Method and system for determining the equilibrium state of a multi-copter in the presence of random rotor failures

Abstract

The present application relates to the aviation equipment industry, the field of rotary wing aircraft, and proposes a kind of multi-rotor aircraft rotor random failure under the method and system of judging equilibrium state, method includes the following steps: S1, determine the azimuth of rotor assembly number and rotor assembly;S2, determine rotor assembly state vector;S3, define the virtual coordinate system of equilibrium state, set initial value as 1;S4, obtain the first angle and second angle in virtual coordinate system time;S5, obtain rotor assembly torque parameter;S6, judge whether the whole machine is in equilibrium state;S7, output judging result.System includes: the azimuth determination module of rotor assembly, rotor assembly state acquisition module, virtual coordinate system record module, angle acquisition module, rotor assembly torque parameter acquisition module, equilibrium state judging module and output module.The present application is fast in calculation, can evaluate aircraft equilibrium state in real time, and lay the foundation for ensuring the safe operation of aircraft.

Description

Technical Field

[0001] The invention relates to the aviation equipment industry and the field of rotorcraft, specifically to a method and system for determining the balance state under random rotor failure of a multi-rotor aircraft. Background Technology

[0002] Multirotor aircraft are typically low-altitude unmanned or manned aircraft that generate lift and thrust using an even number of coaxially symmetrically distributed rotors, such as quadcopters, hexacopterers, and octocopters. Multirotor aircraft can achieve various flight states, including vertical takeoff and landing, hovering, inverted flight, and lateral flight, through multiple rotors. The rotor assembly includes propellers and motors. The motors drive the propellers to rotate, generating lift and torque. By setting adjacent propellers to rotate in opposite directions, the torques generated by each propeller can cancel each other out, keeping the multirotor aircraft in a balanced state.

[0003] However, the operating environment for multirotor aircraft is complex and dynamic. Gusts and obstacles can cause collisions. Furthermore, multirotor aircraft typically use low-cost components. These factors lead to random failures during use, such as propeller breakage, motor malfunction, and motor performance degradation. When the torque cannot be offset by adjusting the remaining propeller speed, the entire aircraft will enter an unbalanced state, causing instability, spin-over, or even a crash, severely impacting the reliability of the multirotor aircraft.

[0004] Therefore, a common safety measure for multi-rotor aircraft in the event of rotor failure is to employ fault-tolerant control algorithms, which improve the safety of multi-rotor aircraft without adding any hardware. For example, Chinese patent application CN115367100A discloses a real-time adjustment method for helicopter rotor balance. This method uses a control model to calculate the adjustment amount of each pitch lever in the helicopter rotor vibration balance adjustment, and uses a PID feedback control algorithm to calculate the adjustment amount of each pitch lever in the helicopter rotor cone balance adjustment. By adjusting the pitch levers, simultaneous control of the helicopter rotor vibration and cone is achieved. CN113039502A discloses a rotary-wing unmanned aerial vehicle (UAV) and its control method, control device, and computer-readable storage medium. When the power of any rotor of the UAV fails, the UAV is controlled to enter a balance mode. In the balance mode, the UAV rotates at an angular velocity greater than a first threshold and less than a second threshold to achieve balance. The examples above illustrate that the primary method currently used by multi-rotor aircraft to address rotor assembly failures is by adjusting the rotational speeds of the remaining usable propellers to maintain the drone's balance. However, this approach has drawbacks. The varying rotational speeds of the odd number of remaining propellers lead to differences in lift, causing the aircraft to yaw. Furthermore, these differences in rotational speeds also result in torque variations that cannot be completely offset, causing the aircraft to spin. The combination of these two factors further increases control complexity and creates a risk of crashes. Most importantly, current technologies directly adjust the aircraft's balance without effectively assessing its equilibrium state, leaving situations where component failures can prevent the aircraft from achieving balance. Therefore, a method and system are needed to quickly determine whether a multi-rotor aircraft can achieve overall balance during adjustments when its rotors fail. Summary of the Invention

[0005] This invention proposes a method and system for determining the balance state of a multirotor aircraft under random rotor failure. Addressing the issue of torque generated by propeller rotation affecting the aircraft's attitude balance, the method considers typical rotor component failure modes during aircraft operation, monitors motor speed parameters in real time to determine the rotor component state, and determines whether the entire aircraft is in a balanced state through steps such as constructing a virtual orthogonal coordinate system and calculating the torque difference along the coordinate axes. This method offers fast calculation speed and can be embedded into the onboard control software of multirotor aircraft for rapid assessment of the aircraft's balance state.

[0006] This invention discloses a method for determining the balance state of a multi-rotor aircraft under random rotor failure, which includes the following steps:

[0007] S1. Determine the rotor assembly number and rotor assembly azimuth angle;

[0008] Starting with any rotor assembly, number the rotor assemblies sequentially in a clockwise direction. The rotor assembly numbers are: , , It is half the total number of rotor components in a multi-rotor aircraft;

[0009] S2. Determine the rotor assembly state vector;

[0010] Determine the time Time rotor assembly status , Rotor assembly state vector at any moment ;

[0011] S3. Define the virtual coordinate system for the equilibrium state. ,set up The initial value is 1;

[0012] Define a virtual coordinate system , and The virtual coordinate systems are numbered using mutually perpendicular virtual coordinate axes. ;

[0013] S4. Obtain the virtual coordinate system The first angle of time Second angle ;

[0014] S5. Obtain rotor assembly torque parameters ;

[0015] S6. Determine if the entire machine is in a balanced state;

[0016] S61, Obtain All rotor components relative to the virtual coordinate system The torque difference is:

[0017] (9);

[0018] in, Indicates rotor assembly state, Indicates rotor assembly The generated perpendicular to the coordinate axis The torque component, ; , , Indicated on the virtual coordinate axis of The set of rotor component numbers included within the range: Indicated on the virtual coordinate axis of The set of rotor component numbers included within the range;

[0019] S62. Overall machine balance status judgment;

[0020] S63, Rotor assembly status adjustment;

[0021] S7. Output the judgment result.

[0022] Preferably, the S62, the determination of the overall machine balance status, specifically involves: according to formula (9) and The proportional relationship of the remaining propeller speeds is solved. If the proportional relationship for adjusting the remaining propeller speeds can be obtained, the result is set as the multirotor aircraft being in a balanced state, and S7 is executed; otherwise, the current... After adding 1, determine the current situation. Is it greater than If not, return to S4; otherwise, execute S63.

[0023] S63, the rotor assembly state adjustment, specifically involves: setting the rotor assemblies in normal state to abnormal state; determining whether the number of rotor assemblies in normal state is greater than or equal to the minimum number of rotor assemblies in operation; if it is greater than or equal to, returning to S2 to obtain the latest current rotor assembly state vector; re-determining whether the multi-rotor aircraft can be in a balanced state; continuing until the number of rotor assemblies in normal state is less than the minimum number of rotor assemblies in operation; outputting the determination result as the multi-rotor aircraft cannot be in a balanced state; and executing S7.

[0024] Preferably, in S1, the azimuth angle of the rotor assembly For rotor assembly To rotor assembly Angle of rotation counterclockwise:

[0025] (1);

[0026] in, Number the rotor assembly. It is half the total number of rotor components in a multi-rotor aircraft. This refers to the azimuth angle of the rotor assembly.

[0027] Preferably, in S2, the rotor assembly status If and only if hour, ;otherwise, Among the conditions Indicates rotor assembly The propeller state and conditions Indicates rotor assembly Motor status and conditions Indicates rotor assembly The motor performance status is set to 1 when the status is normal.

[0028] Preferably, in step S3, when numbering the virtual coordinate system, the coordinate axes are used as the basis. Located in the rotor assembly Starting from the axis, the virtual coordinate system with coordinate axes located on the axis of a rotor assembly of a multi-rotor aircraft or on the angle bisector of the axes of two adjacent rotor assemblies is sequentially numbered in a clockwise direction.

[0029] Preferably, in step S4, specifically:

[0030] S41, Set the coordinate axes To rotor assembly The angle of rotation in the counterclockwise direction is This is called the first angle. The value can be:

[0031] (2);

[0032] in, This is the number of the current virtual coordinate system;

[0033] S42, Set the coordinate axes To rotor assembly The angle of rotation in the counterclockwise direction is This is called the second angle. The value can be:

[0034] (3);

[0035] in, This is the number of the current virtual coordinate system.

[0036] Preferably, in step S5, specifically:

[0037] S51, Obtaining what belongs to The rotor assembly number;

[0038] S52, Obtaining what belongs to The rotor assembly number;

[0039] S53, Obtain rotor assembly in Rotate counterclockwise to the virtual coordinate axis Angle , , ,when hour ,when hour ; It is based on the virtual coordinate axis The assembly of rotor components on the right. It is based on the virtual coordinate axis The assembly consisting of rotor components on the left side;

[0040] S54. Calculate the rotor assembly relative to the virtual coordinate system. The torque is calculated as follows:

[0041] (1) When the rotor assembly At that time, (7);

[0042] (2) When the rotor assembly At that time, (8);

[0043] in, , The coefficients related to the rotor's aerodynamic characteristics This represents the rotor speed.

[0044] Preferably, in S5,

[0045] Indicated on the virtual coordinate axis of The set of rotor assembly numbers included within the range; rotor assemblies conforming to formula (4) Formula (4) is:

[0046] (4);

[0047] Indicated on the virtual coordinate axis of The set of rotor component numbers included within the range, which conforms to formula (5) Formula (5) is:

[0048] (5);

[0049] express rotor assembly in Rotate counterclockwise to the virtual coordinate axis The angle between them Then we have:

[0050] (6);

[0051] in, , Values or , Values or .

[0052] Preferably, in S7,

[0053] The judgment result obtained in S6 is output. Specifically, if the multi-rotor aircraft can be in a balanced state, the judgment result includes information that the multi-rotor aircraft can be in a balanced state, the current rotor component state vector, and the proportional relationship of adjusting the remaining propeller speed; if the multi-rotor aircraft cannot be in a balanced state, the judgment result includes information that the multi-rotor aircraft cannot be in a balanced state.

[0054] This invention also discloses a system for determining the balance state under random rotor failure in the above-mentioned multi-rotor aircraft, comprising:

[0055] The rotor assembly azimuth angle determination module obtains the corresponding rotor assembly azimuth angle based on the determined rotor assembly number;

[0056] The rotor assembly status acquisition module obtains the rotor assembly status vector based on the collected motor speed and rotor assembly status settings.

[0057] The virtual coordinate system recording module is used to save all virtual coordinate systems used for multi-rotor aircraft and output the number of the currently used virtual coordinate system.

[0058] Angle acquisition module is used to obtain the first angle and the second angle based on the virtual coordinate system number given by the virtual coordinate system recording module;

[0059] The rotor assembly torque parameter acquisition module obtains the torque of each rotor assembly relative to the current virtual coordinate system by determining the azimuth angle of the rotor assembly output by the rotor assembly determination module and the first and second angles output by the angle acquisition module.

[0060] The balance state judgment module determines whether the whole machine is in a balanced state based on the torque of each rotor component relative to the virtual coordinate system output by the rotor component torque parameter acquisition module and the rotor component state vector determined by the rotor component state acquisition module.

[0061] The output module is used to output the judgment results stored in the equilibrium state judgment module.

[0062] Preferably, the equilibrium state determination module includes a rotor assembly torque difference submodule, an equilibrium solution submodule, and a rotor assembly state setting submodule, wherein:

[0063] The rotor assembly torque difference submodule is used to obtain the torque difference formula based on the torque of each rotor assembly relative to the virtual coordinate system output by the rotor assembly torque parameter acquisition module and the rotor assembly state vector determined by the rotor assembly state acquisition module.

[0064] The equilibrium solution submodule is used to solve the torque difference formula. If there is a solution, the result is output. If there is no solution, the virtual coordinate system recording module is asked to change the virtual coordinate system.

[0065] The rotor assembly status setting submodule sets normally functioning rotor assemblies to abnormal and sends the information to the rotor assembly status acquisition module. This process continues until the number of normally functioning rotor assemblies is less than the minimum number of working rotor assemblies. At this point, the system outputs a judgment that the multi-rotor aircraft cannot be in a balanced state.

[0066] Compared with the prior art, the technical effects of the present invention are as follows:

[0067] 1. The method for determining the balance state of a multi-rotor aircraft under random rotor failure proposed in this invention treats a group of coaxial rotor components as a whole. That is, when any rotor component fails, the coaxial rotor components are shut down. This provides a method for determining whether the remaining even-numbered propellers are evenly distributed, avoiding the lift-torque coupling control problem of odd-numbered propellers. It can reduce the difficulty of attitude balance control when individual rotor components of a multi-rotor aircraft experience random failure. This method is applicable to aircraft with large payloads, low speeds, and a large number of rotors, such as ten-rotor or twelve-rotor aircraft, and helps promote the application of such aircraft in low-altitude manned flight and industrial scenarios.

[0068] 2. The method for judging the balance state under random failure of multi-rotor aircraft rotor proposed in this invention takes into account the random failure situations that often occur in rotor components, such as propeller breakage and propeller ejection, motor failure and shutdown, and motor performance degradation and speed reduction. It determines whether the corresponding rotor component has failed by monitoring the speed parameters of each motor.

[0069] 3. The method for judging the balance state of a multi-rotor aircraft under random rotor failure proposed in this invention only uses parameters such as rotor azimuth angle and motor speed, and performs traversal calculations on the virtual coordinate system position. It does not involve complex calculations and can quickly output the balance state judgment result. Attached Figure Description

[0070] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0071] Figure 1 This is a schematic diagram showing the rotor rotation direction of the multi-rotor aircraft of the present invention;

[0072] Figure 2This is a flowchart of the method for determining the balance state of a multi-rotor aircraft under random rotor failure according to the present invention;

[0073] Figure 3 This invention provides an algorithmic framework for determining the equilibrium state of a multi-rotor aircraft under random rotor failure.

[0074] Figure 4 This is the monitoring result of the motor speed parameters of the twelve-rotor aircraft in this embodiment of the invention;

[0075] Figure 5 For the present invention , A schematic diagram of the motor status and virtual coordinate system at that time;

[0076] Figure 6 For the present invention , A schematic diagram of the motor status and virtual coordinate system at that time;

[0077] Figure 7 For the present invention , A schematic diagram of the motor status and virtual coordinate system at that time;

[0078] Figure 8 This is a schematic diagram of the torque of the rotor assembly when the propeller rotates clockwise.

[0079] Figure 9 This is a schematic diagram of the torque of the rotor assembly when the propeller rotates counterclockwise according to the present invention;

[0080] Figure 10 This is a schematic diagram of the balance state determination system for a multi-rotor aircraft under random rotor failure according to the present invention. Detailed Implementation

[0081] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0082] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0083] This invention discloses a method for determining the balance state of a multi-rotor aircraft under random rotor failure, such as... Figure 2 and Figure 3 As shown, the method includes the following steps:

[0084] S1. Determine the rotor assembly number And the azimuth angle of the rotor assembly.

[0085] A rotor assembly of a multirotor aircraft includes at least one propeller and a corresponding motor. In this invention, the number of rotor assemblies in the multirotor aircraft is always even. Starting from any rotor assembly, the rotor assemblies are numbered sequentially in a clockwise direction, and the rotor assembly number is... That is, the first Each rotor assembly is referred to as a rotor assembly. The set of rotor components symmetrically distributed on the same axis is numbered as follows: To make the rotor assembly To rotor assembly The angle of rotation in the counterclockwise direction is Therefore The value can be:

[0086] (1);

[0087] in, For rotor assembly number, It is half the total number of rotor components in a multi-rotor aircraft.

[0088] like Figure 1 As shown, taking a twelve-rotor aircraft as an example, the rotor components are numbered sequentially as follows: ,in Therefore, the rotor assembly can be obtained. azimuth rotor assembly To rotor assembly The angle of counterclockwise rotation is shown in Table 1.

[0089] Table 1 Rotor Components azimuth

[0090]

[0091] S2, Determine the rotor assembly status .

[0092] Determine the rotor assembly status If and only if hour, ;otherwise, Among the conditions Indicates rotor assembly The propeller state and conditions Indicates rotor assembly Motor status and conditions Indicates rotor assembly The motor performance status is set to 1 when the status is normal. (Time) At that time, based on the state of each rotor assembly get Rotor assembly state vector at any moment .

[0093] S21, Conditions Indicates rotor assembly The condition of the propeller is important, as a broken propeller can cause a sudden decrease in the load on the corresponding motor, affecting the motor speed. It will rise abnormally when the motor speed... The change per unit time is less than the threshold. At that time, the propeller is considered intact. Therefore:

[0094] .

[0095] S22, Conditions Indicates rotor assembly The motor status and whether a motor malfunction has occurred can be monitored in real time by obtaining the motor speed via the ESC or an external sensor. When a motor malfunctions, its speed drops sharply to zero or near zero, indicating that the motor has stopped. Therefore:

[0096] .

[0097] S23. Conditions Indicates rotor assembly Is the motor in good working order? When the motor is working normally, its speed will be controlled at its maximum speed. and safe speed Between these points, prolonged use of a motor can lead to performance degradation and a decrease in speed. When the speed drops below the safe operating speed, the motor is considered to be in abnormal condition. Therefore:

[0098] .

[0099] S24, When the rotor assembly The state becomes At that time, the order is:

[0100] .

[0101] That is, when the rotor assembly When random failures occur, the rotor assembly Rotor assemblies symmetrically distributed on the same axis are also set to fail. Based on the state of each rotor, the rotor assembly state vector for the corresponding time is obtained.

[0102] Under normal circumstances, the rotational speed of each motor in the twelve-rotor aircraft in this embodiment will be controlled between 2000 rpm and 5500 rpm. and The electronic speed control (ESC) system controls the aircraft's attitude by changing the speed of each motor. The initial moment is... season This means that all rotor components are functioning normally in the initial state. Figure 4 The monitoring results for the speeds of each motor are presented, and it can be seen that:

[0103] (1) At that time, the speed of motor 7 suddenly drops to zero. According to S22, it can be determined that motor 7 has malfunctioned and stopped, i.e., condition... Therefore, motor 1, which is coaxial with it, needs to be shut down. Thus, the rotor assembly state vector is updated as follows:

[0104] ;

[0105] in, This represents the rotor assembly state vector at time 32.

[0106] (2) At that time, the speed of motor 6 gradually decreased to According to S23, it can be determined that motor 6 has experienced performance degradation, i.e., condition... Therefore, the coaxial motor 12 needs to be shut down, so the rotor assembly state vector is updated as follows:

[0107] ;

[0108] in, This represents the rotor assembly state vector at time 88.

[0109] (3) At that time, the speed of motor 3 abnormally increased to Based on S21, it can be determined that the load on motor 3 may be reduced due to propeller breakage, i.e., condition... Therefore, motor 9, which is coaxial with it, needs to be shut down. Thus, the rotor assembly state vector is updated as follows:

[0110] ;

[0111] in, This represents the rotor assembly state vector at time 135.

[0112] S3. Define the virtual coordinate system for the equilibrium state. , The initial value is 1.

[0113] Define a virtual coordinate system Used to assist in determining the overall balance of the machine, among which and The coordinate axes are mutually perpendicular, in this invention axial direction The direction after the axis is rotated 90 degrees counterclockwise.

[0114] Number the virtual coordinate system, using the coordinate axes Located in the rotor assembly Starting from the axis in question, and proceeding clockwise, the virtual coordinate systems whose axes lie on the axis containing one rotor assembly of the multirotor aircraft or on the angle bisector of the axes containing two adjacent rotor assemblies are sequentially numbered. .

[0115] In this embodiment, the coordinate axes are referred to as coordinate axes. The virtual coordinate system located on the axis where rotor assembly 1 is located is virtual coordinate system 1; coordinate axes The virtual coordinate system located on the bisector of the axis containing rotor assembly 1 and rotor assembly 2 is virtual coordinate system 2; coordinate axes The virtual coordinate system located on the axis where rotor assembly 2 is located is virtual coordinate system 3; coordinate axes The virtual coordinate system located on the bisector of the axis containing rotor assembly 2 and rotor assembly 3 is called virtual coordinate system 4; and so on, they are called coordinate axes. The virtual coordinate system located on the bisector of the axis containing rotor assembly 6 and rotor assembly 7 is virtual coordinate system 12.

[0116] S4. Obtain the virtual coordinate system The first and second angles at that time.

[0117] S41, Set the coordinate axes The angle by which rotor assembly 1 rotates counterclockwise is This is called the first angle. The value can be:

[0118] (2);

[0119] in, This is the number of the current virtual coordinate system.

[0120] S42, Set the coordinate axes The angle by which rotor assembly 1 rotates counterclockwise is This is called the second angle. The value can be:

[0121] (3);

[0122] in, This is the number of the current virtual coordinate system.

[0123] The following explanation uses the three times listed in S2 as examples:

[0124] (1) such as Figure 5 As shown, it gives A schematic diagram of the motor state and virtual coordinate system at that time. According to S3, Figure 5 At this point, the virtual coordinate system is virtual coordinate system 1, that is... According to S4, the virtual coordinate axis is known. and The first and second angles of the rotor assembly 1 rotating counterclockwise are:

[0125] .

[0126] (2) For example Figure 6 As shown, it gives A schematic diagram of the motor state and virtual coordinate system at that time. According to S3, Figure 6 At this point, the virtual coordinate system is virtual coordinate system 6, that is... According to S4, the virtual coordinate axis is known. and The first and second angles of the rotor assembly 1 rotating counterclockwise are:

[0127] .

[0128] (3) such as Figure 7 As shown, it gives A schematic diagram of the motor state and virtual coordinate system at that time. According to S3, Figure 7 At this point, the virtual coordinate system is virtual coordinate system 12, that is... According to S4, the virtual coordinate axis is known. and The first and second angles of the rotor assembly 1 rotating counterclockwise are:

[0129] .

[0130] The three examples above are only determined during the calculation process. A demonstration step following the value, actually Determining whether a multirotor aircraft can maintain balance after a random rotor failure requires using a virtual coordinate system. Perform a traversal.

[0131] S5. Calculate the rotor assembly torque parameters .

[0132] S51, Indicated on the virtual coordinate axis of The set of rotor component numbers included within the range:

[0133] (4);

[0134] Rotor assembly conforming to formula (4) .

[0135] S52, Indicated on the virtual coordinate axis of The set of rotor component numbers included within the range:

[0136] (5);

[0137] Rotor assembly conforming to formula (5) .

[0138] S53, express rotor assembly in Rotate counterclockwise to the virtual coordinate axis The angle between them Then we have:

[0139] (6);

[0140] in, ,when time i ,when time i , , Values or ,therefore, Values or , It is based on the virtual coordinate axis The assembly of rotor components on the right. It is based on the virtual coordinate axis The assembly consisting of rotor components on the left side;

[0141] S54. Calculate the rotor assembly relative to the virtual coordinate system. The torque. For example... Figure 8 and Figure 9 As shown, when the propeller rotates, it generates a force perpendicular to the rotor assembly. The torque is located on the axis in question, and its direction is exactly opposite when the propeller rotates in different directions. This torque is perpendicular to the virtual coordinate axis. The amount This will cause the aircraft to have a relative motion tendency, and the calculation method is as follows:

[0142] (1) When the rotor assembly At that time,

[0143] ;(7)。

[0144] (2) When the rotor assembly At that time,

[0145] ;(8);

[0146] in, , The coefficients related to the rotor's aerodynamic characteristics This refers to the rotor speed. When the rotor is directly driven by the motor, then... It equals the motor speed; when the rotor is driven by a reduction gear system, then... , This refers to the motor speed. This is the reduction ratio.

[0147] The following examples illustrate the use of the three times and virtual coordinate axes listed in S2:

[0148] (1) For , The situation.

[0149] As can be seen from S4, Furthermore, based on S51 and the azimuth angles of each rotor assembly given in Table 1, It can be determined that the coordinate axes are contained within the coordinate axes. of Rotor assembly within range See Table 2.

[0150] Table 2 and time

[0151]

[0152] Similarly, from S4, we can see that... Furthermore, based on S52 and the azimuth angles of each rotor assembly given in Table 1, It can be determined that the coordinate axes are contained within the coordinate axes. of Rotor assembly within range See Table 3.

[0153] Table 3 and time

[0154]

[0155] According to S53 and S54, we can obtain... rotor assembly in Rotate counterclockwise to the angle between the corresponding coordinate axes. and As shown in Table 4.

[0156] Table 4 hour The corresponding element in the middle and

[0157]

[0158] (2) For , The situation.

[0159] As can be seen from S4, Furthermore, based on S51 and the azimuth angles of each rotor assembly given in Table 1, It can be determined that the coordinate axes are contained within the coordinate axes. of Rotor assembly within range See Table 5.

[0160] Table 5 and time

[0161]

[0162] Similarly, from S4, we can see that... Furthermore, based on S52 and the azimuth angles of each rotor assembly given in Table 1, It can be determined that the coordinate axes are contained within the coordinate axes. of Rotor assembly within range See Table 6.

[0163] Table 6 and time

[0164]

[0165] According to S53 and S54, we can obtain... rotor assembly in Rotate counterclockwise to the angle between the corresponding coordinate axes. and As shown in Table 7.

[0166] Table 7 hour The corresponding element in the middle and

[0167]

[0168] (3) For , The situation.

[0169] As can be seen from S4, Furthermore, based on S51 and the azimuth angles of each rotor assembly given in Table 1, It can be determined that the coordinate axes are contained within the coordinate axes. of Rotor assembly within range See Table 8.

[0170] Table 8 and time

[0171]

[0172] Similarly, from S4, we can see that... Furthermore, based on S52 and the azimuth angles of each rotor assembly given in Table 1, It can be determined that the coordinate axes are contained within the coordinate axes. of Rotor assembly within range See Table 9.

[0173] Table 9 and time

[0174]

[0175] According to S53 and S54, we can obtain... rotor assembly in Rotate counterclockwise to the angle between the corresponding coordinate axes. and As shown in Table 10.

[0176] Table 10 hour The corresponding element in the middle and

[0177]

[0178] S6. Determine whether the whole machine is in a balanced state.

[0179] S61, Obtain All rotor components relative to the virtual coordinate system The torque difference is:

[0180] (9);

[0181] in, Indicates rotor assembly The state is 1 if normal, otherwise 0; Indicates rotor assembly The generated perpendicular to the coordinate axis The torque component.

[0182] S62. Overall machine balance status judgment.

[0183] Because only when The propellers in the image generate perpendicularity to the coordinate axes. Only when all the torque components cancel each other out will the aircraft's spin tendency disappear. Therefore, when At that time, the multi-rotor aircraft can be in a balanced state, according to formula (9) and The solution is performed. If the proportional relationship of adjusting the remaining propeller speed can be obtained, it means that the multirotor can maintain a balanced attitude through adjustment. The output judgment result is set as the multirotor can be in a balanced state, the current rotor component state vector and the proportional relationship of adjusting the remaining propeller speed, and S7 is executed; otherwise, the current j is increased by 1 and the current state is judged. Is it greater than If not, return to S4, until a pair of mutually perpendicular virtual coordinate systems are found. Otherwise, execute S63.

[0184] S63, Rotor assembly status adjustment

[0185] Set the rotor components in normal condition to abnormal. Determine if the number of rotor components in normal condition is greater than or equal to the minimum number of rotor components in operation. If it is greater, return to S2 to obtain the latest current rotor component state vector. Re-determine if the multi-rotor aircraft can be in a balanced state until the number of rotor components in normal condition is less than the minimum number of rotor components in operation. Output the judgment result as the multi-rotor aircraft cannot be in a balanced state and execute S7.

[0186] In practice, the state of a pair of rotor components currently in normal condition can be set to abnormal, and the process can return to S2. If setting the state of each pair of normally functioning rotor components to abnormal still fails to bring the multirotor to a balanced state, then the state of the two pairs of normally functioning rotor components can be set to abnormal, and the process can return to S2. If setting the state of any two pairs of normally functioning rotor components to abnormal still fails to bring the multirotor to a balanced state, then the state of the three pairs of normally functioning rotor components can be set to abnormal, and the process can return to S2. This process continues until the number of remaining normally functioning rotor components is greater than or equal to the minimum number of operating rotor components. If the number is less than the minimum number of operating rotor components, it indicates that the multirotor cannot adjust its balance, and the output result is set as "multirotor cannot be in a balanced state."

[0187] The following example continues with the three times and virtual coordinate axes listed in S2, because... The coefficient is related to the rotor's aerodynamic characteristics, so let They are all the same.

[0188] (1) For , The situation.

[0189] According to Table 4 Value, determined in step 2 Then, combine with formula (9) to calculate , Torque difference parameters at time for:

[0190] ;

[0191] According to S5, if you want For a statement to be valid, the following conditions must be met:

[0192] ;

[0193] make: and Because a group of rotor components symmetrically distributed on the same axis in S1 must rotate at the same speed, and at the same time relative to... and Only when symmetrical rotors rotate at the same speed can the lift be symmetrically distributed. Therefore, the above equation can be obtained:

[0194] .

[0195] The above formula shows that: When motor 7 malfunctions and stops, motor 1 on the coaxial axis must be shut down, and the remaining propeller speed parameters should be adjusted according to the above proportional relationship to counteract the unbalanced torque, so that the multirotor aircraft can maintain a balanced attitude. At this time, the loop in S62 can be exited directly. The output judgment result prompt message is set to "The multirotor aircraft can be in a balanced state", and the current rotor component state vector is " This indicates that the motors for rotor assemblies 1 and 7 need to be shut down, and the remaining propeller speeds are adjusted proportionally as follows: and ".

[0196] (2) For , The situation.

[0197] According to Table 7 Value, determined in step 2 Then, combine with formula (9) to calculate , Torque difference parameters at time for:

[0198] .

[0199] According to S6, if you want For a statement to be valid, the following conditions must be met:

[0200] ;

[0201] Therefore, we can conclude that: and This indicates that: When motor 6 experiences performance degradation and insufficient speed, motor 12 on the coaxial axis must be shut down, and the remaining propeller speed parameters adjusted according to the aforementioned proportional relationship to counteract the unbalanced torque and maintain the aircraft's balanced attitude. In other words, in Starting from virtual coordinate system 1, when reaching virtual coordinate system 6, it is determined that the multirotor aircraft can maintain a balanced attitude. At this point, the loop in S62 can be exited. The output message for the judgment result is set to "The multirotor aircraft is in a balanced state", and the current rotor component state vector is "". This indicates that motors 1, 7, 6, and 12 of rotor assemblies need to be shut down, and the remaining propeller speed adjustment ratios are as follows: and ".

[0202] (3) For , The situation.

[0203] According to Table 10 Value, determined in step 2 Then, combine with formula (9) to calculate , Torque difference parameters at time for:

[0204] .

[0205] According to S5, if you want For a statement to be valid, the following conditions must be met:

[0206] ;

[0207] We can obtain: Obviously, this formula is not true, that is This is not true. Therefore, it can be concluded that: in When motor 3 experiences an abnormally high speed due to propeller breakage, even shutting down coaxial motor 9 cannot maintain the aircraft's balanced attitude by adjusting the remaining rotor assembly speed parameters. In other words, in... Starting from virtual coordinate system 1, when reaching virtual coordinate system 12, it is determined that the multirotor aircraft cannot maintain a balanced attitude. Then execute S63, at which point the state of the rotor assembly pair 2 and rotor assembly 8 can be set to abnormal, and return to S2 to obtain the current rotor assembly state vector. ,Right now At this point, the number of rotor components in normal state is 4, which equals the set minimum number of rotor components in operation, 4. Therefore, starting from virtual coordinate system 1, it is determined whether the multirotor aircraft can maintain a balanced attitude. Assuming that it is determined from virtual coordinate system 1 to virtual coordinate system 12 that the multirotor aircraft still cannot maintain a balanced attitude, the states of rotor components 4 and 10 are set to abnormal, and the process returns to S2 to obtain the current rotor component state vector. If it still doesn't work, set the status of rotor assembly 5 and rotor assembly 11 to abnormal. If it still doesn't work, set the status of rotor assembly 2, rotor assembly 8, rotor assembly 4, and rotor assembly 10 to abnormal. However, the number of rotor assemblies in normal state is 2, which is less than the minimum number of rotor assemblies in operation set at 4. Therefore, the loop ends and the judgment result is set as the multi-rotor aircraft cannot be in a balanced state.

[0208] S7. Output the judgment result.

[0209] The output will show the judgment result set in S6. Specifically, if the multirotor aircraft can achieve a balanced state, the judgment result will include information about whether the multirotor aircraft is in a balanced state, the current rotor assembly state vector, and the proportional relationship for adjusting the remaining propeller speed. If the multirotor aircraft cannot achieve a balanced state, the judgment result will include information about whether the multirotor aircraft is in a balanced state. Subsequently, based on actual needs, it can be determined whether to shut down the normally functioning rotor assembly and adjust its speed to allow the aircraft to continue flying, or to initiate other emergency procedures.

[0210] This invention also proposes a system for determining the balance state under random rotor failure in multi-rotor aircraft, such as... Figure 10 As shown, it includes: a rotor assembly azimuth angle determination module 21, a rotor assembly state acquisition module 22, a virtual coordinate system recording module 23, an angle acquisition module 24, a rotor assembly torque parameter acquisition module 25, a balance state judgment module 26, and an output module 27, wherein:

[0211] The rotor assembly azimuth angle determination module 21 obtains the azimuth angle of the corresponding rotor assembly based on the determined rotor assembly number.

[0212] The rotor assembly status acquisition module 22 obtains the rotor assembly status vector based on the collected motor speed and rotor assembly status setting value.

[0213] The virtual coordinate system recording module 23 is used to save all virtual coordinate systems used for multi-rotor aircraft and output the number of the currently used virtual coordinate system.

[0214] Angle acquisition module 24 is used to obtain the first angle and the second angle based on the virtual coordinate system number given by the virtual coordinate system recording module.

[0215] The rotor assembly torque parameter acquisition module 25 obtains the torque of each rotor assembly relative to the current virtual coordinate system by determining the azimuth angle of the rotor assembly from the azimuth angle determination module and the first and second angles from the angle acquisition module.

[0216] The balance state determination module 26 determines whether the entire aircraft is in a balanced state based on the torque of each rotor component relative to the virtual coordinate system output by the rotor component torque parameter acquisition module and the rotor component state vector determined by the rotor component state acquisition module. The balance state determination module includes a rotor component torque difference submodule 261, a balance solution submodule 262, and a rotor component state setting submodule 263, specifically as follows:

[0217] The rotor assembly torque difference submodule 261 is used to obtain the torque difference formula based on the torque of each rotor assembly relative to the virtual coordinate system output by the rotor assembly torque parameter acquisition module and the rotor assembly state vector determined by the rotor assembly state acquisition module.

[0218] The equilibrium solution submodule 262 is used to solve the torque difference formula. If there is a solution, the result is output. If there is no solution, the virtual coordinate system recording module is instructed to change the virtual coordinate system.

[0219] The rotor assembly status setting submodule 263 sets the rotor assemblies in normal status to abnormal and sends the status to the rotor assembly status acquisition module until the number of rotor assemblies in normal status is less than the minimum number of rotor assemblies in operation. The output judgment result is that the multi-rotor aircraft cannot be in a balanced state.

[0220] Output module 27 is used to output the judgment results stored in the equilibrium state judgment module.

[0221] This invention proposes a method and apparatus for determining the overall balance state of a multirotor aircraft under random rotor failure. Addressing the issue of propeller rotation generating torque that affects the aircraft's attitude balance, the method considers typical rotor component failure modes during aircraft operation. It determines the rotor component status by real-time monitoring of motor speed parameters and uses steps such as constructing a virtual orthogonal coordinate system and calculating the torque difference along the coordinate axes to determine whether the entire aircraft is in a balanced state. This method offers fast calculation speed and can be embedded into the onboard control software of multirotor aircraft to evaluate the aircraft's balance state in real time, thus laying the foundation for ensuring the safe operation of the aircraft.

[0222] Finally, it should be noted that the above embodiments are for illustration only and not for limiting the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for determining the equilibrium state of a multi-copter aircraft in the presence of random rotor failures, the method comprising: It comprises the following steps: ​ S1, determining rotor assembly number and rotor assembly azimuth angle; With any rotor assembly as a starting point, and in turn sequentially numbering the rotor assemblies in a clockwise direction, the rotor assembly is numbered as , , is half of the total number of rotor assemblies of the multicopter. Rotor assembly azimuth angle For rotor assembly To rotor assembly Angle of rotation in counterclockwise direction: （1）； wherein, is the number of rotor assemblies, is half the total number of rotor assemblies of the multicopter, is the azimuth angle of the rotor assembly; S2, determining rotor assembly state vector; determining a state of a rotor assembly at a time , moment rotor assembly state vector ;​​ S3, define the balance state virtual coordinate system , set initial value is 1; Defining a virtual coordinate system , and are mutually perpendicular virtual coordinate axes, numbering the virtual coordinate system, virtual coordinate system numbering ; S4, obtaining a virtual coordinate system a first angle at a time and a second angle ; S41, the coordinate axis to the rotor assembly the angle of rotation in the counterclockwise direction is , referred to as the first angle, the value of the first angle is: （2）； wherein, is the number of the current virtual coordinate system; S42, the coordinate axis to the rotor assembly the angle of rotation in the counterclockwise direction is , referred to as the second angle, the value of （3）； wherein, is the number of the current virtual coordinate system; S5, obtaining rotor assembly moment parameters ; S6, judging whether the whole machine is in a balanced state; S61、acquire The moment difference of all rotor assemblies in the virtual coordinate system is: （9）； wherein represents the state of the rotor assembly , represents the moment component of the force generated by the rotor assembly perpendicular to the coordinate axis , ; , , represents the set of rotor assembly numbers contained within the range of the virtual coordinate axis , ; represents the set of rotor assembly numbers contained within the range of the virtual coordinate axis , ; S62, whole machine balanced state judgment; S63, rotor assembly state adjustment; S7, outputting the judgment result.

2. The method of claim 1, wherein: The steps S62 and S63 are specifically: S62, whole machine balanced state judgment; According to formula (9) and Solving the proportional relationship of the remaining propeller speed, if the proportional relationship of the remaining propeller speed is obtained, the judgment result is set to be that the multi-rotor aircraft can be in a balanced state, and S7 is executed; otherwise, the current S7 is executed. whether it is greater than If not, return to S4, otherwise execute S63; S63, rotor assembly state adjustment The rotor assembly in a normal state is set as abnormal, and it is judged whether the number of rotor assemblies in a normal state is greater than or equal to the minimum rotor assembly working number. If it is greater than or equal to, it returns to S2 to obtain the latest current rotor assembly state vector, rejudge whether the multi-rotor aircraft can be in a balanced state, until the number of rotor assemblies in a normal state is less than the minimum rotor assembly working number, and the output judgment result is set as that the multi-rotor aircraft cannot be in a balanced state, and S7 is executed.

3. The method of claim 2, wherein: In S2, the rotor assembly is in a state if and only if ; and ; Otherwise, where the condition represents the state of the propeller in the rotor assembly , the condition represents the state of the motor in the rotor assembly , the condition represents the state of the motor performance in the rotor assembly , the value of the corresponding condition is taken as 1 when the state is normal.

4. The method of claim 1, wherein: In the S3, the virtual coordinate system is numbered from the coordinate axis The axis where the rotor assembly The axis where the rotor assembly The virtual coordinate system located on the axis of one rotor assembly or the angle bisector of the axes of two adjacent rotor assemblies of the multicopter is sequentially numbered in the clockwise direction.

5. The method of claim 1, wherein: In the S5, specifically: S51, obtaining the rotor assembly number belonging to the rotor assembly number; S52, obtaining the rotor assembly number belonging to the rotor assembly number; S53, obtain rotor assemblies in rotates to the virtual coordinate axis in the counterclockwise direction angle of the included angle , , when time when time ; is a set composed of rotor assemblies on the right side of the virtual coordinate axis , is a set composed of rotor assemblies on the left side of the virtual coordinate axis ; S54, calculating the moment of the rotor assembly relative to the virtual coordinate system S54, calculating the moment of the rotor assembly relative to the virtual coordinate system (1) when the rotor assembly is in the (7) (2) when the rotor assembly is in flight (8); wherein , is a coefficient related to the aerodynamic characteristics of the rotor, is the rotor rotational speed.

6. The method of claim 5, wherein: In the S5, represents a set of rotor assembly numbers contained within a range of virtual coordinate axes of formula (4); rotor assemblies that satisfy formula (4), formula (4) being: ​ （4）； represents a set of rotor assembly numbers contained in a range of virtual coordinate axes of formula (5), formula (5) being: ​ （5）； indicates rotor assembly in rotates in a counter-clockwise direction to a virtual coordinate axis the angle subtended by, then, （6）； wherein , is or , is or .

7. A system for the method of claim 1, wherein: It comprises: The azimuth angle determination module of the rotor assembly obtains the azimuth angle of the corresponding rotor assembly according to the determined rotor assembly number; The rotor assembly state acquisition module obtains the rotor assembly state vector according to the collected motor speed and rotor assembly state setting value; The virtual coordinate system recording module is used for saving all virtual coordinate systems of the multi-rotor aircraft and outputting the current virtual coordinate system number; The angle acquisition module is used for obtaining the first angle and the second angle according to the virtual coordinate system number given by the virtual coordinate system recording module; The rotor assembly moment parameter acquisition module obtains the moment of each rotor assembly relative to the current virtual coordinate system according to the azimuth angle of the rotor assembly output by the azimuth angle determination module of the rotor assembly, the first angle and the second angle output by the angle acquisition module; The balanced state judgment module judges whether the whole machine is in a balanced state according to the moment of each rotor assembly relative to the virtual coordinate system output by the rotor assembly moment parameter acquisition module and the rotor assembly state vector determined by the rotor assembly state acquisition module; The output module is used for outputting the judgment result saved by the balanced state judgment module.

8. The system of claim 7, wherein: The balanced state judgment module comprises a rotor assembly moment difference sub-module, a balance solving sub-module and a rotor assembly state setting sub-module, wherein: The rotor assembly moment difference sub-module is used for obtaining the moment difference formula according to the moment of each rotor assembly relative to the virtual coordinate system output by the rotor assembly moment parameter acquisition module and the rotor assembly state vector determined by the rotor assembly state acquisition module; The balance solving sub-module is used for solving the moment difference formula. If there is a solution, the result is output. If there is no solution, the virtual coordinate system recording module is replaced with a virtual coordinate system; The rotor assembly state setting sub-module sets the rotor assembly in a normal state as abnormal and sends it to the rotor assembly state acquisition module, until the number of rotor assemblies in a normal state is less than the minimum rotor assembly working number, and the output judgment result is that the multi-rotor aircraft cannot be in a balanced state.

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