Crawler-type unmanned vehicle and power swapping method for unmanned aerial vehicle power swapping

Abstract

The application discloses a crawler unmanned vehicle for unmanned aerial vehicle battery replacement and a battery replacement method, and belongs to the technical field of unmanned aerial vehicle charging. The unmanned vehicle comprises a vehicle main body, crawler chassis, navigation and sensing unit, battery replacement operation platform and master-slave control unit. The vehicle main body is symmetrically provided with two crawler chassis. The navigation and sensing unit is arranged at the front part of the vehicle main body, the battery replacement operation platform is arranged at the middle rear part of the vehicle main body, and the master-slave control unit is embedded in the vehicle main body. The navigation and sensing unit is used for sensing the external environment to realize pose estimation of the unmanned vehicle. The master-slave control unit plans a path according to the pose of the unmanned vehicle in combination with an electronic map, and guides the unmanned vehicle to avoid obstacles and navigate to the destination. The battery replacement operation platform comprises a cross slide, mechanical gripper unit and landing platform. The cross slide is used for driving the mechanical gripper unit to move along the xyz three axes to the position of the unmanned aerial vehicle on the landing platform, and realizes the battery replacement operation of the unmanned aerial vehicle.

Description

Technical Field

[0001] This invention relates to drone battery replacement technology, belonging to the field of drone charging technology. Background Technology

[0002] Existing drone battery swapping systems or platforms are mostly immobile ground-based battery swapping stations or mobile battery swapping platforms installed in truck beds or on car roofs. While these drone battery swapping systems can meet the needs of civilian, agricultural, and specific line inspection work, there is still a lack of autonomously mobile drone battery swapping platforms for special scenarios such as the field, disaster areas, and battlefields, which are difficult for ordinary battery swapping systems or platforms to reach. Summary of the Invention

[0003] To address the lack of autonomous mobile inorganic battery swapping platforms, this invention provides a tracked unmanned vehicle for battery swapping of unmanned aerial vehicles (UAVs) and a battery swapping method.

[0004] In one aspect, the present invention provides a tracked unmanned vehicle for battery swapping of unmanned aerial vehicles, comprising an unmanned vehicle body 1, a tracked chassis 2, a navigation and sensing unit 100, a battery swapping operation platform 200, and a master-slave control unit 300; the unmanned vehicle body 1 is symmetrically provided with two tracked chassis 2; the navigation and sensing unit 100 is provided at the front of the unmanned vehicle body 1, the battery swapping operation platform 200 is provided at the middle and rear of the unmanned vehicle body 1, and the master-slave control unit 300 is embedded inside the unmanned vehicle body 1;

[0005] The navigation perception unit 100 is used to perceive the external environment and estimate the pose of the unmanned vehicle; the master-slave control unit 300 performs path planning based on the pose of the unmanned vehicle and the electronic map, and guides the unmanned vehicle to avoid obstacles and navigate to the destination; the battery swapping operation platform 200 includes a cross slide 6, a mechanical gripper unit 7 and a landing platform 8; the cross slide 6 is used to drive the mechanical gripper unit 7 to move along the xyz three axes to the position of the UAV on the landing platform 8, and realize the battery swapping operation of the UAV.

[0006] Preferably, the navigation perception unit 100 includes a lidar 3, a metal bracket 4, and an inertial measurement unit (IMU) 5. The metal bracket 4 is located at the front of the unmanned vehicle body 1. The lidar 3 is located on the top of the metal bracket 4, and the inertial measurement unit (IMU) 5 is located at the bottom of the metal bracket 4. The external environment data collected by the lidar 3 and the inertial measurement unit (IMU) 5 are sent to the master-slave control unit 300.

[0007] Preferably, the master-slave control unit 300 includes a PC 8 and an MCU 9. The PC 8 receives external environmental data collected by the lidar 3 and the inertial measurement unit IMU 5. The PC 8 sends navigation and obstacle avoidance commands to the MCU 9 based on the external environmental data. The MCU 9 controls the unmanned vehicle to move towards the destination according to the navigation and obstacle avoidance commands.

[0008] Preferably, the cross slide 6 includes an x-direction lead screw 6-1, a y-direction lead screw 6-2, a z-direction slide 6-3, a slide rod 6-4, an x-direction stepper motor 6-5, a y-direction stepper motor 6-6, a z-direction stepper motor 6-7, an x-direction limit switch 6-8, a y-direction limit switch 6-9, and a z-direction limit switch 6-10;

[0009] The x-direction lead screw 6-1 is installed on the unmanned vehicle body 1 along the front-rear direction of the vehicle body. The x-direction lead screw 6-1 is equipped with an x-direction stepper motor 6-5 and an x-direction limit switch 6-8.

[0010] The Y-direction lead screw 6-2 is mounted on the unmanned vehicle body 1 along the left and right directions of the vehicle body. The Y-direction lead screw 6-2 is equipped with a Y-direction stepper motor 6-6 and a Y-direction limit switch 6-9.

[0011] The z-direction slide 6-3 is vertically mounted on the x-direction lead screw 6-1. The z-direction slide 6-3 is equipped with a z-direction stepper motor 6-7, a slide rod 6-4, and a z-direction limit switch 6-10. The mechanical gripper unit 7 moves up and down along the slide rod 6-4 under the drive of the z-direction stepper motor 6-7.

[0012] Preferably, the mechanical gripper unit 7 includes a slider 7-1, a constraint box 7-2, a mechanical gripper 7-4, a camera 7-5, a mechanical gripper switch servo 7-6, a battery switch servo 7-7, and a battery limit servo 7-8.

[0013] The slider 7-1 is provided with a vertical sliding hole, and the slider 7-1 moves along the slider 6-4 through the vertical sliding hole;

[0014] The front face of the slider 7-1 is provided with a mechanical gripper switch servo 7-6, a mechanical gripper 7-4, and a constraint box 7-2 from top to bottom. The mechanical gripper switch servo 7-6 is used to control the mechanical gripper 7-4 to clamp or release. A battery switch servo 7-7 is provided on one side of the mechanical gripper 7-4. The battery switch servo 7-7 moves with the mechanical gripper 7-4 and controls the switching operation of the UAV battery through a toggle mechanism.

[0015] The constraint box 7-2 has a front-opening structure. The left and right sides of the constraint box 7-2 are provided with slots 7-3 for engaging the drone battery latches. The constraint box 7-2 is equipped with a camera 7-5, which is used to observe the drone battery and query the battery level based on vision. The lower end face of the constraint box 7-2 is provided with a battery limiting servo 7-8, which drives the limiting mechanism inside the constraint box 7-2 to constrain the battery during the process of pulling out and inserting the battery.

[0016] Preferably, the landing platform 8 includes a drone platform 8-1, a guidance mechanism 8-2, a locking servo motor 8-5, and a battery compartment 8-4;

[0017] The drone platform 8-1 is suspended at the rear of the drone body 1. A guide mechanism 8-2 is set on the side of the drone platform 8-1 facing the cross slide 6. The guide mechanism 8-2 is a trapezoidal shallow groove structure. The shallow groove has a strip hole 8-3 at the drone locking position. The locking servo 8-5 is set below the drone platform 8-1. The locking part of the locking servo 8-5 extends through the strip hole 8-3 to lock the drone. A battery compartment 8-4 is set on the lower surface of the drone platform 8-1. The battery compartment 8-4 is open on the side facing the cross slide 6 and is used to store fully charged batteries and batteries to be recharged removed from the drone.

[0018] In another aspect, the present invention provides a method for battery swapping of a tracked unmanned vehicle (UAV) using the aforementioned UAV battery swapping system. This method includes the following steps:

[0019] S1. Initialization: The unmanned vehicle moves around the field and uses the lidar 3 and inertial measurement unit IMU5 to collect external environmental data to estimate the vehicle's pose; PC 8 manually builds a map based on the vehicle's pose and combines it with map services to generate a two-dimensional grid map.

[0020] S2. When performing a task, global and local path planning is performed based on the external environment data collected in real time by the lidar 3 and the inertial measurement unit IMU5 and the two-dimensional high-precision grid map generated by S1. The PC 8 sends the speed command obtained from the path planning to the MCU9 to drive the unmanned vehicle to move towards the destination according to the navigation command.

[0021] S3. Upon arrival at the destination, the battery-swapping drone will land under controlled conditions on landing platform 8.

[0022] S4. The cross slide 6 drives the mechanical gripper unit 7 to move along the xyz three axes to the position of the drone on the landing platform 8, and then the mechanical gripper 7-4 is used to adjust the position of the drone and lock it.

[0023] S5. Turn off the drone battery based on visual query of drone battery level;

[0024] S6 and the cross slide 6 drive the mechanical gripper unit 7 to perform plugging and unplugging operations on the drone battery, realizing the battery swapping of the drone; finally, the battery is turned on and the cross slide 6 returns to its original position.

[0025] Preferably, the specific process of step S4 is as follows:

[0026] S101. Return the mechanical gripper unit 7 to its original position via the cross slide 6. Control the x and z directions to return to the limit switch positions in the x and z directions via the x-axis stepper motor 6-5 and the z-axis stepper motor 6-7. Use the position of the slider 7-1 as the position of the mechanical gripper 7-4. At this time, the position is the initial position (x0, z0). The y-axis center of the mechanical gripper 7-4 is aligned with the y-axis center of the UAV battery. Then, reset each servo motor.

[0027] S102. The cross slide 6 is controlled by the x-axis stepper motor 6-5 and the z-axis stepper motor 6-7, so that the slider 7-1 is adjusted from the initial position (x0, z0) to the position (x1, z1) in the x and z directions, so that the center of the mechanical gripper 7-4 in the z direction is aligned with the center of the UAV battery in the z direction. Then the slider 7-1 is moved forward in the positive x direction to the position (x2, z1). During this process, the mechanical gripper 7-4 pushes the UAV so that the UAV enters the locked position under the constraint of the guide mechanism 8-2 of the landing platform. Then the locking servo 8-5 is driven to lock the UAV, so that the UAV is fixedly connected to the landing platform 8.

[0028] Preferably, the specific process of step S5 is as follows:

[0029] S103. Move the cross slide 6 backward along the x-axis to move the slider 7-1 to the (x3, z1) position, where the (x3, z1) position is the safe operating position;

[0030] S104. Adjust the z-axis height of slider 7-1 to move it to the (x3, z2) position so that the center of mechanical gripper 7-4 is at the same height as the center of the drone battery clip; and clamp the mechanical gripper 7-4 onto the drone battery clip.

[0031] S105. Based on visual query of the drone's battery level, if the battery level is below 50%, it is considered that the battery needs to be replaced and S106 is executed; otherwise, the battery replacement operation is stopped.

[0032] S106. The battery switching servo 7-7, which moves along with the mechanical gripper 7-4, shuts off the drone battery. Specifically, the battery switching servo 7-7 shuts off the battery by operating the power button of the drone battery in a short-press-long-press manner through a toggle mechanism.

[0033] Preferably, the specific process of step S6 is as follows:

[0034] S107. Battery removal steps;

[0035] First, operate the mechanical gripper switch servo 7-6 to clamp the mechanical gripper 7-4 and press the battery latch to unlock the battery. Then, move the slider 7-1 along the negative x-axis to the position (x5, z2) to remove the drone battery. Operate the mechanical gripper switch servo 7-6 to release the mechanical gripper 7-4 and release the battery. Next, move the slider 7-1 along the positive z-axis to the position (x5, z3) to align the constraint box 7-2 with the battery. Then, move the slider 7-1 along the positive x-axis to the position (x6, z3) to allow the battery to enter the constraint box 7-2. At this time, the battery latch engages with the side latch 7-3 of the constraint box 7-2. Operate the battery limiting servo 7-8 below the constraint box 7-2 to hold the battery latch with the limiting block and lock the battery in the constraint box 7-2. Finally, move the slider 7-1 along the negative x-axis to the position (x3, z3), and the battery will fall out of the drone through the constraint box 7-2. At this time, the battery is completely removed.

[0036] S108. Battery replacement procedure;

[0037] Lower slider 7-1 so that constraint box 7-2 is aligned with empty battery compartment 8-4. Operate battery limit servo 7-8 to release the old battery in constraint box 7-2 and place it in empty battery compartment 8-4. Then use mechanical gripper 7-4 to take a fully charged new battery from other battery compartment 8-4 and put it into constraint box 7-2, and restore slider 7-1 to position (x3, z3).

[0038] S109. Steps for installing a new battery:

[0039] The process begins by moving slider 7-1 along the positive x-axis to the position (x6, z3) to insert the new battery into the drone's battery compartment, and then operating the battery limiting servo 7-8 to release the battery. Next, slider 7-1 is moved backward along the negative x-axis to the position (x3, z3) to ensure that the constraint box 7-2 is completely separated from the new battery. Then, slider 7-1 is moved along the negative z-axis to the position (x3, z1) to align the center of the mechanical gripper 7-4 with the center of the new battery at the same height. Finally, slider 7-1 is moved again along the positive x-axis to the position (x2, z1). Use the mechanical gripper 7-4 to push the new battery into the drone's battery compartment and lock it in place. Next, move the slider 7-1 along the negative x-axis to the position (x3, z1), and then move it along the positive z-axis to the position (x3, z2), so that the center of the mechanical gripper 7-4 is at the same height as the center of the new battery's locking mechanism. Then, move the slider 7-1 along the positive x-axis to the position (x4, z2), and operate the battery switch servo 7-7 to turn on the battery's power button by short-pressing and then long-pressing. Finally, use the camera 7-5 to visually confirm that the new battery is turned on correctly.

[0040] The beneficial effects of this invention are as follows: This invention designs and methods for a drone battery swapping platform based on a tracked unmanned vehicle (UAV). It achieves high-precision map construction, autonomous positioning, and navigation of the UAV's working area using a tracked UAV equipped with the battery swapping platform. It can automatically remove and install batteries for remotely operated UAVs that have landed on the platform, using motor control and image processing methods. This invention enables efficient, autonomous, and covert UAV battery swapping, significantly improving UAV endurance and expanding their operating area, thus possessing strong practical application value. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the tracked unmanned vehicle for battery swapping of unmanned aerial vehicles as described in this invention;

[0042] Figure 2 This is a block diagram of the drone battery swapping control system;

[0043] Figure 3 This is a schematic diagram of the cross slide and mechanical gripper unit structure;

[0044] Figure 4 This is a schematic diagram of the mechanical gripper unit structure;

[0045] Figure 5 This is a schematic diagram of the mechanical gripper unit structure;

[0046] Figure 6 This is a schematic diagram of the landing platform structure;

[0047] Figure 7 This is a schematic diagram of the landing platform structure;

[0048] Figure 8 This is an overall flowchart of the unmanned aerial vehicle battery swapping method for tracked unmanned vehicles described in this invention;

[0049] Figure 9 This is a flowchart of the battery swapping process;

[0050] Figure 10 This is an image processing flowchart based on visual queries of battery level and on / off status. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0053] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0054] Specific Implementation Method 1: The following is combined with... Figures 1 to 7 This embodiment describes a tracked unmanned vehicle for battery swapping of unmanned aerial vehicles (UAVs). The vehicle includes a main body 1, a tracked chassis 2, a navigation and sensing unit 100, a battery swapping operation platform 200, and a master-slave control unit 300. The main body 1 has two symmetrically arranged tracked chassis 2. The navigation and sensing unit 100 is located at the front of the main body 1, and the battery swapping operation platform 200 is located at the middle and rear of the main body 1. The master-slave control unit 300 is embedded inside the main body 1.

[0055] The navigation perception unit 100 is used to perceive the external environment and estimate the pose of the unmanned vehicle; the master-slave control unit 300 performs path planning based on the pose of the unmanned vehicle and the electronic map, and guides the unmanned vehicle to avoid obstacles and navigate to the destination; the battery swapping operation platform 200 includes a cross slide 6, a mechanical gripper unit 7 and a landing platform 8; the cross slide 6 is used to drive the mechanical gripper unit 7 to move along the xyz three axes to the position of the UAV on the landing platform 8, and realize the battery swapping operation of the UAV.

[0056] To adapt to movement in various complex terrains, the tracked chassis 2 of this invention features a large ground contact area, low pressure, strong adhesion to the ground, good traction, and good ground support and driving performance.

[0057] See Figure 1 The navigation perception unit 100 includes a lidar 3, a metal bracket 4, and an inertial measurement unit (IMU) 5. The metal bracket 4 is located at the front of the unmanned vehicle body 1. The lidar 3 is located on the top of the metal bracket 4, and the inertial measurement unit (IMU) 5 is located at the bottom of the metal bracket 4. The external environment data collected by the lidar 3 and the inertial measurement unit (IMU) 5 are sent to the master-slave control unit 300.

[0058] IMU (Inertial Measurement Unit).

[0059] These sensors are fixed to the front of the tracked vehicle chassis by metal brackets 4, and are used by the tracked vehicle to perceive its environment; the perception module is mainly used to perceive the external environment and estimate its own position during the mapping and navigation process of the unmanned vehicle.

[0060] The lidar 3 uses a VLP-16 lidar, and the inertial measurement unit (IMU5) uses a WHEELTEC N100 inertial measurement unit, which includes a three-axis gyroscope, a three-axis accelerometer, a three-axis magnetometer, and a thermometer. It belongs to the nine-axis attitude sensor series.

[0061] See Figure 2 The master-slave control unit 300 includes a PC 8 and an MCU 9. The PC 8 receives external environmental data collected by the lidar 3 and the inertial measurement unit IMU 5. The PC 8 sends navigation and obstacle avoidance commands to the MCU 9 based on the external environmental data. The MCU 9 controls the unmanned vehicle to move towards the destination according to the navigation and obstacle avoidance commands.

[0062] PC 8 acts as the main controller, receiving specific data collected by each sensor, executing the overall process, and sending messages to the slave controllers. MCU 9 acts as the slave controller, subscribing to messages and controlling the operating platform and control modules to achieve corresponding functions.

[0063] The drone motor uses a BLDC motor, providing efficient, smooth, and quiet control for the tracked unmanned vehicle.

[0064] This invention uses a WX-BYD16S-48V70AH battery to provide power for the tracked unmanned vehicle.

[0065] During the actual operation of the battery swapping platform, the lidar 3 and the inertial measurement unit (IMU5) are connected to the PC 8 via network cable and USB cable, respectively.

[0066] See Figure 3 The cross slide 6 includes an x-direction lead screw 6-1, a y-direction lead screw 6-2, a z-direction slide 6-3, a slide rod 6-4, an x-direction stepper motor 6-5, a y-direction stepper motor 6-6, a z-direction stepper motor 6-7, an x-direction limit switch 6-8, a y-direction limit switch 6-9, and a z-direction limit switch 6-10.

[0067] The x-direction lead screw 6-1 is installed on the unmanned vehicle body 1 along the front-rear direction of the vehicle body. The x-direction lead screw 6-1 is equipped with an x-direction stepper motor 6-5 and an x-direction limit switch 6-8.

[0068] The Y-direction lead screw 6-2 is mounted on the unmanned vehicle body 1 along the left and right directions of the vehicle body. The Y-direction lead screw 6-2 is equipped with a Y-direction stepper motor 6-6 and a Y-direction limit switch 6-9.

[0069] The z-direction slide 6-3 is vertically mounted on the x-direction lead screw 6-1. The z-direction slide 6-3 is equipped with a z-direction stepper motor 6-7, a slide rod 6-4, and a z-direction limit switch 6-10. The mechanical gripper unit 7 moves up and down along the slide rod 6-4 under the drive of the z-direction stepper motor 6-7.

[0070] To save space occupied by the drone battery swapping platform as much as possible, the present invention designs a mechanical gripper unit 7 to lock the position between the drone and the landing platform 8. At this time, it is assumed that there is no rotational relationship between the drone and the landing platform 8. The task of inserting and removing the battery can be completed simply by designing the mechanical gripper 7-4 to move along the x, y, and z axes.

[0071] The displacement required for operations such as inserting or removing batteries in the x-direction can be provided by the x-direction lead screw 6-1. Operations such as storing old batteries or replacing new batteries in the y-direction can be provided by the y-direction lead screw 6-2. Operations such as raising and lowering the slider 7-1 to drive the mechanical gripper 7-4 in the z-direction can be provided by the z-direction slide 6-3. The x-direction stepper motor 6-5 and y-direction stepper motor 6-6, which are power sources for the x and y-direction lead screws, are both 57-stepper motors. The z-direction stepper motor 6-7, which is power source for the z-direction slide 6-3, is a 42-stepper motor.

[0072] The movement of the lead screw and slide table in the x, y, and z directions is constrained by a limit switch. When the lead screw or slide table moves to the limit switch, the limit switch can prevent the motor from being damaged due to continuous operation.

[0073] See Figure 4 and Figure 5 The mechanical gripper unit 7 includes a slider 7-1, a constraint box 7-2, a mechanical gripper 7-4, a camera 7-5, a mechanical gripper switch servo 7-6, a battery switch servo 7-7, and a battery limit servo 7-8.

[0074] The slider 7-1 is provided with a vertical sliding hole, and the slider 7-1 moves along the slider 6-4 through the vertical sliding hole;

[0075] The front face of the slider 7-1 is provided with a mechanical gripper switch servo 7-6, a mechanical gripper 7-4, and a constraint box 7-2 from top to bottom. The mechanical gripper switch servo 7-6 is used to control the mechanical gripper 7-4 to clamp or release. A battery switch servo 7-7 is provided on one side of the mechanical gripper 7-4. The battery switch servo 7-7 moves with the mechanical gripper 7-4 and controls the switching operation of the UAV battery through a toggle mechanism.

[0076] The constraint box 7-2 has a front-opening structure. The left and right sides of the constraint box 7-2 are provided with slots 7-3 for engaging the drone battery latches. The constraint box 7-2 is equipped with a camera 7-5, which is used to observe the drone battery and query the battery level based on vision. The lower end face of the constraint box 7-2 is provided with a battery limiting servo 7-8, which drives the limiting mechanism inside the constraint box 7-2 to constrain the battery during the process of pulling out and inserting the battery.

[0077] To ensure that the mechanical gripper 7-4 can effectively hold the battery latch and remove or insert the battery from the drone's battery compartment, a 35kg servo motor 7-6 is selected to drive the mechanical gripper 7-4 for clamping. A 9g servo motor 7-7 is set above the gripper to switch the battery on and off. Below the mechanical gripper 7-4, the present invention uses 3D printing to create a constraint box 7-2 to provide battery support. Below the constraint box 7-2, the present invention adds a 9g servo motor with a limit block as a battery limiting servo 7-8 to constrain the battery during the removal and insertion of the battery.

[0078] During the battery insertion and removal process, camera 7-5 is also needed to confirm that the drone's battery is properly switched on and off and to check the battery level. Camera 7-5 is a CT-LO200 USB2.0 2MP camera used as a sensor to confirm the normal switching of the drone's battery. It is directly connected to PC 8.

[0079] The battery has four power indicator lights. The number of lights roughly indicates the battery level. 1 to 4 lights indicate 25%, 50%, 75%, and 100% battery level, respectively. Camera 7-5 captures images and identifies the number of lights to check the battery level. Furthermore, the standard for judging whether the battery is properly turned off is that all indicator lights are off. After replacing the battery, turning it on will determine whether it is properly turned on, and the standard for judging whether it is properly turned on is that at least 3 lights are on.

[0080] See Figure 6 and Figure 7 The landing platform 8 includes a drone platform 8-1, a guidance mechanism 8-2, a locking servo motor 8-5, and a battery compartment 8-4;

[0081] The drone platform 8-1 is suspended at the rear of the drone body 1. A guide mechanism 8-2 is set on the side of the drone platform 8-1 facing the cross slide 6. The guide mechanism 8-2 is a trapezoidal shallow groove structure. The shallow groove has a strip hole 8-3 at the drone locking position. The locking servo 8-5 is set below the drone platform 8-1. The locking part of the locking servo 8-5 extends through the strip hole 8-3 to lock the drone. A battery compartment 8-4 is set on the lower surface of the drone platform 8-1. The battery compartment 8-4 is open on the side facing the cross slide 6 and is used to store fully charged batteries and batteries to be recharged removed from the drone.

[0082] To ensure that the relative position between the drone and the operating platform remains unchanged under stress after the drone lands, this invention first designs a trapezoidal landing gear for the drone, and designs a guide mechanism 8-2 and a locking mechanism on the landing platform. After the drone lands on the platform, the mechanical gripper 7-4 can push the drone to move. At this time, the drone landing gear is constrained by the guide mechanism 8-2 and will continue to slide until the locking position is locked by the locking mechanism. In this invention, it is assumed that the center point of the mechanical gripper 7-4 is aligned with the center point of the drone battery after fixing, and there is no deviation in the y direction. Next, the locking mechanism controlled by the 9g locking servo 8-5 is opened in a controlled manner, fixing the drone on the landing platform.

[0083] Specific Implementation Method Two: The following is combined with... Figures 8 to 10 This embodiment describes a method for swapping batteries for unmanned aerial vehicles (UAVs) using a tracked UAV, based on the tracked UAV used for battery swapping described in Embodiment 1. The method includes the following steps:

[0084] S1. Initialization: The unmanned vehicle moves around the field and uses the lidar 3 and inertial measurement unit IMU5 to collect external environmental data to estimate the vehicle's pose; PC 8 manually builds a map based on the vehicle's pose and combines it with map services to generate a two-dimensional grid map.

[0085] S2. When performing a task, global and local path planning is performed based on the external environment data collected in real time by the lidar 3 and the inertial measurement unit IMU5 and the two-dimensional high-precision grid map generated by S1. The PC 8 sends the speed command obtained from the path planning to the MCU9 to drive the unmanned vehicle to move towards the destination according to the navigation command.

[0086] S3. Upon arrival at the destination, the battery-swapping drone will land under controlled conditions on landing platform 8.

[0087] S4. The cross slide 6 drives the mechanical gripper unit 7 to move along the xyz three axes to the position of the drone on the landing platform 8, and then the mechanical gripper 7-4 is used to adjust the position of the drone and lock it.

[0088] S5. Turn off the drone battery based on visual query of drone battery level;

[0089] S6 and the cross slide 6 drive the mechanical gripper unit 7 to perform plugging and unplugging operations on the drone battery, realizing the battery swapping of the drone; finally, the battery is turned on and the cross slide 6 returns to its original position.

[0090] See Figure 8The overall system design mainly includes three parts: manual mapping, autonomous navigation, and automatic battery swapping. The key technologies involved in each part are presented. First, the sensors in the perception module estimate the pose of the battery swapping platform. Then, the system combines global and local path planning to complete the motion control of the battery swapping platform. Finally, a set of motor controls, combined with the mechanical design of the actuators and image processing techniques, completes the control of the UAV's battery swapping operation.

[0091] Step S1, manual mapping, employs the graph optimization-based SLAM method—Cartographer. This method uses graph optimization to optimize the map globally, ensuring map consistency. Cartographer's 2D grid map construction receives sensor data from LiDAR 3 and IMU 5. Its core lies in the front-end matching process and the back-end optimization process. In the front-end matching, continuous LiDAR scan data is divided into multiple sub-maps. Specifically, when a mapping node receives new LiDAR scan data, a probabilistic scan matching method is used to obtain the pose of the tracked unmanned vehicle chassis relative to the nearest sub-map. The current LiDAR data is then matched with the sub-map to obtain a complete sub-map. In the back-end optimization, the constraints between multiple sub-maps are handled, and the robot pose is globally optimized. An optimization algorithm minimizes the pose estimation error, improving map accuracy and consistency. Through these front-end matching and back-end optimization methods, a high-precision 2D grid map is finally constructed.

[0092] Step S2 is the autonomous navigation process. After constructing the two-dimensional grid map, this invention uses the move_base navigation package to achieve real-time localization and obstacle avoidance navigation of the tracked unmanned vehicle based on the high-precision map, realizing path planning with minimal cost and avoiding the impact of newly appearing obstacles in the map on the planned path. The localization and navigation of the tracked unmanned vehicle can be divided into three stages: first, localization; then, global path planning; and finally, local path planning. The velocity commands (linear velocity and angular velocity) calculated by the local path planning are sent to the robot's underlying controller to realize the robot's motion control.

[0093] Motion-based navigation typically uses the AMCL algorithm for localization. This algorithm, based on particle filters, calculates and publishes the robot's pose information by subscribing to LiDAR data and map information. Global path planning uses graph search algorithms (such as Dijkstra's or A*) to plan paths on the map. The algorithm calculates an optimal path from the current position to the target position based on obstacle information on the map, the target position, and the robot's dynamic constraints. Local path planning typically uses sampling-based planning algorithms (such as DWA, Dynamic Window Approach). This algorithm considers the robot's dynamic constraints, sensor data, and environmental obstacle information to calculate a smooth local path that reaches the target position. Finally, the local path planning nodes publish velocity information, and the tracked unmanned vehicle chassis controller subscribes to this velocity information to achieve robot motion control.

[0094] To ensure the efficiency and rationality of chassis motion control, considering the actual control process, and based on the distributed structure of the Robot Operating System (ROS), the speed information is first simplified into motion in four directions. When the speed information changes from 45° to 45° to the left front and rear and the speed value is less than 0.15, the motion control is simplified to a single left turn; when the speed information changes from 45° to 45° to the right front and rear and the speed value is less than 0.15, the motion control is simplified to a single right turn; when there is a negative speed and the speed value is greater than -0.15, the motion control is simplified to a single backward movement; when the speed information changes from 45° to the left and right front and the speed value is greater than 0.15, the motion control is simplified to a single forward movement; other situations are considered as stationary. Then, a one-way communication mechanism is established with the Arduino development board of the slave controller using a serial port, and control commands are sent to the Arduino through the pyserial package of Python.

[0095] To ensure the safety of the unmanned vehicle's movement and in conjunction with the control characteristics of the tracked chassis, the obstacle expansion distance in autonomous navigation is set to 0.5 meters, the maximum allowable positional error upon reaching the target position is set to 0.6 meters, and there is no limit to the maximum allowable angular error upon reaching the target position. When the tracked unmanned vehicle is waiting for the drone to land, since the drone is operated by humans, the drone can provide correction for the directional deviation between the drone and the unmanned vehicle landing platform during the landing process.

[0096] Steps S4-S7 constitute the automatic battery swapping process. The entire battery swapping process is divided into the following steps: initialization, adjusting the drone's position, checking the battery level and turning off the battery, removing the battery, replacing the battery, inserting the new battery and turning on the battery, and returning the cross slide to its original position.

[0097] The specific process of step S4 is as follows:

[0098] S101. Return the mechanical gripper unit 7 to its original position via the cross slide 6. Control the x and z directions to return to the limit switch positions in the x and z directions via the x-axis stepper motor 6-5 and the z-axis stepper motor 6-7. Use the position of the slider 7-1 as the position of the mechanical gripper 7-4. At this time, the position is the initial position (x0, z0). The y-axis center of the mechanical gripper 7-4 is aligned with the y-axis center of the UAV battery. Then, reset each servo motor.

[0099] S102. The cross slide 6 is controlled by the x-axis stepper motor 6-5 and the z-axis stepper motor 6-7, so that the slider 7-1 is adjusted from the initial position (x0, z0) to the position (x1, z1) in the x and z directions, so that the center of the mechanical gripper 7-4 in the z direction is aligned with the center of the UAV battery in the z direction. Then the slider 7-1 is moved forward in the positive x direction to the position (x2, z1). During this process, the mechanical gripper 7-4 pushes the UAV so that the UAV enters the locked position under the constraint of the guide mechanism 8-2 of the landing platform. Then the locking servo 8-5 is driven to lock the UAV, so that the UAV is fixedly connected to the landing platform 8.

[0100] The specific process of step S5 is as follows:

[0101] S103. Move the cross slide 6 backward along the x-axis to move the slider 7-1 to the (x3, z1) position, where the (x3, z1) position is the safe operating position;

[0102] S104. Adjust the z-axis height of slider 7-1 to move it to the (x3, z2) position so that the center of mechanical gripper 7-4 is at the same height as the center of the drone battery clip; and clamp the mechanical gripper 7-4 onto the drone battery clip.

[0103] S105. Based on visual query of the drone's battery level, if the battery level is below 50%, it is considered that the battery needs to be replaced and S106 is executed; otherwise, the battery replacement operation is stopped.

[0104] S106. The battery switching servo 7-7, which moves along with the mechanical gripper 7-4, shuts off the drone battery. Specifically, the battery switching servo 7-7 shuts off the battery by operating the power button of the drone battery in a short-press-long-press manner through a toggle mechanism.

[0105] See Figure 10The device utilizes camera 7-5 to visually query the drone's battery level and determine whether the battery is normally on or off. Since the battery swapping platform proposed in this design uses constraint box 7-2 to fix the relative position of the drone and mechanical gripper 7-4, the drone's battery indicator light, observed by camera 7-5 located within constraint box 7-2, is situated in a specific region of the image. Therefore, a region of interest (ROI) is extracted from the image of the drone's battery compartment area for subsequent detection tasks. The acquired ROI image is then binarized, setting the highlighted areas with pixel values ​​greater than 220 to 1 and the remaining pixels to 0. A two-pass scanning method is then used to distinguish different connected regions, marking all 4-neighbor connected components present in the binary image. Subsequently, to improve the detection speed of battery on / off states, the image information in the ROI is converted into a grayscale image with pixel values ​​from 0 to 255. The highlighted areas with pixel values ​​greater than 220 are retained, while the remaining pixels are set to 0, resulting in a binary image of the highlighted areas. After performing connected component analysis on the binary image using the above process, connected regions with more than 200 pixels are retained. The presence or absence of such connected regions determines whether the drone's battery indicator light is currently on or off. Finally, based on this determination, the on / off state of the drone's battery indicator light is recorded from the start of the short-press-long-press operation, and then again at the end of the short-press-long-press operation. Comparing the differences between these two records determines whether the battery has been correctly turned off or on.

[0106] The specific process of step S6 is as follows:

[0107] S107. Battery removal steps;

[0108] First, operate the mechanical gripper switch servo 7-6 to clamp the mechanical gripper 7-4 and press the battery latch to unlock the battery. Then, move the slider 7-1 along the negative x-axis to the position (x5, z2) to remove the drone battery. Operate the mechanical gripper switch servo 7-6 to release the mechanical gripper 7-4 and release the battery. Next, move the slider 7-1 along the positive z-axis to the position (x5, z3) to align the constraint box 7-2 with the battery. Then, move the slider 7-1 along the positive x-axis to the position (x6, z3) to allow the battery to enter the constraint box 7-2. At this time, the battery latch engages with the side latch 7-3 of the constraint box 7-2. Operate the battery limiting servo 7-8 below the constraint box 7-2 to hold the battery latch with the limiting block and lock the battery in the constraint box 7-2. Finally, move the slider 7-1 along the negative x-axis to the position (x3, z3), and the battery will fall out of the drone through the constraint box 7-2. At this time, the battery is completely removed.

[0109] S108. Battery replacement procedure;

[0110] Lower slider 7-1 so that constraint box 7-2 is aligned with empty battery compartment 8-4. Operate battery limit servo 7-8 to release the old battery in constraint box 7-2 and place it in empty battery compartment 8-4. Then use mechanical gripper 7-4 to take a fully charged new battery from other battery compartment 8-4 and put it into constraint box 7-2, and restore slider 7-1 to position (x3, z3).

[0111] S109. Steps for installing a new battery:

[0112] The process begins by moving slider 7-1 along the positive x-axis to the position (x6, z3) to insert the new battery into the drone's battery compartment, and then operating the battery limiting servo 7-8 to release the battery. Next, slider 7-1 is moved backward along the negative x-axis to the position (x3, z3) to ensure that the constraint box 7-2 is completely separated from the new battery. Then, slider 7-1 is moved along the negative z-axis to the position (x3, z1) to align the center of the mechanical gripper 7-4 with the center of the new battery at the same height. Finally, slider 7-1 is moved again along the positive x-axis to the position (x2, z1). Use the mechanical gripper 7-4 to push the new battery into the drone's battery compartment and lock it in place. Next, move the slider 7-1 along the negative x-axis to the position (x3, z1), and then move it along the positive z-axis to the position (x3, z2), so that the center of the mechanical gripper 7-4 is at the same height as the center of the new battery's locking mechanism. Then, move the slider 7-1 along the positive x-axis to the position (x4, z2), and operate the battery switch servo 7-7 to turn on the battery's power button by short-pressing and then long-pressing. Finally, use the camera 7-5 to visually confirm that the new battery is turned on correctly.

[0113] Finally, return the cross slide to its original position. Operate slider 7-1 back to the (x0, z0) position, and operate drone locking servo 8-5 to unlock the connection between the drone and landing platform 8, then wait for the drone to take off.

[0114] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A tracked unmanned vehicle for battery swapping of unmanned aerial vehicles, characterized in that, It includes an unmanned vehicle body (1), a tracked chassis (2), a navigation and sensing unit (100), a battery swapping operation platform (200), and a master-slave control unit (300); the unmanned vehicle body (1) is symmetrically equipped with two tracked chassis (2); the unmanned vehicle body (1) is equipped with a navigation and sensing unit (100) at the front, and the unmanned vehicle body (1) is equipped with a battery swapping operation platform (200) at the middle and rear, and the unmanned vehicle body (1) is embedded with a master-slave control unit (300); The navigation perception unit (100) is used to perceive the external environment to realize the pose estimation of the unmanned vehicle; the master-slave control unit (300) performs path planning based on the pose of the unmanned vehicle and the electronic map, and guides the unmanned vehicle to avoid obstacles and navigate to the destination; the battery swapping operation platform (200) includes a cross slide (6), a mechanical gripper unit (7) and a landing platform (8); the cross slide (6) is used to drive the mechanical gripper unit (7) to move along the xyz three axes to the position of the UAV on the landing platform (8) and realize the battery swapping operation of the UAV; The cross slide (6) includes an x-direction lead screw (6-1), a y-direction lead screw (6-2), a z-direction slide (6-3), a slide rod (6-4), an x-direction stepper motor (6-5), a y-direction stepper motor (6-6), a z-direction stepper motor (6-7), an x-direction limit switch (6-8), a y-direction limit switch (6-9), and a z-direction limit switch (6-10). The x-direction lead screw (6-1) is installed on the unmanned vehicle body (1) along the front-rear direction of the vehicle body. The x-direction lead screw (6-1) is equipped with an x-direction stepper motor (6-5) and an x-direction limit switch (6-8). The y-direction lead screw (6-2) is set on the unmanned vehicle body (1) along the left and right directions of the vehicle body. The y-direction lead screw (6-2) is equipped with a y-direction stepper motor (6-6) and a y-direction limit switch (6-9). The z-direction slide (6-3) is vertically mounted on the x-direction lead screw (6-1). The z-direction slide (6-3) is equipped with a z-direction stepper motor (6-7), a slide rod (6-4), and a z-direction limit switch (6-10). The mechanical gripper unit (7) moves up and down along the slide rod (6-4) under the drive of the z-direction stepper motor (6-7). The mechanical gripper unit (7) includes a slider (7-1), a constraint box (7-2), a mechanical gripper (7-4), a camera (7-5), a mechanical gripper switch servo (7-6), a battery switch servo (7-7), and a battery limit servo (7-8). The slider (7-1) is provided with a vertical sliding hole, and the slider (7-1) moves along the slider (6-4) through the vertical sliding hole; The front face of the slider (7-1) is provided with a mechanical gripper switch servo (7-6), a mechanical gripper (7-4), and a constraint box (7-2) from top to bottom. The mechanical gripper switch servo (7-6) is used to control the mechanical gripper (7-4) to clamp or release. A battery switch servo (7-7) is provided on one side of the mechanical gripper (7-4). The battery switch servo (7-7) moves with the mechanical gripper (7-4). The battery switch servo (7-7) switches the UAV battery on and off through a toggle mechanism. The constraint box (7-2) has a front-opening structure. The left and right sides of the constraint box (7-2) are provided with slots (7-3) for attaching the drone battery clips. The constraint box (7-2) is equipped with a camera (7-5) inside. The camera (7-5) is used to observe the drone battery and query the battery level based on vision. The lower end face of the constraint box (7-2) is provided with a battery limiting servo (7-8). The battery limiting servo (7-8) constrains the battery by driving the limiting mechanism inside the constraint box (7-2) during the process of pulling out and inserting the battery.

2. The tracked unmanned vehicle for battery swapping of unmanned aerial vehicles according to claim 1, characterized in that, The navigation perception unit (100) includes a lidar (3), a metal bracket (4) and an inertial measurement unit (IMU) (5). The metal bracket (4) is located at the front of the unmanned vehicle body (1). The lidar (3) is located on the top of the metal bracket (4) and the inertial measurement unit (IMU) (5) is located at the bottom of the metal bracket (4). The external environment data collected by the lidar (3) and the inertial measurement unit (IMU) (5) are sent to the master-slave control unit (300).

3. The tracked unmanned vehicle for battery swapping of unmanned aerial vehicles according to claim 2, characterized in that, The master-slave control unit (300) includes a PC and an MCU (9). The PC receives external environmental data collected by the lidar (3) and the inertial measurement unit (IMU) (5). The PC sends navigation and obstacle avoidance instructions to the MCU (9) based on the external environmental data. The MCU (9) controls the unmanned vehicle to move towards the destination according to the navigation and obstacle avoidance instructions.

4. The tracked unmanned vehicle for battery swapping of unmanned aerial vehicles according to claim 3, characterized in that, The landing platform (8) includes a drone platform (8-1), a guidance mechanism (8-2), a locking servo motor (8-5), and a battery compartment (8-4). The UAV platform (8-1) is suspended at the rear of the UAV body (1). The UAV platform (8-1) is equipped with a guide mechanism (8-2) on the side facing the cross slide (6). The guide mechanism (8-2) is a trapezoidal shallow groove structure. The shallow groove is provided with a strip hole (8-3) at the UAV locking position. The locking servo (8-5) is located below the UAV platform (8-1). The locking part of the locking servo (8-5) extends through the strip hole (8-3) to lock the UAV. The lower surface of the UAV platform (8-1) is provided with a battery compartment (8-4). The battery compartment (8-4) is open on the side facing the cross slide (6) and is used to store fully charged batteries and batteries to be recharged removed from the UAV.

5. A method for swapping unmanned aerial vehicle (UAV) batteries using a tracked unmanned vehicle, implemented based on the tracked unmanned vehicle for UAV battery swapping as described in claim 4, characterized in that... The method includes the following steps: S1. Initialize the unmanned vehicle to move around the field and use the lidar (3) and inertial measurement unit (IMU) (5) to collect external environmental data to estimate the position and pose of the unmanned vehicle; the PC manually builds a map based on the position and pose of the unmanned vehicle and in combination with map services to generate a two-dimensional grid map. S2. When performing a task, global and local path planning is carried out based on the external environment data collected in real time by the lidar (3) and the inertial measurement unit (IMU) (5) and the two-dimensional high-precision grid map generated by S1. The PC sends the speed command obtained from the path planning to the MCU (9) to drive the unmanned vehicle to move towards the destination according to the navigation command. S3. After arriving at the destination, the battery-swapping drone will land in a controlled manner on the landing platform (8); S4. The cross slide (6) drives the mechanical gripper unit (7) to move along the xyz three axes to the position of the UAV on the landing platform (8), and then the mechanical gripper (7-4) adjusts and locks the position of the UAV. S5. Turn off the drone battery based on visual query of drone battery level; S6, the cross slide (6) drives the mechanical gripper unit (7) to perform plug-in / plug-out operations on the drone battery to achieve battery swapping for the drone; finally, the battery is turned on and the cross slide (6) returns to its original position.

6. The method for battery swapping of a tracked unmanned vehicle according to claim 5, characterized in that, The specific process of step S4 is as follows: S101. Return the mechanical gripper unit (7) to its original position via the cross slide (6). Control the x and z directions to return to the limit switch positions in the x and z directions via the x-axis stepper motor (6-5) and z-axis stepper motor (6-7). Use the position of the slider (7-1) as the position of the mechanical gripper (7-4). The position at this time is the initial position (x0, z0). The y-axis center of the mechanical gripper (7-4) is aligned with the y-axis center of the UAV battery. Then reset each servo motor. S102. Control the cross slide (6) through the x-axis stepper motor (6-5) and the z-axis stepper motor (6-7) to adjust the slider (7-1) from the initial position (x0, z0) to the position (x1, z1) in the x and z directions, so that the center of the mechanical gripper (7-4) in the z direction is aligned with the center of the UAV battery in the z direction. Then move the slider (7-1) forward in the positive x direction to the position (x2, z1). During this process, the mechanical gripper (7-4) pushes the UAV to enter the locked position under the constraint of the guide mechanism (8-2) of the landing platform. Then drive the locking servo (8-5) to lock the UAV, so that the UAV is fixedly connected to the landing platform (8).

7. The method for battery swapping of a tracked unmanned vehicle according to claim 6, characterized in that, The specific process of step S5 is as follows: S103. Move the cross slide (6) backward along the x-axis to move the slider (7-1) to the (x3, z1) position, where the (x3, z1) position is the safe operating position; S104. Adjust the z-axis height of the slider (7-1) to move it to the (x3, z2) position so that the center of the mechanical gripper (7-4) is at the same height as the center of the drone battery clip; and clamp the mechanical gripper (7-4) onto the drone battery clip. S105. Based on visual query of the drone's battery level, if the battery level is below 50%, it is considered that the battery needs to be replaced and S106 is executed; otherwise, the battery replacement operation is stopped. S106. The battery switch servo (7-7), which moves along with the mechanical gripper (7-4), shuts off the drone battery. Specifically, the battery switch servo (7-7) shuts off the battery by operating the power button of the drone battery in a short-press-long-press manner through a toggle mechanism.

8. The method for battery swapping of a tracked unmanned vehicle according to claim 7, characterized in that, The specific process of step S6 is as follows: S107. Battery removal steps; First, operate the mechanical gripper switch servo (7-6) to tighten the mechanical gripper (7-4) and press the battery latch to unlock the battery; then move the slider (7-1) along the negative x-axis to the (x5, z2) position to remove the drone battery, operate the mechanical gripper switch servo (7-6) to release the mechanical gripper (7-4) and release the battery; next, move the slider (7-1) along the positive z-axis to the (x5, z3) position to align the constraint box (7-2) with the battery; then move the slider (7-1) along the positive x-axis... Move the battery from position -1 to (x6, z3) so that it enters the constraint box (7-2). At this time, the battery clip engages with the side slot (7-3) of the constraint box (7-2). Operate the battery limiting servo (7-8) below the constraint box (7-2) to hold the battery clip through the limiting block and lock the battery in the constraint box (7-2). Finally, move the slider (7-1) along the negative x-axis to position (x3, z3). The battery will be pulled out of the UAV through the constraint box (7-2). At this time, the battery is completely removed. S108. Battery replacement procedure; Lower slider (7-1) to align constraint box (7-2) with empty battery compartment (8-4). Operate battery limit servo (7-8) to release the old battery from constraint box (7-2) and place it in empty battery compartment (8-4). Then, use mechanical gripper (7-4) to take a fully charged new battery from other battery compartment (8-4) and put it into constraint box (7-2), and restore slider (7-1) to position (x3, z3). S109. Steps for installing a new battery: The process begins by moving slider (7-1) along the positive x-axis to position (x6, z3) to insert the new battery into the drone's battery compartment, and then operating the battery limiting servo (7-8) to release the battery. Next, slider (7-1) is moved backward along the negative x-axis to position (x3, z3) to ensure the constraint box (7-2) is completely separated from the new battery. Then, slider (7-1) is moved along the negative z-axis to position (x3, z1) to align the center of the mechanical gripper (7-4) with the center of the new battery at the same height. Finally, slider (7-1) is moved along the positive x-axis to position (x2, z1). The new battery is pushed into the drone's battery compartment and locked in place using the mechanical gripper (7-4). Next, the slider (7-1) is moved to the position (x3, z1) along the negative x-axis, and then moved to the position (x3, z2) along the positive z-axis, so that the center of the mechanical gripper (7-4) is at the same height as the center of the new battery latch. Then, the slider (7-1) is moved to the position (x4, z2) along the positive x-axis, and the battery switch servo (7-7) is operated to turn on the battery power button by short-pressing and long-pressing. Finally, the camera (7-5) is used to visually confirm that the new battery is turned on normally.

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