Unmanned aerial vehicle jet reverse thrust type super-speed braking method and braking device

Abstract

This application relates to the field of unmanned aerial vehicle (UAV) control technology, and discloses a jet-driven high-speed braking method and device for UAVs. The method includes: a control unit acquiring flight attitude data of the UAV and relative correlation data between the UAV and obstacles; the control unit generating a braking command based on the relative correlation data and generating a nozzle angle adjustment command based on the flight attitude data; the control unit controlling a servo drive module to drive the nozzle to adjust the airflow injection direction and controlling the nozzle to inject airflow in the airflow injection direction, thereby generating an instantaneous reverse braking force until the control unit generates a safety command based on the relative correlation data to complete the braking of the UAV. This application can improve braking response speed and ensure the flight safety of UAVs.

Description

Technical Field

[0001] This application relates to the field of unmanned aerial vehicle (UAV) control technology, and in particular to a jet-driven high-speed braking method and braking device for UAVs. Background Technology

[0002] With the rapid development of drone technology, the application scenarios of drones are becoming increasingly widespread. Medium and large drones, with their advantages of large payload capacity and long endurance, have been widely used in various fields such as logistics transportation, aerial surveying, formation performances, and emergency rescue. However, during drone flight, braking performance directly determines flight safety. Especially in low-altitude flight, dense formation operations, or complex environments with many obstacles, untimely or ineffective braking can easily lead to a series of safety risks. Currently, safety hazards caused by braking problems during drone flight are frequent, specifically including: drones failing to brake quickly when encountering sudden obstacles, leading to uncontrolled falls, collisions with buildings, and collisions between drones; if drones are used for logistics delivery or performance tasks in densely populated areas, braking failure may also cause personal injury and property damage, severely restricting the promotion and application of medium and large drones in urban and complex scenarios.

[0003] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0004] The main purpose of this application is to provide a jet-driven high-speed braking method and device for unmanned aerial vehicles (UAVs), which aims to solve the problem that the existing UAV flight braking relies on reverse propeller braking, resulting in poor safety due to slow braking response speed.

[0005] The first aspect of this application provides a jet-driven reverse thrust high-speed braking method for unmanned aerial vehicles (UAVs). This method is applied to a jet-driven reverse thrust high-speed braking device, which includes a control unit, a servo drive module, and a gas tank mounted on the UAV. The control unit is connected to both the servo drive module and the gas tank. A nozzle is connected to the gas tank, and the servo drive module is connected to the nozzle. The gas tank stores gas, and the nozzle converts the gas into a jet stream. The control unit controls the start and stop of gas jet injection from the gas tank, generates an angle adjustment command for the nozzle, and sends it to the servo drive module. The servo drive module drives the nozzle to adjust the jet stream direction. The jet-driven reverse thrust high-speed braking method for UAVs includes: The control unit acquires the flight attitude data of the drone and the relative correlation data between the drone and obstacles; The control unit generates a braking command based on the relative correlation data and generates an nozzle angle adjustment command based on the flight attitude data; The control unit controls the servo drive module to drive the nozzle to adjust the airflow direction and controls the nozzle to spray airflow in the airflow direction, so as to generate instantaneous reverse braking force until the control unit generates a safety command based on the relative correlation data to complete the braking of the UAV.

[0006] Optionally, in one embodiment of this application, the flight attitude data includes pitch angle and yaw angle, and the relative correlation data includes relative distance and relative speed; The control unit acquires the drone's flight attitude data and the relative correlation data between the drone and obstacles, specifically: The control unit receives pitch and yaw angles from the attitude sensors on the UAV, and receives the relative distance and relative speed between the UAV and obstacles from the distance detection module on the UAV.

[0007] Optionally, in one embodiment of this application, the control unit generates a braking command based on the relative correlation data and generates a nozzle angle adjustment command based on the flight attitude data, specifically including: If the relative distance is less than or equal to a preset safe braking distance threshold, the control unit generates a braking command; The control unit calculates the difference between the current attitude and the set target attitude based on the pitch angle and the yaw angle, calculates the correction torque required by the nozzle based on the difference, and generates an angle adjustment command corresponding to the yaw angle based on the yaw angle of the nozzle.

[0008] Optionally, in one embodiment of this application, the control unit controls the nozzle to spray airflow in the airflow injection direction, thereby generating a momentary reverse braking force until the control unit generates a safety command based on the relative correlation data, specifically including: The control unit calculates the required reverse thrust based on the relative velocity; An equation is constructed to calculate the braking distance of the UAV's jet thrust reverse. Based on the equation, the control unit calculates the braking distance according to the relative speed and the reverse thrust, such that the braking distance is less than the relative distance, until the relative speed of the UAV is 0. At this point, the control unit generates a safety command based on the relative correlation data.

[0009] Optionally, in one embodiment of this application, the equation for calculating the jet thrust reverse braking distance of the UAV is expressed as: ; in, Let the initial velocity be squared. For the square derivative of the velocity, The reverse thrust generated by the jet engine, The air drag coefficient, air density, For the windward area of ​​the drone, For the square of the velocity, For the quality of drones, Braking distance, It is the differential of the distance.

[0010] The second aspect of this application also provides a jet-reverse thrust high-speed braking device for the jet-reverse thrust high-speed braking method for any of the above-described solutions for unmanned aerial vehicles (UAVs). The jet-reverse thrust high-speed braking device includes a control unit, a servo drive module, and an air tank mounted on the UAV. The control unit is connected to the servo drive module and the air tank. A nozzle is connected to the air tank. The servo drive module is connected to the nozzle. The air tank stores gas. The nozzle converts the gas into a jet stream. The control unit controls the start and stop of gas jetting from the air tank, generates an angle adjustment command for the nozzle, and sends it to the servo drive module. The servo drive module drives the nozzle to adjust the jet stream direction. The control unit is used to acquire the flight attitude data of the UAV and the relative correlation data between the UAV and obstacles; The control unit is used to generate braking commands based on the relative correlation data, generate nozzle angle adjustment commands based on the flight attitude data, and send them to the servo drive module. The servo drive module is used to drive the nozzle to adjust the airflow injection direction; The control unit is used to control the start and stop of gas injection from the gas tank and to control the nozzle to inject airflow in the direction of airflow injection, thereby generating instantaneous reverse braking force until the control unit generates a safety command based on the relative correlation data to complete the braking of the UAV.

[0011] Optionally, in one embodiment of this application, the jet reverse thrust high-speed braking device further includes an attitude sensor and a distance detection module, the attitude sensor and the distance detection module are respectively mounted on the UAV, and the attitude sensor and the distance detection module are respectively connected to the control unit; The attitude sensor is used to collect the pitch and yaw angles of the UAV and send them to the control unit. The distance detection module is used to collect the relative distance and relative speed between the UAV and the obstacle and send them to the control unit.

[0012] Optionally, in one embodiment of this application, the nozzle is connected to the outlet of the gas tank, the spray angle of the nozzle in the horizontal direction is adjustable from 0 to 360°, and the servo drive module drives the nozzle to move, so that the airflow spray angle is adjusted accordingly to adapt to the braking attitude of the UAV. The distance detection module is a lidar or millimeter-wave radar.

[0013] Optionally, in one embodiment of this application, the gas stored in the gas storage tank is hydrogen, and an electromagnetic control valve is provided at the gas outlet of the gas storage tank. The electromagnetic control valve is connected to the control unit, and the control unit controls the start and stop of the gas source injection through the electromagnetic control valve.

[0014] Optionally, in one embodiment of this application, the attitude sensor, the distance detection module, the servo drive module, and the control unit are integrated into one unit. The integrated attitude sensor, the distance detection module, the servo drive module, and the control unit are disposed at the lower end of the UAV, and the air tank is disposed at the lower end of the control unit.

[0015] Beneficial Effects: This application provides a jet-driven high-speed braking method and device for unmanned aerial vehicles (UAVs). The braking device includes an air tank fixedly installed at the lower end of the UAV body. The air outlet of the air tank is connected to an adjustable vector nozzle. The flight status of the UAV and the surrounding obstacles are collected in real time through attitude sensors and distance detection modules. The nozzle direction is adjusted and the jet-driven device is started and stopped by a servo drive module to eject high-speed airflow. The braking method of this application is based on the fluid momentum equation. It uses an adjustable vector nozzle to eject high-speed gas and utilizes the instantaneous huge thrust generated by the jet to achieve high-speed braking. Compared with the traditional braking method that relies on blade reversal, it has a faster response, higher braking efficiency, and is not affected by low-altitude airflow, thereby improving the braking response speed and ensuring the flight safety of the UAV. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a preferred embodiment of the jet reverse thrust type high-speed braking device of this application; Figure 2 This is a cross-sectional schematic diagram of the nozzle couple in a preferred embodiment of the jet reverse thrust type high-speed braking device of this application; Figure 3 This is a flowchart of a preferred embodiment of the jet-driven reverse thrust high-speed braking method for unmanned aerial vehicles (UAVs) according to this application.

[0018] Explanation of reference numerals in the attached figures: 1. UAV body; 2. Air tank; 3. Nozzle; 4. Integrated components; 5. Throat diameter; 6. Nozzle diameter; 7. Expansion angle; 8. Connecting pipes.

[0019] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0020] To make the objectives, technical solutions, and effects of this application clearer and more explicit, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only possible technical implementations of this application and not all possible implementations. Based on the embodiments in this application, those skilled in the art can obtain other embodiments without creative effort, and these embodiments are also within the protection scope of this application.

[0021] To facilitate understanding, the application scenarios of the embodiments of this application will be introduced first. This application is particularly applicable to medium and large logistics drones, formation performance drones, and other scenarios with high requirements for braking response speed and safety.

[0022] In related technologies, existing UAV braking methods mostly rely on propeller reversal braking. This method generates reverse thrust by changing the direction of propeller rotation to decelerate and brake the UAV. However, this type of braking method has obvious drawbacks: First, the braking response time is long. Propeller reversal requires a complete process of speed decay, direction switching, and speed increase, making instantaneous braking impossible. When facing sudden obstacles, the best braking opportunity is easily missed. Second, the braking distance is long. The reverse thrust generated by propeller reversal is limited. For medium and large UAVs, it is difficult to reduce the flight speed to a safe range within a short distance, resulting in low braking efficiency. Third, it is greatly affected by environmental factors. In high-altitude, low-pressure, strong airflow, or turbulent environments, the propellers are prone to stalling, leading to a significant decrease in braking performance or even braking failure. Fourth, the attitude stability is poor. During propeller reversal braking, the UAV is prone to pitch and yaw attitude deviations, further increasing the risk of collision. Besides propeller reversal braking, some UAVs employ auxiliary methods such as air resistance braking and parachute braking. However, air resistance braking is only suitable for low-speed flight scenarios and has a weak braking effect; parachute braking has a slow response speed, cannot be reused, and can only be used for emergency landings, failing to meet the immediate braking needs of UAVs during normal flight. Therefore, existing braking methods are insufficient to meet the core requirements of medium and large UAVs for high-speed braking, short-distance braking, and attitude-stabilized braking. There is an urgent need for a UAV braking solution that is fast-responding, highly efficient, and attitude-stabilized to address the shortcomings of existing technologies.

[0023] The technical solutions of this application will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0024] like Figure 1 As shown, the jet-driven high-speed braking device of the preferred embodiment of this application includes a control unit, a servo drive module, and an air tank 2 mounted on the UAV. The control unit is connected to the servo drive module and the air tank 2. A nozzle 3 is connected to the air tank 2. The servo drive module is connected to the nozzle 3. The air tank 2 is used to store gas. The nozzle 3 is used to convert the gas into jet airflow. The control unit is used to control the start and stop of gas jetting from the air tank 2, generate an angle adjustment command for the nozzle 3, and send it to the servo drive module. The servo drive module is used to drive the nozzle 3 to adjust the jet airflow direction. The control unit is used to acquire the flight attitude data of the UAV and the relative correlation data between the UAV and obstacles; The control unit is used to generate braking commands based on the relative correlation data, generate nozzle angle adjustment commands based on the flight attitude data, and send them to the servo drive module. The servo drive module is used to drive the nozzle to adjust the airflow injection direction; The control unit is used to control the start and stop of gas injection from the gas tank and to control the nozzle to inject airflow in the direction of airflow injection, thereby generating instantaneous reverse braking force until the control unit generates a safety command based on the relative correlation data to complete the braking of the UAV.

[0025] It should be noted that the control unit can dynamically adjust the gas injection volume of the gas tank according to the relative speed. The greater the relative speed, the greater the injection volume, and the stronger the reverse braking force, thus achieving graded braking.

[0026] See Figure 1 The braking device includes a UAV body 1, an air tank 2, an adjustable vector nozzle 3, an attitude sensor, a distance detection module, a servo drive module, and a control unit. The air tank 2 is fixedly installed at the lower end of the UAV body 1 and is used to store high-pressure gas and provide a gas source for jet thrust. The adjustable vector nozzle 3 is connected to the air outlet of the air tank 2 and is used to convert high-pressure gas into high-speed jet airflow to generate instantaneous reverse braking force, and the jet direction can be adjusted to adapt to the UAV's braking attitude. The attitude sensor is installed on the UAV body 1 and is used to collect the UAV's flight attitude data in real time. The distance detection module is installed on the UAV body 1 and is used to collect the relative distance and relative speed between the UAV and surrounding obstacles in real time. The servo drive module is connected to the adjustable vector nozzle 3 and the control unit respectively and is used to receive control commands from the control unit and drive the adjustable vector nozzle 3 to adjust the jet direction. The control unit is electrically connected to the air tank 2, the attitude sensor, and the servo drive module respectively and is used to control the start and stop of gas jet from the air tank 2, receive flight attitude data from the attitude sensor and generate nozzle 3 direction adjustment commands, and send them to the servo drive module.

[0027] In one embodiment of this application, see Figure 1 The attitude sensor, the distance detection module, the servo drive module, and the control unit are integrated into one unit (forming an integrated component 4). The integrated attitude sensor, the distance detection module, the servo drive module, and the control unit are located at the lower end of the UAV body 1, and the air tank 2 is located at the lower end of the control unit.

[0028] In other words, integrated component 4 includes an attitude sensor, a distance detection module, a servo drive module, and a control unit. (See [link]). Figure 2 The throat diameter 5 is the diameter at the throat of the adjustable vector nozzle 3, the nozzle diameter 6 is the diameter at the nozzle of the adjustable vector nozzle 3, the expansion angle 7 is the expansion angle of the adjustable vector nozzle 3, and the connecting pipe 8 is the connecting pipe between the nozzle 3 and the outlet of the gas storage tank 2.

[0029] In one embodiment of this application, the jet reverse thrust high-speed braking device further includes an attitude sensor and a distance detection module. The attitude sensor and the distance detection module are respectively mounted on the UAV and are respectively connected to the control unit. The attitude sensor is used to collect the pitch and yaw angles of the UAV and send them to the control unit. The distance detection module is used to collect the relative distance and relative speed between the UAV and the obstacle and send them to the control unit.

[0030] Specifically, the attitude sensor is installed on the UAV body 1 to collect the UAV's flight attitude data in real time; the distance detection module is installed at the front end of the UAV body 1 to collect the relative distance and relative speed data between the UAV and obstacles; the servo drive module is connected to the adjustable vector nozzle 3 and the control unit respectively, and is used to receive the instructions from the control unit and drive the adjustable vector nozzle 3 to adjust the spray direction. The control unit is electrically connected to the air tank 2, the adjustable vector nozzle 3, the attitude sensor, the servo drive module, and the distance detection module, respectively, and is used to control the start and stop of air source injection, receive data from various sensors and generate control commands to realize closed-loop control of the braking process.

[0031] In one embodiment of this application, the nozzle 3 is connected to the air outlet of the air tank 2, and the spray angle of the nozzle 3 in the horizontal direction is adjustable from 0 to 360°. The servo drive module drives the nozzle 3 to move, so that the airflow spray angle is adjusted accordingly to adapt to the braking attitude of the UAV. The distance detection module is a lidar or millimeter-wave radar.

[0032] Specifically, the adjustable vector nozzle 3 can achieve 360° horizontal spray angle adjustment with a response time in milliseconds. The adjustable vector nozzle 3 is connected to the air outlet of the integrated air storage unit, used to convert the air source into a high-speed jet stream to generate reverse braking force, and the spray direction can be adjusted to adapt to the UAV's braking attitude. The distance detection module is electrically connected to the control unit, used to collect the relative distance and relative speed data between the UAV and obstacles, and send it to the control unit to trigger a braking command. The control unit has a pre-stored safe braking distance threshold; when the relative distance collected by the distance detection module is less than the threshold, the control unit triggers the air tank 2 to spray air and perform a reverse thrust braking process.

[0033] In one embodiment of this application, the gas stored in the gas storage tank 2 is hydrogen gas. An electromagnetic control valve is provided at the gas outlet of the gas storage tank 2. The electromagnetic control valve is connected to the control unit, and the control unit controls the start and stop of the gas source injection through the electromagnetic control valve.

[0034] In one embodiment of this application, the flight speed of the drone is less than or equal to 30 m / s, the flight altitude of the drone is less than or equal to 1000 m, and the takeoff weight of the drone is less than or equal to 100 kg.

[0035] Specifically, the braking device also includes an electromagnetic control valve, which is mounted at the outlet of the gas storage tank 2 and connected to the control unit. This valve is used to quickly open or close the gas source channel, achieving instantaneous braking response. The gas storage tank 2 is made of lightweight, high-temperature and high-pressure resistant materials, with a volume adapted to the weight of the UAV body 1. It can store high-pressure gas, which is ejected through the nozzle 3 to generate a high-speed jet stream. The gas storage tank 2 is linked to the fuel supply system of the hydrogen fuel cell-powered UAV, directly using hydrogen from the fuel cell as its gas source, eliminating the need for additional gas loading and dedicated storage devices.

[0036] It is understood that the gas source is hydrogen, and for hydrogen fuel cell powered drones, the amount of hydrogen supplied can be dynamically adjusted according to braking requirements.

[0037] Compared to traditional propeller reversal braking methods, which suffer from long response times, long braking distances, susceptibility to environmental influences, and poor attitude stability, the braking device provided by this invention has a simple structure, consisting only of a gas storage tank, an adjustable vector nozzle, various sensors, and a control unit. Assembly is convenient, requiring no significant modifications to the original power system of the UAV. It is particularly suitable for hydrogen fuel cell-powered UAVs, directly reusing hydrogen as a gas source without the need for additional gas and storage devices, effectively reducing the UAV's weight while balancing endurance and braking performance. Specifically, this invention uses high-speed gas injection to generate reverse thrust for braking, eliminating the need for propeller reversal. Utilizing the rapid response characteristics of the electromagnetic control valve, combined with the attitude control capabilities of the adjustable vector nozzle, it achieves millisecond-level braking response. Simultaneously, precise control of the gas injection volume and nozzle direction ensures UAV attitude stability during braking. When using hydrogen as a gas source, the injected hydrogen diffuses rapidly in the atmosphere without pollutant emissions, meeting environmental protection requirements. Furthermore, the high-temperature hydrogen helps decompose trace impurities that may be generated during braking, further reducing pollution.

[0038] The preferred embodiment of this application describes a jet-powered reverse-thrust high-speed braking method for unmanned aerial vehicles, such as... Figure 3 As shown, the UAV jet reverse thrust high-speed braking method includes the following steps: In step S101, the control unit acquires the flight attitude data of the UAV and the relative correlation data between the UAV and the obstacle.

[0039] It should be noted that this method is applicable to medium and large-sized logistics drones, formation flying drones, and emergency rescue drones. It is suitable for drones with takeoff weights up to 100kg, flight altitudes up to 1000m, and flight speeds up to 30m / s. In other words, for takeoff weights ≤100kg, the device is designed to support a maximum takeoff weight of 100kg, covering everything from small drones weighing a few kilograms to medium and large-sized industrial drones weighing 100kg; for flight altitudes ≤1000m, the device's braking performance (jet thrust, aerodynamic effects) is guaranteed in the low-altitude troposphere at altitudes of 1000 meters and below; and for flight speeds ≤30m / s (i.e., 108 km / h), at a cruising speed of 30 m / s, the system can control the braking distance within the calculated value (approximately 2 meters).

[0040] In one possible implementation, the flight attitude data includes pitch angle and yaw angle, and the relative correlation data includes relative distance and relative speed. Step S101 specifically includes: the control unit receiving the pitch angle and yaw angle sent by the attitude sensor on the UAV, and receiving the relative distance and relative speed between the UAV and the obstacle sent by the distance detection module on the UAV.

[0041] Specifically, the braking device is assembled and fixed to the drone body. If it is a hydrogen fuel cell powered drone, the gas storage integration unit is connected to the fuel pipeline branch to complete the device initialization. The control unit then activates the attitude sensor and distance detection module, preloads the safe braking distance threshold and the initial attitude parameters of the nozzle. During the drone's flight, the attitude sensor collects flight attitude data such as pitch and yaw angles in real time, and the distance detection module collects relative distance and relative speed data with obstacles in real time, all of which are transmitted to the control unit.

[0042] In step S102, the control unit generates a braking command based on the relative correlation data and generates a nozzle angle adjustment command based on the flight attitude data.

[0043] In one possible implementation, step S102 specifically includes: if the relative distance is less than or equal to a preset safe braking distance threshold, the control unit generates a braking command; the control unit calculates the difference between the current attitude and the set target attitude based on the pitch angle and the yaw angle, calculates the correction torque required by the nozzle based on the difference, and generates an angle adjustment command corresponding to the yaw angle based on the yaw angle of the nozzle according to the correction torque.

[0044] Specifically, the control unit determines whether the relative distance is less than the preset safe braking distance threshold. If so, it triggers a braking command, controls the electromagnetic control valve to open quickly, and the air source is ejected at high speed through the adjustable vector nozzle to generate reverse braking force. At the same time, the control unit sends an angle adjustment command to the servo drive module based on the feedback data from the attitude sensor, drives the nozzle to adjust the spray direction, and counteracts the attitude deviation of the UAV.

[0045] Furthermore, the control unit internally stores a safe braking distance threshold and performs a judgment: whether the current relative distance is less than the preset safe braking distance threshold; if the condition is true, a trigger signal is immediately generated. This signal contains two parallel instructions: open the solenoid control valve, the instruction is sent to the solenoid control valve at the gas tank outlet, requiring it to open within milliseconds to release high-pressure gas; initiate attitude control, activating the subsequent nozzle direction adjustment algorithm (based on attitude sensor data). If the condition is false, monitoring continues, and braking is not triggered. Note: Although only distance is used as the trigger condition, the relative speed is recorded at the moment of triggering for subsequent staged braking.

[0046] Furthermore, during the generation of angle adjustment commands, the control unit calculates the difference between the current attitude and the target attitude. The control unit then inputs this error into the control algorithm to calculate the correction torque required to eliminate this attitude deviation, thus obtaining the torque that the nozzle needs to provide (specifically divided into pitch torque and yaw torque). Torque distribution and angle mapping (converting into physical motion) are then performed. The torque generated by the nozzle is equal to the thrust multiplied by the lever arm (the distance from the nozzle mounting point to the center of gravity) and then by a trigonometric function of the nozzle deflection angle. Based on the currently known thrust F (determined by staged braking), the control unit calculates the specific angle that the nozzle needs to deflect. The control unit converts the calculated target angle into a pulse width modulation signal or digital command. The servo drive module receives the command, and the drive motor physically rotates the adjustable vector nozzle to the specified angle.

[0047] In step S103, the control unit controls the servo drive module to drive the nozzle to adjust the airflow injection direction, and controls the nozzle to spray airflow in the airflow injection direction, so as to generate instantaneous reverse braking force until the control unit generates a safety command based on the relative correlation data to complete the braking of the UAV.

[0048] In one possible implementation, step S103 specifically includes: the control unit calculates the required reverse thrust based on the relative speed; constructs an equation expression for calculating the UAV jet reverse thrust braking distance; the control unit calculates the braking distance based on the equation expression, the relative speed, and the reverse thrust, such that the braking distance is less than the relative distance, until the relative speed of the UAV is 0; and the control unit generates a safety command based on the relative correlation data.

[0049] Specifically, the control unit monitors the relative distance and drone speed in real time through the distance detection module. When the drone speed drops to a preset safety value or the distance to the obstacle no longer decreases, the control electromagnetic valve is closed, the jet propulsion stops, the braking process ends, and the drone switches to hovering mode.

[0050] In one possible implementation, the equation for calculating the UAV's jet thrust reverse braking distance is expressed as follows: ; in, Let the initial velocity be squared. For the square derivative of the velocity, The reverse thrust generated by the jet engine, The air drag coefficient, air density, For the windward area of ​​the drone, For the square of the velocity, For the quality of drones, Braking distance, It is the differential of the distance.

[0051] Furthermore, once braking is triggered, the control unit enters closed-loop control mode, calculates the target braking force, and dynamically calculates the required reverse thrust F based on the current relative speed v, where F = kv, and k is the system calibration coefficient, ensuring that the greater the speed, the stronger the braking force (i.e., staged braking). The gas injection quantity is adjusted by controlling the opening of the solenoid valve through pulse width modulation or a proportional valve, so that the thrust generated by the actual gas injection quantity approximates the target. Real-time feedback updates are provided; the distance detection module continuously updates the relative speed and relative distance, and the control unit repeatedly performs the above calculations, resulting in dynamic adjustments to the braking force until the speed approaches zero.

[0052] The control unit monitors two conditions simultaneously, terminating braking if either condition is met: speed condition, the drone's speed drops to a preset safe value; distance condition, the relative distance to the obstacle no longer decreases (i.e., the drone has stopped moving forward or begun to move away). When one of these conditions is met, the control unit sends a command to close the electromagnetic control valve, stop the jet propulsion, and the drone switches to hovering mode.

[0053] The specific implementation of this application will be described below with reference to a specific application scenario.

[0054] Step K1: Device initialization. Assemble and fix the braking device to the UAV body. If it is a hydrogen fuel cell powered UAV, connect the gas storage integration unit to the fuel pipeline branch to complete the device initialization. The control unit starts the attitude sensor and distance detection module, and preloads the safe braking distance threshold and the initial attitude parameters of the nozzle. Step K2: During the flight of the UAV, the attitude sensor collects flight attitude data such as pitch and yaw angles in real time, and the distance detection module collects relative distance and relative speed data with obstacles in real time, all of which are transmitted to the control unit. Step K3: The control unit determines whether the relative distance is less than the preset safe braking distance threshold. If so, it triggers the high-speed braking process, controls the electromagnetic control valve of the gas tank to open, and the high-pressure gas is ejected through the adjustable vector nozzle to generate reverse braking force. Step K4: The control unit generates a nozzle direction adjustment command based on the flight attitude data fed back by the attitude sensor and sends it to the servo drive module. The servo drive module drives the adjustable vector nozzle to adjust the spray direction, which counteracts the pitch and yaw deviations during the UAV braking process and maintains the braking attitude stability. Step K5: The control unit monitors the relative distance and drone speed in real time through the distance detection module. When the drone speed drops to a preset safety value or the distance to the obstacle no longer decreases, the control electromagnetic valve is closed, the jet propulsion stops, the braking process ends, and the drone switches to hovering mode.

[0055] In this embodiment of the application, in order to verify the performance of the braking device and method of the present invention, hydrogen was used as the jet thrust medium, and a medium-to-large logistics drone with a takeoff weight of 100kg was selected as the test object. The test scenario was set at an altitude of 1000m and a cruising speed of 30m / s. The pressure of the high-pressure gas in the gas tank of the braking device was set to 5MPa, the nozzle size was set to a throat radius of 54mm, an outlet radius of 65.5mm, and an expansion angle of 8°.

[0056] In this embodiment of the invention, when an obstacle is detected during drone flight, the drone immediately stops providing power and triggers the braking device until its speed drops to 0, at which point braking is complete, and the drone switches to hovering mode. A traditional reverse propeller braking method is used as a control group to test braking performance under the same scenario. The propeller parameters of the control group drone are the same as those of the test group, and there are no other braking assistance devices.

[0057] (1) The present invention.

[0058] Calculate air resistance : ; in, For the drone's flight speed, the air density at an altitude of 1000 meters is taken as... The drag coefficient is taken as Windward area taken .

[0059] After the drone stops providing power, the net external force acting on it is The direction is opposite to the direction of velocity, where The thrust generated by the ejected gas, This refers to air resistance.

[0060] ; in, For the drone's flight distance, For the drone's flight time. ,but The above equation can be written as: ; ; in, The drone's cruising speed before braking was 30 m / s. , Braking distance, For braking time, then ; ; ; ; Depend on We can obtain: ; ; ; .

[0061] (2) Control group (traditional blade reversal braking).

[0062] Calculate air resistance : ; in, For the drone's flight speed, For the drone's flight distance, For the drone's flight time, the air density at an altitude of 1000 meters is taken as... The drag coefficient is taken as Windward area taken .

[0063] Calculate propeller reverse drag : ; Wherein, the propeller braking drag coefficient is taken as The propeller sweep area (assuming the drone is a quadcopter, the propeller diameter is taken as...) ,but 。 Calculate total resistance : ; Since braking force is proportional to the square of velocity, when a drone undergoes variable acceleration and deceleration, the instantaneous acceleration (in the opposite direction to velocity) is calculated. : ; Calculate braking time : ; ; ; ; Calculate braking distance : ; ; ; in, Since it is negative infinity, theoretically the speed cannot be strictly reduced to 0. If the safe threshold for the drone's flight speed is set at 1 m / s, then the calculation can be obtained as follows: , .

[0064] The comparison shows that the braking time of the present invention is only 0.186% of that of traditional propeller reversal braking, and the braking distance is only 1.60% of that of traditional solutions. The braking efficiency is greatly improved, which can effectively deal with sudden obstacles at high altitudes and avoid collision risks. At the same time, the attitude stability during braking is better, and it is compatible with hydrogen fuel cell powered drones. No additional gas source is required, which takes into account both environmental protection and endurance, and fully meets the safety braking requirements of medium and large drones in complex scenarios.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0066] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0067] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0068] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable storage medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable storage medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable storage medium could be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0069] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0070] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0071] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0072] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

[0073] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A jet-driven reverse-thrust high-speed braking method for unmanned aerial vehicles (UAVs), characterized in that, This invention relates to a jet-powered high-speed braking device, comprising a control unit, a servo drive module, and an air tank mounted on a UAV. The control unit is connected to both the servo drive module and the air tank. A nozzle is connected to the air tank, and the servo drive module is connected to the nozzle. The air tank stores gas, and the nozzle converts the gas into a jet stream. The control unit controls the start and stop of gas jetting from the air tank, generates an angle adjustment command for the nozzle, and sends it to the servo drive module. The servo drive module drives the nozzle to adjust the direction of the air stream jetting. The jet-propelled high-speed braking method for UAVs includes: The control unit acquires the flight attitude data of the drone and the relative correlation data between the drone and obstacles; The control unit generates a braking command based on the relative correlation data and generates an nozzle angle adjustment command based on the flight attitude data; The control unit controls the servo drive module to drive the nozzle to adjust the airflow direction and controls the nozzle to spray airflow in the airflow direction, so as to generate instantaneous reverse braking force until the control unit generates a safety command based on the relative correlation data to complete the braking of the UAV.

2. The jet-powered reverse thrust high-speed braking method for unmanned aerial vehicles according to claim 1, characterized in that, The flight attitude data includes pitch angle and yaw angle, and the relative correlation data includes relative distance and relative speed; The control unit acquires the drone's flight attitude data and the relative correlation data between the drone and obstacles, specifically: The control unit receives pitch and yaw angles from the attitude sensors on the UAV, and receives the relative distance and relative speed between the UAV and obstacles from the distance detection module on the UAV.

3. The jet-powered reverse thrust high-speed braking method for unmanned aerial vehicles according to claim 2, characterized in that, The control unit generates braking commands based on the relative correlation data and generates nozzle angle adjustment commands based on the flight attitude data, specifically including: If the relative distance is less than or equal to a preset safe braking distance threshold, the control unit generates a braking command; The control unit calculates the difference between the current attitude and the set target attitude based on the pitch angle and the yaw angle, calculates the correction torque required by the nozzle based on the difference, and generates an angle adjustment command corresponding to the yaw angle based on the yaw angle of the nozzle.

4. The jet-powered reverse thrust high-speed braking method for unmanned aerial vehicles according to claim 3, characterized in that, The control unit controls the nozzle to spray airflow in the direction of airflow injection, thereby generating a momentary reverse braking force until the control unit generates a safety command based on the relative correlation data, specifically including: The control unit calculates the required reverse thrust based on the relative velocity; An equation is constructed to calculate the braking distance of the UAV's jet thrust reverse. Based on the equation, the control unit calculates the braking distance according to the relative velocity and the reverse thrust, such that the braking distance is less than the relative distance, until the relative velocity of the UAV is 0. At this point, the control unit generates a safety command based on the relative correlation data.

5. The jet-powered reverse thrust high-speed braking method for unmanned aerial vehicles according to claim 4, characterized in that, The equation for calculating the jet thrust reverse braking distance of the UAV is as follows: ； in, Let the initial velocity be squared. For the square derivative of the velocity, The reverse thrust generated by the jet engine, The air drag coefficient, air density, For the windward area of ​​the drone, For the square of the velocity, For the quality of drones, Braking distance, It is the differential of the distance.

6. A jet-reverse thrust-type high-speed braking device for implementing the jet-reverse thrust-type high-speed braking method for unmanned aerial vehicles according to any one of claims 1 to 5, characterized in that, The jet-propelled high-speed braking device includes a control unit, a servo drive module, and an air tank mounted on the UAV. The control unit is connected to the servo drive module and the air tank. A nozzle is connected to the air tank. The servo drive module is connected to the nozzle. The air tank is used to store gas. The nozzle is used to convert the gas into a jet stream. The control unit is used to control the start and stop of gas jetting from the air tank, generate an angle adjustment command for the nozzle, and send it to the servo drive module. The servo drive module is used to drive the nozzle to adjust the direction of the air jetting. The control unit is used to acquire the flight attitude data of the UAV and the relative correlation data between the UAV and obstacles; The control unit is used to generate braking commands based on the relative correlation data, generate nozzle angle adjustment commands based on the flight attitude data, and send them to the servo drive module. The servo drive module is used to drive the nozzle to adjust the airflow injection direction; The control unit is used to control the start and stop of gas injection from the gas tank and to control the nozzle to inject airflow in the direction of airflow injection, thereby generating instantaneous reverse braking force until the control unit generates a safety command based on the relative correlation data to complete the braking of the UAV.

7. The jet-powered reverse-thrust high-speed braking device according to claim 6, characterized in that, The jet-powered high-speed braking device also includes an attitude sensor and a distance detection module. The attitude sensor and the distance detection module are respectively mounted on the UAV and are respectively connected to the control unit. The attitude sensor is used to collect the pitch and yaw angles of the UAV and send them to the control unit. The distance detection module is used to collect the relative distance and relative speed between the UAV and the obstacle and send them to the control unit.

8. The jet-powered reverse-thrust high-speed braking device according to claim 7, characterized in that, The nozzle is connected to the air outlet of the air tank. The spray angle of the nozzle in the horizontal direction is adjustable from 0 to 360°. The servo drive module drives the nozzle to move, so that the airflow spray angle is adjusted accordingly to adapt to the braking attitude of the UAV. The distance detection module is a lidar or millimeter-wave radar.

9. The jet-powered reverse-thrust high-speed braking device according to claim 7, characterized in that, The gas stored in the gas storage tank is hydrogen. An electromagnetic control valve is provided at the gas outlet of the gas storage tank. The electromagnetic control valve is connected to the control unit, and the control unit controls the start and stop of the gas source injection through the electromagnetic control valve.

10. The jet-powered reverse-thrust high-speed braking device according to claim 8, characterized in that, The attitude sensor, the distance detection module, the servo drive module, and the control unit are integrated into one unit. The integrated attitude sensor, the distance detection module, the servo drive module, and the control unit are located at the lower end of the UAV, and the air tank is located at the lower end of the control unit.

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