementioned rocket racing drone, comprising the following steps:

[0035] Step S1: Real-time acquisition of the three-axis angular velocity and three-axis acceleration of the cylindrical fuselage using an inertial measurement unit;

[0036] Step S2: The flight control computer performs a fusion calculation of the three-axis angular velocity and three-axis acceleration to obtain the real-time attitude of the cylindrical fuselage;

[0037] Step S3: The flight control computer calculates the attitude deviation between the real-time attitude and the desired attitude, and the cascade PID controller calculates the three-axis control torque.

[0038] Step S4: The flight control computer's control distributor distributes the three-axis control torque into independent rotor speed distribution and control surface angle distribution.

[0039] Step S5: The rotor speed distribution is converted into speed commands for four brushless motors via the speed control channel, driving the four rotor power units to generate basic attitude control torque; simultaneously, the control surface angle distribution is converted into deflection angle commands for four all-moving control surfaces via the control angle control channel, and each deflection angle command is limited so that the absolute value of the deflection angle does not exceed 15°. The servos of the four control surface drive mechanisms drive the corresponding all-moving control surfaces to deflect, and the rotor power units deflect synchronously with the all-moving control surfaces.

[0040] Step S6: The aerodynamic forces generated by the four rotor power units are combined with the aerodynamic forces generated by the four all-moving control surfaces, so that the net external force and net external torque on the cylindrical fuselage tend to be balanced at the same time, thus achieving overall aircraft trim.

[0041] Step S7: Return to step S1 and repeat the process with a preset control cycle to achieve continuous automatic trim adjustment of the rocket racing machine; wherein, the speed control channel and the rudder angle control channel remain independent of each other throughout the entire control process;

[0042] In step S2, the flight control computer uses a complementary filtering algorithm or an extended Kalman filtering algorithm to perform fusion calculations to obtain the pitch angle, roll angle, and yaw angle of the cylindrical fuselage.

[0043] In step S3, when the absolute value of the attitude deviation is less than the preset trim threshold, the flight control computer keeps the current yaw angle of the four all-moving control surfaces unchanged; the yaw angle command is only updated when the absolute value of the attitude deviation is greater than or equal to the preset trim threshold.

[0044] In step S4, the control distributor takes the minimum three-axis control torque error and the minimum control surface deflection power consumption as optimization objectives, and solves the rotor speed distribution and control surface angle distribution respectively.

[0045] In step S5, pitching or yaw torque is generated by differential deflection of two relative to each other among the four all-moving control surfaces, and rolling torque is generated by differential deflection of two adjacent all-moving control surfaces. The all-moving control surfaces generate aerodynamic force by utilizing the downwash slipstream of the corresponding rotor in hovering and low-speed states, and generate aerodynamic force by utilizing the incoming flow in forward high-speed states.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The present invention introduces four independently deflectable all-moving control surfaces on the quadcopter rocket racing machine, forming a dual-channel collaborative control with the rotor. The control surfaces can share the attitude control torque, reduce the burden of rotor attitude correction, and enable the fuselage to automatically maintain the overall balance of the aircraft under various flight conditions, significantly improving flight stability and reducing energy consumption.

[0048] (2) The arm of the present invention also serves as the rudder shaft, which realizes a high degree of structural integration, simplifies the mechanical structure, reduces weight and lowers cost, and avoids the complex structure of the rudder surface being installed by an independent rudder arm in the prior art.

[0049] (3) The rotor power unit of the present invention deflects synchronously with the all-moving control surface, so that the direction of the rotor thrust vector changes synchronously when the control surface deflects, generating a control torque superimposed with the aerodynamic force of the control surface, which further enhances the attitude control capability and response speed; at the same time, the fixed connection between the rotor and the control surface ensures that the relative position between the two is constant, so that the control surface is always in the optimal action area of ​​the rotor slipstream, which improves aerodynamic efficiency.

[0050] (4) The four all-moving control surfaces of the present invention adopt the NACA0012 airfoil, which can generate symmetrical and linear control torque when differentially deflected; at the same time, the control surfaces are located in the rotor slipstream influence zone, and can effectively generate aerodynamic force by using the downwash slipstream in hovering and low-speed states, and by using the incoming flow in forward high-speed states, taking into account the aerodynamic efficiency of the entire speed range.

[0051] (5) The control surface angle control and rotor speed control of the present invention are independent of each other. The speed control channel and the control surface angle control channel are not coupled, can be adjusted independently and isolated from faults independently. The control allocation is flexible and robust. The control surface deflection angle is limited to ±15°, avoiding flow separation and stall caused by large deflection angles, and ensuring the linearity and control accuracy of the control surface aerodynamic characteristics.

[0052] (6) This invention does not require changing the basic configuration of the quadcopter racing machine. It only adds control surfaces and servos to the arms. The structure is simple, lightweight, easy to modify and maintain, and is especially suitable for rocket-shaped racing machines and various quadcopter drones. Attached Figure Description

[0053] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0054] Figure 1 This is a schematic diagram of the overall layout of the rocket racing machine of the present invention.

[0055] Figure 2 This is a block diagram of the automatic adjustment and control system for all control surfaces of the present invention.

[0056] Figure 3 This is a flowchart of the independent dual-channel control of the rotor and control surfaces of the present invention.

[0057] Figure 4 This is a schematic diagram of the servo control principle of the present invention. Detailed Implementation

[0058] This invention provides a rocket racing drone with automatically adjustable control surfaces. The rocket racing drone is a quadcopter configuration, such as... Figure 1 As shown, it includes a cylindrical fuselage 1, four rotor power units 2 (including brushless motors and rotors, namely rotors ①②③④), four all-moving control surfaces 3, four arms 3a arranged in a cross shape, a first-person view (FPV) camera 4, four servos, an inertial measurement unit (IMU), and a flight control computer (flight controller).

[0059] The fuselage 1 is a slender, streamlined, cylindrical rocket shape. A fairing is installed at the nose to reduce aerodynamic drag, and an FPV camera 4 is located at the fairing for first-person view control. The tail section of the fuselage has a tail boom structure for vertical parking support. Four arms 3a are symmetrically mounted on the fuselage 1 in a cross shape. Each arm 3a has a rotor power unit 2 installed at its end. The four rotor power units 2 together provide the main lift and basic attitude control torque.

[0060] Four all-moving control surfaces 3 are installed one-to-one on the four arms 3a and are located within the downwash slipstream influence zone of the corresponding rotor power unit 2 (in this embodiment, they are installed at the end of the arm, below the corresponding rotor), so that each all-moving control surface 3 is in the downwash slipstream generated by the corresponding rotor. Each arm 3a not only serves as a structural support but also as the control shaft (rotation shaft) of the corresponding all-moving control surface 3.

[0061] The rotor power unit 2 (including a brushless motor and a rotor) is mounted on the end of the arm 3a via bearings or rigid connectors and is rigidly fixedly connected to the all-moving control surface 3. When the servo drives the all-moving control surface 3 to deflect around the arm 3a, the rotor power unit 2 deflects synchronously with the all-moving control surface 3, thereby ensuring that the rotor always maintains a fixed relative position with the control surface, so that the downwash of the rotor always acts on the control surface, ensuring the consistency of the aerodynamic performance of the control surface.

[0062] Each all-moving control surface 3 can deflect independently around its respective control axis (i.e., arm 3a), and the deflection angle range relative to the neutral position does not exceed ±15°. The airfoil of each all-moving control surface 3 is NACA0012. The deflection angle is limited to ±15°, which can avoid flow separation and stall caused by large deflection angles, and ensure the linearity of the control surface aerodynamic characteristics and control accuracy.

[0063] like Figure 4 As shown, each all-moving control surface 3 is driven by an independent digital servo. The flight control computer outputs PWM control angle commands, which drive the digital servo to rotate via the servo drive circuit. The output shaft of the digital servo is connected to the control shaft (i.e., arm 3a) of the corresponding all-moving control surface 3 via a rocker arm and connecting rod. Pushing or pulling the control shaft causes the all-moving control surface 3 to deflect, simultaneously driving the rotor power unit 2 to deflect synchronously. The digital servo has a built-in position feedback potentiometer, which feeds back the actual control angle to form a closed-loop position servo control, achieving precise control of the control surface angle. This control angle control channel is independent of the rotor speed control channel.

[0064] Because the rotor power unit 2 rotates synchronously with the all-moving control surface 3, the direction of the thrust vector generated by the rotor also changes accordingly. This results in an additional control torque that is superimposed on the aerodynamic force of the control surface when the control surface deflects, further enhancing the attitude control capability. At the same time, the fixed connection between the rotor and the control surface ensures that the relative position between the two remains constant, so that the control surface is always in the optimal action area of ​​the rotor slipstream, improving aerodynamic efficiency.

[0065] like Figure 2 and Figure 3 As shown, the rotor-rudder dual-channel independent control process in this embodiment is as follows:

[0066] The inertial measurement unit (IMU) acquires the three-axis angular velocity ω and three-axis acceleration a of the fuselage in real time and sends them to the flight control computer. The IMU includes a three-axis MEMS gyroscope and a three-axis MEMS accelerometer. The flight control computer uses a complementary filtering algorithm or an extended Kalman filter algorithm to fuse the three-axis angular velocity and three-axis acceleration to obtain the real-time attitude of the fuselage, such as the roll angle φ, pitch angle θ, and yaw angle ψ.

[0067] The flight control computer calculates the attitude deviation between the real-time attitude and the desired attitude. Taking the roll channel as an example, the roll angle error... for:

[0068] (1),

[0069] In the formula, For the desired roll angle, This is the calculated actual roll angle. The error between the pitch and yaw channels. , The definition is similar.

[0070] The cascaded PID controller calculates the three-axis control torque based on the attitude deviation, and the control law is as follows:

[0071] (2),

[0072] In the formula, Here, 'e' represents the three-axis control torque, and 'e' represents the attitude deviation. The rate of change of attitude deviation, , , These represent the proportional, differential, and integral gains, respectively. d denotes the differential sign; t is time.

[0073] The control distributor will control the torque of the three axes. The rotor speed allocation and control surface angle allocation are assigned as independent values. The control surface angle allocation is then subjected to gain mapping and amplitude limiting to obtain the deflection angle command for each all-moving control surface.

[0074] , i=1,2,3,4 (3).

[0075] In the formula, For the i-th all-moving control surface, the deflection angle command is given. A gain matrix is ​​assigned to the control surfaces, with sat(·) as the saturation function, limiting the deflection angle to within ±15°. The rotor speed distribution is mapped to obtain the speed commands for each rotor power unit.

[0076] , i=1,2,3,4 (4).

[0077] In the formula, This is the rotational speed command for the i-th rotor power unit. The rotor speed is assigned a mapping, where T is the desired total lift. The rudder angle control channel of Equation (3) and the speed control channel of Equation (4) are independent and output in parallel.

[0078] The aerodynamic forces / torques generated by the four rotor power units and the aerodynamic forces / torques generated by the four all-moving control surfaces are combined to form the total torque M of the entire aircraft:

[0079] (5),

[0080] In the formula, The basic attitude control torque generated by the rotor power unit The aerodynamic torque generated by the four all-moving control surfaces. The flight control computer coordinates the rotor speed and control surface deflection angle to make the net external force ΣF on the fuselage approach the target value and the net external torque ΣM approach zero, thereby achieving overall aircraft trim.

[0081] In terms of three-axis attitude control, the flight control computer generates pitch or yaw moments through differential deflection of two of the four all-moving control surfaces relative to each other, and roll moments through differential deflection of two adjacent control surfaces, which are then superimposed on the basic attitude control moments generated by the rotor power unit. When the absolute value of the attitude deviation is less than a preset trim threshold, the flight control computer maintains the current deflection angle of the four all-moving control surfaces unchanged (dead zone) to avoid frequent control surface jitter; the deflection angle command is only updated when the absolute value of the attitude deviation is greater than or equal to the trim threshold. The above control process is repeated at a preset control cycle (e.g., 200Hz to 1000Hz) to achieve continuous automatic trim adjustment.

[0082] In terms of operating modes, during hovering and low-speed states, the four rotor power units are the primary source of lift and attitude control, while the four all-moving control surfaces utilize the rotor downwash slipstream to generate auxiliary aerodynamic torque, improving attitude response speed. During forward high-speed flight, the four all-moving control surfaces utilize the incoming flow to generate aerodynamic force, gradually taking over the main attitude control torque, reducing the attitude correction burden on the rotor power units, lowering energy consumption, and improving aerodynamic efficiency. Because the control surface angle control and rotor speed control are independent of each other, the two channels can be adjusted independently, and if one channel malfunctions, the other channel can compensate, improving the robustness and safety of the control system.

[0083] This embodiment adds four fully movable control surfaces with NACA0012 airfoil to the cross-shaped arm of the quadcopter rocket racing drone. The arm also serves as the control shaft, and the rotor power unit deflects synchronously with the control surfaces. It adopts a dual-channel coordinated control with independent rotor speed control channels and control angle control channels. Without changing the basic configuration of the quadcopter, it achieves active trim of the entire aircraft, taking into account the flight stability and aerodynamic efficiency in the full speed range of hovering and forward flight. It has a simple structure, fast response, high control precision, and is easy to modify and maintain.

[0084] In this embodiment, the control cycle of the flight control computer is set to 500Hz, that is, a complete attitude calculation and control allocation process is performed every 2 milliseconds.

[0085] The parameters for the cascade PID controller are configured as follows:

[0086] Pitch / Roll Channel: =4.5, =0.8, =0.15;

[0087] Yaw channel: = 3.0, =0.5, =0.10;

[0088] Angular velocity loop: =0.12, =0.02, =0.003;

[0089] The trim threshold is set to 2°, meaning that when the attitude deviation is less than 2°, the flight control computer keeps the current deflection angle of the four all-moving control surfaces unchanged in order to avoid frequent control surface jitter.

[0090] The control surface deflection rate limit is set to 200° / s, meaning the maximum angular velocity of the control surface deflection driven by the servo motor is 200° / s, to prevent the control surface from responding too quickly and causing oscillation.

[0091] The above parameters are exemplary configurations and can be optimized in actual applications based on the specific size, weight, control surface area, and flight conditions of the aircraft.

[0092] When the rocket drone flies forward at a speed V > 15 m / s, the incoming flow pressure increases significantly, and the aerodynamic torque generated by the four all-moving control surfaces under the influence of the incoming flow increases substantially. At this time, the control distributor of the flight control computer automatically adjusts the distribution weights, increasing the weight of the control surface angle distribution and decreasing the weight of the rotor speed distribution. Specifically, the distribution matrix of the control distributor is dynamically adjusted based on feedback from the airspeed sensor:

[0093] (6),

[0094] In the formula, Assign a matrix to the rudder surface angle. Assign gain to the control surfaces during hovering. is the transition speed threshold (set to 15m / s in this embodiment), and k is the adjustment coefficient (set to 0.3 in this embodiment).

[0095] Therefore, during high-speed forward flight, the four all-moving control surfaces bear the main attitude control torque, while the four rotor power units focus on providing lift, reducing the amplitude of rotor speed differential and lowering energy consumption. Actual test results show that at a forward flight speed of 20 m / s, compared to traditional pure rotor control, the attitude control energy consumption of this invention is reduced by approximately 25%.

[0096] In this embodiment, the end of the arm directly serves as the rudder shaft (rotation shaft) of the all-moving control surface, and the rotor power unit is coaxially mounted on the rotating component at the end of the arm with the all-moving control surface, achieving integrated design.

[0097] Specifically, each arm has a cylindrical journal at its end, which is either integral with the arm or fixedly connected via an interference fit, serving as the fixed part of the control shaft. A rotating sleeve is coaxially fitted onto the outside of this journal via bearings, allowing it to rotate freely around the arm's axis. The root of the all-moving control surface is fixedly connected to one side of the rotating sleeve, while the rotor power unit (including a brushless motor and a rotor) is fixedly connected to the other side or above the rotating sleeve via a motor mount, so that the all-moving control surface and the rotor power unit are located in different positions on the rotating sleeve, but both are rigidly fixed to the rotating sleeve.

[0098] The servo motor's output shaft is driven by a rocker arm and a connecting rod to a rotating sleeve. When the flight control computer issues a control surface deflection command, the servo motor drives the rocker arm to swing, which in turn pushes the rotating sleeve to rotate around the arm axis via the connecting rod, thereby simultaneously driving the all-moving control surfaces and the rotor power unit to deflect synchronously around the arm.

[0099] The advantages of this mechanical structure are:

[0100] (1) The arm itself is the rudder shaft, so there is no need to set up a separate rudder shaft or an additional U-shaped bracket. The structure is highly integrated, with fewer parts and lighter weight.

[0101] (2) Only one servo motor is needed to drive the control surface deflection and rotor tilt at the same time, realizing the linkage control of thrust vector and control surface aerodynamics, avoiding the complex structure of multiple actuators required in the traditional scheme;

[0102] (3) The relative position of the all-moving control surface and the rotor power unit is constant, ensuring that the control surface is always in the optimal action area of ​​the rotor downwash slipstream;

[0103] (4) The rotating sleeve is fitted with the machine arm journal through the bearing, resulting in low rotational friction, sensitive response, and high control precision.

[0104] In one specific implementation of this embodiment, the journal diameter at the end of the arm is 6mm to 10mm, the inner diameter of the rotating sleeve is matched with the journal diameter, and the bearing is a miniature rolling bearing or a sliding bearing. The servo is a digital servo with an output torque of not less than 5kg·cm to ensure reliable synchronous deflection of the all-moving control surface and the rotor power unit.

[0105] In another implementation, the servo motor is connected to the rotating sleeve drive through a worm gear reduction mechanism to obtain greater driving torque and self-locking capability, so that the control surface can maintain the current deflection angle when there is no control command, reducing the continuous power consumption of the servo motor.

[0106] In hover, the four rotor power units generate a high-speed downwash slipstream with a velocity of 15-25 m / s. The four all-moving control surfaces are located within the influence zone of the corresponding rotor's downwash slipstream; even without forward speed, the control surfaces remain in the high-speed airflow. When the flight control computer issues a control surface deflection command, the control surfaces generate aerodynamic forces within the high-speed downwash slipstream, creating attitude control torque.

[0107] Unlike the control surfaces of traditional fixed-wing aircraft, the control surfaces of this invention are not ineffective in the hovering state, but rather continuously generate effective aerodynamic forces using the rotor downwash. This significantly improves the attitude response speed of the rocket racing drone in the hovering state. Actual measurements show that the attitude control torque generated by the control surfaces in the hovering state can reach 15% to 30% of the torque generated by the rotor speed differential, effectively reducing the burden on the rotor.

[0108] This invention provides a rocket racing drone with automatically adjustable control surfaces and its control method. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A rocket racing drone with automatically adjustable control surfaces, characterized in that, It includes a cylindrical fuselage, four arms, four all-moving control surfaces, four rotor power units, four control surface drive mechanisms, an inertial measurement unit, and a flight control computer; The four arms are symmetrically mounted in a cross shape on the columnar fuselage, and each arm also serves as the rudder shaft for the corresponding fully movable control surface. The four fully movable control surfaces are installed on the four arms in a one-to-one correspondence. Each fully movable control surface can deflect independently around the corresponding arm. The airfoil of each fully movable control surface is a symmetrical airfoil, and the deflection angle of each fully movable control surface relative to the neutral position does not exceed ±15°. The four rotor power units are respectively installed at the ends of the four arms. Each rotor power unit includes a brushless motor and a rotor driven by the brushless motor. The four rotor power units together provide the lift and basic attitude control torque required for the rocket racing machine to fly. Each rotor power unit is rigidly fixed to its corresponding all-moving control surface. When the all-moving control surface deflects around the arm, the rotor power unit deflects synchronously with the all-moving control surface. The four control surface drive mechanisms are connected to the four all-moving control surfaces in a one-to-one correspondence, and are used to drive the corresponding all-moving control surfaces and rotor power units to deflect synchronously around the arm. The inertial measurement unit is installed inside the cylindrical fuselage and is used to measure the triaxial angular velocity and triaxial acceleration of the cylindrical fuselage in real time. The flight control computer is housed inside the cylindrical fuselage and is electrically connected to the inertial measurement unit, the brushless motors of the four rotor power units, and the four control surface drive mechanisms. The flight control computer is used to calculate the real-time attitude of the cylindrical fuselage based on the three-axis angular velocity and three-axis acceleration. Based on the deviation between the real-time attitude and the desired attitude, it independently generates speed commands for the four brushless motors through the speed control channel and independently generates deflection commands for the four all-moving control surfaces through the rudder angle control channel. The rotor of the rotor power unit works in conjunction with the corresponding all-moving control surface, and the speed control channel and the control angle control channel are independent of each other. The flight control computer coordinates the rotational speed of the four rotor power units and the deflection angle of the four all-moving control surfaces to simultaneously balance the net external force and net external torque on the cylindrical fuselage, thereby achieving stable flight of the rocket racing drone while maintaining overall aircraft trim.

2. The rocket racing drone according to claim 1, characterized in that, The four all-moving control surfaces are respectively installed on the four arms of the aircraft and located within the downwash slipstream influence zone of the corresponding rotor power unit. This allows each all-moving control surface to obtain effective aerodynamic force by utilizing the downwash slipstream generated by the corresponding rotor in hovering and low-speed states, and to generate aerodynamic force by utilizing the incoming flow in forward high-speed states.

3. The rocket racing drone according to claim 2, characterized in that, The four control surface drive mechanisms are driven by servo motors, rocker arms, or direct drive motors. The four control surface drive mechanisms are connected to the control shafts of the corresponding fully moving control surfaces via output shafts, forming a closed-loop position servo control.

4. The rocket racing drone according to claim 3, characterized in that, The inertial measurement unit includes a three-axis MEMS gyroscope and a three-axis MEMS accelerometer; the flight control computer uses a complementary filtering algorithm or an extended Kalman filtering algorithm to fuse the three-axis angular velocity and three-axis acceleration to obtain the pitch angle, roll angle and yaw angle of the cylindrical fuselage.

5. The rocket racing drone according to claim 4, characterized in that, The flight control computer includes a cascaded PID controller and a control distributor; The cascaded PID controller calculates the three-axis control torque based on the deviations between the pitch angle, roll angle, and yaw angle and the desired attitude. The control distributor distributes the three-axis control torque into independent rotor speed distribution and control surface angle distribution. The rotor speed distribution is output as speed commands for four brushless motors via the speed control channel, and the control surface angle distribution is output as deflection angle commands for four all-moving control surfaces via the control angle control channel.

6. The rocket racing drone according to claim 5, characterized in that, The control distributor limits the distribution of control surface angles so that the absolute value of the deflection angle command for each all-moving control surface does not exceed 15°. When the absolute value of the deviation is less than the preset trim threshold, the flight control computer keeps the current deflection angle of the four all-moving control surfaces unchanged. The deviation is the difference between the pitch angle, roll angle and yaw angle and the corresponding desired attitude.

7. The rocket racing drone according to claim 6, characterized in that, The flight control computer generates pitch or yaw torque by differentially deflecting two of the four all-moving control surfaces relative to each other, and generates roll torque by differentially deflecting two adjacent all-moving control surfaces. These torques are then superimposed with the basic attitude control torques generated by the four rotor power units to achieve three-axis attitude control.

8. The rocket racing drone according to claim 7, characterized in that, It also includes a first-person perspective camera and an image transmission module. The first-person perspective camera is located at the head of the columnar fuselage, and the image transmission module is used to transmit real-time images to the ground control terminal. The columnar fuselage is rocket-shaped, and the tail of the columnar fuselage is provided with a tail support structure for vertical parking support.

9. The rocket racing drone according to any one of claims 1 to 8, characterized in that, The four rotor power units provide the main lift, and the four all-moving control surfaces gradually take on the attitude control torque as the rocket racing drone's forward speed increases, thereby reducing the attitude correction burden of the rotor power units, reducing energy consumption, and improving aerodynamic efficiency.

10. A control method for automatically adjusting all control surfaces, applied to the rocket racing drone as described in claim 1, characterized in that, Includes the following steps: Step S1: Real-time acquisition of the three-axis angular velocity and three-axis acceleration of the cylindrical fuselage using an inertial measurement unit; Step S2: The flight control computer performs a fusion calculation of the three-axis angular velocity and three-axis acceleration to obtain the real-time attitude of the cylindrical fuselage; Step S3: The flight control computer calculates the attitude deviation between the real-time attitude and the desired attitude, and the cascade PID controller calculates the three-axis control torque. Step S4: The flight control computer's control distributor distributes the three-axis control torque into independent rotor speed distribution and control surface angle distribution. Step S5: The rotor speed distribution is converted into speed commands for four brushless motors via the speed control channel, driving the four rotor power units to generate basic attitude control torque; simultaneously, the control surface angle distribution is converted into deflection angle commands for four all-moving control surfaces via the control angle control channel, and each deflection angle command is limited so that the absolute value of the deflection angle does not exceed 15°. The servos of the four control surface drive mechanisms drive the corresponding all-moving control surfaces to deflect, and the rotor power units deflect synchronously with the all-moving control surfaces. Step S6: The aerodynamic forces generated by the four rotor power units are combined with the aerodynamic forces generated by the four all-moving control surfaces, so that the net external force and net external torque on the cylindrical fuselage tend to be balanced at the same time, thus achieving overall aircraft trim. Step S7: Return to step S1 and repeat the process with a preset control cycle to achieve continuous automatic trim adjustment of the rocket racing machine; wherein, the speed control channel and the rudder angle control channel remain independent of each other throughout the entire control process; In step S2, the flight control computer uses a complementary filtering algorithm or an extended Kalman filtering algorithm to perform fusion calculations to obtain the pitch angle, roll angle, and yaw angle of the cylindrical fuselage. In step S3, when the absolute value of the attitude deviation is less than the preset trim threshold, the flight control computer keeps the current yaw angle of the four all-moving control surfaces unchanged; the yaw angle command is only updated when the absolute value of the attitude deviation is greater than or equal to the preset trim threshold. In step S4, the control distributor takes the minimum three-axis control torque error and the minimum control surface deflection power consumption as optimization objectives, and solves the rotor speed distribution and control surface angle distribution respectively. In step S5, pitching or yaw torque is generated by differential deflection of two relative to each other among the four all-moving control surfaces, and rolling torque is generated by differential deflection of two adjacent all-moving control surfaces. The all-moving control surfaces generate aerodynamic force by utilizing the downwash slipstream of the corresponding rotor in hovering and low-speed states, and generate aerodynamic force by utilizing the incoming flow in forward high-speed states.

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