Unmanned aerial vehicle based multi-attitude adjustment type fire extinguishing bomb launching system and launching method

Abstract

The present application relates to the field of unmanned aerial vehicle and fire fighting technology, especially to a multi-attitude adjusting fire extinguishing bomb launching system and method based on unmanned aerial vehicle, the system comprises: a launching execution mechanism, which contains a fire extinguishing bomb slide, a single-degree-of-freedom rotating guide sleeve capable of being adjusted and locked, an angle driving unit and a state locking unit. The method comprises: constructing a gravity self-adaptive launching execution mechanism; establishing a multi-dimensional collaborative launching decision model based on flight state sensing; and executing a collaborative launching control process. The present application solves or at least alleviates the problem of launching precision decline caused by the deviation of the launching direction of the fire extinguishing bomb from the direction of gravity and the inertial lag during the dynamic flight of the unmanned aerial vehicle, provides a multi-attitude adjusting fire extinguishing bomb launching system and method based on unmanned aerial vehicle, realizes high-precision launching of the fire extinguishing bomb along the preset direction of gravity under various flight attitudes, effectively compensates for the dynamic lag effect, and improves the launching reliability and efficiency.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) and fire protection technology, and in particular relates to a multi-attitude adjustable fire extinguishing bomb delivery system and delivery method based on UAV. Background Technology

[0002] With the increasing demands for public safety response efficiency in modern society, drone technology is being applied more and more widely in the field of fire rescue, especially in scenarios where traditional rescue methods are difficult to reach quickly, such as high-rise building fires, forest fires, and hazardous chemical leaks. Drones equipped with fire extinguishing bombs have demonstrated unique operational advantages. Against this backdrop, ensuring the accuracy of fire extinguishing bomb delivery systems and their adaptability to complex flight conditions has become a key technical bottleneck restricting further improvements in the firefighting effectiveness of drones. Precise delivery can not only significantly improve fire extinguishing efficiency and reduce secondary disasters, but also ensure the safety of personnel. Therefore, developing a high-precision, highly adaptable drone fire extinguishing bomb delivery system has significant practical implications and far-reaching social value.

[0003] Within the existing technological framework, the industry has actively explored and implemented solutions to address the accuracy issue of drone payload delivery. For example, patent document CN119590617B discloses a drone precision delivery device and operating method. Its core concept lies in precisely pre-adjusting the overall attitude of the drone through a ground control station, supplemented by integrated sensor modules for status perception, and then using a signal transmission module to dynamically control the opening and closing timing of the electric telescopic rod and electromagnetic block. This solution aims to improve delivery accuracy and overall reliability through macroscopic control of the drone's flight attitude and refined management of the delivery mechanism's action sequence. Specifically, this technology, through predictive attitude adjustment, strives to adjust the drone to a relatively ideal delivery attitude at the moment of delivery, and uses an electromagnetic mechanism to precisely control the release of the projectile, thereby improving the landing accuracy to a certain extent under static or slowly changing flight conditions.

[0004] Building upon this foundation, some technical solutions focus on the attitude adjustment capabilities of the delivery mechanism itself. For example, patent CN113071677B discloses an attitude-adaptive radiosonde ejection device and method, proposing a technical concept of adjusting the direction of the radiosonde ejection mechanism via an electric mechanism. This solution cleverly solves the problem of traditional ejection mechanisms' excessive structural size adversely affecting the aerodynamic characteristics of UAVs, and by endowing the ejection mechanism with a certain attitude adaptability, the radiosonde can still be ejected and delivered in a specific direction even when the UAV is not flying horizontally. Its design principle lies in compensating for changes in the attitude of the UAV body through the rotation or deflection of a local mechanism, thereby providing a certain calibration for the initial ejection direction of the payload.

[0005] However, with the continuous development of related technologies and the increasingly stringent performance requirements of drone firefighting and rescue applications, some inherent characteristics of the aforementioned existing technical solutions at the principle level have gradually revealed their limitations and inherent contradictions when facing new challenges such as strong winds, turbulence, high-speed maneuvers, or complex terrain. Specifically analyzing the CN119590617B solution, its core reliance is on pre-adjustment of the overall drone attitude and compensation for the release force. This global control strategy, when facing rapidly changing complex flight conditions, often suffers from limitations in response speed and adjustment range due to the drone's own dynamic characteristics and stability margin. That is, when the drone performs dynamic maneuvers such as dives, climbs, or lateral drifts, precisely adjusting the entire drone to an attitude that perfectly aligns the fire extinguishing projectile's release direction with the target path can be time-consuming and easily lead to an unstable flight state at the moment of release, introducing new attitude disturbances. More importantly, this solution lacks a dynamic alignment mechanism for the fire extinguishing projectile's exit direction. This means that even if the UAV is roughly facing the target area through attitude pre-adjustment, the initial direction vector of the fire extinguishing projectile when it actually leaves the slide is still significantly affected by the UAV's instantaneous slight attitude deviation. This causes the initial parabolic trajectory of the fire extinguishing projectile to deviate from the preset trajectory, ultimately resulting in secondary problems such as a large dispersion of impact points and poor hit accuracy. This "attitude feedback and adjustment" mechanism focuses more on correcting deviations than on fundamentally solving the problem of autonomous adaptation of local delivery direction, making it difficult to achieve deep coupling of direction and timing under complex flight conditions.

[0006] Correspondingly, while the CN113071677B scheme possesses the capability to adjust the direction of the delivery mechanism, its initial design was for the catapult delivery of radiosondes, and its control logic and hardware design did not fully consider the high-precision collaborative optimization requirements for fire extinguishing projectile delivery. There are significant differences between catapult delivery and free-fall delivery in terms of the control requirements for initial velocity and direction. More importantly, this scheme can only adjust the catapult direction, failing to achieve dynamic compensation for the delivery timing. When the UAV is undergoing high-speed, high-acceleration dynamic flight, the fire extinguishing projectile will lag behind the UAV's movement within the track due to inertia. If the dynamic lag time of the fire extinguishing projectile within the track is not accurately estimated and compensated based on the UAV's real-time angular acceleration (such as pitch acceleration, roll acceleration, etc.), even if the delivery mechanism is precisely aligned at a certain moment, the actual release time of the fire extinguishing projectile may still deviate from the ideal delivery time. Such minute timing deviations, in high-speed or high-altitude delivery scenarios, will be amplified into significant landing point errors, thus greatly limiting its applicability in fire extinguishing grenade delivery scenarios with higher precision requirements. The inherent contradiction lies in the fact that simple direction adaptation fails to form an effective logical connection and physical coupling with dynamic timing compensation. As a result, under complex dynamic conditions, the disconnect between the two prevents the system from outputting a truly high-precision delivery window.

[0007] In summary, the core technical challenge of existing UAV fire extinguishing projectile delivery systems under complex flight conditions is not simply a matter of direction or timing, but rather the failure to construct a control strategy and actuator that can deeply integrate real-time multi-dimensional attitude dynamics data of the UAV to achieve highly coordinated and dynamically optimized fire extinguishing projectile exit direction and delivery timing. Existing solutions either focus on indirectly influencing the delivery direction through global attitude adjustments, resulting in sluggish response, or, while able to locally adjust the direction, ignore the inertial hysteresis effect of the fire extinguishing projectile itself under dynamic flight. This leads to a fundamental disconnect between direction and timing, failing to create a high-precision delivery window that can generate direction alignment and optimal timing under any flight attitude. Therefore, how to overcome the significant shortcomings of existing technologies in direction alignment and timing compensation under complex flight conditions through refined modification of the delivery mechanism and the construction of a more intelligent and coordinated control method, thereby significantly improving the landing accuracy and hit rate of the fire extinguishing projectile, has become a key challenge and an urgent technical problem for those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art, solve or at least alleviate the problems of deviation between the fire extinguishing bullet delivery direction and the gravity direction when the drone's attitude changes dynamically, especially when it is in pitch, roll or yaw maneuvering flight state, and the inconsistency between the actual release time and the command time caused by the inertia of the fire extinguishing bullet. The invention provides a multi-attitude adjustable fire extinguishing bullet delivery system and delivery method based on a drone.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a multi-attitude adjustable fire extinguishing bomb delivery system based on an unmanned aerial vehicle (UAV), comprising:

[0010] At least one delivery execution mechanism is disposed below the fuselage of the UAV and fixedly connected to the airframe structure; the delivery execution mechanism includes:

[0011] The fire extinguishing bomb slide is set on the path of the fire extinguishing bomb. When the UAV is in a horizontal flight attitude, the fire extinguishing bomb slide is arranged along the Z-axis of the UAV's body coordinate system.

[0012] A single-degree-of-freedom rotating guide sleeve is coaxially sleeved at the outlet end of the fire extinguishing bomb slide. Its axis is connected to the axial movement direction of the fire extinguishing bomb in the fire extinguishing bomb slide, and it can rotate around a horizontal rotation axis within a preset angle range so that the outlet direction of the guide sleeve can be aligned with the local gravity direction. The inner wall of the guide sleeve forms the last guiding channel before the fire extinguishing bomb leaves the fire extinguishing bomb slide.

[0013] An angle drive unit is used to drive the guide sleeve to rotate about its horizontal rotation axis and provide real-time angular position feedback of the guide sleeve.

[0014] A state locking unit is used to lock the guide sleeve after it reaches the target angle to ensure its position is rigidly fixed; and

[0015] The UAV flight control system connects to the angle drive unit and the status locking unit via electrical connection lines, controls the rotation and locking action of the guide sleeve, and receives angle and position feedback signals.

[0016] To further realize the present invention, the following technical solutions may be preferred:

[0017] Preferably, the single-degree-of-freedom rotary guide sleeve is made of lightweight, high-strength material, and its length and inner diameter match the outer diameter of the fire extinguishing projectile, ensuring that the fire extinguishing projectile can slide smoothly without excessive shaking; the guide sleeve is supported on the frame of the delivery actuator by a precision bearing structure, and can rotate with high precision around its horizontal rotation axis with low frictional resistance.

[0018] Preferably, the angle driving unit adopts high-precision servo motor technology, which has sufficient output torque to drive the guide sleeve to rotate, and the rotation accuracy meets the deployment accuracy requirements and the response time is short; the angle driving unit includes a position feedback encoder, which can provide the current rotation angle information of the guide sleeve in real time.

[0019] Preferably, the state locking unit includes an electromagnetic locking pin, which extends out and is embedded in a preset positioning structure on the rotating base of the guide sleeve under normal conditions, and retracts when energized to release the lock on the guide sleeve; the locking pin can provide sufficient anti-rotation torque in the locked state to ensure that the guide sleeve remains stable during deployment.

[0020] Preferably, the UAV flight control system integrates an inertial measurement unit for continuously collecting linear acceleration, angular velocity, and attitude angle data of the UAV in the body coordinate system; the angle driving unit and the state locking unit are connected to the UAV flight control system via shielded cables.

[0021] A method for delivering fire extinguishing projectiles using a multi-attitude adjustable fire extinguishing projectile delivery system based on an unmanned aerial vehicle (UAV) includes the following steps:

[0022] S1: Real-time acquisition of multi-dimensional flight status parameters of the UAV;

[0023] S2: Based on flight state parameters, calculate the target alignment angle of the single-degree-of-freedom rotating guide sleeve, so that the exit direction of the guide sleeve is parallel to the projection vector of the local gravity direction in the UAV body coordinate system.

[0024] S3: Based on the angular acceleration and attitude change rate of the UAV, estimate the dynamic lag time of the fire extinguishing bomb in the fire extinguishing bomb slide.

[0025] S4: Integrates target alignment angle, dynamic lag time, servo motor rotation characteristics, and preset settling time to generate a coordinated action timing plan; and

[0026] S5: Based on the coordinated action sequence planning, execute the coordinated delivery control process, including driving the guide sleeve to rotate in advance, monitoring the guide sleeve to reach the target angle and stabilize it, locking the guide sleeve, and triggering the fire extinguishing bomb release mechanism to release the fire extinguishing bomb at the predetermined time after the guide sleeve is successfully locked.

[0027] Preferably, the step of calculating the target alignment angle of the single-degree-of-freedom rotary guide sleeve in step S2 includes:

[0028] Based on the real-time collected attitude data, determine the projection vector of the local gravity direction in the UAV's body coordinate system; and

[0029] Calculate the target rotation angle of the guide sleeve so that the exit direction of the guide sleeve is precisely parallel to the direction of gravity projection.

[0030] Preferably, the step of estimating the dynamic lag time of the fire extinguishing projectile within the fire extinguishing projectile track in step S3 includes:

[0031] Based on real-time angular acceleration data and attitude change rate, combined with fire extinguishing projectile parameters and slide characteristics, a dynamic model is established to estimate the time delay required from the issuance of the release command to the actual departure of the fire extinguishing projectile from the guide sleeve outlet; the dynamic model considers the influence of the UAV's motion state at the moment of release on the movement of the fire extinguishing projectile in the slide.

[0032] Preferably, the step of generating the coordinated action timing plan in step S4 includes calculating the moment when the guide sleeve starts to rotate, the moment when the locking is triggered, and the moment when the fire extinguishing bomb is actually released; the determination of the three key time points is based on the ideal deployment time, the dynamic lag time, the time required for the guide sleeve to rotate, and the preset stabilization time.

[0033] Preferably, the step of executing the collaborative delivery control process in step S5 includes:

[0034] Send the target angle command to the angle drive unit, and simultaneously release the lock on the guide sleeve;

[0035] Once the rotation angle of the guide sleeve enters the tolerance range of the target alignment angle and stabilizes, locking is triggered to rigidly fix the guide sleeve at the target alignment angle.

[0036] Set a "sleeve ready" flag, which is set to true only when the guide sleeve has been successfully locked and remains stable; and

[0037] When the "sleeve ready" flag is true and the system time reaches the predetermined moment, a trigger signal is sent to the fire extinguishing bomb release mechanism to release the fire extinguishing bomb.

[0038] The beneficial effects of this invention are:

[0039] This invention constructs a single-degree-of-freedom rotary guide sleeve with dual functions of active drive and rigid locking, realizing gravity self-adaptation of the fire extinguishing bomb's delivery direction and solving the core problem of delivery direction deviation caused by changes in UAV attitude.

[0040] Meanwhile, a multi-dimensional collaborative delivery decision-making model integrating real-time flight status perception, precise target angle calculation, and detailed estimation of dynamic lag time was established, providing intelligent support for the precise scheduling of delivery commands. The model incorporates the UAV's angular acceleration and pitch angle change rate into the lag time estimation, making delivery timing compensation more accurate and solving the inertial lag problem under dynamic flight conditions.

[0041] Furthermore, a strict collaborative deployment control process was designed, especially the introduction of a state constraint mechanism for the sleeve ready flag, which ensures that the fire extinguishing bomb is only allowed to be deployed after the guide sleeve has been precisely aligned and successfully locked. This achieves reverse constraint of the physical state on the control command, greatly improving the reliability and accuracy of deployment and avoiding invalid deployment under misalignment conditions.

[0042] This method, through precise timing planning, seamlessly coordinates the rotation and locking actions of the guide sleeve with the release timing of the fire extinguishing bomb, ensuring the consistency and effectiveness of directional alignment and timing compensation on the same time axis. Attached Figure Description

[0043] Figure 1 This is a schematic block diagram of the overall structure of the delivery system of the present invention;

[0044] Figure 2 This is a schematic block diagram of the structure of the actuator of the present invention;

[0045] Figure 3 This is a schematic block diagram of the guide sleeve in the actuator of the present invention;

[0046] Figure 4 This is a schematic diagram illustrating the gravity direction alignment of the guide sleeve when the UAV of the present invention is in an inclined posture;

[0047] Figure 5 This is a system block diagram of the multi-dimensional collaborative delivery decision-making model of the present invention;

[0048] Figure 6 This is a flowchart illustrating the delivery method of the present invention;

[0049] Figure 7 This is a flowchart illustrating the collaborative delivery control process of the present invention;

[0050] Figure 8 This is a three-dimensional schematic diagram of the delivery system of the present invention;

[0051] Figure 9 This is a front view of the delivery system of the present invention.

[0052] The attached figures are labeled as follows:

[0053] 1-Unmanned aerial vehicle platform; 2-Fire extinguishing bomb slide; 3-Single degree of freedom rotary guide sleeve; 4-Angle drive unit; 5-Status locking unit. Detailed Implementation

[0054] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] This embodiment discloses a multi-attitude adjustable fire extinguishing projectile delivery system based on a UAV. Its overall architecture is based on a high-performance UAV platform 1, which integrates a flight control system for mission planning and execution, and a delivery execution mechanism for sensing devices. The delivery execution mechanism is the key physical unit for achieving precise delivery of the fire extinguishing projectile, and its design fully considers engineering indicators such as lightweight, high rigidity, rapid response, and environmental adaptability. The delivery execution mechanism is preferably integrally molded from aerospace-grade aluminum alloy or carbon fiber composite material, and its total mass does not exceed 10% of the UAV's effective payload, ensuring that it will not have a significant negative impact on the UAV's flight performance. The delivery execution mechanism is typically fixedly installed under the UAV fuselage, near its center of gravity, to minimize the impact of the delivery action on the UAV's attitude.

[0058] The core component of the delivery mechanism includes a fire extinguishing projectile chute 2. This chute is designed to ensure that the fire extinguishing projectile can accelerate smoothly and without obstruction under gravity. The inner wall of the chute is precision polished, with a surface roughness Ra value controlled below 0.8 micrometers, and coated with an ultra-low coefficient of friction polytetrafluoroethylene (PTFE) coating to minimize frictional resistance of the fire extinguishing projectile within the chute. A precise clearance fit is maintained between the inner diameter of the chute and the outer diameter of the fire extinguishing projectile, typically set between 0.5 mm and 1.0 mm. This prevents the fire extinguishing projectile from getting stuck or excessively swaying within the chute and effectively guides its trajectory. The geometry of the chute is not a simple straight line, but an optimized, gradually changing curve to accommodate the slight lateral forces that may exist when the fire extinguishing projectile initially exits the magazine, ensuring that it achieves a stable initial descent attitude before entering the guide sleeve.

[0059] At the exit end of the fire extinguishing projectile chute, the single-degree-of-freedom rotary guide sleeve 3 is integrated. This guide sleeve is the core component for achieving gravity-adaptive deployment in this invention. The guide sleeve is preferably made of lightweight, high-strength composite material (such as carbon fiber reinforced resin matrix composite material) to minimize its own mass while ensuring structural strength, thereby reducing the load on the angle drive unit and shortening the response time. The length of the guide sleeve is set at 150 mm, and its inner diameter maintains a gap of 0.5 mm to 1.0 mm with the outer diameter of the fire extinguishing projectile, ensuring that the projectile can slide smoothly through it. The guide sleeve is supported on the frame of the deployment actuator by a precision bearing structure.

[0060] Furthermore, the delivery mechanism is equipped with the angle drive unit 4, whose function is to precisely control the rotation angle of the guide sleeve. The angle drive unit is a micro servo motor, specially selected for its high torque density, high-precision encoder feedback, and rapid response. The motor's rotation angle range is designed to be ±90 degrees, covering the entire range of gravity adjustment requirements from vertically upward to vertically downward, with a rotation accuracy better than 0.05 degrees and a response time of less than 40 milliseconds. The output shaft of the micro servo motor is rigidly connected to the rotation shaft of the guide sleeve via a high-rigidity flexible coupling to avoid the impact of mechanical backlash on angle control accuracy. The angle drive unit also incorporates a high-resolution position feedback encoder, typically a magnetic encoder or photoelectric encoder, with a resolution of 16 bits or higher. This encoder provides real-time information on the current rotation angle of the guide sleeve with an accuracy of 0.01 degrees and transmits the data to the UAV flight control system, providing precise feedback for closed-loop angle control.

[0061] Simultaneously, the delivery mechanism is also equipped with the state locking unit 5, which mechanically locks the guide sleeve after it reaches the target angle. This ensures that the guide sleeve will not unexpectedly deflect due to UAV vibration, aerodynamic load, or insufficient holding force of the micro servo motor when the fire extinguishing projectile passes through, thus guaranteeing the stability of the delivery direction. The state locking unit is an electromagnetic locking pin, which locks when de-energized and unlocks when energized. Under normal conditions, the locking pin is extended under the action of an internal spring with a preload of not less than 60 Newtons and is precisely embedded in one or more pre-set positioning holes on the rotating base of the guide sleeve, thereby keeping the guide sleeve rigidly fixed. When the electromagnetic coil of the electromagnetic locking pin is energized, the locking pin quickly retracts under the action of the generated electromagnetic force, releasing the lock on the guide sleeve and allowing it to rotate freely. The diameter of the locking pin is typically 4 mm, and the stroke is 8 mm to ensure reliable locking depth and sufficient unlocking stroke. The action of the electromagnetic locking pin is precisely controlled by an independent digital signal from the flight control system; that is, a simple switching signal can realize its locking and unlocking functions.

[0062] Both the angle drive unit and the state locking unit are connected to the execution interface of the UAV flight control system. The flight control system can send high-precision PWM signals to the micro servo motor through an independent PWM output channel to control its rotation angle and speed, and achieve closed-loop control through feedback from the motor's built-in encoder. Simultaneously, the flight control system sends ON / OFF digital signals to the electromagnetic locking pin to control its locked or unlocked state.

[0063] Example 2

[0064] This embodiment discloses a multi-attitude adjustable fire extinguishing bomb delivery method based on UAV. Through the coordinated control of perception, decision-making and execution, it ensures that the fire extinguishing bomb can still be delivered with high precision along the preset gravity direction under the dynamic flight attitude of the UAV, and effectively compensates for the inertial hysteresis effect of the fire extinguishing bomb.

[0065] This method first involves constructing a delivery actuator with gravity-adaptive capability and state-locking function. The core of this construction process lies in precise mechanical assembly and electrical integration. At the exit end of the fire extinguishing projectile chute, the single-degree-of-freedom rotary guide sleeve is integrated into the frame of the delivery actuator via the aforementioned precision bearing structure, ensuring its rotation axis is perpendicular to the fire extinguishing projectile chute axis and can rotate smoothly. Simultaneously, the angle drive unit and the state-locking unit are configured for the guide sleeve. A micro servo motor is connected to the main shaft of the guide sleeve via a flexible coupling, and its zero position is calibrated. An electromagnetic locking pin is installed near the rotating base of the guide sleeve, and the alignment of its pin body with the positioning hole is adjusted at the micrometer level using a laser calibrator to ensure no loosening in the locked state. Finally, the angle drive unit and the state-locking unit are connected to the execution interface of the UAV flight control system.

[0066] Next, the method of this invention establishes a multi-dimensional collaborative delivery decision model based on flight state perception. This model is the core software module for realizing intelligent delivery decisions. The UAV flight control system integrates a high-performance inertial measurement unit (IMU), preferably a microelectromechanical system (MEMS) IMU. This IMU integrates a three-axis MEMS accelerometer, a three-axis MEMS gyroscope, and a three-axis magnetometer. The IMU continuously collects the UAV's three-axis acceleration, three-axis angular velocity, and attitude angles (pitch, roll, and yaw) data in the body coordinate system, as well as the attitude angles calculated by attitude fusion algorithms (such as extended Kalman filtering or complementary filtering).

[0067] Based on real-time acquired flight status parameters, the flight control system first converts the attitude in the body coordinate system to an attitude representation in the inertial coordinate system using quaternions or direction cosine matrices, based on the attitude data collected in real-time by the IMU. Then, the system calculates the projection vector of the local gravity direction in the UAV's body coordinate system. The target alignment angle... The angle defined is the angle at which the axis of the guide sleeve needs to be rotated to be parallel to the gravity projection vector. The specific calculation process is as follows: when the roll angle of the UAV... Within a preset small range (e.g., When the roll has a negligible effect on the falling direction of the fire extinguishing projectile, the target alignment angle is... It is directly approximated to the pitch angle of the UAV. However, when the roll angle When the gravity vector is large, the flight control system needs to perform a three-dimensional rotational transformation to convert the gravity vector from the inertial coordinate system to the UAV's body coordinate system, and then project it onto the rotation plane of the guide sleeve (i.e., the plane where the UAV's roll axis is located). For example, let the gravity vector be represented in the body coordinate system as... The target rotation angle of the guide sleeve can be obtained through the arctangent function. Calculations were performed to ensure that its axis is precisely parallel to the direction of gravity projection.

[0068] Furthermore, to compensate for the dynamic lag effect of the fire extinguishing projectile, the flight control system estimates the dynamic lag time of the projectile within the slide in real time based on the UAV's angular acceleration and pitch rate of change. The flight control system utilizes real-time three-axis angular acceleration data (including pitch acceleration) provided by the IMU. Roll acceleration and yaw acceleration and pitch angular velocity Combined with the known mass of the fire extinguishing bomb (e.g., kilograms), the length of the slide (e.g., (meters), and the average coefficient of friction between the inner wall of the slide and the fire extinguishing bomb (e.g., meters ...). (This parameter was precisely measured through ground experiments). By establishing a simplified two-degree-of-freedom dynamic model, the time delay required from the issuance of the release command to the actual departure of the fire extinguishing projectile from the guide sleeve exit can be estimated in real time. The dynamic model considers the complex influence of the UAV's angular velocity and angular acceleration at the moment of deployment on the trajectory and speed of the fire extinguishing projectile within the slide. For example, the UAV's pitch acceleration causes the fire extinguishing projectile to experience additional inertial forces within the slide, altering its normal pressure on the slide's inner wall and thus affecting friction. The flight control system obtains the dynamic model using numerical integration methods (such as the fourth-order Runge-Kutta method) or lookup table methods (based on pre-calculated mapping relationships between dynamic lag times and UAV state parameters under various operating conditions). The aforementioned The estimation accuracy is controlled within 5 milliseconds to ensure the effectiveness of delivery timing compensation.

[0069] Subsequently, the flight control system integrates the target angle and the dynamic lag time to generate a precise coordinated action timing plan. The flight control system then uses the calculated target alignment angle... The estimated dynamic lag time The average rotational speed of the micro servo motor (e.g., (degrees / second), and the preset minimum stabilization time after the guide sleeve rotates into place. (the aforementioned) Set to 200 milliseconds (to ensure mechanical vibration decays to an acceptable level and gives the locking mechanism sufficient response time), a coordinated action timing plan with three key time points is generated:

[0070] a. The formula for calculating the moment when the guide sleeve begins to rotate is as follows: .in For the ideal delivery time, For the guide sleeve from the current angle Rotate to the target alignment angle Required execution time This formula ensures that the guide sleeve has enough time to complete its rotation and stabilize before the fire extinguishing bomb is about to detach.

[0071] b. The calculation formula for the moment when the electromagnetic locking pin is triggered to lock after the guide sleeve has rotated into place and stabilized is as follows: This moment ensures that the guide sleeve is in a rigidly locked state before the fire extinguishing bomb separates from the drone body.

[0072] c. The actual moment when the fire extinguishing grenade release mechanism is triggered is calculated using the following formula: This moment is the actual release time after lag compensation, designed to ensure that the fire extinguishing bomb is deployed at the ideal time. At that time, it can truly fall freely along the direction of gravity.

[0073] The coordinated action timing plan, through rigorous mathematical calculations and time margin allocation, ensures that the guide sleeve has completed precise alignment and locking before the fire extinguishing projectile actually leaves the drone, and compensates for the inertial lag of the fire extinguishing projectile, thereby ensuring that the fire extinguishing projectile... It is deployed with high precision along the direction of gravity at all times.

[0074] After the decision model generates the coordinated action timing plan, the method of this invention will enter the coordinated delivery control process. Upon receiving an external delivery command, such as a mission planning module from a ground station or a direct command from a remote operator, the flight control system initiates the coordinated delivery control process. The delivery command may include the ideal delivery time for one or more fire extinguishing projectiles. If the release command requires immediate release, the flight control system will adjust the current time... As If the delivery instruction requires delivery at a future time, such as during formation flying or multi-point coordinated delivery missions, then... Set to a predetermined future time.

[0075] According to the aforementioned timing schedule, the flight control system will drive the guide sleeve to rotate in advance. When the system time arrives... At a specific moment, the flight control system sends a target angle command to the micro servo motor via a preset PWM output channel, and simultaneously sends a release command to the electromagnetic locking pin via a digital output channel. Specifically, the electromagnetic coil of the electromagnetic locking pin is energized, and the locking pin rapidly retracts under electromagnetic force, releasing the mechanical lock on the guide sleeve. After receiving the command, the micro servo motor begins to drive the guide sleeve to align with the target angle. The rotation process is fed back in real time by the built-in encoder, and the flight control system accurately tracks the target angle through the PID (proportional-integral-derivative) control algorithm.

[0076] During this period, the flight control system continuously monitors whether the guide sleeve has reached the target alignment angle and achieved stabilization. By continuously reading the real-time angle data fed back by the position feedback encoder built into the micro servo motor, the flight control system determines whether the current rotation angle of the guide sleeve has entered the target alignment angle. The preset tolerance range (e.g., Within this tolerance range (degrees). Once the guide sleeve angle enters this tolerance range and its angular velocity falls below a preset stabilization threshold (e.g., 0.5 degrees / second), the flight control system activates an internal timer to wait for the aforementioned minimum stabilization time. (200 milliseconds). This settling time ensures that the mechanical vibration of the guide sleeve is sufficiently damped, providing a stable basis for subsequent locking actions. After the settling time ends, and the system time reaches [a certain value], [the system will proceed]. At any given moment, the flight control system sends a locking command to the electromagnetic locking pin through the digital output channel. The electromagnetic coil is de-energized, and the locking pin quickly extends and re-embeds into the positioning hole under the preload of the spring, rigidly fixing the guide sleeve at the target alignment angle.

[0077] To further enhance the reliability and safety of deployment, this invention establishes a strict state constraint mechanism: the deployment trigger preparation state is only allowed after the guide sleeve is successfully locked. The flight control system sets an internal status flag named "Sleeve Ready." The "Sleeve Ready" flag is only set to true when the guide sleeve is determined to be successfully locked and the locking state remains stable (e.g., no abnormality in the locking pin feedback signal for 10 consecutive milliseconds). If the guide sleeve fails to lock on time or successfully due to mechanical failure (e.g., stuck positioning pin), drive failure (e.g., servo motor malfunction), or abnormal sensor feedback, the flight control system immediately aborts the deployment mission and keeps the "Sleeve Ready" flag false. Simultaneously, the system reports detailed abnormal information to the ground control station, issues warnings via the UAV's onboard display or indicator lights, and triggers a preset fault handling procedure, such as attempting to retry the locking action, switching to a backup deployment mechanism (if available), or entering a safety mode to await manual intervention, thereby preventing accidental release of fire extinguishing bombs when the deployment direction is misaligned or the mechanism is not locked.

[0078] When the "sleeve ready" flag is true and the system time arrives precisely... At the designated moment, the flight control system sends a trigger signal to the electromagnetic release device or push rod actuator of the fire extinguishing grenade magazine via an independent digital output channel. Under its own gravity, the fire extinguishing grenade smoothly slides out along the precisely aligned and rigidly locked guide sleeve, ultimately detaching from the UAV. The response time of the fire extinguishing grenade release mechanism has been optimized, typically less than 8 milliseconds, ensuring extremely high accuracy in deployment timing.

[0079] After the fire extinguishing projectile is deployed, the method of this invention also includes post-deployment state reset and anomaly handling. 0.5 seconds after the fire extinguishing projectile release trigger signal is issued, the flight control system will delay to release the locking of the guide sleeve. This 0.5-second delay is designed to ensure that the fire extinguishing projectile has completely detached from the guide sleeve, preventing the sleeve from unexpectedly swinging due to high-speed airflow disturbances or inertial impact at the moment of projectile detachment, which could affect the flight stability of the UAV or potentially interfere with subsequent deployment tasks. After the delay, the flight control system sends a release command to the electromagnetic locking pin through the digital output channel, re-energizing the electromagnetic coil, causing the locking pin to retract, and allowing the guide sleeve to resume free rotation.

[0080] Subsequently, the flight control system drives the guide sleeve to reset to the default horizontal position, preparing for the next deployment. The flight control system sends commands to the micro servo motor via the PWM output channel, driving the guide sleeve to rotate to the preset default horizontal position (e.g., 0 degrees relative to the UAV's structural axis or parallel to the UAV's flight direction), and then reactivates the electromagnetic locking pin at this position for locking. This default horizontal position helps reduce aerodynamic drag on the UAV when not in operation, improving endurance, and also facilitates routine system maintenance, self-checks, and rapid deployment for the next deployment mission.

[0081] To continuously optimize system performance and trace faults, the flight control system meticulously records the flight status, action sequence, and result feedback for each deployment. Specifically, the system records all key data from the deployment mission at a high frequency (e.g., 100Hz), including but not limited to the UAV's three-axis attitude angles, linear velocity, angular velocity, and angular acceleration at the time of deployment; the actual alignment angle of the guide sleeve; the estimated dynamic lag time; the action status of the electromagnetic locking pin; the fire extinguishing grenade release trigger time; and the system response time, into onboard non-volatile memory (such as an industrial-grade SD card or solid-state drive). If the UAV carries target tracking or deployment effect evaluation sensors (e.g., a high-resolution visual sensor combined with a laser rangefinder), the feedback information on the fire extinguishing grenade's impact point (if any) will also be recorded for comparison and analysis with the expected impact point. This recorded data is a valuable basis for subsequent deployment decision model optimization, system performance evaluation, fault diagnosis, and retrospective analysis of deployment effects.

[0082] Example 3

[0083] In a specific case, the system of this invention was applied to a hexacopter UAV with a maximum takeoff weight of 25 kg to perform a targeted firefighting mission in the initial stage of a forest fire. The UAV carried a fire extinguishing bomb with a diameter of 100 mm, a length of 300 mm, and a mass of 2.0 kg. During a certain phase of the mission, the UAV was flying level at a speed of 15 m / s when it suddenly encountered a crosswind, causing a drastic change in its attitude: the pitch angle instantly changed from 0 degrees to -10 degrees (nose down), the roll angle reached -5 degrees (leftward tilt), and at this time the pitch velocity was -3 degrees / s and the pitch acceleration was -1 degree / s². The ground command center then issued an instruction requiring the UAV to respond within 2 seconds of receiving the instruction (i.e., Precisely deliver fire extinguishing bombs to the target area.

[0084] The flight control system immediately initiates the deployment decision process. First, the IMU acquires and fuses attitude data in real time at a frequency of 400Hz. Based on the current UAV's pitch angle of -10 degrees and roll angle of -5 degrees, the flight control system calculates the projection of the gravity vector onto the plane of rotation of the guide sleeve through a three-dimensional rotation transformation. Under this specific attitude, the target alignment angle of the guide sleeve is determined. It was precisely calculated to be -10.45 degrees. This angle ensures that the axis of the guide sleeve remains parallel to the projection of the actual direction of gravity in the body coordinate system.

[0085] Meanwhile, based on the UAV's pitch velocity of -3 degrees / second, pitch acceleration of -1 degree / second², and parameters such as the fire extinguishing projectile's mass of 2.0 kg, slide length of 0.5 m, and slide friction coefficient of 0.02, the flight control system, through a simplified two-degree-of-freedom dynamic model, estimated the dynamic lag time from the issuance of the command to the actual departure of the fire extinguishing projectile from the guide sleeve exit. The latency is 85 milliseconds. This latency takes into account the effect of the inertial forces of the drone during attitude changes on the movement of the fire extinguishing projectile within the track.

[0086] Assume the current time is Ideal delivery time Milliseconds. Flight control system fusion. Spend, Milliseconds, average rotation speed of micro servo motors degrees / second and minimum settling time Milliseconds. Assuming the current angle of the guide sleeve... The angle is 0 degrees. Therefore, the time required for the guide sleeve to rotate from 0 degrees to -10.45 degrees is... millisecond.

[0087] Based on this, the coordinated action timing plan is generated:

[0088] 1. The moment when the guide sleeve begins to rotate millisecond.

[0089] 2. The moment when the electromagnetic locking pin is triggered to lock. millisecond.

[0090] 3. The actual moment when the fire extinguishing grenade release mechanism is triggered. millisecond.

[0091] When the system time arrives At milliseconds, the flight control system sends an unlock command to the electromagnetic locking pin and a target angle command of -10.45 degrees to the micro servo motor. The guide sleeve begins to rotate rapidly. After approximately 34.8 milliseconds of rotation, the guide sleeve... It reaches -10.45 degrees in approximately milliseconds. Once the flight control system detects that the angle has entered and stabilized within the 0.2-degree tolerance range, it initiates a 200-millisecond stabilization timer. When the timer ends and the system time reaches [the specified value], [the timer continues]. milliseconds (i.e.) The flight control system sends a locking command to the electromagnetic locking pin, which quickly resets, rigidly locking the guide sleeve at -10.45 degrees. The system detects successful locking and sets the "sleeve ready" flag to true.

[0092] Since the "sleeve ready" flag is true and the system time has expired... milliseconds (i.e.) The flight control system immediately sends a trigger signal to the fire extinguishing grenade release mechanism. Under its own weight, the fire extinguishing grenade slides out along a guide sleeve precisely aligned and locked to the direction of gravity, and... milliseconds (i.e.) It precisely detaches from the drone at the optimal time and flies to the target area along the best trajectory.

[0093] Under dynamic flight conditions, this invention reduces the actual launch direction angle error and landing point deviation of the fire extinguishing projectile through precise adaptive attitude adjustment of the guide sleeve and fine compensation for the dynamic lag time of the projectile. Compared with existing fixed slide schemes, the launch accuracy of this invention is improved by at least one order of magnitude, and the launch success rate is significantly increased. This fully demonstrates the superiority of the technical solution provided by this invention and its important value in engineering practice.

[0094] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles (UAVs), characterized in that, The drone includes: At least one delivery execution mechanism is disposed below the fuselage of the UAV and fixedly connected to the airframe structure; the delivery execution mechanism includes: The fire extinguishing bomb slide is set on the path of the fire extinguishing bomb. When the UAV is in a horizontal flight attitude, the fire extinguishing bomb slide is arranged along the Z-axis of the UAV's body coordinate system. A single-degree-of-freedom rotating guide sleeve is coaxially sleeved at the outlet end of the fire extinguishing bomb slide. Its axis is connected to the axial movement direction of the fire extinguishing bomb in the fire extinguishing bomb slide, and it can rotate around a horizontal rotation axis within a preset angle range so that the outlet direction of the guide sleeve can be aligned with the local gravity direction. The inner wall of the guide sleeve forms the last guiding channel before the fire extinguishing bomb leaves the fire extinguishing bomb slide. An angle drive unit is used to drive the guide sleeve to rotate about its horizontal rotation axis and provide real-time angular position feedback of the guide sleeve. A state locking unit is used to lock the guide sleeve after it reaches the target angle to ensure its position is rigidly fixed; and The UAV flight control system connects to the angle drive unit and the status locking unit via electrical connection lines, controls the rotation and locking action of the guide sleeve, and receives angle position feedback signals; The method includes the following steps: S1: Real-time acquisition of multi-dimensional flight status parameters of the UAV; S2: Based on flight state parameters, calculate the target alignment angle of the single-degree-of-freedom rotating guide sleeve, so that the exit direction of the guide sleeve is parallel to the projection vector of the local gravity direction in the UAV body coordinate system. S3: Based on the angular acceleration and attitude change rate of the UAV, estimate the dynamic lag time of the fire extinguishing bomb in the fire extinguishing bomb slide. S4: Integrates target alignment angle, dynamic lag time, servo motor rotation characteristics, and preset settling time to generate a coordinated action timing plan; and S5: Based on the coordinated action sequence planning, execute the coordinated delivery control process, including driving the guide sleeve to rotate in advance, monitoring the guide sleeve to reach the target angle and stabilize it, locking the guide sleeve, and triggering the fire extinguishing bomb release mechanism to release the fire extinguishing bomb at the predetermined time after the guide sleeve is successfully locked.

2. The method for delivering multi-attitude adjustable fire extinguishing projectiles based on unmanned aerial vehicles according to claim 1, characterized in that, The single-degree-of-freedom rotary guide sleeve is made of lightweight, high-strength material. Its length and inner diameter match the outer diameter of the fire extinguishing bomb, ensuring that the fire extinguishing bomb can slide smoothly without excessive shaking. The guide sleeve is supported on the frame of the delivery actuator by a precision bearing structure, and can rotate with high precision around its horizontal rotation axis with low frictional resistance.

3. The method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles according to claim 1, characterized in that, The angle driving unit adopts high-precision servo motor technology, which has sufficient output torque to drive the guide sleeve to rotate. The rotation accuracy meets the deployment accuracy requirements and the response time is short. The angle driving unit includes a position feedback encoder, which can provide the current rotation angle information of the guide sleeve in real time.

4. The method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles according to claim 1, characterized in that, The state locking unit includes an electromagnetic locking pin, which extends and is embedded in a preset positioning structure on the rotating base of the guide sleeve under normal conditions. When energized, it retracts and releases the lock on the guide sleeve. The locking pin can provide sufficient anti-rotation torque in the locked state to ensure that the guide sleeve remains stable during deployment.

5. The method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles according to claim 1, characterized in that, The UAV flight control system integrates an inertial measurement unit for continuously collecting linear acceleration, angular velocity, and attitude angle data of the UAV in the body coordinate system; the angle drive unit and the state locking unit are connected to the UAV flight control system via shielded cables.

6. The method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles according to claim 1, characterized in that, The step of calculating the target alignment angle of the single-degree-of-freedom rotary guide sleeve in step S2 includes: Based on the real-time collected attitude data, determine the projection vector of the local gravity direction in the UAV's body coordinate system; and Calculate the target rotation angle of the guide sleeve so that the exit direction of the guide sleeve is precisely parallel to the direction of gravity projection.

7. The method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles according to claim 1, characterized in that, The step of estimating the dynamic lag time of the fire extinguishing projectile within the fire extinguishing projectile track in step S3 includes: Based on real-time angular acceleration data and attitude change rate, combined with fire extinguishing projectile parameters and slide characteristics, a dynamic model is established to estimate the time delay required from the issuance of the release command to the actual departure of the fire extinguishing projectile from the guide sleeve outlet; the dynamic model considers the influence of the UAV's motion state at the moment of release on the movement of the fire extinguishing projectile in the slide.

8. The method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles according to claim 1, characterized in that, The step of generating the coordinated action timing plan in step S4 includes calculating the moment when the guide sleeve starts to rotate, the moment when the locking is triggered, and the moment when the fire extinguishing bomb is actually released. The determination of the three key time points is based on the ideal deployment time, the dynamic lag time, the time required for the guide sleeve to rotate, and the preset stabilization time.

9. The method for delivering multi-attitude adjustable fire extinguishing bombs based on unmanned aerial vehicles according to claim 1, characterized in that, The steps in step S5 that execute the collaborative delivery control process include: Send the target angle command to the angle drive unit, and simultaneously release the lock on the guide sleeve; Once the rotation angle of the guide sleeve enters the tolerance range of the target alignment angle and stabilizes, locking is triggered to rigidly fix the guide sleeve at the target alignment angle. Set a sleeve-ready flag, which is set to true only when the guide sleeve has been successfully locked and remains stable; and When the sleeve is ready flag is true and the system time reaches the predetermined moment, a trigger signal is sent to the fire extinguishing bomb release mechanism to release the fire extinguishing bomb.

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