WO2024087271A1

WO2024087271A1 - Multi-rotor aircraft, control method therefor, device, and computer-readable storage medium

Info

Publication number: WO2024087271A1
Application number: PCT/CN2022/133003
Authority: WO
Inventors: 沈阳; 陶永康; 张均; 苏江城; 段鹏; 王磊; 周英
Original assignee: 广东汇天航空航天科技有限公司
Priority date: 2022-10-26
Filing date: 2022-11-18
Publication date: 2024-05-02
Also published as: CN115407802B; CN115407802A

Abstract

A multi-rotor aircraft, a control method therefor, a device, and a computer-readable storage medium. The method comprises: based on a present operating state of a multi-rotor unmanned aerial vehicle, determining an operation efficiency matrix corresponding to each rotor; acquiring control allocation matrices corresponding to the operation efficiency matrices; based on the control allocation matrices, determining rotational speed vectors corresponding to the rotor system; and based on the rotational speed vectors, adjusting the rotational speed corresponding to each rotor, and returning to the step for determining an operation efficiency matrix corresponding to each rotor on the basis of the present operating state of the multi-rotor unmanned aerial vehicle.

Description

Multirotor aircraft and control method, device and computer readable storage medium thereof

This application claims priority to a Chinese patent application filed with the China Patent Office on October 26, 2022, with application number 202211314841.0 and invention name “Multi-rotor aircraft and its control method, device, and computer-readable storage medium”, the entire contents of which are incorporated by reference in the application.

Technical Field

The present application relates to the field of aircraft control, and in particular to a multi-rotor aircraft and a control method, device, and computer-readable storage medium thereof.

Background technique

As the application scenarios of drones become more and more extensive, the speed control of the motor rotors of drones is becoming more and more important during the flight of drones. In the existing technology, for multi-rotor drones with more than 4 rotors, power failure fault-tolerant control is mainly performed through the robustness of the control algorithm itself. This technology can easily cause the multi-rotor drone body to vibrate too much or even become uncontrollable at the moment of failure, resulting in a crash. This results in poor power failure fault-tolerant control of multi-rotor drones, making it difficult to meet the stability requirements of multi-rotor drone flight.

technical problem

The main purpose of the present application is to provide a control method and device for a multi-rotor aircraft, and a computer-readable storage medium, aiming to solve the technical problem of poor power failure fault-tolerant control of multi-rotor drones.

Technical Solutions

To achieve the above object, the present application provides a control method for a multi-rotor aircraft, the control method for a multi-rotor aircraft comprising:

Determine, based on the current operating state of the multi-rotor UAV, a control efficiency matrix corresponding to each rotor in a rotor system of the multi-rotor UAV;

If the control efficiency matrix satisfies the preset speed distribution condition, obtaining a control distribution matrix corresponding to the control efficiency matrix;

Determine a rotation speed vector corresponding to the rotor system based on the control allocation matrix, wherein the rotation speed vector includes rotation speeds to be allocated corresponding to each of the rotors;

The rotation speed corresponding to each of the rotors is adjusted based on the rotation speed vector, and the step of returning to execute, based on the current operating state of the multi-rotor UAV, determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV.

Preferably, the step of determining a rotation speed vector corresponding to the rotor system based on the control allocation matrix comprises:

Based on the multiple control channels, obtaining a virtual control vector to be allocated corresponding to each of the rotors;

The rotation speed vector is determined based on the virtual control vector to be allocated and the control allocation matrix.

Preferably, the step of determining the rotation speed vector based on the virtual control vector to be allocated and the control allocation matrix comprises:

Based on the virtual control vector to be allocated, obtaining a maximum virtual control vector corresponding to the rotor system;

Based on the maximum virtual control vector and the control allocation matrix, a rotation speed vector corresponding to the rotor system is determined.

Preferably, the step of obtaining the maximum virtual control vector corresponding to the rotor system based on the virtual control vector to be allocated comprises:

Determine a ratio range corresponding to each of the rotors based on the control allocation matrix, the virtual control vector to be allocated, a preset maximum rotational speed corresponding to each of the rotors, and a preset minimum rotational speed corresponding to each of the rotors, and obtain a maximum ratio within the ratio range as a first ratio corresponding to each of the rotors;

Based on the largest first ratio among the first ratios corresponding to the rotors and the virtual control vector to be allocated, the maximum virtual control vector corresponding to the rotor system is obtained.

Preferably, after the step of determining the rotation speed vector corresponding to the rotor system based on the maximum virtual control vector and the control allocation matrix, the method further comprises:

Determining a remaining allocatable maximum speed and a remaining allocatable minimum speed based on a preset maximum speed, a preset minimum speed, and a speed vector;

The remaining allocatable maximum rotation speed is set as the preset maximum rotation speed, and the remaining allocatable minimum rotation speed is set as the preset minimum rotation speed.

Preferably, if the manipulation efficiency matrix satisfies a preset speed distribution condition, the step of obtaining a control distribution matrix corresponding to the manipulation efficiency matrix comprises:

Based on the manipulation efficiency matrix, obtaining a transposed matrix of the manipulation efficiency matrix, and based on the manipulation efficiency matrix and the transposed matrix, obtaining a product matrix;

If the product matrix is reversible, it is determined that the manipulation efficiency matrix satisfies a preset speed distribution condition, and a control distribution matrix corresponding to the manipulation efficiency matrix is obtained.

Preferably, the step of obtaining a control allocation matrix corresponding to the manipulation efficiency matrix comprises:

Obtaining an inverse matrix of the product matrix;

Based on the inverse matrix and the transposed matrix, a control allocation matrix corresponding to the manipulation efficiency matrix is obtained.

Preferably, the step of adjusting the rotational speed corresponding to each of the rotors based on the rotational speed vector comprises:

Based on the maximum virtual control vector and the virtual control vector to be allocated, obtaining a second ratio corresponding to each of the rotors, and based on the second ratio and the rotation speed vector, obtaining an actual allocation rotation speed;

Based on the actual allocated rotation speed, the rotation speed corresponding to each of the rotors is adjusted.

Preferably, the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV based on the current operating state of the multi-rotor UAV comprises:

Determine the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone;

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.

Preferably, the current operating state includes the current of the motor corresponding to each of the rotors or the rotational speed of each of the rotors.

The present application also provides a multi-rotor aircraft, the multi-rotor aircraft comprising:

A first determination module is used to determine a control efficiency matrix corresponding to each rotor in a rotor system of the multi-rotor UAV based on a current operating state of the multi-rotor UAV;

an acquisition module, configured to acquire a control allocation matrix corresponding to the manipulation efficiency matrix if the manipulation efficiency matrix satisfies a preset speed allocation condition;

A second determination module is used to determine a rotation speed vector corresponding to the rotor system based on the control allocation matrix, wherein the rotation speed vector includes a rotation speed to be allocated corresponding to each of the rotors;

An adjustment module is used to adjust the speed corresponding to each of the rotors based on the speed vector, and return to execute the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV based on the current operating state of the multi-rotor UAV

An embodiment of the present application also proposes a multi-rotor UAV device, which includes a memory, a processor, and computer-readable instructions stored in the memory and executable on the processor, and the computer-readable instructions, when executed by the processor, implement the steps of the control method of the multi-rotor aircraft as described above.

An embodiment of the present application further provides a computer-readable storage medium having computer-readable instructions stored thereon. When the computer-readable instructions are executed by a processor, the steps of the control method for the multi-rotor aircraft as described above are implemented.

Beneficial Effects

The present application determines the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV based on the current operating state of the multi-rotor UAV. If the control efficiency matrix satisfies a preset speed distribution condition, a control allocation matrix corresponding to the control efficiency matrix is obtained. Then, based on the control allocation matrix, a speed vector corresponding to the rotor system is determined, wherein the speed vector includes a speed to be allocated corresponding to each rotor. Finally, based on the speed vector, the speed corresponding to each rotor is adjusted, and the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV based on the current operating state of the multi-rotor UAV is returned to execute.

By monitoring the current operating status of the multi-rotor UAV, when the multi-rotor UAV fails to fly stably due to power failure, the manipulation efficiency matrix and the control allocation matrix are used to allocate excess rotation speed to the rotor, so as to better control the rotor rotation speed and stabilize the flight state of the multi-rotor UAV. When the multi-rotor UAV encounters power problems during flight, the rotor speed can be adjusted in real time to obtain sufficient power, which improves the effect of the fault-tolerant control of the multi-rotor UAV power failure and improves the stability of the multi-rotor UAV flight process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a control device for a multi-rotor aircraft in a hardware operating environment involved in an embodiment of the present application;

FIG2 is a schematic diagram of a flow chart of a first embodiment of a multi-rotor aircraft control method of the present application;

FIG3 is a schematic diagram of the control configuration of the multi-rotor aircraft of the present application;

FIG. 4 is a schematic diagram of functional modules of an embodiment of a multi-rotor aircraft control device of the present application.

The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

Embodiments of the present application

It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

As shown in FIG. 1 , FIG. 1 is a schematic diagram of the structure of a multi-rotor aircraft control device in a hardware operating environment involved in an embodiment of the present application.

The multi-rotor aircraft control device of the embodiment of the present application may be a PC. As shown in FIG1 , the multi-rotor aircraft control device may include: a processor 1001, such as a CPU, a network interface 1004, a user interface 1003, a memory 1005, and a communication bus 1002. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1005 may be a high-speed RAM memory, or a stable memory (non-volatile memory), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

Optionally, the multi-rotor aircraft control device may also include a camera, an RF (Radio Frequency) circuit, a sensor, an audio circuit, a WiFi module, etc. Among them, sensors such as light sensors, motion sensors and other sensors are not described here.

Those skilled in the art will appreciate that the terminal structure shown in FIG. 1 does not constitute a limitation on the multi-rotor aircraft control device, and may include more or fewer components than shown, or a combination of certain components, or a different arrangement of components.

As shown in FIG. 1 , the memory 1005 as a computer storage medium may include an operating system, a network communication module, a user interface module, and computer-readable instructions.

In the multi-rotor aircraft control device shown in Figure 1, the network interface 1004 is mainly used to connect to the background server and communicate data with the background server; the user interface 1003 is mainly used to connect to the client (user end) and communicate data with the client; and the processor 1001 can be used to call the computer-readable instructions stored in the memory 1005.

The multi-rotor aircraft control device includes: a memory 1005, a processor 1001, and computer-readable instructions stored in the memory 1005 and executable on the processor 1001, wherein the processor 1001 calls the computer-readable instructions stored in the memory 1005 and executes the steps of the multi-rotor aircraft control method in the following embodiments.

The present application also provides a method, referring to FIG. 2 , which is a flow chart of a first embodiment of a control method for a multi-rotor aircraft of the present application.

The control method of the multi-rotor aircraft is applied to a multi-rotor UAV, and comprises the following steps:

Step S101, based on the current operating state of the multi-rotor UAV, determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV.

A multi-rotor UAV refers to an unmanned rotorcraft with more than 4 rotors. The control efficiency matrix is a matrix that describes the relationship between the UAV control channel and the rotational speed of the multi-rotor UAV. The number of column vectors in the control efficiency matrix is determined by the number of rotors of the multi-rotor UAV, and the number of row vectors is determined by the number of control channels of the UAV. For example, a multi-rotor UAV has 8 propellers and 4 control channels. The 4 control channels control the thrust, rolling moment, pitching moment, and yaw moment respectively. In the control efficiency matrix, each column represents a propeller, and there are 8 columns in total. The first row represents the contribution of each propeller to the thrust, the second row represents the contribution to the rolling moment, the third row represents the contribution to the pitching moment, and the fourth row represents the contribution to the yaw moment.

Specifically, when the multi-rotor UAV is in flight, the electronic control of the multi-rotor UAV monitors the operating status of the multi-rotor UAV in real time, including the current/speed in the motor/rotor, etc. The operating status of the motor/rotor system can be evaluated in the form of a numerical ratio, for example, the current speed/expected speed, the current tension/theoretical tension at the current speed. If the current motor/rotor operates as expected, it is represented by 1. If the motor/rotor does not operate as expected, it is represented by a numerical ratio, and a complete failure is 0. The range of the numerical ratio can be set to 0 to 1, and the current speed/expected speed or current tension/theoretical tension at the current speed of each rotor is used as a row vector, and the number of control channels is used as a column vector to determine the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV. In general, each propeller in the control efficiency matrix of a multi-rotor drone in normal flight is operating normally, providing stable force for each control channel of the multi-rotor drone. If the current/speed provided by the motor/rotor changes, such as insufficient energy, resulting in insufficient current, or damage to the rotor, resulting in its speed not being able to provide the required force, the control efficiency matrix will change. For example, if motor No. 1 fails completely, the first column of the control efficiency matrix will become 0. At this time, based on the state change of the multi-rotor drone, the control efficiency matrix of the rotor drone must be re-determined. By real-time monitoring of the operating status of the multi-rotor drone, the control efficiency matrix corresponding to each rotor in the rotor system is determined, which realizes the control of the specific power situation of the drone flight, and can better understand the power situation of the drone, so as to maintain the stability of the drone in the future.

Step S102: if the control efficiency matrix satisfies a preset speed distribution condition, a control distribution matrix corresponding to the control efficiency matrix is obtained.

The control allocation matrix is used to calculate the speed distribution matrix that each propeller needs to allocate. During the flight of a multi-rotor drone, if the operating state of the motor/rotor changes, the control efficiency matrix will change. The control efficiency matrix can be converted into a control allocation matrix by inverting the control efficiency matrix, that is, the control allocation matrix is the inverse matrix of the control efficiency matrix. If the control efficiency matrix cannot be inverted, the control efficiency matrix cannot be obtained. Therefore, whether the control efficiency matrix can be inverted is used as a preset speed distribution condition, and the control efficiency matrix is inverted in real time to obtain the control allocation matrix. However, for multi-rotors with more than 4 rotors, such as 4-axis eight-propeller, its B matrix is not a square matrix and cannot be directly inverted. Therefore, its generalized inverse matrix is taken to obtain the control allocation matrix. The transposed matrix of the control efficiency matrix can be taken first, and then the generalized inverse matrix, that is, the control efficiency matrix, can be obtained based on the control efficiency matrix and its transposed matrix. The change of the control efficiency matrix is mainly reflected in the motor/rotor. For example, as shown in Figure 3, CW (Clockwise) means that the synchronous motor rotates clockwise, CCW (Counter Clockwise) indicates that the synchronous motor rotates counterclockwise, motors/rotors 1/4/6/7 are the right motors/rotors of the multi-rotor drone, motors/rotors 2/3/5/8 are the left motors/rotors of the multi-rotor drone, and x and y are vector axes. When motors/rotors 2/5/3/8 fail completely, control allocation cannot be performed. Intuitively, the four propellers on the left side of the aircraft do not rotate, so the aircraft cannot maintain balance. At this time, the control allocation matrix cannot be obtained through the control efficiency matrix, and then there is no adjustment of the speed of the remaining propellers. At this time, the control efficiency matrix does not meet the preset speed allocation conditions, but assuming that motors 5/6/7/8 fail completely, that is, the upper four propellers stop rotating, then the lower four propellers can still maintain balance, and the flight of the multi-rotor drone can be stabilized by controlling the speed of the rotors. Mathematically speaking, the control allocation matrix can be calculated through the control efficiency matrix at this time, that is, the preset speed allocation conditions are met, and the control efficiency matrix can be inverted to obtain the control allocation matrix. By judging whether the current multi-rotor UAV's control efficiency matrix meets the preset speed distribution conditions, the corresponding control distribution matrix is obtained, which enables precise control of the multi-rotor UAV's control distribution speed. The obtained control distribution matrix can greatly improve the accuracy of subsequent rotor speed distribution.

Step S103: determining a rotation speed vector corresponding to the rotor system based on the control allocation matrix, wherein the rotation speed vector includes rotation speeds to be allocated corresponding to each of the rotors.

The speed vector includes the speed size and speed direction allocated to each rotor; the speed to be allocated refers to the speed amount that each rotor needs to increase or decrease at the current speed.

During the flight of a multi-rotor drone, the motor/rotor changes, which in turn changes the control efficiency matrix and the control allocation matrix. At this time, the current rotation speed of some rotors needs to be adjusted. The changes of motors/rotors of multi-rotor drones during flight may be continuous, the control efficiency matrix may also be constantly changing, and the corresponding control allocation matrix is also changing. At this time, based on the row and column values in the control allocation matrix, the remaining motor throttle of the multi-rotor drone is allocated to the corresponding motor to increase the motor power, or based on the row and column values in the control allocation matrix, all speed vectors to be allocated are allocated to the rotors to be allocated, and the speed vectors corresponding to each rotor are determined. For example, the control allocation matrix shows that the expected pulling force of the No. 1 propeller of the multi-rotor drone is 10N, but due to the insufficient speed of the No. 1 propeller, the pulling force provided is only 8N. At this time, based on the control allocation matrix, a part of the allocable speed of the multi-rotor drone is allocated to the No. 1 propeller, so as to achieve the purpose of making the multi-rotor drone fly stably in the air, so as to achieve the purpose of making the multi-rotor drone fly stably in the air, and adjust the speed vector of the corresponding rotor by controlling the changes of the column and row vectors in the allocation matrix, so as to realize the fault-tolerant control of the real-time power situation of the multi-rotor drone, greatly improve the control degree of the rotor speed of the multi-rotor drone, and ensure its stability during flight.

Step S104, adjusting the rotation speed corresponding to each of the rotors based on the rotation speed vector, and returning to execute the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV based on the current operating state of the multi-rotor UAV.

When a multi-rotor UAV is flying in the air, the corresponding control allocation matrix is obtained by manipulating the efficiency matrix to obtain the speed vector corresponding to the rotor. After the rotor system of the multi-rotor UAV obtains the speed vector, it adjusts the speed corresponding to the rotor according to the value of the vector. For example, the speed vector of propeller No. 1 changes from +1 to +5, then 4 unit speeds are added to the original rotation direction of propeller No. 1. After the speed of the corresponding rotor is adjusted, it can generate enough force to make the multi-rotor UAV reach the desired operating state. At the same time, as the flight state of the multi-rotor UAV changes, the above steps are repeated to adjust the speed of the rotor. By continuously calculating the speed vector of the multi-rotor UAV, the speed corresponding to the rotor is adjusted so that the rotor can generate enough force, thereby realizing the detection and control of the power situation of the multi-rotor UAV, improving the fault-tolerant control capability of the rotor system to deal with various power situations, and improving the flight stability of the multi-rotor UAV.

Based on the current running state of the multi-rotor UAV, the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV is determined. If the control efficiency matrix meets the preset speed distribution condition, the control distribution matrix corresponding to the control efficiency matrix is obtained. Then, based on the control distribution matrix, the speed vector corresponding to the rotor system is determined, wherein the speed vector includes the speed to be distributed corresponding to each rotor. Finally, the speed corresponding to each rotor is adjusted based on the speed vector, and the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV based on the current running state of the multi-rotor UAV is returned. By monitoring the current running state of the multi-rotor UAV, when the multi-rotor UAV fails to fly stably due to power failure, the control efficiency matrix and the control distribution matrix are used to distribute excess speed to the rotor, so as to better control the speed of the rotor and stabilize the flight state of the multi-rotor UAV. When the multi-rotor UAV encounters power problems during flight, the rotor speed can be adjusted in real time to obtain sufficient power, thereby improving the flight stability of the multi-rotor UAV and solving the problem of poor fault tolerance control of power failure of the multi-rotor UAV.

Based on the first embodiment, a second embodiment of the control method of the multi-rotor aircraft of the present application is proposed, which includes in step S103:

Step S201, based on multiple control channels, obtaining a virtual control vector to be allocated corresponding to each of the rotors;

Step S202: determining the rotation speed vector based on the virtual control vector to be allocated and the control allocation matrix.

The control channel is the channel inside the flight control system that controls the operating status of the multi-rotor drone, such as the thrust control channel, roll control channel, pitch control channel, and yaw control channel. The virtual control vector to be allocated is the control quantity that is expected to be allocated calculated by the flight control system through the control algorithm on the control channel.

A typical flight control algorithm generally consists of two parts: a controller and a distributor. The controller mainly generates the expected virtual control vectors to be allocated for the four control channels (including altitude channel, roll channel, pitch channel, and yaw channel) based on instructions and sensor data. It is generally composed of a position loop/velocity loop/attitude loop/angular velocity loop, and is usually implemented using PID algorithm, ADRC algorithm, MPC algorithm, LQR algorithm, etc. These algorithms are roughly the same on aircraft of different configurations and can be shared.

During the flight of the multi-rotor drone, the flight control of the multi-rotor drone will calculate the virtual control vectors to be allocated on the four control channels through the PID control algorithm, namely the thrust virtual control vector to be allocated, the roll virtual control vector to be allocated, the pitch virtual control vector to be allocated, and the yaw virtual control vector to be allocated. The four virtual control vectors to be allocated constitute a virtual control vector to be allocated with a length of 4. Then the distributor of the multi-rotor drone mainly allocates the desired speed vector of each motor/rotor based on the four virtual control vectors to be allocated output by the controller, combined with the control allocation matrix and the multi-rotor configuration, and then obtains the specific speed from the speed vector and outputs the speed to the motor/rotor. Note that the speed here can be reflected in both physical speed and throttle. In essence, it is to make the motor/rotor generate the desired speed and then generate the desired force, thereby realizing power fault-tolerant control. Specifically, in one embodiment, step S202 includes:

Step a, based on the virtual control vector to be allocated, obtaining the maximum virtual control vector corresponding to the rotor system;

Step b: determining the rotation speed vector corresponding to the rotor system based on the maximum virtual control vector and the control allocation matrix.

The maximum virtual control vector refers to the maximum control vector that can be currently allocated to each rotor. When a multi-rotor drone is in flight, the flight control internal control algorithm will calculate the virtual control vectors to be allocated on the four control channels, and then calculate the maximum virtual control vector that each rotor can currently accept, and then calculate the speed vector allocated this time through the following formula:

u_i=B+*v_i;

Among them, u_i is the speed vector assigned to the i-th rotor, B+ is the control allocation matrix, and vi_i is the maximum virtual control quantity vector of the i-th rotor. The maximum virtual control quantity vector assigned at each step ensures that the speed does not exceed the remaining assignable speed, that is, each step of allocation will always saturate the speed of a certain motor/rotor, which is equivalent to seeking a value on the boundary at each step, which will neither exceed the boundary (the assigned speed is less than the preset maximum speed) nor be within the boundary (the assigned speed is greater than the preset minimum speed). The specific expression is: umin_i≤u_i≤umax_i;

Wherein, umin_i is the preset minimum speed, umax_i is the preset maximum speed, and u_i is the speed assigned to the i-th rotor. Specifically, in one embodiment, step a includes:

Step c, determining a ratio range corresponding to each of the rotors based on the control allocation matrix, the virtual control vector to be allocated, a preset maximum rotational speed corresponding to each of the rotors, and a preset minimum rotational speed corresponding to each of the rotors, and obtaining a maximum ratio within the ratio range as a first ratio corresponding to each of the rotors;

Step d: obtaining a maximum virtual control vector corresponding to the rotor system based on the largest first ratio among the first ratios corresponding to the rotors and the virtual control vector to be allocated.

The preset maximum speed and the preset minimum speed are the maximum speed and the minimum speed that each rotor can provide. The ratio range is calculated based on the condition that the currently assigned speed is greater than or equal to the preset minimum speed and less than or equal to the preset maximum speed. The first ratio is the largest ratio in the ratio range, which is mainly used as a parameter for calculating the maximum virtual control vector corresponding to the rotor system. When a multi-rotor drone is flying, based on the control allocation matrix, the virtual control vector to be allocated, the preset maximum speed corresponding to each rotor, and the preset minimum speed corresponding to each rotor, the ratio range corresponding to each rotor is obtained. For example, if a multi-rotor drone has 8 propellers, there are 8 ratio ranges. Then, each rotor takes the largest ratio in the corresponding ratio range as the first ratio. Finally, the largest first ratio among all the first ratios and the virtual control vector to be allocated are selected to obtain the maximum virtual control vector. The formula is: v_i=k1*v_0;

Among them, v_i is the maximum virtual control quantity vector of the i-th rotor, v_0 is the virtual control vector to be allocated, and k1 is the first ratio.

Through multiple control channels, the virtual control vectors to be allocated corresponding to each rotor are obtained, and based on the virtual control vectors to be allocated and the control allocation matrix, the speed vector is determined, thereby realizing the real-time speed control of the multi-rotor UAV, greatly improving the fault tolerance of the power of the multi-rotor UAV rotor during flight, and ensuring its stability during flight.

Based on the second embodiment, a third embodiment of the control method of the multi-rotor aircraft of the present application is proposed, which, after step b, further includes:

Step S301, determining a remaining allocatable maximum speed and a remaining allocatable minimum speed based on a preset maximum speed, a preset minimum speed and a speed vector;

Step S302: setting the remaining allocatable maximum speed as a preset maximum speed, and setting the remaining allocatable minimum speed as a preset minimum speed.

The remaining allocable maximum speed is the maximum speed value that can be further allocated after the current speed allocation of each rotor, and the remaining allocable minimum speed is the minimum speed value that can be further allocated after the current speed allocation of each rotor.

After the multi-rotor drone calculates the speed assigned to each rotor through the control allocation matrix and the virtual control vector to be allocated, because the speed that can be allocated to the multi-rotor drone is limited, each time the speed is allocated to each rotor, the preset maximum speed and the preset minimum speed must be subtracted from the current allocated speed to ensure that the speed allocated in the next round will not exceed the remaining speed. The specific formula is: umax_(i+1)=umax_(i)-u_i, umin_(i+1)=umin_(i)-u_i;

Among them, umax_(i+1) is the maximum speed of each rotor at time i+1, umin_(i+1) is the minimum speed of each rotor at time i+1, umin_(i) is the preset minimum speed of each rotor at time i, umax_(i) is the preset maximum speed of each rotor at time i, and u_i is the speed allocated to each rotor at time i. After updating the remaining allocatable speed, the remaining allocatable maximum speed is set to the preset maximum speed for the next allocation, and the remaining allocatable minimum speed is set to the preset minimum speed for the next allocation, to ensure that the speed of each allocation will not exceed the preset value, specifically:

umin_(i+1)≤u_(i+1)≤umax_(i+1);

Among them, u_(i+1) is the rotation speed assigned to each rotor at time i+1.

By presetting the maximum speed, the minimum speed and the speed vector, the remaining allocatable maximum speed and the remaining allocatable minimum speed are determined, and then the remaining allocatable maximum speed is set as the preset maximum speed, and the remaining allocatable minimum speed is set as the preset minimum speed, so that the speed of each speed distribution will not exceed the remaining allocatable speed, thereby improving the accuracy of speed distribution.

Based on the first embodiment, a fourth embodiment of the control method of the multi-rotor aircraft of the present application is proposed, and step S102 includes:

Step S401, based on the manipulation efficiency matrix, obtaining a transposed matrix of the manipulation efficiency matrix, and based on the manipulation efficiency matrix and the transposed matrix, obtaining a product matrix;

Step S402: If the product matrix is reversible, determine whether the control efficiency matrix satisfies a preset speed distribution condition, and obtain a control distribution matrix corresponding to the control efficiency matrix.

After the multi-rotor UAV obtains the control efficiency matrix based on the current operating state, it determines whether the current state of the multi-rotor UAV is suitable for continuing to distribute the speed. The specific judgment method is to determine whether the control allocation matrix can be obtained based on the control efficiency matrix. However, for a multi-rotor with more than 4 rotors, such as a 4-axis 8-propeller, its control efficiency matrix is not a square matrix and cannot be directly inverted. The usual practice is to take its generalized inverse matrix B+=BT(BBT)-1, where B is the control efficiency matrix, BT is the transposed matrix of the control efficiency matrix, and B+ is the control allocation matrix. Therefore, the judgment method is to determine whether the BBT matrix is reversible. If the product matrix is reversible, it is determined that the control efficiency matrix meets the preset speed distribution condition, and the control allocation matrix corresponding to the control efficiency matrix is obtained. Specifically, in one embodiment, step S402 includes:

Step e, obtaining the inverse matrix of the product matrix;

Step f: obtaining a control allocation matrix corresponding to the manipulation efficiency matrix based on the inverse matrix and the transposed matrix.

If the current control efficiency matrix of the multi-rotor UAV meets the preset speed distribution condition, that is, the product matrix of the control efficiency matrix and its transposed matrix is invertible, then the inverse matrix of their product matrix is calculated, and then the control distribution matrix is obtained based on the generalized inverse matrix using the inverse matrix and the transposed matrix, specifically: B+=BT(BBT)-1;

Among them, BBT is the product matrix, (BBT)-1 is the inverse matrix, BT is the transposed matrix of the manipulation efficiency matrix, and B+ is the control allocation matrix.

Through the control efficiency matrix, the transposed matrix of the control efficiency matrix is obtained, and based on the control efficiency matrix and the transposed matrix, the product matrix is obtained; if the product matrix is reversible, it is determined that the control efficiency matrix satisfies the preset speed distribution condition, and the control distribution matrix corresponding to the control efficiency matrix is obtained, thereby realizing accurate judgment of the speed distribution of the multi-rotor UAV and better clarifying the speed that each rotor currently needs to be allocated.

Based on the first embodiment, a fifth embodiment of the control method of the multi-rotor aircraft of the present application is proposed, which includes in step S104:

Step S501, obtaining a second ratio corresponding to each of the rotors based on the maximum virtual control vector and the virtual control vector to be allocated, and obtaining an actual allocated rotational speed based on the second ratio and the rotational speed vector;

Step S502: adjusting the rotation speed corresponding to each of the rotors based on the actual allocated rotation speed.

The second ratio represents that the maximum virtual control vector is a multiple of the virtual control amount to be allocated, and the actual allocated rotational speed is the rotational speed actually allocated to each rotor.

The speed vector obtained by each iterative calculation is the maximum virtual control vector that can be allocated under the current power state and its corresponding speed vector. The maximum virtual control vector here refers to the vector with the longest length along the direction of the virtual control vector to be allocated. For example, the virtual control vector v_0 to be allocated is [0.60.1,0.1,0.1], and the maximum virtual control vector v_i after a motor fails completely is [0.6,0.1,0.1,0.1]*1.5. Then, the speed corresponding to the distribution of the v_0 virtual control quantity we want to achieve is u_i*v_0/v_i, that is, u_i/1.5 for the above example. The above method can complete the control distribution under the condition of motor failure, and then adjust the speed corresponding to each rotor.

Through the maximum virtual control vector and the virtual control vector to be allocated, the second ratio corresponding to each of the rotors is obtained, and based on the second ratio and the speed vector, the actual allocated speed is obtained. Then, based on the actual allocated speed, the speed corresponding to each of the rotors is adjusted, thereby achieving effective allocation of the speeds corresponding to each of the rotors, enabling the rotors to obtain more accurate allocation, and ensuring the flight stability of the multi-rotor UAV.

Based on the above embodiments, a sixth embodiment of the control method of the multi-rotor aircraft of the present application is proposed, which includes in step S101:

Step S601, determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone;

Step S602: determining the manipulation efficiency matrix based on the conventional manipulation efficiency matrix and the health coefficient.

The health coefficient represents the theoretical tension at the current tension/current speed, that is, it represents the tension loss. The conventional control efficiency matrix is the control efficiency matrix of the multi-rotor UAV when all the motors/rotors are operating normally. Specifically, in one embodiment, the operating status includes the current of the motor corresponding to each of the rotors or the speed of each of the rotors.

The electronic control of a multi-rotor drone monitors the operating status of the motor/rotor in real time, such as current/speed, etc. Through monitoring, the health coefficient of the motor/rotor system can be evaluated. The health coefficient represents the theoretical tension at the current thrust/current speed, that is, the thrust loss. When the motor/rotor system works normally, the health coefficient is 1, and when the motor/rotor system fails completely, the health coefficient is 0. The electronic control will feed back the evaluated health coefficient to the flight control. When the electronic control and the flight control lose contact (when two-way communication cannot be achieved for a period of time, the electronic control is considered to be lost, usually because the communication line is physically disconnected or the power supply battery fails), the flight control considers that the health coefficient of the motor/rotor system is 0. For a multi-rotor system, there are several channels of health coefficients for several motors/rotors. For example, the eight electronic controls of an eight-rotor all feed back the health coefficients of the motor/rotor systems they control to the flight control, and the flight control obtains a health coefficient vector of length 8. The flight control determines the control efficiency matrix based on the above health coefficients. For example, for a four-axis eight-propeller aircraft, the normal control efficiency matrix of its normal state is:

Among them, B0 is the conventional control efficiency matrix. The positive and negative signs are determined by the corresponding rotor position and rotation direction, representing the contribution of the force generated by each rotor to the overall force of the aircraft. As shown in Figure 3, the influence of the two rotors on the rolling moment on the left and right sides is naturally one positive influence and one negative influence. Each column represents a propeller, and each column represents a control channel. The first row represents the contribution of each propeller to the thrust (virtual control quantity), the second row represents the contribution to the rolling moment, the third row represents the contribution to the pitch moment, and the fourth row represents the contribution to the yaw moment. Naturally, when the rotor layout scheme changes, the conventional control efficiency matrix will also be adjusted accordingly. The general control efficiency matrix is: B=B0*[k1,k2……kn];

Among them, B0 is the control efficiency matrix under normal conditions, k is the column vector of the health coefficient, n is the number of motors/rotors, and B is the control efficiency matrix. Subsequently, based on the conventional control efficiency matrix and the health coefficient, the control efficiency matrix is determined. For example, when motor No. 1 fails completely (i.e., k1=0), the control efficiency matrix is:

The health coefficient corresponding to each rotor in the rotor system of the multi-rotor UAV is determined by the current operating state of the multi-rotor UAV, and then the control efficiency matrix is determined based on the conventional control efficiency matrix and the health coefficient, thereby realizing the expression of the operating state of the multi-rotor UAV in the form of numerical values. The control efficiency matrix more clearly describes the contribution of the corresponding rotation speed of each rotor to the virtual control quantity of each control channel, making the monitoring and control of the rotation speed more accurate and maintaining the flight stability of the multi-rotor UAV.

The present application also provides a multi-rotor aircraft, referring to FIG. 4 , the multi-rotor aircraft comprises:

A first determination module 10 is used to determine a control efficiency matrix corresponding to each rotor in a rotor system of the multi-rotor UAV based on a current operating state of the multi-rotor UAV;

An acquisition module 20, configured to acquire a control allocation matrix corresponding to the manipulation efficiency matrix if the manipulation efficiency matrix satisfies a preset speed allocation condition;

A second determination module 30 is used to determine a rotation speed vector corresponding to the rotor system based on the control allocation matrix, wherein the rotation speed vector includes a rotation speed to be allocated corresponding to each of the rotors;

The adjustment module 40 is used to adjust the rotation speed corresponding to each of the rotors based on the rotation speed vector, and return to execute the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone.

Furthermore, the first determining module 10 is further configured to:

Furthermore, the acquisition module 20 is further used for:

Furthermore, the multi-rotor aircraft is also used for:

Obtaining an inverse matrix of the product matrix;

Furthermore, the second determining module 30 is further configured to:

Furthermore, the multi-rotor aircraft is also used for:

Furthermore, the adjustment module 40 is also used for:

The methods executed by the above-mentioned program units can refer to the various embodiments of the control method of the multi-rotor aircraft in the present application, and will not be repeated here.

The present application also provides a computer-readable storage medium.

The computer-readable storage medium of the present application stores computer-readable instructions, and when the computer-readable instructions are executed by a processor, the steps of the control method of the multi-rotor aircraft as described above are implemented.

Among them, the method implemented when the computer-readable instructions running on the processor are executed can refer to the various embodiments of the control method of the multi-rotor aircraft in the present application, and will not be repeated here.

In addition, an embodiment of the present application also proposes a computer program product, which includes computer-readable instructions, and when the computer-readable instructions are executed by a processor, the steps of the control method of the multi-rotor aircraft as described above are implemented.

It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

The serial numbers of the embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present application.

The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

A control method for a multi-rotor aircraft is applied to a multi-rotor unmanned aerial vehicle, wherein the control method for the multi-rotor aircraft comprises the following steps:

Determine, based on the current operating state of the multi-rotor UAV, a control efficiency matrix corresponding to each rotor in a rotor system of the multi-rotor UAV;

If the control efficiency matrix satisfies the preset speed distribution condition, obtaining a control distribution matrix corresponding to the control efficiency matrix;

Based on the control allocation matrix, determining a rotation speed vector corresponding to the rotor system, wherein the rotation speed vector includes rotation speeds to be allocated corresponding to each of the rotors; and

The rotation speed corresponding to each of the rotors is adjusted based on the rotation speed vector, and the step of returning to execute, based on the current operating state of the multi-rotor UAV, determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV.
The control method of a multi-rotor aircraft according to claim 1, wherein the step of determining the rotation speed vector corresponding to the rotor system based on the control allocation matrix comprises:

Based on multiple control channels, obtaining a virtual control vector to be allocated corresponding to each of the rotors; and

The rotation speed vector is determined based on the virtual control vector to be allocated and the control allocation matrix.
The control method of a multirotor aircraft according to claim 2, wherein the step of determining the speed vector based on the virtual control vector to be allocated and the control allocation matrix comprises:

Based on the virtual control vector to be allocated, obtaining a maximum virtual control vector corresponding to the rotor system; and

Based on the maximum virtual control vector and the control allocation matrix, a rotation speed vector corresponding to the rotor system is determined.
The control method of a multi-rotor aircraft according to claim 3, wherein the step of obtaining the maximum virtual control vector corresponding to the rotor system based on the virtual control vector to be allocated comprises:

Determine a ratio range corresponding to each of the rotors based on the control allocation matrix, the virtual control vector to be allocated, a preset maximum rotational speed corresponding to each of the rotors, and a preset minimum rotational speed corresponding to each of the rotors, and obtain a maximum ratio within the ratio range as a first ratio corresponding to each of the rotors; and

Based on the largest first ratio among the first ratios corresponding to the rotors and the virtual control vector to be allocated, the maximum virtual control vector corresponding to the rotor system is obtained.
The control method of a multi-rotor aircraft according to claim 4, wherein after the step of determining the rotation speed vector corresponding to the rotor system based on the maximum virtual control vector and the control allocation matrix, the method further comprises:

Based on the preset maximum speed, the preset minimum speed and the speed vector, determining the remaining allocatable maximum speed and the remaining allocatable minimum speed; and,

The remaining allocatable maximum rotation speed is set as the preset maximum rotation speed, and the remaining allocatable minimum rotation speed is set as the preset minimum rotation speed.
The control method of a multi-rotor aircraft according to claim 1, wherein if the control efficiency matrix satisfies a preset speed distribution condition, the step of obtaining a control distribution matrix corresponding to the control efficiency matrix comprises:

Based on the manipulation efficiency matrix, obtaining a transposed matrix of the manipulation efficiency matrix, and based on the manipulation efficiency matrix and the transposed matrix, obtaining a product matrix; and,

If the product matrix is reversible, it is determined that the manipulation efficiency matrix satisfies a preset speed distribution condition, and a control distribution matrix corresponding to the manipulation efficiency matrix is obtained.
The control method of a multirotor aircraft according to claim 6, wherein the step of obtaining a control allocation matrix corresponding to the control efficiency matrix comprises:

Obtaining the inverse matrix of the product matrix; and,

Based on the inverse matrix and the transposed matrix, a control allocation matrix corresponding to the manipulation efficiency matrix is obtained.
The control method of a multi-rotor aircraft according to claim 1, wherein the step of adjusting the rotation speed corresponding to each of the rotors based on the rotation speed vector comprises:

Based on the maximum virtual control vector and the virtual control vector to be allocated, obtaining a second ratio corresponding to each of the rotors, and based on the second ratio and the rotation speed vector, obtaining an actual allocation rotation speed; and,

Based on the actual allocated rotation speed, the rotation speed corresponding to each of the rotors is adjusted.
The control method of a multi-rotor aircraft according to claim 1, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
The control method of a multi-rotor aircraft as described in claim 9, wherein the current operating state includes the current of the motor corresponding to each of the rotors or the rotational speed of each of the rotors.
The control method of a multi-rotor aircraft according to claim 2, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
The control method of a multi-rotor aircraft according to claim 3, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
The control method of a multi-rotor aircraft according to claim 4, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
The control method of a multi-rotor aircraft according to claim 5, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
The control method of a multi-rotor aircraft according to claim 6, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
The control method of a multi-rotor aircraft according to claim 7, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
The control method of a multi-rotor aircraft according to claim 8, wherein the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone comprises:

Determining the health coefficient corresponding to each rotor in the rotor system of the multi-rotor UAV based on the current operating state of the multi-rotor UAV; and

The steering efficiency matrix is determined based on a conventional steering efficiency matrix and the health factor.
A multi-rotor aircraft, wherein the multi-rotor aircraft comprises:

A first determination module is used to determine a control efficiency matrix corresponding to each rotor in a rotor system of the multi-rotor UAV based on a current operating state of the multi-rotor UAV;

an acquisition module, configured to acquire a control allocation matrix corresponding to the manipulation efficiency matrix if the manipulation efficiency matrix satisfies a preset speed allocation condition;

A second determination module is used to determine a rotation speed vector corresponding to the rotor system based on the control allocation matrix, wherein the rotation speed vector includes a rotation speed to be allocated corresponding to each of the rotors;

The adjustment module is used to adjust the rotation speed corresponding to each of the rotors based on the rotation speed vector, and return to execute the step of determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor drone based on the current operating state of the multi-rotor drone.
A control device for a multi-rotor aircraft, wherein the control device for the multi-rotor aircraft comprises a memory, a processor, and computer-readable instructions stored in the memory and executable on the processor, wherein when the computer-readable instructions are executed by the processor, the following steps are implemented:

Determine, based on the current operating state of the multi-rotor UAV, a control efficiency matrix corresponding to each rotor in a rotor system of the multi-rotor UAV;

If the control efficiency matrix satisfies the preset speed distribution condition, obtaining a control distribution matrix corresponding to the control efficiency matrix;

Based on the control allocation matrix, determining a rotation speed vector corresponding to the rotor system, wherein the rotation speed vector includes rotation speeds to be allocated corresponding to each of the rotors; and

The rotation speed corresponding to each of the rotors is adjusted based on the rotation speed vector, and the step of returning to execute, based on the current operating state of the multi-rotor UAV, determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV.
A computer-readable storage medium, wherein the computer-readable storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by a processor, the following steps are implemented:

Determine, based on the current operating state of the multi-rotor UAV, a control efficiency matrix corresponding to each rotor in a rotor system of the multi-rotor UAV;

If the control efficiency matrix satisfies the preset speed distribution condition, obtaining a control distribution matrix corresponding to the control efficiency matrix;

Based on the control allocation matrix, determining a rotation speed vector corresponding to the rotor system, wherein the rotation speed vector includes rotation speeds to be allocated corresponding to each of the rotors; and

The rotation speed corresponding to each of the rotors is adjusted based on the rotation speed vector, and the step of returning to execute, based on the current operating state of the multi-rotor UAV, determining the control efficiency matrix corresponding to each rotor in the rotor system of the multi-rotor UAV.