A control method of a tiltable three-rotor unmanned aerial vehicle

Abstract

The application discloses a control method of a tiltable three-rotor unmanned aerial vehicle, and relates to the technical field of unmanned aerial vehicles. The control method comprises the following steps: acquiring real-time state data of the unmanned aerial vehicle; acquiring a task instruction of the unmanned aerial vehicle; performing double-loop control calculation based on the real-time state data and the task instruction to generate a pseudo control instruction; and performing control distribution calculation based on the pseudo control instruction to generate a motor throttle and a rudder deflection angle instruction of the three-rotor unmanned aerial vehicle. The control method generates the motor throttle and the rudder deflection angle instruction of the three-rotor unmanned aerial vehicle through distribution calculation after double-loop control calculation based on state data and a task instruction, realizes decoupling of pitch attitude control and forward flight control and a control mode of fixed-inclination forward flight of the unmanned aerial vehicle, and solves the problem of single control mode and limited adjustment effect of a conventional multi-rotor unmanned aerial vehicle flight control method.

Description

Technical Field

[0001] This invention relates to the field of multi-rotor unmanned aerial vehicle (UAV) technology, and more specifically to a control method for a tiltable tri-rotor UAV. Background Technology

[0002] In recent years, multi-rotor drones have been widely used in aerial surveying, security monitoring, power line inspection, agriculture, and emergency search and rescue. Tilting tri-rotor drones are a type of multi-rotor drone. Compared to traditional multi-rotor drones, tilting tri-rotor drones are more compact and energy-efficient. However, they also exhibit dynamic characteristics such as static instability, strong coupling, and strong nonlinearity, making them more difficult to control.

[0003] Specifically, traditional multi-rotor UAV flight control methods couple pitch attitude with forward flight motion, making it impossible to freely combine forward flight and pitch attitude. This reduces the flexibility of mission payload use, increases the requirements for the self-adjustment capability of mission payload equipment, and reduces the overall system efficiency.

[0004] In summary, traditional flight control methods for multi-rotor UAVs suffer from limitations in control modes and adjustment effectiveness. Summary of the Invention

[0005] In view of this, the present invention provides a control method for a tiltable tri-rotor unmanned aerial vehicle (UAV). By improving the control calculation and control allocation methods, it solves the problems of the relatively simple control mode and limited adjustment effect of the traditional flight control method for multi-rotor UAVs.

[0006] To address the above problems, the technical solution of this invention is to employ a control method for a tiltable tri-rotor unmanned aerial vehicle (UAV), comprising: acquiring real-time status data of the UAV; acquiring mission instructions of the UAV; performing dual-loop control calculations based on the real-time status data and the mission instructions to generate pseudo-control instructions; and performing control allocation calculations based on the pseudo-control instructions to generate motor throttle and servo deflection angle instructions for the tri-rotor.

[0007] Optionally, dual-loop control calculation is performed based on the real-time status data and the mission instructions, including: in the outer loop, control calculation is performed based on the velocity and position data in the real-time status data and the target velocity and target position instructions in the mission instructions to generate forward direct force pseudo-control instructions, altitude control direct force pseudo-control instructions, and roll attitude instructions; in the inner loop, control calculation is performed based on the attitude and angular rate data in the real-time status data, the roll attitude instructions, and the pitch attitude and yaw attitude instructions in the mission instructions to generate roll moment pseudo-control instructions, yaw moment pseudo-control instructions, and pitch moment pseudo-control instructions.

[0008] Optionally, control calculation is performed based on the velocity and position data in the real-time status data and the target velocity and target position commands in the mission commands, including: performing control calculation based on the forward flight velocity and axial position in the velocity and position data and the target velocity and target position commands to generate the forward flight direct force pseudo control command; performing control calculation based on the lateral velocity and lateral position in the velocity and position data and the target velocity and target position commands to generate the roll attitude command; and performing control calculation based on the axial velocity and altitude in the velocity and position data and the target velocity and target position commands to generate the altitude control direct force pseudo control command.

[0009] Optionally, control calculation is performed based on the attitude and angular rate data in the real-time status data, the roll attitude command, and the pitch and yaw attitude commands in the mission commands. This includes: performing control calculation based on the roll angle, roll rate, and roll attitude command in the attitude and angular rate data to generate the pseudo-roll torque control command; performing control calculation based on the yaw angle, yaw rate, and yaw attitude command in the attitude and angular rate data to generate the pseudo-yaw torque control command; and performing control calculation based on the pitch angle, pitch rate, and pitch attitude command in the attitude and angular rate data to generate the pseudo-pitch torque control command.

[0010] Optionally, the control allocation calculation based on the pseudo-control command and the generation of motor throttle and servo deflection angle commands for the tri-rotor include: converting the deflection parameters of the servo to be controlled into a direct force mechanical relationship matrix; calculating the direct force control quantity based on the pseudo-control command and the direct force mechanical relationship matrix; and generating the motor throttle and servo deflection angle commands for the tri-rotor based on the direct force control quantity.

[0011] Optionally, the control method further includes: presetting the priority of various pseudo-control instructions in the pseudo-control instructions; when the generated pseudo-control instructions contain multiple types of pseudo-control instructions, based on the preset priority of various types of pseudo-control instructions in the pseudo-control instructions, performing control allocation calculation on the pseudo-control instructions in descending order of priority.

[0012] Optionally, the control method further includes: presetting the operating parameter range of the motor and the operating parameter range of the servo motor; when performing control allocation calculations on the pseudo control commands in descending order of priority, if there is a generated motor throttle command that does not belong to the operating parameter range of the motor and / or a generated servo motor deflection angle command that does not belong to the operating parameter range of the servo motor, the channel output corresponding to the pseudo control command with the lowest priority currently participating in the control allocation calculation is suppressed until the generated motor throttle command belongs to the operating parameter range of the motor and the generated servo motor deflection angle command belongs to the operating parameter range of the servo motor.

[0013] Optionally, the drone is configured such that: the motor of the first rotor has the function of tilting forward and backward; the motor of the second rotor has the function of tilting forward and backward; and the motor of the third rotor does not have the function of tilting.

[0014] Optionally, acquiring the drone's mission instructions includes: acquiring the drone's real-time remote control mission instructions; or acquiring the drone's mission instructions from an offline planning mission; or acquiring the drone's mission instructions from an online planning mission.

[0015] The primary improvement of this invention is the provision of a control method for a tiltable tri-rotor UAV. By performing dual-loop control calculations based on state data and mission commands, and then allocating the calculations, the method generates motor throttle and servo deflection angle commands for the tri-rotor. This achieves decoupling of pitch attitude control and forward flight control, as well as a fixed tilt angle forward flight control mode for the UAV. This solves the problems of relatively simple control modes and limited adjustment effects in traditional multi-rotor UAV flight control methods. Attached Figure Description

[0016] Figure 1 This is a simplified flowchart of the control method for the tiltable tri-rotor UAV of the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown, a control method for a tiltable tri-rotor unmanned aerial vehicle includes:

[0019] S1: Obtain real-time status data of the drone.

[0020] Furthermore, the real-time status data includes at least the drone's position, speed, attitude, overload, angular rate, and other data.

[0021] S2: Obtain the drone's mission instructions.

[0022] Furthermore, acquiring the drone's mission instructions includes: acquiring real-time remote control mission instructions for the drone; or acquiring mission instructions from the drone's offline planning mission; or acquiring mission instructions from the drone's online planning mission. The drone is configured such that: the motor of the first rotor has a tilting function; the motor of the second rotor has a tilting function; and the motor of the third rotor does not have a tilting function.

[0023] S3: Perform dual-loop control calculation based on the real-time status data and the task instructions to generate pseudo-control instructions.

[0024] Furthermore, dual-loop control calculation is performed based on the real-time status data and the mission instructions, including: in the outer loop, control calculation is performed based on the speed and position data in the real-time status data and the target speed and target position instructions in the mission instructions to generate forward direct force pseudo-control instructions, altitude control direct force pseudo-control instructions, and roll attitude instructions; in the inner loop, control calculation is performed based on the attitude and angular rate data in the real-time status data, the roll attitude instructions, and the pitch attitude instructions and yaw attitude instructions in the mission instructions to generate roll moment pseudo-control instructions, yaw moment pseudo-control instructions, and pitch moment pseudo-control instructions.

[0025] This invention uses a dual-loop parallel computing approach, which reduces the waiting time of individual tasks and lowers the system response time, thus reducing the latency of UAV control. On the other hand, it controls the speed and position of the UAV through the outer loop and controls the attitude of the UAV through the inner loop, effectively improving the diversity of control modes and realizing the decoupling of pitch attitude control and forward flight control, as well as the control mode of UAV forward flight at a fixed tilt angle.

[0026] Furthermore, control calculations are performed based on the speed and position data in the real-time status data and the target speed and target position commands in the mission instructions. This includes: performing control calculations based on the forward flight speed and axial position in the speed and position data and the target speed and target position commands to generate the forward flight direct force pseudo-control command; performing control calculations based on the lateral speed and lateral position in the speed and position data and the target speed and target position commands to generate the roll attitude command; and performing control calculations based on the axial speed and altitude in the speed and position data and the target speed and target position commands to generate the altitude control direct force pseudo-control command, thereby completing the control calculations for the outer loop.

[0027] Furthermore, control calculations are performed based on the attitude and angular rate data in the real-time status data, the roll attitude command, and the pitch and yaw attitude commands in the mission commands. This includes: performing control calculations based on the roll angle, roll rate, and roll attitude command in the attitude and angular rate data to generate the pseudo-roll torque control command; performing control calculations based on the yaw angle, yaw rate, and yaw attitude command in the attitude and angular rate data to generate the pseudo-yaw torque control command; and performing control calculations based on the pitch angle, pitch rate, and pitch attitude command in the attitude and angular rate data to generate the pseudo-pitch torque control command, thereby completing the inner loop control calculations.

[0028] S4: Based on the pseudo-control commands, perform control allocation calculations and generate motor throttle and servo yaw angle commands for the three rotors. The basic logic of the control allocation includes: yaw control is achieved through differential forward and backward yaw of the first and second rotor motors; roll control is achieved through differential speed of the first and second rotor motors. Compared to traditional anti-torque control methods, this invention achieves higher efficiency in generating yaw torque through dynamic yaw, improving the rotorcraft's anti-saturation capability and enhancing the system's anti-interference capability. This invention achieves pitch control through differential speed of the first and third rotor motors; forward flight control is achieved by generating axial direct force through synchronous forward and backward tilt of the first and second rotor motors; and altitude control is achieved through speed control of the first, second, and third rotor motors.

[0029] Furthermore, the control allocation calculation based on the pseudo-control command and the generation of motor throttle and servo deflection angle commands for the tri-rotor include: converting the deflection parameters of the servo to be controlled into a direct force mechanical relationship matrix; calculating the direct force control quantity based on the pseudo-control command and the direct force mechanical relationship matrix; and generating the motor throttle and servo deflection angle commands for the tri-rotor based on the direct force control quantity.

[0030] Furthermore, the direct force mechanical relationship matrix includes the normal force along the negative Z-axis of the UAV body axis and the axial force along the X-axis of the UAV body axis, with the normal force F... zi With axial force F xi With motor tension F i and motor deflection

[0031] F zi =F i cos(δ i )

[0032] F xi =F i sin(δ i )

[0033] Angle δ i The relationship is shown in the following formula: i = 1, 2.

[0034] Furthermore, based on the pseudo-control command and the mechanical relationship matrix of the direct force, the calculation formula for the direct force control quantity is as follows: Among them, M f Let C be the mechanical relationship matrix of the direct forces. pseudo For the pseudo control command, F dis It is a direct force control quantity.

[0035] Furthermore, the calculation formula for generating the motor throttle and servo deflection angle commands of the tri-rotor based on the direct force control quantity is: C real =f(F dis ), where C real These are the commands for the motor throttle and the servo motor deflection angle.

[0036] Furthermore, the control method also includes: pre-setting the priorities of various pseudo-control commands in the pseudo-control instructions; when the generated pseudo-control instructions contain multiple types of pseudo-control commands, based on the pre-set priorities of various pseudo-control commands in the pseudo-control instructions, and sequentially calculating the control allocation of the pseudo-control commands in descending order of priority. The priorities are flexibly set by the user according to factors such as the application environment and purpose of use, and this invention does not impose specific limitations. By setting the priorities of pseudo-control commands in conjunction with the saturation processing method described below, this invention can effectively ensure that commands with higher priorities are executed first, and can maximize the utilization of the UAV's performance to execute as many commands as possible while ensuring flight safety.

[0037] Furthermore, the control method also includes: presetting the operating parameter ranges of the motor and the servo motor; when performing control allocation calculations on the pseudo-control commands in descending order of priority, if a generated motor throttle command does not belong to the operating parameter range of the motor and / or a generated servo motor deflection angle command does not belong to the operating parameter range of the servo motor, the output of the channel corresponding to the lowest priority pseudo-control command currently participating in the control allocation calculation is suppressed until the generated motor throttle command and the generated servo motor deflection angle command belong to the operating parameter range of the servo motor. The operating parameter ranges of the motor and the servo motor are determined by the rated operating parameter ranges of the motor and the servo motor, and this invention does not impose specific limitations on them.

[0038] This invention generates motor throttle and servo deflection angle commands for a tri-rotor by performing dual-loop control calculations based on state data and task instructions, and then allocating the calculations. This achieves decoupling of pitch attitude control and forward flight control, as well as a fixed tilt angle forward flight control mode for the UAV. It solves the problems of relatively simple control modes and limited adjustment effects in traditional multi-rotor UAV flight control methods.

[0039] The above describes the control method for a tiltable trirotor UAV provided by the embodiments of the present invention. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0040] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can implement the described functions using different methods for each specific application, but such implementation should not be considered beyond the scope of the invention. The steps of the methods or algorithms described in connection with the embodiments disclosed herein can be implemented directly in hardware, software modules executed by a processor, or a combination of both. Software modules can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art.

Claims

1. A control method for a tiltable tri-rotor unmanned aerial vehicle, characterized in that, include: Acquire real-time status data of the drone; Obtain mission instructions from the drone; Based on the real-time status data and the task instructions, a dual-loop control calculation is performed to generate pseudo-control instructions; Based on the pseudo-control commands, control allocation calculations are performed to generate motor throttle and servo deflection angle commands for the tri-rotor. This also includes: The priority of each type of pseudo-control instruction in the preset pseudo-control instructions is determined. When the generated pseudo control instructions contain multiple types of pseudo control instructions, the pseudo control instructions are allocated and calculated in order of priority from high to low based on the preset priority of each type of pseudo control instruction. Preset the operating parameter ranges for the motor and the servo motor. When performing control allocation calculations on the pseudo-control commands in descending order of priority, if a generated motor throttle command does not belong to the working parameter range of the motor and / or a generated servo deflection angle command does not belong to the working parameter range of the servo, the channel output corresponding to the lowest priority pseudo-control command currently participating in the control allocation calculation is suppressed until the generated motor throttle command belongs to the working parameter range of the motor and the generated servo deflection angle command belongs to the working parameter range of the servo.

2. The control method according to claim 1, characterized in that, Dual-loop control calculation based on the real-time status data and the task instructions includes: In the outer loop, control calculations are performed based on the speed and position data in the real-time status data and the target speed and target position commands in the mission commands to generate forward flight direct force pseudo control commands, altitude control direct force pseudo control commands and roll attitude commands. In the inner loop, control calculations are performed based on the attitude and angular rate data in the real-time status data, the roll attitude command, and the pitch and yaw attitude commands in the mission commands to generate pseudo-control commands for roll moment, yaw moment, and pitch moment.

3. The control method according to claim 2, characterized in that, Control calculations are performed based on the velocity and position data in the real-time status data and the target velocity and target position commands in the task commands, including: Based on the forward flight speed and axial position in the speed and position data and the target speed and target position command, control calculation is performed to generate the forward flight direct force pseudo control command; Based on the lateral velocity and lateral position in the velocity and position data and the target velocity and target position commands, control calculations are performed to generate the roll attitude commands; Based on the celestial velocity and altitude in the velocity and position data, and the target velocity and target position commands, control calculations are performed to generate the altitude control direct force pseudo-control command.

4. The control method according to claim 2, characterized in that, Control calculations are performed based on the attitude and angular rate data in the real-time status data, the roll attitude command, and the pitch and yaw attitude commands in the mission commands, including: Based on the roll angle, roll angular rate and roll attitude command in the attitude and angular rate data, control calculation is performed to generate the roll torque pseudo control command. Based on the yaw angle, yaw rate and yaw attitude command in the attitude and angular rate data, control calculation is performed to generate the yaw torque pseudo control command. Based on the pitch angle, pitch rate, and pitch attitude command in the attitude and angular rate data, control calculations are performed to generate the pseudo-control command for pitch torque.

5. The control method according to claim 1, characterized in that, Based on the pseudo-control commands, control allocation calculations are performed to generate motor throttle and servo deflection angle commands for the tri-rotor, including: The deflection parameters of the servo motor to be controlled are equivalent to the mechanical relationship matrix of direct forces; The direct force control quantity is calculated based on the pseudo control command and the mechanical relationship matrix of the direct force. Based on the direct force control quantity, the motor throttle and servo deflection angle commands of the tri-rotor are generated by inverse calculation.

6. The control method according to claim 1, characterized in that, The drone is configured as follows: The motor of the first rotor has the function of tilting forward and backward; The motor of the second rotor has the function of tilting forward and backward; The motor of the third rotor does not have a tilting function.

7. The control method according to claim 1, characterized in that, Obtain mission instructions from the drone, including: Obtain real-time remote control command for the drone; or Obtain the task instructions from the drone's offline planning task; or Obtain task instructions from the online planning task of the drone.

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