Unmanned aerial vehicle cable descent control method and program product

Abstract

The present disclosure provides a kind of unmanned aerial vehicle cable drop control method and program product, it is related to unmanned aerial vehicle control technology and logistics distribution technical field.The method comprises: obtaining the flight height of unmanned aerial vehicle, current rope amount and the height compensation amount of the load;Based on flight height, current rope amount and height compensation amount, determine the ground clearance of the bottom of the load relative to ground;According to the distance interval where ground clearance is located, determine the cable drop stage, wherein different distance intervals correspond to different target descent speeds;According to current rope amount and the target descent speed corresponding to cable drop stage, control the rope speed.According to the embodiment of the present disclosure, the cable drop efficiency, near-person safety and landing stability can be improved.

Description

Technical Field

[0001] This disclosure relates to the fields of unmanned aerial vehicle (UAV) control technology and logistics delivery technology, and in particular to a UAV rappelling control method and program product. Background Technology

[0002] With the rapid development of drone technology, its application in logistics, emergency rescue, and material delivery is becoming increasingly widespread. In many application scenarios, hovering a drone and lowering a payload (such as a takeout bag) to a designated location via a rappelling system is a common and efficient delivery method. However, existing drone rappelling control schemes still have shortcomings in terms of safety and stability, and urgently need improvement.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This disclosure provides a method and program product for controlling rappelling of unmanned aerial vehicles (UAVs), which can improve rappelling efficiency, near-person safety, and landing stability.

[0005] Other features and advantages of this disclosure will become apparent from the following detailed description, or may be learned in part from practice of this disclosure.

[0006] According to one aspect of this disclosure, a method for controlling rappelling of an unmanned aerial vehicle (UAV) is provided, comprising: acquiring the UAV's flight altitude, current rope release amount, and altitude compensation amount of the payload; determining the ground clearance of the bottom of the payload relative to the ground based on the flight altitude, current rope release amount, and altitude compensation amount; determining a rappelling stage based on the distance range in which the ground clearance falls, wherein different distance ranges correspond to different target descent speeds; and controlling the rope release speed based on the current rope release amount and the target descent speed corresponding to the rappelling stage.

[0007] In one embodiment of this disclosure, determining the rappelling phase based on the distance range of the ground clearance includes: when the ground clearance is greater than a first distance threshold, determining the rappelling phase as a rapid descent phase; when the ground clearance is less than or equal to the first distance threshold and greater than a second distance threshold, determining the rappelling phase as a safe avoidance descent phase; and when the ground clearance is less than or equal to the second distance threshold, determining the rappelling phase as a near-ground slow descent phase. Wherein, the first distance threshold is greater than the second distance threshold, the target descent speed corresponding to the rapid descent phase is greater than the target descent speed corresponding to the safe avoidance descent phase, and the target descent speed corresponding to the safe avoidance descent phase is greater than the target descent speed corresponding to the near-ground slow descent phase.

[0008] In one embodiment of this disclosure, the first distance threshold is a preset obstacle avoidance safety distance, or the effective detection range of the UAV's downward-looking perception; the second distance threshold is the ground contact deceleration distance determined based on the target's descent speed during the near-ground slow-motion phase.

[0009] In one embodiment of this disclosure, during the safe avoidance and lowering phase, the method further includes: acquiring environmental perception data and / or a permission instruction to continue lowering; if a preset risk is detected based on the environmental perception data, or if a permission instruction to continue lowering is not received, then suspending the lowering of the rope or limiting the lowering speed.

[0010] In one embodiment of this disclosure, controlling the rope release speed based on the current rope release amount and the target descent speed corresponding to the descent stage includes: obtaining a calibration relationship between the rope release amount and the motor control amount; obtaining the target control amount of the motor of the descent winch based on the calibration relationship and the current rope release amount; and controlling the motor to operate according to the target control amount to control the rope release speed.

[0011] In one embodiment of this disclosure, the calibration relationship between the amount of rope laid and the motor control quantity includes: a quadratic fitting relationship between the amount of rope laid and the angle of the motor; based on the calibration relationship and the current amount of rope laid, the target control quantity of the descent winch motor is obtained, including: differentiating the quadratic fitting relationship and combining it with the number of angle units per revolution of the motor to obtain the conversion relationship between the motor speed and the linear velocity of the descent cable; according to the conversion relationship and the current amount of rope laid, the target descent speed is back-calculated into the target speed or target angle of the motor as the target control quantity.

[0012] In one embodiment of this disclosure, the method further includes: monitoring the load status of the suspended object; stopping the rope release when the distance from the ground is less than or equal to a second distance threshold and the load status meets preset release conditions; controlling the rappelling hook to release the suspended object, and retrieving the rappelling cable after confirming that the release is complete.

[0013] In one embodiment of this disclosure, the load state of the mounted object includes the load force value; the load state satisfies preset release conditions, including: the load force value is less than or equal to a preset force release threshold; and / or, the rate of change of the load force value within a preset time window is less than or equal to a preset rate of change threshold.

[0014] In one embodiment of this disclosure, controlling the release of the load by the descent hook includes: sending a hook release command and waiting to receive release confirmation information; if no release confirmation information is received, resending the hook release command according to a preset retransmission limit; if the number of retransmissions reaches the retransmission limit and no release confirmation information is received, entering a fault protection state.

[0015] According to another aspect of this disclosure, an electronic device is provided, comprising: a memory for storing program instructions; and a processor for calling the program instructions stored in the memory to implement the above-described UAV rappelling control method.

[0016] According to another aspect of this disclosure, a computer program product is provided, the computer program product including program instructions for implementing the above-described unmanned aerial vehicle (UAV) rappelling control method.

[0017] The technical solutions provided in this disclosure can include the following beneficial effects: This embodiment of the invention accurately calculates the true ground clearance of the bottom of the payload by comprehensively considering the flight altitude, the current amount of rope released, and the height compensation of the payload, effectively eliminating errors caused by the size of the payload or its position in traditional ranging methods. Based on this, the descent stages are dynamically divided according to the precise ground clearance, and differentiated target descent speeds are matched. This enables adaptive switching between efficient and rapid descent at high altitude and safe, slow descent near the ground. This significantly improves the efficiency of material delivery while effectively avoiding the risk of low-altitude collisions and excessive impact upon ground contact. Furthermore, rope release control, combined with the current amount of rope released and the target descent speed, further ensures the stability and accuracy of the payload descent process, comprehensively improving the overall safety and reliability of UAV descent operations.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0020] Obviously, the accompanying drawings described below are merely some embodiments of this disclosure. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0021] Figure 1 This diagram illustrates a flowchart of a UAV rappelling control method according to an embodiment of the present disclosure. Figure 2 This diagram illustrates the dynamic compensation mechanism flowchart in an embodiment of the present disclosure. Figure 3 This diagram illustrates a UAV rappelling control flowchart according to an embodiment of the present disclosure; Figure 4 This diagram illustrates another UAV rappelling control method according to an embodiment of the present disclosure. Figure 5a and Figure 5bThis diagram illustrates the speed compensation relationship related to the amount of rope released by the winch in an embodiment of this disclosure. Figure 6 This diagram illustrates the near-ground and ground-contact release and rope-retrieval closed loop of the food bag in an embodiment of this disclosure. Figure 7 This diagram illustrates a flowchart of yet another UAV rappelling control method according to an embodiment of the present disclosure; Figure 8 A structural block diagram of an electronic device according to an embodiment of the present disclosure is shown. Detailed Implementation

[0022] To facilitate understanding of the technical solutions of this disclosure, the disclosure will be further described below with reference to the accompanying drawings.

[0023] The terms "first" and "second," etc., used in this disclosure are only used to distinguish different objects and not to describe a specific order. The terms "comprising" and "having," and any variations thereof, in the embodiments of this disclosure are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may also include steps or units not listed.

[0024] Throughout this disclosure, the references to "embodiments" do not necessarily refer to the same embodiments, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described in this disclosure can be combined with other embodiments.

[0025] In the embodiments of this disclosure, "at least one" refers to one or more, "more" refers to two or more, "at least two" refers to two or three or more, and "and / or" is used to describe the relationship between associated objects. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0026] Existing drone-based food delivery solutions typically employ a one-time deployment, fixed-speed rope release, and manual setting of height thresholds based on experience, or rely on a winch for independent rope control. While these solutions can achieve basic deployment, they still have the following shortcomings in low-altitude rappelling scenarios for drone-delivered food bags: A single speed or a simple two-speed approach makes it difficult to balance efficiency and safety. Continuing to descend at a low speed during the high-altitude phase increases the drone's hovering time and energy consumption; descending at a high speed when close to ground level or near pedestrian height poses a higher risk of the food bag impacting pedestrians, vehicles, or ground objects.

[0027] Judging ground proximity solely based on the drone's height cannot accurately reflect the true distance between the bottom of the food bag and the ground, which can easily lead to premature deceleration, delayed deceleration, or unstable ground contact judgment.

[0028] Traditional winch speed control often treats the motor speed and cable linear speed as a fixed ratio. However, as the cable is released layer by layer, the winding radius changes, and the actual lowering speed corresponding to the same motor speed will vary with the amount of rope released.

[0029] If the ground contact, stop, release, and retrieval are implemented using decentralized logic, problems such as premature release before ground contact, continued rope release after ground contact, retrieval without confirmation of release, or excessive rope release entanglement in the bag handle may easily occur.

[0030] Both the control terminal and the embedded terminal of the rappelling mechanism have internal states. If the control terminal sends a one-time command such as soft stop, release, closure, rope abandonment, rope melting, or retrieval immediately during a window when the locking mechanism is not yet receiving commands, the command may be rejected or lost.

[0031] To address the aforementioned issues, the present invention combines the actual ground proximity judgment of the food bag, phased speed control, cable speed compensation, ground contact release and retrieval closed loop, and one-time command waiting conditions. This ensures that the externally observable delivery process not only has high-altitude rapid descent efficiency but also clear safety control behaviors under risk conditions such as proximity to people, ground, and temporary non-receiving of commands by institutions.

[0032] The following detailed description of this exemplary implementation method is provided in conjunction with the accompanying drawings and embodiments.

[0033] Figure 1 This diagram illustrates a flowchart of a UAV rappelling control method according to an embodiment of the present disclosure. This UAV rappelling control method can be executed by a UAV rappelling control system or a UAV control module, such as... Figure 1 As shown, the UAV rappelling control method provided in this embodiment includes S101 to S104.

[0034] In S101, the drone's flight altitude, current rope release amount, and altitude compensation amount of the payload are obtained.

[0035] The payload can be a takeout bag or other hanging item used for drone delivery. Height compensation refers to the height compensation value of the payload itself or the mounting structure (such as hooks, connectors, etc.), used to characterize the distance from the release point at the end of the cable to the bottom of the payload.

[0036] In S102, the distance between the bottom of the payload and the ground is determined based on the flight altitude, the current amount of rope laid, and the altitude compensation.

[0037] In some embodiments, the ground clearance of the payload's bottom relative to the ground can be calculated by subtracting the current rope release amount from the drone's flight altitude, and then subtracting the payload's height compensation amount. Traditional methods typically rely solely on the drone's height above the ground to determine its near-ground status, failing to accurately reflect the true distance between the payload's bottom and the ground. This step, however, incorporates both the current rope release amount and the height compensation amount for comprehensive calculation, resulting in a ground clearance that more closely approximates the payload's true ground clearance. This disclosed solution triggers the subsequent near-ground slow-release or touch-down release closed loop only when the payload is actually close to the ground, avoiding issues such as premature deceleration, delayed deceleration, or unstable ground clearance caused by relying solely on the drone's height, thus making the deceleration and release closed loop more accurate.

[0038] In S103, the rappelling stage is determined based on the distance range of the distance above the ground, where different distance ranges correspond to different target descent speeds.

[0039] In some embodiments, determining the rappelling phase based on the distance range of the ground clearance includes: when the ground clearance is greater than a first distance threshold, determining the rappelling phase as a rapid descent phase; when the ground clearance is less than or equal to the first distance threshold and greater than a second distance threshold, determining the rappelling phase as a safe avoidance descent phase; when the ground clearance is less than or equal to the second distance threshold, determining the rappelling phase as a near-ground slow descent phase; wherein the first distance threshold is greater than the second distance threshold, the target descent speed corresponding to the rapid descent phase is greater than the target descent speed corresponding to the safe avoidance descent phase, and the target descent speed corresponding to the safe avoidance descent phase is greater than the target descent speed corresponding to the near-ground slow descent phase.

[0040] In some embodiments, the first distance threshold is a preset obstacle avoidance safety distance, or the effective detection range of the UAV's downward-looking perception; the second distance threshold is the ground contact deceleration distance determined based on the target's descent speed during the near-ground slow-motion phase.

[0041] The three-stage process control described above balances rappelling efficiency and safety. A higher target descent speed during the rapid descent phase effectively shortens the drone's hovering time and improves descent efficiency. A moderate target descent speed during the safe avoidance descent phase, combined with environmental perception or permission to continue descent, allows for waiting or speed limiting, reducing the risk of the payload injuring pedestrians or hitting obstacles. A lower target descent speed during the near-ground slow descent phase effectively reduces landing impact, shortens braking distance, and prevents the cable from excessively releasing and entangled in the payload.

[0042] In S104, the rope release speed is controlled based on the current rope release amount and the target descent speed corresponding to the descent stage.

[0043] This disclosed embodiment, through real-time ground-level judgment of the payload and phased speed control, enables the externally observable deployment process to possess both the efficiency of rapid high-altitude descent and clear safety control behaviors under risky conditions such as close proximity to people and ground, thereby comprehensively improving the efficiency, safety near people, landing stability, and reliability of key actions of UAV rappelling operations.

[0044] In some embodiments, during the safe avoidance descent phase, environmental perception data and / or a permission to continue descent can also be acquired. If a preset risk is detected based on the environmental perception data, or if no permission to continue descent is received, rope deployment is paused or the deployment speed is limited. Environmental perception data can be ground environment information collected by sensors such as downward-facing cameras, lidar, ultrasonic sensors, or millimeter-wave radar mounted on the UAV. Preset risks can include situations that may affect deployment safety, such as detecting pedestrians entering a preset deployment safety area, the presence of moving vehicles or fixed obstacles on the ground. The permission to continue descent can be a confirmation signal manually triggered by a user terminal application, a back-end scheduling system, or ground receiving personnel, allowing the payload to continue descent. Pausing rope deployment means controlling the winch to stop outputting the cable, causing the payload to suspend at the current height. Limiting the deployment speed means reducing the descent speed to an extremely low creeping speed, below the normal safe avoidance speed. The solution of this disclosure can automatically pause or limit the rope release speed, effectively preventing the load from injuring pedestrians or colliding with obstacles during the descent, and greatly improving the safety of near-person delivery; by waiting for the permission instruction to continue the descent, it ensures that the delivery action will only continue after the user or the backend has given explicit authorization, which enhances the system's adaptability and robustness to complex and changeable low-altitude environments.

[0045] As the cable is continuously released during the rappelling process, the winding radius of the winch changes constantly. This means that the actual linear speed of the released cable corresponding to the same motor speed will change with the increase of the current amount of cable released. If a traditional fixed ratio conversion is used, the actual descent speed will deviate significantly from the expected speed. To address the above problem, embodiments of this disclosure introduce a dynamic compensation mechanism when controlling the cable release speed. In some embodiments, controlling the cable release speed based on the current amount of cable released and the target descent speed corresponding to the rappelling stage may include... Figure 2 S201 to S203 are shown.

[0046] In S201, the calibration relationship between the rope release amount and the motor control quantity is obtained; In S202, the target control quantity of the cable-lowering winch motor is obtained based on the calibration relationship and the current rope release amount; In S203, the control motor operates according to the target control quantity to control the rope release speed.

[0047] In some embodiments, the calibration relationship between the amount of rope released and the motor control quantity includes: a quadratic fitting relationship between the amount of rope released and the angle of the motor of the cable-lowering winch; the quadratic fitting relationship can be an empirical formula obtained through previous calibration experiments, which can accurately characterize the nonlinear characteristics of the winding radius changing with the amount of rope released when the cable is stacked layer by layer.

[0048] Based on the calibration relationship and the current rope release amount, the target descent speed is compensated to obtain the target control quantity of the winch motor. This can include differentiating the quadratic fitting relationship and combining it with the number of angle units per revolution of the motor to obtain the conversion relationship between the motor speed and the linear speed of the descent cable. According to the conversion relationship and the current rope release amount, the target descent speed is back-calculated into the target speed or target angle of the motor as the target control quantity. Through the above winch speed compensation mechanism, the speed control error caused by the dynamic change of the cable winding radius can be effectively eliminated. This ensures that the actual descent linear speed of the load always accurately matches the target descent speed set for each descent stage under different rope release lengths. This not only ensures the stability and accuracy of the three-stage process control boundaries of high-altitude rapid descent, safe avoidance, and near-ground slow descent, but also significantly improves the speed control accuracy at near-ground braking and the moment of ground contact. It effectively avoids problems such as excessive landing impact or cable entanglement of the load due to speed loss, and comprehensively improves the stability and reliability of UAV descent operations.

[0049] In some embodiments, the above-described UAV rappelling control method may further include Figure 3 S301 to S303 are shown.

[0050] In S301, the load status of the mounted objects is monitored.

[0051] In S302, when the distance from the ground is less than or equal to the second distance threshold and the load condition meets the preset release conditions, the rope release is stopped.

[0052] This disclosed solution employs a dual judgment method, combining near-ground distance conditions and load condition conditions. This effectively avoids errors that may arise from relying solely on a single distance judgment and prevents damage to the load caused by prematurely releasing the hook before it has actually touched the ground. Furthermore, by promptly stopping rope release after confirming ground contact, it avoids problems such as excessive cable release and entanglement of the load that could occur if rope release continues after ground contact.

[0053] In S303, the control hook releases the load, and after confirming that the release is complete, the rappelling cable is retrieved.

[0054] In some embodiments, the load state of the mounted object includes the current load force value; the load state satisfies preset release conditions, including: the load force value is less than or equal to a preset force release threshold; and / or, the rate of change of the load force value within a preset time window is less than or equal to a preset rate of change threshold.

[0055] The load force value can be obtained through a force sensor installed on the hook or connection. When the load touches the ground, its weight is partially or entirely borne by the ground, causing a significant decrease in the load force value of the rope. Therefore, the load release threshold is used to characterize the state where the load has touched the ground and the rope load has significantly decreased. Simultaneously, considering that the load may experience instantaneous fluctuations in force due to wind disturbance or its own swaying during descent, a rate of change threshold is introduced to filter out these transient interferences. This disclosed solution significantly improves the accuracy and robustness of ground contact determination through dual verification of the absolute value of the force and the stability of its change, effectively preventing false ground contact and false release caused by air swaying or airflow interference.

[0056] In some embodiments, controlling the release of the load by the descent hook includes: sending a hook release command and waiting to receive a release confirmation message; if no release confirmation message is received, retransmitting the hook release command according to a preset retransmission limit; if the number of retransmissions reaches the retransmission limit and no release confirmation message is received, entering a fault protection state.

[0057] The release confirmation information can be a hardware level signal or status code fed back after the descent mechanism (such as an electromagnet, motor, or mechanical pin) completes the unlocking or opening-loop action. This disclosed solution ensures that the release command is reliably received and executed by the mechanism, reducing the risk of losing critical one-time commands due to mechanism overload or communication anomalies. Simultaneously, by setting a limit on the number of retransmissions and triggering fault protection, it avoids resource waste or logical deadlock caused by the system infinitely retransmitting commands in abnormal states, thus improving the fault tolerance and overall reliability of the UAV descent system under complex operating conditions.

[0058] The following example uses rappelling and food throwing, combined with the attached... Figure 4 This paper details the unmanned aerial vehicle (UAV) rappelling control method disclosed herein. For example... Figure 4 As shown, the drone rappelling control method may include task input, rappelling status acquisition, near-ground judgment of the food bag, phased speed control, winch speed compensation, and ground contact release and recovery.

[0059] This disclosure receives automatic rappelling and meal-throwing commands via task input. Rappelling status acquisition includes acquiring the UAV's altitude above the ground, current rope release amount, rope release speed, hook status, load changes, and mechanism operating status. Meal bag proximity assessment includes calculating the remaining distance between the bottom of the meal bag and the ground. Staged speed control includes selecting the descent speed based on the remaining distance and safety clearance. Winch speed compensation includes converting the target linear velocity into a more accurate motor control value based on the current rope release amount. Ground contact release and retrieval includes stopping the descent, releasing the hook, and retrieving the cable after confirming the meal bag is close to the ground and the load is released. For one-time actions such as soft stop, release, closure, rope abandonment, rope melting, and retrieval, the corresponding task state machine waits until the mechanism can receive commands before issuing them.

[0060] This publicly disclosed solution does not directly use the drone's altitude above the ground as the near-ground altitude of the food bag. Instead, it combines the drone's altitude, the amount of rope currently released, and the altitude compensation of the food bag or mounting structure.

[0061]

[0062] Where d is the estimated distance between the bottom of the food bag and the ground, H is the aircraft altitude, S is the amount of released rope, and C is the altitude compensation amount for the food bag or its mounting structure. When this distance is not greater than the near-ground threshold D, the food bag is determined to have entered a near-ground state.

[0063] In other words, when drones hover at the same height but with different amounts of rope released, the system will only enter the near-ground slow release or touch-ground release closed loop when the food bag is actually close to the ground, rather than switching earlier or later based solely on the drone's height.

[0064] This embodiment of the disclosure sets three control stages according to the height of the food bag from the ground: the first stage is rapid lowering, the second stage is safe lowering with avoidance, and the third stage is slow lowering near the ground.

[0065] In some implementations, the safety avoidance phase begins approximately 2.5 meters above the ground with the food bag, while the near-ground slow-release phase begins approximately 1 meter above the ground with the food bag. The corresponding rope release boundaries can be calculated from the aircraft altitude, the food bag compensation altitude, and two altitude thresholds.

[0066] When the current rope release has not yet reached the first boundary (e.g., 2.5 meters), the system is in the rapid descent phase, outputting a higher target speed, such as about 1.5 meters per second, to improve descent efficiency and shorten the drone's hovering waiting time. When the rope release is between the first boundary (e.g., 2.5 meters) and the second boundary (e.g., 1 meter), the system enters the safe avoidance descent phase, outputting a medium target speed, such as about 0.5 meters per second. It can also combine pedestrian detection, environmental perception, or permission to continue descent to execute waiting or speed limiting, reducing the risk of the food bag hitting pedestrians or contacting obstacles. When the rope release reaches the second boundary (e.g., 1 meter), the system enters the near-ground slow release phase, outputting a low target speed, such as about 0.2 meters per second, to reduce landing impact, shorten braking distance, and avoid excessive cable release and entanglement.

[0067] The motor angle of a rappelling winch is not strictly linearly related to the amount of rope released. As the cable is released layer by layer, the winding radius changes, and the actual linear velocity corresponding to the same motor speed will vary with the current amount of rope released. Therefore, this disclosure uses the current amount of rope released to compensate for the target descent speed.

[0068] In one engineering implementation, the relationship between the rope release amount S and the motor angle P can be expressed using a quadratic fitting:

[0069] Where a and b are coefficients obtained from the winch structure calibration. Differentiating the above relationship and combining it with the number of angle units per revolution, we can obtain the relevant conversion relationship between the motor speed N and the linear velocity V for the amount of rope released:

[0070] Therefore, when the three-stage process control provides the target linear velocity, the winch speed compensation unit can calculate the target motor control quantity based on the current rope release amount:

[0071] In other words, different motor control quantities correspond to different lowering speeds for the same target under different rope lengths; after compensation, the actual lowering speed of the food bag is closer to the set speed, the three speed boundaries are more stable, and the near-ground braking and ground contact control are more predictable. The speed compensation relationship related to the winch rope length is as follows: Figure 5a and Figure 5b As shown.

[0072] This embodiment combines the near-ground state of the food bag with load changes to determine whether the food bag has reached a releaseable state. A force sensor can be used to determine whether the food bag is still primarily supported by a rope. Let F be the current load indication and F0 be the release threshold, then the following formula can be used to determine whether the release closed-loop trigger condition is met:

[0073] like Figure 6 As shown, when the combined conditions are met, it indicates that the food bag is close to the ground and the rope load has significantly decreased, indicating that the food bag has touched the ground or the release conditions have been met. At this point, the process executes the following steps in sequence: stop lowering, release the hook, and retrieve the cable: first, a stop lowering or soft stop command is sent; then, a hook release command is sent and release confirmation is awaited; finally, a retrieval command is sent to retrieve the cable towards the drone.

[0074] In other words, the speed of the food bag decreases as it approaches the ground; the rope stops releasing after it touches the ground; the hook opens to release the food bag; and the rope retracts towards the drone after the food bag is released. This closed loop avoids premature release before touching the ground and also avoids over-releasing and tangling caused by continuing to release the rope after touching the ground.

[0075] In the current engineering implementation, for one-time command actions such as soft stop, retrieval, release, closure, rope abandonment, and rope melting, the command waiting logic is distributed in their respective task state machines: when the descent mechanism is in a state of not receiving commands, such as when the pin is unlocked, the task remains in the initial waiting state and does not send a one-time command; when the mechanism state is restored to the receiving state, it enters the command state and sends the corresponding command.

[0076] This processing method serves as a prerequisite for a one-time command action. Externally, this means that a one-time command is not immediately issued during the latch unlocking process; the organization can receive the command before executing the corresponding action, thereby reducing the risk of losing critical commands.

[0077] In some embodiments, the above-described UAV rappelling control method may include Figure 7 S701 to S708 are shown.

[0078] In the S701, the automatic rappelling and food throwing command is received, and the drone altitude, current rope release amount, descent speed, food bag height compensation, load information, hook status, and mechanism operating status are read.

[0079] In S702, the actual distance of the food bag from the ground is calculated based on the drone altitude, the current amount of rope released, the height compensation of the food bag, and the near-ground threshold, and it is determined whether the food bag has entered the near-ground state.

[0080] In S703, the descent is divided into three stages based on two height boundaries of approximately 2.5 meters and approximately 1 meter: rapid descent, safe descent, and slow descent near the ground. The decision to continue descent is made based on optional pedestrian detection or permission to continue descent.

[0081] In S704, the target linear velocity at each stage is converted into motor angle, speed or equivalent control quantity based on the compensation relationship between the current rope release and winch speed.

[0082] In S705, the load change and near-ground status of the food bag are continuously monitored during the near-ground slow release phase. The release is stopped when the food bag touches the ground or the release conditions are met.

[0083] In S706, a hook release command is sent and a release confirmation is awaited; if no confirmation is received, the retransmission is limited by the number of retransmissions or the fault protection is activated.

[0084] In S707, after confirming release, a retrieval command is sent to retrieve the cable; when retrieval is complete or an abnormality occurs, it enters a completion or failure state.

[0085] In S708, one-time commands such as soft stop, release, closure, rope discard, rope melt, and recovery are subject to command waiting conditions; the mechanism waits when it does not receive the command, and can issue the command after receiving it.

[0086] This disclosed embodiment addresses the automated rappelling and food-throwing process using a drone. It organizes the process into three stages based on the actual distance of the food bag relative to the ground: rapid descent, safe descent with obstacle avoidance, and slow descent near the ground. Upon contact with the ground or reaching the release condition, the process executes in a closed-loop sequence: stopping descent, releasing the hook, and retrieving the cable. Simultaneously, it compensates for the winch output speed based on the current amount of rope released and sets command waiting conditions based on the mechanism's operating status for some one-time actions. This prevents the loss of critical actions when the mechanism is not receiving commands, thereby improving rappelling efficiency, near-person safety, landing stability, and the reliability of critical actions.

[0087] Based on the same inventive concept, this disclosure also provides an electronic device. For example... Figure 8 As shown, the electronic device provided in this embodiment includes a processor 801 and a memory 802; the memory 802 is used to store program instructions; the processor 801 is used to call the program instructions stored in the memory 802 to implement the UAV rappelling control method described in the above method embodiment.

[0088] In some embodiments, processor 801 is a device with data processing capabilities, including but not limited to a central processing unit (CPU), a field-programmable gate array (FPGA), and other programmable logic devices. Processor 801 may include one or more processing cores.

[0089] In some embodiments, the memory 802 is a device with data storage capability, including but not limited to random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and flash memory.

[0090] In some embodiments, the processor 801 and memory 802 can be configured separately or integrated together. As an example, the processor 801 and memory 802 can be integrated on a single board or a system on a chip (SOC).

[0091] like Figure 8 As shown, the electronic device provided in this embodiment may further include an interface 803. The interface 803 is connected between the processor 801 and the memory 802, enabling information exchange between the processor 801 and the memory 802. In some embodiments, the processor 801, the memory 802, and the interface 803 are interconnected via a bus 804.

[0092] In some embodiments, there may be one or more processors 801.

[0093] In some embodiments, there may be one or more memories 802.

[0094] In some embodiments, there may be one or more interfaces 803.

[0095] In some embodiments, the memory 802 stores one or more program instructions. When the one or more program instructions are executed by the one or more processors 801, the one or more processors 801 implement the UAV rappelling control method described in the above method embodiments and achieve the corresponding technical effects.

[0096] In some embodiments, the electronic device may also communicate with one or more external devices, such as a keyboard, pointing device, Bluetooth device, etc. In some embodiments, the electronic device may also communicate with one or more devices that enable a user to interact with the electronic device. In some embodiments, the electronic device may also communicate with devices that enable the electronic device to communicate with one or more other computing devices. In some embodiments, the above communication may be performed through interface 803.

[0097] Understandable, Figure 8 The illustrated structure does not constitute a specific limitation on the electronic device. In some embodiments, the electronic device may include... Figure 8 The number of components shown may be more or fewer. In some embodiments, the electronic device has... Figure 8 Based on the above, some components can be combined, some components can be separated, or different component arrangements can be made.

[0098] In some embodiments, Figure 8 The components shown can be implemented in hardware, software, or a combination of both.

[0099] Based on the same inventive concept, this disclosure also provides a computer-readable storage medium storing program instructions. When the program instructions are executed by a computer, they implement the UAV rappelling control method described in the above method embodiments, achieving the corresponding technical effects.

[0100] In some embodiments, the computer-readable storage medium can be any available medium capable of storing program instructions or a data storage device such as a data center containing one or more available media. In some embodiments, the available medium can be a magnetic medium, an optical medium, or a semiconductor medium, etc. As an example, a magnetic medium can be a floppy disk, a hard disk, a magnetic tape, etc. As an example, an optical medium can be a high-density digital video optical disc. As an example, a semiconductor medium can be a solid-state drive.

[0101] Based on the same inventive concept, this disclosure also provides a computer program product, which includes program instructions for implementing the UAV rappelling control method described in the above method embodiments. When executed by a computer, the program instructions cause the computer to implement the UAV rappelling control method described in the above method embodiments, achieving the corresponding technical effects. In specific implementations, the program instructions can be written using any combination of one or more programming languages. The program instructions can be executed entirely on the user device, partially on the user device, as a standalone software package, partially on the user device and partially on a remote device, or entirely on a remote device or server.

[0102] Those skilled in the art will understand that all or part of the steps of the above embodiments can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation, or an implementation combining hardware and software aspects.

[0103] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for controlling the rappelling of an unmanned aerial vehicle (UAV), characterized in that, include: Obtain the drone's flight altitude, current rope release amount, and altitude compensation amount of the payload; Based on the flight altitude, the current rope release amount, and the altitude compensation amount, determine the ground clearance of the bottom of the payload relative to the ground. The rappelling stage is determined based on the distance range in which the distance above the ground falls, wherein different distance ranges correspond to different target descent speeds; The rope release speed is controlled based on the current rope release amount and the target descent speed corresponding to the descent stage.

2. The method according to claim 1, characterized in that, Determining the rappelling stage based on the distance range of the ground clearance includes: When the distance from the ground is greater than the first distance threshold, the descent phase is determined to be a rapid descent phase. When the distance from the ground is less than or equal to the first distance threshold and greater than the second distance threshold, the rappelling phase is determined to be a safe avoidance descent phase. When the distance from the ground is less than or equal to the second distance threshold, the descent phase is determined to be a near-ground slow-motion phase. Wherein, the first distance threshold is greater than the second distance threshold, the target descent speed corresponding to the rapid descent phase is greater than the target descent speed corresponding to the safe avoidance descent phase, and the target descent speed corresponding to the safe avoidance descent phase is greater than the target descent speed corresponding to the near-ground slow descent phase.

3. The method according to claim 2, characterized in that, The first distance threshold is a preset obstacle avoidance safety distance, or the effective detection range of the UAV's downward-looking perception; the second distance threshold is the ground contact deceleration distance determined based on the target's descent speed during the near-ground slow-motion phase.

4. The method according to claim 2, characterized in that, During the safe avoidance and describance phase, the method further includes: Acquire environmental awareness data and / or continue to issue licensing instructions; If a preset risk is detected based on the environmental perception data, or if the permission to continue releasing the rope is not received, then the rope release will be paused or the rope release speed will be limited.

5. The method according to claim 1, characterized in that, The step of controlling the rope release speed based on the current rope release amount and the target descent speed corresponding to the descent stage includes: Obtain the calibration relationship between the rope release amount and the motor control quantity; Based on the calibration relationship and the current rope release amount, the target control quantity of the cable descent winch motor is obtained; The motor is controlled to operate according to the target control value in order to control the rope release speed.

6. The method according to claim 5, characterized in that, The calibration relationship between the rope release amount and the motor control quantity includes: a quadratic fitting relationship between the rope release amount and the motor angle quantity; The process of obtaining the target control quantity of the cable-lowering winch motor based on the calibration relationship and the current rope release includes: By differentiating the quadratic fitting relationship and combining it with the number of angle units per revolution of the motor, the conversion relationship between the motor speed and the linear velocity of the descent cable is obtained. Based on the conversion relationship and the current rope release amount, the target descent speed is back-calculated into the target rotational speed or target angle of the motor, which is then used as the target control quantity.

7. The method according to claim 2, characterized in that, The method further includes: Monitor the load status of the mounted object; When the distance from the ground is less than or equal to the second distance threshold, and the load state meets the preset release conditions, the rope release is stopped; Control the rappelling hook to release the load, and retrieve the rappelling cable after confirming that the release is complete.

8. The method according to claim 7, characterized in that, The load state of the mounted object includes the load force value; the load state satisfies preset release conditions, including: the load force value is less than or equal to a preset force release threshold; and / or, the rate of change of the load force value within a preset time window is less than or equal to a preset rate of change threshold.

9. The method according to claim 7, characterized in that, The control descent hook releases the load, including: Send a hook release command and wait to receive a release confirmation message; If the release confirmation information is not received, the hook release command will be resent according to the preset retransmission limit. If the release confirmation information is not received after the number of retransmissions reaches the retransmission limit, the system enters fault protection mode.

10. A computer program product, characterized in that, It includes a computer program or instructions that, when executed by a processor, implement the UAV rappelling control method as described in any one of claims 1 to 9.

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