Aerial vehicle hitching device for photovoltaic cleaning robot and control method

Abstract

A drone mounting device and control method for a photovoltaic cleaning robot are disclosed. The mounting device, from top to bottom, includes a descent rope, a tension sensor, a control box, a connecting column, a deployment ball, and a micro-electric push rod and locking pin coupling mechanism. The tension sensor detects changes in rope tension in real time. The control box determines the current flight status based on the real-time tension data from the tension sensor and sends adjustment commands to the micro-electric push rod and locking pin coupling mechanism. The control box, connecting column, and deployment ball form a rigid connection. The micro-electric push rod and locking pin coupling mechanism includes two sets of micro-electric push rods symmetrically installed at the equator position of the deployment ball. Locking pins at the ends of the push rods extend horizontally from both sides of the deployment ball, passing through the top hanging ring of the cleaning robot to form a symmetrical clamping on both sides. This invention, combined with the control method, can improve the operation and maintenance efficiency and reliability of a drone-mounted mobile photovoltaic cleaning robot.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic power plant operation and maintenance equipment technology, specifically relating to a drone mounting device and control method for photovoltaic cleaning robots. Background Technology

[0002] Module cleaning in large-scale photovoltaic (PV) power plants is a critical operation and maintenance (O&M) aspect affecting power generation efficiency. Currently, the deployment of PV panel cleaning robots mainly relies on manual handling or ground vehicle transport, resulting in low efficiency, high labor costs, and difficulty in implementation in complex terrain scenarios such as mountainous or floating PV systems. Utilizing drones to carry cleaning robots and deploy them to designated PV panel areas is an effective way to improve O&M efficiency.

[0003] However, existing drone-mounted delivery devices suffer from problems such as high power consumption of the locking mechanism, easy loss of lock when power is off, insufficient structural reliability, poor adaptability to photovoltaic scenarios, and low accuracy of attachment recognition, making it difficult to meet the application requirements of safe, accurate, and efficient delivery of photovoltaic cleaning robots. Summary of the Invention

[0004] The purpose of this invention is to provide a drone attachment, deployment, and retrieval device and its control method for photovoltaic cleaning robots, which solves the problems of high power consumption, overheating, and detachment of electromagnetic latches in the prior art, solves the problem of square control boxes getting stuck in the guide net, solves the problem of loosening of split structures, and provides a multi-stage autonomous control method adapted to the entire photovoltaic cleaning process.

[0005] The first aspect of this application discloses a drone mounting device for a photovoltaic cleaning robot, which adopts the following technical solution: The attachment device, from top to bottom, includes a descent rope, a tension sensor, a control box, a connecting column, a release ball, and a miniature electric push rod and locking pin attachment mechanism; The descent rope is connected to the descent device of the drone above and hangs down from the descent device to achieve the overall lifting and lowering adjustment of the attachment device relative to the drone. The tension sensor is connected to the descent rope and the top lug of the control box via a double-ear fork pin structure, and is used to detect changes in rope tension in real time; the control box is installed below the tension sensor, with a lug at the top center, and is connected to the lower end of the tension sensor via a pin. The control box is used to determine the current flight status through real-time tension data from the tension sensor and to send adjustment commands to the micro electric push rod and locking pin engagement mechanism. The connecting column is connected to the upper control box via a threaded connection and thread-locking agent, and is locked to the lower launching ball via a threaded connection and pin; the control box, connecting column and launching ball are rigidly integrated; The micro electric push rod and locking pin connection mechanism includes two sets of micro electric push rods, which are symmetrically installed at the equator position of the delivery ball; each set of micro electric push rods is fixedly connected to a locking pin at its end, and the two locking pins extend horizontally from both sides of the delivery ball at the same time, and pass through the top hanging ring of the photovoltaic cleaning robot to form a double-sided symmetrical clamping.

[0006] Preferably, two push rod mounting windows are symmetrically opened at the equator position of the launch sphere, and a mounting bracket integrally formed with the shell of the sphere is provided on the inner side of the window; the cylinder of the miniature electric push rod is fixed to the mounting bracket by means of bolts, flat washers and spring washers, and a reinforcing rib is provided in the extension and retraction direction of the push rod to bear the reaction force when the locking pin moves; a guide hole integrally formed with the shell is provided at the push rod mounting window, and the locking pin (62) passes through the guide hole and can slide along the axial direction; The axis of the miniature electric push rod is coplanar with the horizontal equator of the ball being deployed, allowing the locking pin to extend horizontally to the lifting ring position of the photovoltaic cleaning robot; the diameter of the locking pin and the inner diameter of the lifting ring form a clearance fit.

[0007] Preferably, two sets of miniature electric push rods are symmetrically installed at the equator of the delivery sphere, with the two sets of miniature electric push rods arranged in a 180° opposite layout, so that the locking pins on both sides can extend and retract synchronously, and the load of the photovoltaic cleaning robot is evenly distributed on the locking pins on both sides during the suspension and transportation process.

[0008] Preferably, the miniature electric actuator has a power-off self-locking function, which keeps the actuator in its current position when the power supply is interrupted; the two sets of miniature electric actuators are energized only when they extend or retract, and are de-energized after the action is completed, and the position is maintained by mechanical self-locking.

[0009] The second aspect of this application discloses a control method for a drone attachment device for a photovoltaic cleaning robot, comprising: The control method is executed by a microcontroller control board inside the control box. Based on the tension data collected by the tension sensor, it calls a multi-level tension threshold system to determine the hanging status; including the following steps: S1. The descent device releases the descent rope, and the attachment device descends. During the descent, the tension sampling value falls into the first threshold range. When the tension sampling value continuously decreases from the first threshold range and falls into the relaxation threshold range, and the duration exceeds the set time window, it is determined that the attachment device has reached the support surface. S2. The single-chip microcomputer control board synchronously sends extension commands to the two sets of miniature electric push rods, and the double-sided locking pins extend horizontally, pass into the lifting ring, and lock. S3. The descent device is pulled up, and the tension sensor continuously samples the tension data of the descent rope. If the tension sample value falls into the third threshold range and the fluctuation amplitude does not exceed the allowable fluctuation range, the attachment is determined to be successful and proceed to S5; otherwise, proceed to S4. S4. The descent device lowers the descent rope, causing the tension to drop back to the relaxation threshold range; the microcontroller control board simultaneously sends retraction commands to the two sets of miniature electric push rods, repeating S1 to S3. S5. Continuously monitor tension data. If the rate of change of tension is greater than or equal to the absolute value of the allowable rate of change, the load is determined to be abnormal, and the microcontroller control board instructs the drone to hover and wait. S6. After reaching the target point, the descent device releases the descent rope. After the tension sampling value drops to the first threshold range and continues to reach the set time window, the microcontroller control board issues a retraction command to release the photovoltaic cleaning robot.

[0010] Preferably, the tension threshold system includes a relaxation threshold interval, a first threshold interval, a second threshold interval, and a third threshold interval; The relaxation threshold range corresponds to the state where the descent rope is relaxed and the suspended object is supported by the support surface, and its value is not greater than the set proportion of the self-weight of the hanging device; The first threshold range is the product of the self-weight of the mounting device and the first tolerance coefficient; The third threshold range is the product of the sum of the weight of the mounting device and the weight of the photovoltaic cleaning robot and the third tolerance coefficient. The second threshold interval is between the upper limit of the first threshold interval and the lower limit of the third threshold interval.

[0011] Preferably, the miniature electric linear actuator motor is equipped with current monitoring, and a 4-state finite state machine is used to control the extension and retraction of the miniature electric linear actuator, including: Status 0 is a fault state, indicating that the current of the miniature electric actuator exceeds the protection threshold and enters an overcurrent state; State 1 is the extended / locked state, indicating that the load-bearing state is entered when both locking pins are inserted into the lifting ring; State 2 is the retracted / released state, indicating that the robot enters the unlocked state when the double-sided locking pins retract from the lifting ring; State 3 is the action execution state, indicating that the micro electric actuator is in the process of extending or retracting.

[0012] Preferably, in S3: when the tension sampling value falls into the second threshold range, it is determined to be a partial connection, and proceeds to S4 for retry; If the tension does not fall within the third threshold range, the connection is deemed to have failed, and the process proceeds to step S4 for a retry.

[0013] The beneficial effects of this invention are that, compared with the prior art, 1. The miniature electric push rod replaces the electromagnetic latch, fundamentally solving the three major problems of power consumption, heat generation, and power failure safety. The push rod is energized only momentarily during action, without continuous power supply and heat generation; the power failure self-locking feature ensures that the locking pin remains in the locked position under any power failure. The double-sided symmetrical locking pin clamping structure provides uniform force and anti-sway capability, ensuring the stability of the cleaning robot's posture during transportation. The circular control box shell is adapted to the photovoltaic array guide net structure, allowing it to glide smoothly through the guide net without getting stuck, a dedicated structural design for photovoltaic cleaning scenarios. The integrated rigid connection structure eliminates the risk of loosening in split designs.

[0014] 2. A multi-stage state machine enables fully autonomous process management across six stages: pickup, transportation, placement, waiting for cleaning, retrieval, and return. An automatic retry mechanism reduces manual intervention. A multi-level tension threshold system, combined with high-frequency sampling and RTK high-precision positioning, ensures reliable engagement / release status confirmation. A four-level safety protection system, along with the electric push rod's power-off self-locking feature, forms a complete safety protection chain. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the mounting device; Figure 2 A schematic diagram showing the mating structure between the latch and the lifting ring of the cleaning robot; Figure 3 Logic diagram for multi-level tension threshold judgment; Figure 4 A flowchart of a multi-stage state machine; Figure 5 This is a diagram of a four-level security protection system architecture; Figure 6 This is a diagram of a three-way, three-channel communication architecture.

[0016] In the diagram: 1. Descending rope; 11. Descending device; 2. Tension sensor; 3. Control box; 31. Microcontroller control board; 32. Communication module; 33. Power management module; 4. Connecting column; 5. Launching ball; 51. Battery; 52. Electronic control module; 53. Heat dissipation and weight reduction slot; 6. Miniature electric push rod and locking pin connection mechanism; 61. Miniature electric push rod; 62. Locking pin; 63. Guide hole; 7. Photovoltaic cleaning robot; 71. Lifting ring. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0018] Existing technologies for drone-mounted delivery devices have the following shortcomings: (1) Inherent defects of electromagnetic latch. Existing solutions mostly use electromagnetic latches as the hook-locking mechanism. The electromagnetic latch needs to be continuously energized to maintain the locked state, resulting in high power consumption and shortened flight time. Long-term energization causes the coil to heat up, posing a risk of thermal failure in high-temperature photovoltaic scenarios. More importantly, the electromagnetic latch automatically releases when the power is cut off. If a power supply failure occurs during flight, the cleaning robot will accidentally fall off, causing equipment damage or even safety accidents.

[0019] (2) The shape of the control box is not suitable for photovoltaic scenarios. A guide net and other cable structures are usually installed on top of the photovoltaic array to guide the movement path of the cleaning robot. The control boxes of the existing mounting devices are mostly square in design with protruding corners. During the take-off and landing of the drone, they are very easy to get caught on the guide net cables, causing the device to jam, be damaged, or even lose control of the drone.

[0020] (3) The reliability of the split structure is insufficient. The control box and the launch ball of the existing device are designed separately and assembled by connecting parts such as bolts or buckles. Under the vibration of the UAV flight and the impact load of the launch, the mechanical connection points are prone to loosening, which increases the failure rate.

[0021] (4) The control logic lacks scenario adaptability. The existing control scheme only uses a simple weight threshold judgment and lacks multi-stage state management for the entire photovoltaic cleaning process; there is no automatic retry mechanism, and manual intervention is required for each failed connection; and there is a lack of hierarchical safety protection.

[0022] (5) The method of confirming the connection is too simple. The existing solutions mostly rely on GPS positioning (accuracy ±1~2m), which cannot meet the requirements of accurate placement on photovoltaic panels; the connection confirmation relies only on a single weight judgment and lacks multi-level tension threshold verification, resulting in a high misjudgment rate.

[0023] Example 1 In one embodiment, a structural description of a drone attachment, deployment, and retrieval device for a photovoltaic cleaning robot provided by the present invention is given. The overall structure of the attachment device is described below. Figure 1 From top to bottom, it includes: The components include: 1. Descending rope; 2. Tension sensor; 3. Control box; 4. Connecting column; 5. Launching ball; and 6. Miniature electric push rod and locking pin engagement mechanism.

[0024] The descent rope 1 is connected to the descent device 11 of the drone above, and hangs down from the descent device 11 to realize the overall lifting and lowering adjustment of the hanging device relative to the drone. The tension sensor 2 is connected to the descent rope 1 and the top lug of the control box 3 via a double-eared fork-head pin structure. The fork-head pin allows free rotation around its axis (eliminating the transmission of torsional torque from the rope to the sensor), but restricts the axial offset between the rope and the device body (avoiding off-center loading in the tensile direction), achieving the connection characteristic of "allowing torsional rotation and restricting off-center tension". The tension sensor 2 is used to detect changes in rope tension in real time, providing force data for determining the attachment status. The tension sensor 2 uses high-frequency continuous sampling and reports data to the control terminal at a set period.

[0025] The control box 3 is installed below the tension sensor 2, with a lifting lug at the top center, which is connected to the lower end of the tension sensor 2 via a pin shaft; the outer shell of the control box 3 is a circular disc design with a smooth outer surface without any sharp edges or protrusions, and the installation position is located on the central axis of the device, so that the hanging device can slide smoothly through the photovoltaic array guide network cable without getting stuck; the control box 3 contains a single-chip microcomputer control board 31, a communication module 32, and a power management module 33.

[0026] The connecting post 4 is used to connect the control box 3 and the launching ball 5. The connecting post 4 is connected to the upper control box 3 by a threaded connection and thread locking agent (anaerobic adhesive curing). The connecting post 4 adopts a rigid integrated structure, eliminating the risk of loosening of detachable connecting parts in traditional split designs. The control box 3, connecting post 4, and launching ball 5 are rigidly integrated to form a non-detachable whole structure.

[0027] The launching sphere 5 is connected to the lower part of the connecting column 4 by a threaded connection and a locking pin. The launching sphere 5 is a spherical shell structure that houses the battery 51 and the electronic control module 52; the bottom of the sphere is provided with a heat dissipation and weight reduction groove 53.

[0028] In one description, the bottom of the control box 3, the connecting post 4, and the top of the launch ball 5 employ a triple anti-loosening process: threaded connection + anaerobic adhesive curing + pin locking. The threaded connection provides the main load-bearing capacity, the anaerobic adhesive filling the thread gaps provides vibration damping and anti-loosening capabilities, and the pin passing through the through hole between the connecting post and the ball shell provides final anti-rotation protection. This triple anti-loosening process ensures that the three-section rigid integrated connection remains reliable and does not loosen under the loads of UAV flight vibration (typically 5–50Hz) and launch impact (typically ≤5g).

[0029] The connecting sphere 5 connects the lower miniature electric push rod to the locking pin hooking mechanism 6; two push rod mounting windows are symmetrically opened at the equator position of the launching sphere 5, and the inner side of the window is provided with a mounting bracket integrally formed with the shell of the sphere; the cylinder of the miniature electric push rod 61 is fixed to the mounting bracket by bolts plus flat washers and spring washers, the extension and retraction direction of the push rod is arranged horizontally along the radial direction of the sphere, and the mounting window is provided with reinforcing ribs along the extension and retraction direction to withstand the reaction force when the locking pin 62 is activated.

[0030] Reference Figure 2 The micro electric push rod and locking pin engagement mechanism 6 includes two sets of micro electric push rods 61, symmetrically installed at the equator position of the deployment sphere 5, with the two sets of micro electric push rods 61 facing each other at 180°. Each set of micro electric push rods 61 has a locking pin 62 fixedly connected to its end. The locking pin 62 is a cylindrical metal rod with a guide rounded corner at its head, which facilitates its natural sliding into the lifting ring 71 on the top of the photovoltaic cleaning robot 7 during descent and docking. The diameter of the locking pin 62 and the inner diameter of the lifting ring 71 form a clearance fit, ensuring reliable hooking while allowing for fine-tuning of the position during docking.

[0031] Furthermore, the axis of the miniature electric push rod 61 is coplanar with the horizontal equator of the delivery ball 5, allowing the locking pin 62 to extend horizontally to the lifting ring 71 of the photovoltaic cleaning robot 7; the opposing arrangement of the two sets of miniature electric push rods 61 allows the locking pins 62 on both sides to extend and retract synchronously; the miniature electric push rod 61 and the delivery ball 5 are connected by bolts + flat washers + spring washers, and reinforcing ribs are provided in the extension and retraction direction of the push rod to withstand the reaction force when the locking pin 62 moves.

[0032] Furthermore, two locking pins 62 extend horizontally from both sides of the launching ball 5 and pass through the top hanging ring 71 of the photovoltaic cleaning robot 7, forming a double-sided symmetrical clamping; the symmetrical layout ensures that the load of the photovoltaic cleaning robot 7 is evenly distributed on both sides of the locking pins 62 during the suspension and transportation process, preventing swaying and rotation caused by unilateral force.

[0033] The equatorial mounting window of the launch sphere 5 is provided with a guide hole 63 integrally formed with the shell. The locking pin 62 passes through the guide hole 63 and can slide along the axial direction. During normal mounting, the vertical shear load of the photovoltaic cleaning robot 7 acting on the locking pin 62 through the lifting ring 71 is borne by the hole wall of the guide hole 63 and transmitted to the sphere shell 5. The micro electric push rod 61 only drives the locking pin 62 to extend and retract horizontally and does not bear the vertical load.

[0034] Furthermore, the miniature electric push rod 61 has a power-off self-locking function, meaning that the push rod remains stationary in its current position when the power supply is interrupted. When the locking pin 62 is in the locked position, it remains extended and will not retract even in the event of a power failure, fundamentally eliminating the safety hazard of the cleaning robot falling off due to a power outage. This is fundamentally different from the characteristic of an electromagnetic latch that releases upon power failure.

[0035] Furthermore, the two sets of miniature electric actuators 61 are energized only for the brief moment of extension or retraction, and automatically de-energized after the action is completed, maintaining their position through mechanical self-locking. There is no issue of continuous power-on heating, making them suitable for long-term operation in high-temperature environments in photovoltaic scenarios.

[0036] Furthermore, under normal loading conditions, the gravity of the photovoltaic cleaning robot 7 is transmitted to the double-sided locking pins 62 via the lifting ring 71, then to the deployment ball 5 via the micro electric push rod and locking pin engagement mechanism 6, and finally to the descent rope 1 via the connecting column 4 and tension sensor 2. The symmetrical force on both sides distributes the load along the central axis of the device, avoiding uneven loading.

[0037] In one reference embodiment, examples of the specific specifications / materials / assembly methods of each component in the mounting device of this embodiment are given: Tension sensor 2, S-type load cell, range 0–20kg, accuracy 0.1%FS, sampling rate ≥200Hz; connected to the descent rope lugs and the top lugs of the control box via M6 thread at both ends, anti-torsion structure (double lug fork pin connection).

[0038] The control box 3 is a circular disc with an outer diameter of approximately 120mm and a height of approximately 40mm. The outer shell is made of ABS engineering plastic injection molding with a surface finish of Ra≤1.6μm. The outer edge has a rounded corner R≥8mm. An integrated injection / welding interface for the connecting column is provided at the bottom.

[0039] Connecting column 4 is made of 6061-T6 aluminum alloy bar material, machined by turning, with an outer diameter of 30mm and a length of about 80mm; the upper end is threaded to the bottom of the control box and cured with anaerobic adhesive (non-removable), and the lower end is threaded to the top of the launching ball and locked with a pin.

[0040] The launch sphere 5 is a spherical shell with a diameter of approximately 180mm. It is formed by die-casting two halves of 6061 aluminum alloy and then bolting them together. The wall thickness is 3mm. Two push rod mounting windows are symmetrically opened at the equator, and the windows are reinforced with ribs.

[0041] There are 53 weight-reducing and heat-dissipating slots, a total of 4, which are symmetrically fan-shaped slots on the bottom of the sphere; each slot is 30mm long and 6mm wide, providing heat dissipation and weight reduction for the battery compartment.

[0042] The miniature electric actuator 61 uses a 12VDC miniature actuator with a working current of 0.2A, a stroke of 30mm, a thrust of ≥50N, and an action time of approximately 2s. It features mechanical self-locking (worm gear transmission) and will not retract after power failure. It has an IP54 protection rating.

[0043] Locking pin 62 is made of stainless steel SUS304, with a diameter of 8mm, a length of 40mm, and an end radius of R4mm. Locking pin 62 has a clearance fit H8 / f7 with the inner diameter of the lifting ring 71 of the photovoltaic cleaning robot 7 (typical clearance 0.05–0.12mm).

[0044] Battery 51 uses an 11.1V / 5000mAh lithium battery with a capacity of approximately 55Wh, which can support continuous operation of the device for ≥8 hours.

[0045] The communication module 32 uses a 4GCat.1 cellular module + patch antenna and an independent SIM card slot.

[0046] In response to the characteristics of photovoltaic power plants, such as "high temperature, vibration, dense guide netting, and strong wind interference", this invention makes three exclusive adaptation optimizations: (a) a circular disc-shaped control box with a surface finish Ra≤1.6μm and rounded corners R≥8mm, designed specifically for cables passing through the photovoltaic array guide netting to avoid snagging caused by square corners; (b) an integrated connection structure with triple anti-loosening technology (thread + anaerobic adhesive + pins), designed specifically for withstanding the vibration of drone flight (5–50Hz) and the impact of deployment (≤5g), which is significantly better than ordinary bolt assembly; (c) a force verification system with multi-level tension thresholds + high-frequency continuous sampling (≥200Hz) + automatic retry ≤3 times, designed specifically for reliable connection verification under strong wind disturbance above the photovoltaic panel, which is significantly better than a single weight threshold solution.

[0047] Example 2 In one embodiment, based on the mounting device described in Embodiment 1, the force path of the photovoltaic cleaning robot 7 in the mounted state is given as follows: The photovoltaic cleaning robot 7 has a self-weight of G (typically 6.2 kg, approximately 62 N). The robot's structure consists of: a top lifting ring 71 (symmetrically distributed on both sides); double-sided locking pins 62 (each side bears a vertical shear load of approximately G / 2 = 31 N); guide holes 63 on the shell of the deployed sphere 5 (the locking pins 62 pass through the guide holes 63, and the vertical shear load exerted on the locking pins 62 by the robot via the lifting ring 71 is borne by the hole wall of the guide holes 63 and transferred to the sphere shell); the shell of the deployed sphere 5 (centrally symmetrically stressed); connecting column 4 (axial tension along the central axis); tension sensor 2 (axial tension, range 0–20 kg); and a descent rope 1 (axial tension, rope safety factor ≥ 5). All connection interfaces in this path are located on the central axis to avoid off-center load moments. The output end of the miniature electric push rod 61 is connected to the locking pins 62, providing only the driving force for the horizontal extension and retraction of the locking pins, and does not bear the vertical load of the robot, thus separating the driving function from the load-bearing function.

[0048] Example 3 Based on the mounting device described in Embodiment 1, referring to Figure 3This embodiment provides a control method for a mounting device, executed by a microcontroller control board 31 within the control box 3. Tension sensor 2 continuously reports tension data at a sampling rate of no less than 200Hz. A pre-set tension threshold system includes, from low to high, a relaxation threshold F0, a first threshold F1, a second threshold F2, and a third threshold F3: the relaxation threshold F0 corresponds to the state where the descent rope is relaxed and the suspended object is supported by the support surface; its value is close to zero (typically no more than 10% of the device's own weight); the first threshold F1 corresponds to the unloaded, suspended state of the mounting device; its value is equal to the device's own weight (typical tolerance ±10%); the second threshold F2 is the boundary of the partially loaded area; and the third threshold F3 corresponds to the fully loaded state; its value is equal to the sum of the device's own weight and the cleaning robot's own weight (typical tolerance ±15%). The control method includes the following steps: Step S1, Ground Contact Determination: During the descent of the attachment device, the tension of the descent rope 1 is equal to the weight of the device (i.e., the first threshold F1); when the bottom of the device touches the support surface and the weight of the device is borne by the support surface, the descent rope 1 relaxes, and the tension continuously decreases from the first threshold range F1 and falls into the relaxation threshold range F0 (approaching zero), and continues to exceed the set time window (typically 200ms, i.e. no less than 40 consecutive sampling points), it is determined that the device has touched the support surface; Step S2, Locking: After the ground contact determination is established, the two sets of miniature electric push rods 61 are simultaneously sent with an extension command, and the double-sided locking pins 62 extend horizontally and enter the lifting ring 71; after the push rods are in place, the power is automatically cut off, and the locking position is maintained by mechanical self-locking. Step S3, Lifting Confirmation (Multi-level Tension Threshold Confirmation): The descent device 11 pulls up the rope, and the tension sensor 2 continuously samples the tension: If the tension is stably within the third threshold range within the set confirmation window and the fluctuation amplitude does not exceed the allowable fluctuation range (typical ±5%FS) and lasts for more than 1 second, the hooking is determined to be successful and the transportation stage begins; if the tension is between the second and third threshold ranges and does not enter the third threshold range, it is determined to be a partial hooking (single-sided hooking or jamming), and the process proceeds to step S4; if the tension is always lower than the lower limit of the third threshold, the hooking is determined to be a failure, and the process proceeds to step S4. Step S4, Safety Retry: First, the descent device 11 releases the rope, allowing the device and the photovoltaic cleaning robot to fall back to the support surface and gain support. The descent rope 1 slackens (tension returns to the slackening threshold F0 range). Then, the locking pin 62 is instructed to retract. After repositioning, steps S1 to S3 are repeated. A single retry includes the complete action of the push rod retracting, the descent device slightly raising (typically 200mm), a brief hover (typically 3s), descending again to touch the tension, and the push rod extending and locking again. The interval between two retryes should not be less than 5s, and the number of retryes should not exceed 3. If all 3 attempts fail, the locking pin remains in the retracted state and an alarm is reported through the event channel, awaiting manual intervention. In this step, the locking pin retraction action is only allowed to be performed when the tension is below the first threshold range (i.e., the suspended object is in a supported state). In further explanation, the push rod current is continuously monitored during the extension / retraction of the locking pin. If the current exceeds the threshold, the state is determined to be 0, the action is stopped, and the drone hovers to await manual intervention to avoid the push rod jamming or the motor burning out.

[0049] Step S5, Transportation Monitoring: After successful attachment, continuously monitor the tension throughout the flight: If the tension suddenly drops to the first threshold range or below the lower limit (the tension change rate is greater than or equal to the absolute value of the allowable change rate), determine that the load is abnormal, immediately trigger an alarm and instruct the UAV to hover and wait; If the locking pin 62 is in the locked position and the tension remains in the second threshold range, determine that the tension sensor or attachment status is abnormal. At this time, keep the locking pin locked and prohibit retraction, and report to manual handling. Step S6, Deployment and Release: After reaching the target point, the descent device 11 releases the rope. The tension drops to the first threshold range and continues for a set time window (when the weight of the cleaning robot is supported by the photovoltaic panel) before a retraction command is issued to release the photovoltaic cleaning robot 7. After the locking pin 62 retracts, the rope is pulled back. If the tension rises again to exceed the second threshold during the rope pulling process, it is determined that the detachment has not been successful (hooked or entangled). The rope pulling is stopped, the rope is released again, and the release action is repeated. Step S7, Status Reporting: The stage status, tension data, and push rod position status of each of the above steps are reported to the ground control terminal in real time via the heartbeat channel and event channel through the communication module 32.

[0050] In the above control method, the correspondence between the three core designs and method steps is as follows: the multi-level tension threshold confirmation system constitutes the quantitative basis for determining the hanging, detachment, and release states in steps S1, S3, S5, and S6; the micro electric push rod's power-off self-locking characteristic ensures that the locking state is not lost under any power supply abnormality in steps S2 and S5; the constraint in steps S4 and S6 that "the suspended object can only be retracted when it is supported" together with the four-level safety protection system eliminates the risk of falling in mid-air from the control logic.

[0051] Example 4 Based on the attachment device described in Embodiment 1, a multi-stage state machine is used to manage the entire process of deployment and retrieval of the photovoltaic cleaning robot 7, which includes six stages: pickup, transportation, deployment, waiting for cleaning, retrieval, and return.

[0052] Phase 1: Retrieval. The drone flies above the storage area of ​​the photovoltaic cleaning robot 7 and hovers using RTK (Real-Time Kinematic) positioning. The descent device 11 releases the descent rope 1, and the attachment device descends. The tension sensor 2 detects that the rope tension has dropped to the slack threshold range (descent rope 1 is slack / the device has contacted the support surface), confirming a contact. The control box 3 sends an extension command to the miniature electric push rod 61, and the double locking pins 62 simultaneously extend horizontally and insert into the hanging ring 71 on the top of the photovoltaic cleaning robot 7 to complete the locking. The descent device retracts the descent rope 1, and the tension sensor 2 confirms that the tension has risen to the third threshold range (corresponding to the robot's fully loaded state), confirming a successful attachment. If the tension always falls within the second threshold range (not reaching full load), the attachment is considered a failure, and the system automatically retryes, up to 3 times. If all 3 attempts fail, an alarm is reported, awaiting manual intervention.

[0053] Phase 2: Transportation. The drone carrying the photovoltaic cleaning robot 7 flies to the target photovoltaic panel area along the RTK route. Throughout the flight, the tension sensor 2 continuously samples and monitors at high frequency. The normal value should be stable within the third threshold range. If the tension suddenly drops to the first threshold range (the absolute value of the tension change rate is greater than or equal to the allowable change rate), it is determined that the load has abnormally fallen off, an emergency alarm is immediately triggered, and the drone is instructed to hover and wait.

[0054] Phase 3: Deployment. The drone hovers above the target point using RTK; the descent device releases the descent rope 1, and the photovoltaic cleaning robot 7 lands on the photovoltaic panel surface; the tension sensor 2 confirms that the tension has dropped to the first threshold range (the robot's weight is now supported by the photovoltaic panel); the control box 3 sends a retraction command, and the double-sided locking pins 62 retract simultaneously, disengaging from the lifting ring 71, releasing the photovoltaic cleaning robot 7; the descent device retracts the descent rope 1, and the circular control box 3 smoothly passes through the guide net structure, allowing the drone to fly away.

[0055] Phase 4: Waiting for Cleaning. The attachment device waits at a preset location with the drone or returns to the base station. After the photovoltaic cleaning robot 7 independently completes the cleaning operation, it reports a cleaning completion signal, and the control terminal dispatches the drone to retrieve it.

[0056] Phase 5: Retrieval. The same hooking process is performed as in the retrieval phase, and the automatic retry mechanism and multi-level tension confirmation logic are also applied.

[0057] Phase 6: Return. The drone carrying the photovoltaic cleaning robot 7 returns to the base, with continuous tension monitoring during transport. Upon arrival, the miniature electric push rod 61 retracts and releases the photovoltaic cleaning robot 7 to its storage position. Once the tension is confirmed to have dropped to the first threshold range, the operation cycle ends.

[0058] In one implementation, a multi-level tension threshold system is used to determine the attachment status: Relaxation threshold: The rope is relaxed or the device has landed / released. Used for both touch confirmation and release confirmation scenarios.

[0059] First threshold range: The mounting device is suspended in the air. Second threshold range: The tension is between no load and full load, indicating that the mounting was not completely successful or the load is abnormal. An automatic retry process is triggered. Third threshold range: The tension matches the weight of the cleaning robot, indicating that the robot is fully supported by the locking pins and the mounting was successful.

[0060] The specific values ​​of the multi-level tension threshold system are calibrated during the system debugging phase based on the actual weight of the cleaning robot and the sensor range: (1) Relaxation threshold range F0. Relaxation threshold F0 corresponds to the state where the descent rope is relaxed and the suspended object is supported by the support surface. Its value is close to zero (typically no more than 10% of the device's own weight). (2) First threshold interval = Device weight The device's self-weight is the total weight of the mounting device. This is the first tolerance factor (typically ±10%). When the tension drops to At this time, it indicates that the mounting device is in a suspended state; the first threshold interval is ; and These are the lower and upper limits of the first threshold interval, respectively.

[0061] (3) Third threshold ; The photovoltaic cleaning robot has a weight of 7 and a third tolerance factor. Typical ±15%; when tension rises to When this time, it indicates a fully mounted state, and it is determined that the robot has been fully mounted and successfully attached. The third threshold interval is... , and These are the lower and upper limits of the third threshold interval, respectively.

[0062] (4) Second threshold interval This refers to the interval between the upper limit of the first threshold interval and the lower limit of the third threshold interval. As the boundary value for "not fully loaded," it represents a partially loaded state where some load has been borne but not yet fully loaded.

[0063] It should be noted that the first tolerance coefficient and the third tolerance factor The value of should ensure that the upper limit of the first threshold interval is less than the lower limit of the third threshold interval, meaning that the three intervals do not overlap and the second threshold interval is not empty. Taking the 6.2kg cleaning robot adapted to this invention as an example, the typical threshold is: ≈22–28N, ≈50N, ≈75–100N (corresponding to 11%–50% of the tension sensor range of 20kg).

[0064] The multi-level tension thresholds are calibrated on-site during the initial deployment of the system: the tension recorded when the device is suspended is used as the threshold value. The baseline is the stable tension recorded after the robot is mounted. The benchmark and calibrated threshold values ​​are then fixed to the control box 3 firmware and can be remotely updated to adapt to different models of cleaning robots.

[0065] In one implementation, refer to Figure 4 The state transition conditions and timeout mechanisms of the six-stage state machine of the attachment device are given in Table 1.

[0066] Table 1. State transition conditions and timeout mechanisms for a six-stage state machine.

[0067] In a further specific implementation, a latch state machine is constructed: the control of the micro electric push rod 61 adopts a 4-state FSM (finite state machine), and the states and descriptions are given in Table 2 below.

[0068] Table 2. Latch Status Machine Status Description

[0069] In a further specific embodiment, the miniature electric actuator 61 motor is equipped with current monitoring. When the real-time current exceeds the set protection threshold, the power supply is automatically cut off and the operation stops, entering a fault state.

[0070] In a further specific implementation, refer to Figure 5 Four levels of security protection are set up: Level 1: Software emergency stop. Upon receiving a remote emergency stop command, all actuators immediately cease operation. Level 2: Overcurrent protection, automatically shuts down the motor when the current exceeds the limit; Level 3: Heartbeat timeout. If the control terminal does not receive heartbeat data from the device within a set time, it determines that the device is offline and triggers an alarm. Level 4: Physical fuse, the ultimate protection measure at the hardware circuit level.

[0071] When any level of protection is triggered, the locking pin remains in its current position due to the power-off self-locking characteristic of the electric actuator, and the load will not be accidentally released due to power failure.

[0072] In a further specific implementation, the parameterization settings of the automatic retry mechanism are as follows: a single retry includes the complete action of "pull rod retraction → slight increase of the descent device (typically 200mm) → brief hovering (typically 3s) → re-descent to the contact tension → push rod re-extend and lock"; the interval between two retryes is ≥5s to avoid overheating of the push rod due to continuous action; the maximum number of retryes N=3, and if it still fails after 3 attempts, it enters the "manual intervention" state and reports an alarm through the event channel.

[0073] The principle for setting the heartbeat timeout threshold is as follows: Under the condition that RSSI ≥ -90dBm of the communication link, the connected device reports the heartbeat to the control terminal at a frequency of 1Hz; the typical heartbeat timeout threshold of the control terminal is set to 30s (i.e., no heartbeat is received for 30 consecutive heartbeat cycles). If the threshold is exceeded, the device is judged to be offline and the third level heartbeat alarm in the four-level protection is triggered.

[0074] As a preferred embodiment, refer to Figure 6 The communication module 32 of the mounting device communicates with the ground control terminal via a cellular network, using a publish / subscribe message middleware for data exchange. The communication channels are divided into three categories: Command channel: The control terminal sends control commands such as locking pin extension / retraction to the hook-up device.

[0075] Heartbeat Channel: The attachment device periodically reports equipment status, tension sensor data, and current data.

[0076] Event Channel: The cleaning robot reports business events such as landing ready, cleaning completed, arrival at the recycling point, and malfunction.

[0077] The above communication protocols and message formats are not limited to specific implementation methods. Any solution that uses a publish / subscribe model to achieve three-way separate communication between the three parties (control terminal, attachment device, and cleaning robot) falls within the scope of the communication solutions of this invention.

[0078] Example 5 Based on the entire process of deployment and retrieval of the photovoltaic cleaning robot 7 described in Example 4, the timing sequence of the item retrieval operation in the item retrieval stage is described.

[0079] Step 1: The drone flies over the storage area of ​​the photovoltaic cleaning robot 7 and hovers based on RTK positioning.

[0080] Step 2: The descent device releases the descent rope 1, and the attachment device descends. The guide radius of the locking pin 62 head provides positional tolerance as it approaches the lifting ring 71 at the top of the photovoltaic cleaning robot 7, allowing natural alignment within the clearance fit between the diameter of the locking pin 62 and the inner diameter of the lifting ring.

[0081] Step 3: Tension sensor 2 detects that the tension of the descent rope 1 has dropped to the first threshold range, and control box 3 determines that the device has touched the top of the robot.

[0082] Step 4: Control box 3 simultaneously sends extension commands to both sets of miniature electric actuators 61. Both locking pins 62 extend horizontally simultaneously, inserting into the robot's top lifting ring 71. The miniature electric actuators 61 automatically de-energize after completing their extension within approximately 2 seconds, maintaining their locked position through mechanical self-locking.

[0083] Step 5: The descent device retracts the descent rope 1. The gravity of the photovoltaic cleaning robot 7 is transmitted through the path of the lifting ring 71 → double-sided locking pins 62 → miniature electric push rod 61 → release ball 5 → connecting column 4 → tension sensor 2 → descent rope 1. The symmetrical force on both sides ensures that the load is distributed along the central axis of the device.

[0084] Step 6: Tension sensor 2 confirms that the tension is stable within the third threshold range (matching the robot's own weight of 6.2kg), and the connection is determined to be successful.

[0085] Step 7: If the tension does not fall within the third threshold range, the connection is deemed to have failed. Control box 3 sends a retraction command to release locking pin 62, and the slow descent device 11 rises slightly and then descends again, repeating steps 3-6. It will automatically retry a maximum of 3 times. If all 3 attempts fail, an alarm will be reported and manual intervention will be required.

[0086] Example 6 Based on the entire process of deployment and retrieval of the photovoltaic cleaning robot 7 described in Example 4, the deployment operation sequence of the item retrieval stage is described.

[0087] Step 1: The drone carrying the photovoltaic cleaning robot 7 arrives above the target photovoltaic panel and hovers in RTK mode.

[0088] Step 2: The descent device releases the descent rope 1, allowing the photovoltaic cleaning robot 7 to land on the photovoltaic panel surface.

[0089] Step 3: Tension sensor 2 detects that the tension has dropped to the first threshold range, confirming that the gravity of the photovoltaic cleaning robot 7 is now supported by the photovoltaic panel.

[0090] Step 4: The control box 3 sends a retraction command to the two sets of miniature electric push rods 61, and the locking pins 62 on both sides retract simultaneously, disengaging from the lifting rings 71 and releasing the photovoltaic cleaning robot 7.

[0091] Step 5: The descent device retracts the descent rope 1, and the attachment device rises. The smooth, circular outer surface of the circular control box 3 smoothly glides through the photovoltaic array guide network cable without getting caught.

[0092] Step 6: The drone flies away from the deployment area.

[0093] Example 7 In one embodiment, an abnormal scenario handling method is given.

[0094] Scenario 1: Sudden drop in tension during transport. During flight, tension sensor 2 continuously monitors at high frequency. If the tension suddenly drops from the third threshold range to the first threshold range, an abnormal load is determined. The system immediately triggers an emergency alarm, instructing the drone to hover and wait, while simultaneously notifying the operator at the control terminal. Due to the self-locking mechanism of the miniature electric actuator 61 in the event of a power failure, the locking pin remains extended even in this situation.

[0095] Scenario 2: Overcurrent in the actuator motor. During the operation of the miniature electric actuator 61, if the motor current exceeds the protection threshold, the system automatically cuts off the power supply to the actuator, the latch state machine enters a fault state (state 0), and reports the fault information. The miniature electric actuator 61 maintains its current position by mechanical self-locking.

[0096] Scenario 3: Communication Interruption. If the control unit does not receive heartbeat data from the attached device within a set time, it determines that the device is offline and triggers an alarm. The drone executes the preset communication interruption emergency strategy (such as hovering or automatic return).

[0097] Example 8 In one embodiment, an automatic retry sequence is provided for connection failures.

[0098] Step 1: After the first connection is completed, tension sensor 2 detects the tension. If it falls within the second threshold range, the connection is determined to be incomplete.

[0099] Step 2: The control box 3 sends a retraction command, and the double-sided locking pins 62 retract; the descent device raises the device by 200mm to a safe distance directly above the photovoltaic cleaning robot 7 and hovers for 3 seconds.

[0100] Step 3: The descent device releases the descent rope 1 again, and the attachment device descends to the contact tension (less than or equal to the first threshold range). Due to the presence of the guide fillet and clearance fit, this descent will re-align within a small range.

[0101] Step 4: Repeat the hook-up process (i.e., the pickup process) from Step 4 to Step 6 of Example 2, and record it as the second attempt.

[0102] Step 5: If the second attempt is successful (tension ≥ F3 × 90%), proceed to the transportation stage; if it still fails, repeat steps 2 to 4 for a third attempt.

[0103] Step 6: If three consecutive attempts fail, control box 3 will report a "failed to connect" alarm to the control terminal through the event channel. The drone will then enter a hovering waiting state for operator intervention.

[0104] In further explanation, the RTK hovering error in this application is not a fixed position, but a dynamic random fluctuation within a centimeter range; and the attachment device of the descent rope 1 exhibits pendulum-like swing with a different phase each time. Each time the descent is re-released, the relative position of the locking pin 62 and the hanging ring 71 is resampled, rather than repeating the same deviation. Multiple retries can improve the cumulative docking success rate, rather than repeating the same position in place. Furthermore, before retrying, the horizontal position of the UAV can be corrected using RTK / visual feedback before descent.

[0105] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0106] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0107] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0108] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0109] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A drone attachment device for a photovoltaic cleaning robot, comprising, from top to bottom, a descent rope (1), a tension sensor (2), a control box (3), a connecting column (4), a release ball (5), and a micro electric push rod and locking pin attachment mechanism (6); characterized in that: The descent rope (1) is connected to the descent device (11) of the UAV above, and is connected downward from the descent device (11) to realize the overall lifting and lowering adjustment of the hanging device relative to the UAV. The tension sensor (2) is connected to the descent rope (1) and the top lug of the control box (3) via a double-ear fork pin structure, and is used to detect the change in rope tension in real time; the control box (3) is installed below the tension sensor (2), with a lug at the top center, and is connected to the lower end of the tension sensor (2) via a pin. The control box (3) is used to determine the current flight status through the real-time tension data of the tension sensor (2) and send adjustment commands to the micro electric push rod and locking pin coupling mechanism (6); The connecting column (4) is connected to the upper control box (3) by a threaded connection and thread-locking agent, and the lower launching ball (5) is locked by a threaded connection and pin; the control box (3), the connecting column (4) and the launching ball (5) are rigidly integrated; The micro electric push rod and locking pin connection mechanism (6) includes two sets of micro electric push rods (61), which are symmetrically installed at the equator position of the delivery ball (5); each set of micro electric push rods (61) is fixedly connected to a locking pin (62) at its end. The two locking pins (62) extend horizontally from both sides of the delivery ball (5) and pass through the top hanging ring (71) of the photovoltaic cleaning robot (7) to form a double-sided symmetrical clamping.

2. The drone mounting device for a photovoltaic cleaning robot according to claim 1, characterized in that: The launch sphere (5) has two push rod mounting windows symmetrically opened at the equator position. The inner side of the window is provided with a mounting bracket integrally formed with the shell of the sphere. The cylinder of the miniature electric push rod (61) is fixed to the mounting bracket by means of bolts, flat washers and spring washers. A reinforcing rib is provided in the extension and retraction direction of the push rod to bear the reaction force when the locking pin (62) moves. The push rod mounting window is provided with a guide hole (63) integrally formed with the shell. The locking pin (62) passes through the guide hole (63) and can slide along the axial direction. The axis of the miniature electric push rod (61) is coplanar with the horizontal equator of the ball (5), so that the locking pin (62) can extend horizontally to the position of the lifting ring (71) of the photovoltaic cleaning robot (7); the diameter of the locking pin (62) and the inner diameter of the lifting ring (71) form a clearance fit.

3. The drone mounting device for a photovoltaic cleaning robot according to claim 1, characterized in that: Two sets of miniature electric push rods (61) are symmetrically installed at the equator of the delivery ball (5). The two sets of miniature electric push rods (61) are arranged in a 180° opposite layout, so that the locking pins (62) on both sides can extend and retract synchronously, and the load of the photovoltaic cleaning robot (7) is evenly distributed on the locking pins (62) on both sides during the suspension and transportation process.

4. The drone mounting device for a photovoltaic cleaning robot according to claim 1, characterized in that: The miniature electric push rod (61) has a power-off self-locking function, and the push rod remains in its current position when the power supply is interrupted; the two sets of miniature electric push rods (61) are only powered on when they extend or retract, and are powered off after the action is completed, and the position is maintained by mechanical self-locking.

5. A control method for a drone mounting device for a photovoltaic cleaning robot as described in any one of claims 1-4, characterized in that, The process is executed by the microcontroller control board (31) inside the control box (3), based on the tension data collected by the tension sensor (2), and calls the multi-level tension threshold system to determine the hanging status; including the following steps: S1. The descent device (11) releases the descent rope (1), and the attachment device descends. During the descent, the tension sampling value falls into the first threshold range. When the tension sampling value continuously decreases from the first threshold range and falls into the relaxation threshold range, and the duration exceeds the set time window, it is determined that the attachment device has reached the support surface. S2. The single-chip microcomputer control board (31) simultaneously sends an extension command to the two sets of micro electric push rods (61), and the double-sided locking pins (62) extend horizontally and enter the lifting ring (71) to lock. S3, the descent device (11) is lifted, and the tension sensor (2) continuously samples the tension data of the descent rope (1); if the tension sample value falls into the third threshold range and the fluctuation amplitude does not exceed the allowable fluctuation range, the hooking is determined to be successful and proceed to S5; otherwise, proceed to S4. S4, the descent device (11) lowers the descent rope (1) so that the tension falls back to the relaxation threshold range; the microcontroller control board (31) sends retraction commands to the two sets of micro electric push rods (61) simultaneously, repeating S1 to S3; S5. Continuously monitor tension data. If the tension change rate is greater than or equal to the absolute value of the allowable change rate, the load is determined to be abnormal. The microcontroller control board (31) instructs the UAV to hover and wait. S6. After reaching the target point, the descent device (11) releases the descent rope (1). After the tension sampling value drops to the first threshold range and continues to reach the set time window, the microcontroller control board (31) issues a retraction command to release the photovoltaic cleaning robot (7).

6. The control method according to claim 5, characterized in that, The tension threshold system includes a relaxation threshold interval, a first threshold interval, a second threshold interval, and a third threshold interval; The relaxation threshold range corresponds to the state where the descent rope (1) is relaxed and the suspended object is supported by the support surface, and its value is not greater than the set proportion of the self-weight of the hanging device; The first threshold range is the product of the self-weight of the mounting device and the first tolerance coefficient; The third threshold interval is the product of the weight of the mounting device and the weight of the photovoltaic cleaning robot (7) and the third tolerance coefficient; the second threshold interval is between the upper limit of the first threshold interval and the lower limit of the third threshold interval.

7. The control method according to claim 5, characterized in that, The miniature electric linear actuator (61) motor is equipped with current monitoring and uses a 4-state finite state machine to control the extension and retraction of the miniature electric linear actuator (61), including: State 0 is a fault state, indicating that the current of the miniature electric actuator (61) exceeds the protection threshold and enters an overcurrent state; State 1 is the extended / locked state, indicating that when the double-sided locking pins (62) are inserted into the lifting ring (71), the load-bearing state is entered; State 2 is the retracted / released state, which means that when the double-sided locking pins (62) are removed from the lifting ring (71), the robot enters the unlocked state; State 3 is the action execution state, indicating that the micro electric push rod (61) is extending or retracting.

8. The control method according to claim 6, characterized in that, In S3: When the tension sampling value falls into the second threshold range, it is determined to be a partial connection, and the process is switched to S4 for retry. If the tension does not fall within the third threshold range, the connection is deemed to have failed, and the process proceeds to step S4 for a retry.

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