Airborne propeller deployment control system and method for air-dropped multi-copter unmanned aerial vehicles

Abstract

The application relates to an aerial propeller starting control system and method of an air-dropping type multi-rotor unmanned aerial vehicle power device. The aerial propeller starting control system comprises a multi-rotor unmanned aerial vehicle power control unit, an arm folding mechanism control unit, a position feedback unit and a total control unit; the multi-rotor unmanned aerial vehicle power control unit, the arm folding mechanism control unit and the position feedback unit are connected with the total control unit. The motor speed regulator in the application combines two control methods, adopts a sensor power device driving control mode at low speed and adopts a sensorless power device driving control mode at high speed; meanwhile, the motor speed regulator can not only reduce the occupied space of the multi-rotor unmanned aerial vehicle on a mother machine, but also can quickly unfold the arm in an air-dropping state, provide support for the arm, and ensure that the power device is quickly started and the aircraft attitude is stable.

Description

Technical Field

[0001] The present invention belongs to the field of unmanned aerial vehicles (UAVs), and in particular relates to an airborne propeller control system and method for an airdrop-type multi-rotor UAV power unit. Background Art

[0002] In multi-rotor drone technology, the power unit is a crucial component of the drone, primarily consisting of individual components such as the power supply, power unit, motor speed regulator, and propellers. The basic principle of the power unit is that the power supply acts as an energy source to power the motor speed regulator, which in turn drives the power unit to rotate the propellers. The propellers generate upward force, driving the drone in flight. As the source of power for the drone's flight, the power unit plays a key role in its overall stability and dynamic characteristics.

[0003] The working mode of traditional multi-rotor drone is as follows Figure 1 As shown, the system is assembled on the ground, powered on while stationary, and then launched and performed. This operating mode has certain limitations and is not suitable for applications where an airdrop multi-rotor drone is mounted on a mother aircraft for flight and airdrop missions. If an airdrop multi-rotor drone still uses the traditional multi-rotor drone operating mode, when mounted on the mother aircraft, the large arm space of the multi-rotor drone will not only waste the mother aircraft's carrying space, but may also affect the mother aircraft's aerodynamic characteristics. Furthermore, traditional multi-rotor drones are affected by reverse airflow during the airdrop process, causing the propellers to reverse. This reverse rotation of the power unit not only affects the power supply, but also risks burning the motor speed regulator, power unit, and other power components when the motor speed regulator drives the power unit to overcome the reverse rotation and launch the propellers forward. Furthermore, the reverse rotation may cause uneven force on the rotors of each arm, resulting in deflection of the multi-rotor drone's posture and, in severe cases, the aircraft may roll. Summary of the Invention

[0004] The present invention discloses an aerial propeller control system and method and a multi-rotor unmanned aerial vehicle (UAV) to solve any of the above-mentioned and other potential problems of the prior art.

[0005] In order to solve the above problems, the technical solution of the present invention is: an aerial propeller launch control system for an airdrop-type multi-rotor UAV power device, the aerial propeller launch control system comprising: a multi-rotor UAV power control unit, an arm folding mechanism control unit, a position feedback unit and a general control unit;

[0006] The multi-rotor UAV power control unit is used to start the power device of the multi-rotor UAV and adjust and control the speed of the power device;

[0007] The arm folding mechanism control unit is used to control the unfolding and folding of the arms of the multi-rotor drone;

[0008] The position feedback unit is used to monitor and control the deployment position of the multi-rotor drone in real time;

[0009] The general control unit is used to control whether the multi-rotor drone power control unit, the arm folding mechanism control unit and the position feedback unit are started according to the release signal.

[0010] Among them, the multi-rotor UAV power control unit, the arm folding mechanism control unit and the position feedback unit are all connected to the general control unit.

[0011] Furthermore, the multi-rotor UAV power control unit includes a Hall sensor and a motor speed regulator.

[0012] The Hall sensor and the motor speed regulator are both connected to the power device of the multi-rotor UAV, the motor speed regulator is connected to the Hall sensor, and the general control unit is connected to the motor speed regulator.

[0013] Furthermore, the arm folding mechanism control unit includes an electric servo, a servo rocker arm, a connecting rod and a locking mechanism.

[0014] In which, the electric servo is arranged on the multi-rotor drone, the output end of the electric servo is connected to one end of the servo rocker arm, the other end of the servo rocker arm is connected to one end of the connecting rod, and the other end of the connecting rod is connected to the arm of the multi-rotor drone, and the locking mechanism is arranged on the fuselage or arm of the multi-rotor drone at the connection between the fuselage and the arm.

[0015] Furthermore, the position feedback unit is a photoelectric sensor; and the overall control unit is an embedded single-chip microcomputer system.

[0016] Another object of the present invention is to provide a method for controlling the airborne propellers of the above-mentioned airdrop multi-rotor UAV power unit, the method specifically comprising the following steps:

[0017] S1) When the mother aircraft flies above the mission area, the mother aircraft controls the multi-rotor drone to power on autonomously and gives a release signal. The multi-rotor drone separates from the mother aircraft and the multi-rotor drone's built-in parachute opens.

[0018] S2) After the multi-rotor drone detects the release signal, the main control unit performs an arm extension action via the arm folding mechanism control unit. When the arm is extended to a predetermined position, S2) is completed; otherwise, the arm extension action continues;

[0019] S3) The general control unit releases the power unit brake via the rotorcraft power control unit and performs a propeller start operation. If the normal working mode requirements are met, the propeller start operation is confirmed to be completed, and S3) is executed. Otherwise, the propeller start operation is repeated.

[0020] S4) When the multi-rotor drone descends to a suitable altitude, it executes the parachute separation procedure and then enters the flight mission execution phase.

[0021] Furthermore, the specific steps of S1) are:

[0022] S2.1) When the multi-rotor drone detects the release signal, the drone's power supply begins to supply power to the entire drone, and the motor speed controller enters electronic braking mode, locking the drone's power unit to prevent the propellers from rotating in the opposite direction.

[0023] S2.2) The arm folding mechanism control unit controls the arm deployment, while the position feedback unit provides real-time feedback on the deployed arm position. When the arm is deployed and the multirotor drone's attitude stabilizes, the arm is locked and S2 is executed. Otherwise, the arm deployment continues.

[0024] Furthermore, the specific steps of S2) are:

[0025] S3.1) The motor speed regulator releases the electronic brake mode and switches to the sensor feedback control mode. The power unit rotates at a low speed. The judgment conditions determine whether the power unit starts normally. If it starts normally, the power unit speed is increased. If the normal working mode is met, execute S3.2). Otherwise, restart;

[0026] S3.2) Enter sensorless feedback control mode, control the power unit to reach normal flight speed, and then determine whether the normal flight attitude conditions are met based on the attitude. If they are met, enter normal flight working mode; if not, continue to adjust.

[0027] Furthermore, the specific steps of S2.1) are:

[0028] S3.11) First read the current and speed indicators of the power unit to see if they meet the start judgment conditions. If they do, start normally. Otherwise, restart.

[0029] S3.12) Continue to read the speed index. If the speed index does not reach the threshold of the normal working mode, the motor speed regulator and the power unit continue to operate in the normal working mode with the position sensor. If the speed index reaches the threshold of the normal working mode, the motor speed regulator and the power unit operate in the normal working mode without the position sensor.

[0030] Furthermore, the start judgment condition in S3.11) is:

[0031] After the multi-rotor drone is started, it is determined whether the current parameters of each power unit of the whole machine are normal.

[0032] After the multi-rotor drone is started, the speed parameters of each power unit of the entire machine are determined and detected.

[0033] The posture judgment condition in S3.2) is:

[0034] The pitch angle stability attitude is within ±5°,

[0035] The roll angle stability is within ±5°.

[0036] The azimuth stable attitude is within ±20°.

[0037] A multi-rotor drone comprises a fuselage and multiple rotors, and further comprises an aerial propeller control system.

[0038] The beneficial effects of the present invention are as follows: due to the adoption of the above technical solution, the system of the present invention can not only reduce the space occupied by the multi-rotor UAV on the mother aircraft, but also ensure that the arms of the multi-rotor UAV are quickly deployed and support is provided for the arms when in the airdrop state, and at the same time ensure that the power device is quickly started, the aircraft attitude is stabilized, and the mission reconnaissance area is quickly entered, thereby ensuring that the multi-rotor UAV can further obtain reconnaissance intelligence;

[0039] The motor speed regulator has motor speed regulation and electronic brake functions. It can control the power unit (motor) brake during the free fall of the multi-rotor drone to prevent the propeller from being affected by reverse airflow, thereby preventing the power unit from reversing and protecting the motor speed regulator and power unit.

[0040] The motor speed regulator in the present invention combines the drive control of the sensored power device and the drive control of the sensorless power motor, and has an electronic brake function. The drive control of the sensored power device can make the motor start smoothly and minimize the vibration during startup, but the efficiency is not high when rotating at high speed; the drive control of the sensorless power device can achieve higher efficiency when the motor rotates at high speed, but the vibration of the motor is large when starting, which is not conducive to maintaining a stable posture of the airdrop multi-rotor drone in the air. The motor speed regulator in the present invention combines the two control methods, adopting the drive control method of the sensored power device at low speed and the drive control method of the sensorless power device at high speed;

[0041] The traditional power unit of a multi-rotor UAV is a sensorless DC brushless motor. In the present invention, a Hall sensor module is added to the power unit so that the power unit can use both a sensor-controlled driving mode and a sensorless control driving mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a flowchart of the working mode of a traditional multi-rotor drone.

[0043] Figure 2 This is a flowchart of the control method of the aerial propeller control system of the present invention.

[0044] Figure 3 This is a schematic diagram of the installation of the arm folding mechanism control unit of the aerial propeller control system of the present invention.

[0045] Figure 4 This is a schematic diagram of the installation of the position feedback unit of the aerial propeller launch control system of the present invention.

[0046] Figure 5 This is a flow chart of the motor controller control method of the present invention.

[0047] In the picture:

[0048] 1. Arm, 2. Propeller, 3. Power unit, 4. Motor speed regulator, 5. Arm folding mechanism control unit, 5-1. Electric servo, 5-2. Servo rocker arm, 5-3. Connecting rod, 5-4. Locking mechanism, 6. Position feedback unit. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below with reference to schematic diagrams, but the embodiments of the present invention are not limited thereto.

[0050] like Figure 3-Figure 4 As shown, the present invention provides an airborne propeller control system for an airdrop-type multi-rotor UAV power device, the airborne propeller control system comprising: a multi-rotor UAV power control unit, an arm folding mechanism control unit 5, a position feedback unit 6 and a general control unit;

[0051] The multi-rotor UAV power control unit is used to start the power device of the multi-rotor UAV and adjust and control the speed of the power device;

[0052] The arm folding mechanism control unit 5 is used to control the deployment and folding of the arms of the multi-rotor drone;

[0053] The position feedback unit 6 is used to monitor and control the deployment position of the multi-rotor drone in real time;

[0054] The main control unit is used to control whether the multi-rotor drone power control unit, the arm folding mechanism control unit and the position feedback unit are started according to a release signal (the release signal is sent by the mother machine).

[0055] Among them, the multi-rotor UAV power control unit, the arm folding mechanism control unit and the position feedback unit are all connected to the general control unit.

[0056] The multi-rotor UAV power control unit includes a Hall sensor and a motor speed regulator 4,

[0057] The Hall sensor and the motor speed regulator are both connected to the power device of the multi-rotor UAV, the motor speed regulator 4 is connected to the Hall sensor (not shown in the figure), and the main control unit is connected to the motor speed regulator.

[0058] The arm folding mechanism control unit 5 includes an electric servo 5-1, a servo rocker arm 5-2, a connecting rod 5-3 and a locking mechanism 5-4.

[0059] In which, the electric servo 5-1 is arranged on the multi-rotor UAV, the output end of the electric servo 5-1 is connected to one end of the servo rocker arm 5-2, the other end of the servo rocker arm 5-2 is connected to one end of the connecting rod 5-3, and the other end of the connecting rod 5-3 is connected to the arm 1 of the multi-rotor UAV, and the locking mechanism 5-4 is arranged on the fuselage or arm 1 of the multi-rotor UAV at the connection between the fuselage and the arm 1.

[0060] The position feedback unit is a photoelectric sensor; the overall control unit is an embedded single-chip microcomputer system.

[0061] like Figure 2 As shown, the present invention provides a method for controlling the airborne propellers of the above-mentioned airdrop multi-rotor UAV power device, and the method specifically comprises the following steps:

[0062] S1) When the mother aircraft flies above the mission area, the mother aircraft controls the multi-rotor drone to power on autonomously and gives a release signal. The multi-rotor drone separates from the mother aircraft and the multi-rotor drone's built-in parachute opens.

[0063] S2) After the multi-rotor drone detects the release signal, the main control unit performs an arm extension action via the arm folding mechanism control unit. When the arm is extended to a predetermined position, S2) is completed; otherwise, the arm extension action continues;

[0064] S3) The general control unit releases the power unit brake via the rotorcraft power control unit and performs a propeller start operation. If the normal working mode requirements are met, the propeller start operation is confirmed to be completed, and S3) is executed. Otherwise, the propeller start operation is repeated.

[0065] S4) When the multi-rotor drone descends to a suitable altitude, it executes the parachute separation procedure and then enters the flight mission execution phase.

[0066] The specific steps of S1) are:

[0067] S2.1) When the multi-rotor drone detects the release signal, the multi-rotor drone's power supply begins to supply power to the entire drone, and the motor speed regulator 4 enters electronic braking mode, locking the multi-rotor drone's power unit to prevent propeller 2 from rotating in the opposite direction;

[0068] S2.2) The arm folding mechanism control unit controls the arm deployment, while the position feedback unit provides real-time feedback on the deployed arm position. When the arm is deployed and the multirotor drone's attitude stabilizes, the arm is locked and S2 is executed. Otherwise, the arm deployment continues.

[0069] The specific steps of S2) are:

[0070] S3.1) The motor speed regulator releases the electronic brake mode and switches to the sensor feedback control mode. The power unit rotates at a low speed. The judgment conditions determine whether the power unit starts normally. If it starts normally, the power unit speed is increased. If the normal working mode is met, execute S3.2). Otherwise, restart;

[0071] S3.2) Enter the sensorless feedback control mode, control the power unit to reach the normal flight speed, and then judge whether the conditions for normal flight attitude are met based on the attitude. If they are met, enter the normal flight working mode. If not, continue to adjust the speed and attitude (speed adjustment is to increase the electrical energy to increase the speed of the power unit; during attitude adjustment: the gyroscope of the multi-rotor drone sends the pitch angle, roll angle and azimuth angle errors to the main control unit, and the main control unit adjusts the attitude state to meet the normal flight through the motor speed regulator).

[0072] The specific steps of S2.1) are:

[0073] S3.11) First read the current and speed indicators of the power unit to see if they meet the start judgment conditions. If they do, start normally. Otherwise, restart.

[0074] S3.12) Continue to read the speed index. If the speed index does not reach the threshold of the normal working mode, the motor speed regulator and the power unit continue to operate in the normal working mode with the position sensor. If the speed index reaches the threshold of the normal working mode, the motor speed regulator and the power unit operate in the normal working mode without the position sensor.

[0075] The start judgment conditions in S3.11) are:

[0076] After the multi-rotor drone is started, it is determined whether the current parameters of each power unit of the whole machine are normal.

[0077] After the multi-rotor drone is started, the speed parameters of each power unit of the entire machine are determined and detected.

[0078] The posture judgment condition in S3.2) is:

[0079] The pitch angle stability attitude is within ±5°,

[0080] The roll angle stability is within ±5°.

[0081] The azimuth stable attitude is within ±20°.

[0082] A multi-rotor UAV comprises a fuselage and multiple rotors, and further comprises an air propeller control system.

[0083] Example:

[0084] The airdrop-type multi-rotor drone (hereinafter referred to as the multi-rotor drone) in the present invention is mounted under the wing of the mother aircraft. When the mother aircraft flies above the mission area, the mother aircraft releases the multi-rotor drone. When the multi-rotor drone detects the release signal, it opens the parachute to decelerate. At the same time, the multi-rotor drone power device extends its arms and raises its propellers. When the altitude drops to an appropriate height, the multi-rotor drone executes the parachute separation procedure and then enters the flight mission execution phase.

[0085] The power unit of a multi-rotor UAV consists of an arm folding mechanism, a motor speed regulator, an electric motor and a propeller.

[0086] The arm folding mechanism is used to drive the expansion and folding of the arms. It includes an electric servo, a connecting rod mechanism, and a locking mechanism. This design not only reduces the space occupied by the multi-rotor drone on the mother aircraft, but also ensures that the arms can be quickly deployed during airdrop and provide support for the arms.

[0087] The motor speed regulator has motor speed regulation and electronic brake functions. It can control the motor brake during the free fall of the multi-rotor drone to prevent the propeller from being affected by the reverse airflow, thereby preventing the motor power unit from reversing and protecting the motor speed regulator and motor.

[0088] The conventional motor speed regulator has the capability of sensorless motor drive control. The motor speed regulator in the present invention combines the sensored motor power unit drive control and the sensorless power motor drive control, and has an electronic brake function. The sensored motor drive control can make the motor start smoothly and minimize the vibration during startup, but the efficiency is not high when rotating at high speed; the sensorless power unit drive control can achieve higher efficiency when the motor rotates at high speed, but the motor vibrates more when starting, which is not conducive to maintaining a stable posture of the airdrop multi-rotor drone in the air. The motor speed regulator in the present invention combines the two control methods, adopting the sensored motor drive control method at low speed and the sensorless motor power unit drive control method at high speed;

[0089] The traditional motor of a multi-rotor UAV is a sensorless DC brushless motor. In the present invention, a Hall sensor module is added to the motor so that the motor can use both a sensor-controlled driving mode and a sensorless control driving mode.

[0090] The propeller in the present invention adopts a folding propeller, which is convenient for folding and unfolding the multi-rotor UAV arm. At the same time, a torsion spring and a limit device are installed at the folding position of the propeller to ensure that the propeller can be quickly unfolded into place when the arm is unfolded.

[0091] The working process of the multi-rotor UAV power device in the present invention is as follows: Figure 2 As shown, the main steps are:

[0092] 1. The multi-rotor UAV power supply is enabled and the power unit starts to be powered up in mid-air;

[0093] 2. The electronic brake mode of the motor speed controller is enabled;

[0094] 3. The multi-rotor drone is released from the mother aircraft in the air;

[0095] 4. The arm folding mechanism controls the arm to unfold into place, and the arm position feedback unit provides feedback on the arm position;

[0096] 5. The folding propeller is unfolded into place under the action of the torsion spring and the limit mechanism;

[0097] 6. After the multi-rotor drone's attitude stabilizes, the motor speed controller's electronic brake is released and the propellers are ready to start;

[0098] 7. Before launching the propellers, the aircraft enters sensor feedback control mode. The motor speed regulator reads the Hall effect sensor feedback to launch the propellers in mid-air, rotating at a low speed.

[0099] 8. After the motor drives the propeller to rotate normally at low speed, the operating mode switches to sensorless feedback control mode. The motor speed regulator controls the motor to rotate at high speed and enters normal flight operating mode.

[0100] 1. The folding mechanism of the multi-rotor UAV arm includes an electric servo, a connecting rod mechanism, and a locking mechanism. The electric servo is fixed to the body of the aircraft, and the universal joint at one end of the connecting rod mechanism is connected to the rocker arm. The other end of the connecting rod mechanism is connected to the root of the arm through a universal joint. Figure 3 As shown;

[0101] 2. The multi-rotor UAV motor speed controller control algorithm adopts a fusion of position sensor DC brushless motor control and position sensorless DC brushless motor control, such as Figure 5 As shown, the motor speed regulator enters the electronic brake starting state when powered on, and the motor is locked. When the main control unit starts the control command, the motor speed regulator enters the DC brushless motor starting mode with a position sensor (Hall sensor) after receiving the valid command. Then, it judges whether the motor starts normally by reading the current and speed two indicators. If it does not start normally, it restarts. If it starts normally, it enters the normal working mode with a position sensor. Finally, it continues to read the speed indicator. If the speed indicator does not reach the preset threshold, the motor speed regulator and the motor continue to work in the normal working mode with the position sensor. If the speed indicator reaches the preset threshold, the motor speed regulator and the motor work in the normal working mode without the position sensor, and the propeller start is completed.

[0102] 3. The motor power unit of the multi-rotor UAV is modified by using a sensorless DC brushless motor and a rotor position detection circuit is installed at the stator, such as Figure 5 As shown;

[0103] 4. The propeller of the multi-rotor drone uses a two-blade foldable propeller. A torsion spring device is installed at the propeller disc position. The torsion spring and the propeller shaft are connected with screws and structural adhesive. A mechanical limit pin is installed near the propeller shaft of the two-blade propeller and fixed with screws, such as Figure 4 Propeller position shown.

[0104] The above is a detailed introduction to the airborne propeller control system and method for an airdrop-type multi-rotor drone power unit provided in the embodiments of this application. The description of the above embodiments is only intended to help understand the method and core concept of this application; at the same time, for those skilled in the art, based on the concept of this application, there will be changes in the specific implementation method and application scope. In summary, the contents of this specification should not be understood as limiting this application.

[0105] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" and "comprising" mentioned throughout the specification and claims are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problems within a certain error range and basically achieve the technical effects. The subsequent description in the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be as defined in the attached claims.

[0106] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or system. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or system comprising the element.

[0107] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0108] The above description shows and describes several preferred embodiments of the present application. However, as previously mentioned, it should be understood that the present application is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Instead, the present application can be used in various other combinations, modifications, and environments and can be modified within the scope of the application concept described herein through the above teachings or technology or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present application should be protected by the claims appended hereto.

Claims

1. A method for controlling the propellers of an airdrop multi-rotor UAV power unit in the air, characterized in that: The air propeller launching control system adopted in the method includes: a multi-rotor UAV power control unit, an arm folding mechanism control unit, a position feedback unit and a general control unit; The multi-rotor UAV power control unit is used to start the power device of the multi-rotor UAV and adjust and control the working state of the power device; The arm folding mechanism control unit is used to control the unfolding and folding of the arms of the multi-rotor drone; The position feedback unit is used to monitor and control the deployment position of the multi-rotor drone in real time; The general control unit is used to control whether the multi-rotor drone power control unit, the arm folding mechanism control unit and the position feedback unit are started according to the release signal; The multi-rotor UAV power control unit, the arm folding mechanism control unit and the position feedback unit are all connected to the main control unit; The arm folding mechanism control unit includes a Hall sensor and a motor speed regulator; The Hall sensor and the motor speed regulator are both connected to the power device of the multi-rotor UAV, the motor speed regulator is connected to the Hall sensor, and the main control unit is connected to the motor speed regulator; The arm folding mechanism control unit includes an electric servo, a servo rocker arm, a connecting rod and a locking mechanism. The electric servo is provided on the multi-rotor UAV, the output end of the electric servo is connected to one end of the servo rocker arm, the other end of the servo rocker arm is connected to one end of the connecting rod, the other end of the connecting rod is connected to the arm of the multi-rotor UAV, and the locking mechanism is provided on the fuselage or arm of the multi-rotor UAV at the connection between the fuselage and the arm; the position feedback unit is a photoelectric sensor; and the overall control unit is an embedded single-chip microcomputer system; The method specifically comprises the following steps: S1) When the mother aircraft flies above the mission area, the mother aircraft controls the multi-rotor drone to power on autonomously and gives a release signal. The multi-rotor drone separates from the mother aircraft and the multi-rotor drone's built-in parachute opens. S2) After the multi-rotor drone detects the release signal, the main control unit performs an arm extension action via the arm folding mechanism control unit. When the arm is extended to a predetermined position, S2) is completed; otherwise, the arm extension action continues; The specific steps are: S2.1) When the multi-rotor drone detects the release signal, the power supply of the multi-rotor drone begins to supply power to the entire drone, and the motor speed regulator enters electronic braking mode, locking the power unit of the multi-rotor drone to prevent the propellers from rotating in the opposite direction; S2.2) The arm folding mechanism control unit controls the arm deployment, while the position feedback unit provides real-time feedback on the deployed arm position. Once the arm is deployed and the multirotor drone's attitude stabilizes, the arm is locked. Upon completion, S2) is executed. Otherwise, the arm deployment continues. S3) The general control unit releases the power unit brake via the rotorcraft power control unit and performs a propeller start operation. If the normal working mode requirements are met, the propeller start operation is confirmed to be completed, and S3) is executed. Otherwise, the propeller start operation is repeated. S4) When the multi-rotor drone descends to a suitable altitude, it executes the parachute separation procedure and then enters the flight mission execution phase.

2. The method according to claim 1, characterized in that The specific steps of S3) are: S3.1) The motor speed regulator releases the electronic brake mode and switches to the sensor feedback control mode. The power unit rotates at a low speed. The judgment conditions determine whether the power unit starts normally. If it starts normally, the power unit speed is increased. If the normal working mode is met, execute S3.2). Otherwise, restart; S3.2) Enter sensorless feedback control mode, control the power unit to reach normal flight speed, and then determine whether the conditions for normal flight attitude are met based on the attitude. If they are met, enter normal flight working mode; if not, continue to adjust the speed and attitude.

3. The method according to claim 2, characterized in that The specific steps of S3.1) are: S3.11) First read the current and speed indicators of the power unit to see if they meet the start judgment conditions. If they do, start normally. Otherwise, restart. S3.12) Continue to read the speed index. If the speed index does not reach the threshold of the normal working mode, the motor speed regulator and the power unit continue to operate in the normal working mode with the position sensor. If the speed index reaches the threshold of the normal working mode, the motor speed regulator and the power unit operate in the normal working mode without the position sensor.

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