An unmanned vehicle automatic charging device based on UWB and visual fusion positioning

Abstract

The utility model discloses an unmanned vehicle automatic charging device based on UWB and vision fusion positioning belongs to automatic driving technical field. The device includes pile end system and car end system, and the pile end system contains UWB positioning module, visual mark and wireless charging transmitting end, and the car end system contains UWB base station, visual positioning module and wireless charging receiving end. UWB system realizes long-distance rough positioning guide, and visual system realizes close-range accurate positioning docking, and the fusion of both constitutes the far, middle and near whole process positioning chain, ensures that unmanned vehicle accurate parking, makes wireless charging transmitting end and receiving end in 2cm to 4cm efficient interval face each other, and then starts wireless charging. The utility model solves the problem of insufficient reliability and precision of single sensor positioning in complex environment, improves the success rate of pile and system robustness, realizes automatic charging whole process seamless connection, and is suitable for automatic driving scooter, logistics unmanned vehicle, warehousing AGV etc. scene.

Description

Technical Field

[0001] This utility model belongs to the field of autonomous driving technology, specifically relating to a device for achieving precise docking and wireless charging of unmanned vehicles. It can be widely used in scenarios requiring precise docking and charging, such as logistics unmanned vehicles, warehouse AGVs, and service robots. Background Technology

[0002] With the increasing application of autonomous vehicles in logistics, warehousing, industry, and services, the demand for automatic charging is also increasing significantly. Achieving precise and stable docking between autonomous vehicles and charging stations is a key technological aspect to ensure the continuous and efficient operation of these vehicles. Currently, common positioning methods each have their own shortcomings. GPS positioning is prone to signal attenuation indoors or in environments with multiple obstructions, resulting in large positioning errors and failing to meet the centimeter-level docking requirements of unmanned vehicles. Visual recognition solutions cannot achieve positioning outside the field of view, and the sensing distance is greatly limited by light intensity, the size and clarity of the marker, and environmental factors such as obstruction, making the recognition rate unstable and unreliable. Near-field communication technologies such as Bluetooth, Wi-Fi, and UWB are greatly affected by multipath effects and electromagnetic interference, and their positioning accuracy is usually only at the meter level, making it difficult to support precise docking operations. Furthermore, these near-field communication technologies mostly require more than three base stations, resulting in high costs.

[0003] Therefore, existing single-sensor positioning solutions cannot balance positioning accuracy and stability in complex environments, making it difficult to meet the full-scenario requirements of autonomous vehicle automatic charging. Thus, it is necessary to provide a device that combines the dual advantages of UWB technology's strong anti-interference capability and visual technology's high precision, enabling reliable operation of the entire process from far-field coarse guidance to near-field fine alignment and finally automatic charging. Utility Model Content

[0004] This invention aims to solve the problems of insufficient reliability and inability to achieve both high accuracy and low reliability of single-sensor positioning in complex environments during the charging process of unmanned vehicles. It provides an automatic charging device for unmanned vehicles based on UWB and vision fusion positioning. By complementing the advantages of the two technologies, it achieves precise guidance and efficient connection of the entire charging process of unmanned vehicles.

[0005] This utility model is achieved through the following technical solution: An automatic charging device for unmanned vehicles based on UWB and vision fusion positioning includes two parts: a charging station system and a vehicle-side system. The specific structure and functions are as follows: The charging station system is installed on the charging station and includes a UWB positioning module, visual identifiers, and a wireless charging transmitter. The UWB positioning module is used to transmit UWB signals with identity and location information to achieve long-distance coarse positioning guidance for the autonomous vehicle; the visual identifiers are used to provide a precise identification reference when the autonomous vehicle approaches at close range; and the wireless charging transmitter is used to transmit power to the autonomous vehicle through electromagnetic induction after the vehicle is accurately aligned. Only two UWB positioning modules are needed. Each module consists of a UWB signal transmitting unit, an encoding processing unit, a low-power control unit, and a metal casing. The casing has a protection rating of at least IP54. The casing and mounting bracket are installed on the top or side of the charging pile and secured with bolts, at a height of 1.5 to 2 meters above the ground. This installation position effectively avoids obstruction and collisions. The relative distance between the two base stations should be greater than 10 cm, and the relative positional deviation should be less than 5 mm. The UWB positioning module incorporates relevant dedicated algorithms, enabling precise positioning of the vehicle's attitude.

[0006] The vehicle-mounted system, installed on the autonomous vehicle, includes a UWB base station, a visual positioning module, and a wireless charging receiver. The UWB base station receives signals from the UWB positioning module for long-range positioning; the visual positioning module identifies visual markers on the charging station at close range for precise positioning and docking; and the wireless charging receiver receives power from the wireless charging transmitter to charge the autonomous vehicle's battery.

[0007] The UWB base station consists of a high-sensitivity receiving unit, a signal analysis unit, a filtering circuit, and a data transmission interface. It is installed on the top center of the unmanned vehicle via a dedicated bracket and is connected to the vehicle control system via CAN bus or Ethernet. It features vibration-resistant and electromagnetic shielding design and can adapt to the complex environment during the unmanned vehicle's operation. The visual positioning module includes a high-definition vehicle-mounted camera, installed near the charging port of the autonomous vehicle. The camera's viewpoint is directly in front of the vehicle, used to identify pre-set visual markers on the charging station. The visual marker is a QR code label pattern affixed near the wireless charging transmitter of the charging station, with a size of no less than 10cm by 10cm. It maintains a fixed relative position with the center of the wireless charging transmitter to ensure accurate location of the charging transmitter after recognition. The wireless charging transmitter is integrated inside or on the surface of the charging pile, and the positional relationship between the center of its transmitting coil and the visual marker is precisely calibrated. The wireless charging receiver is integrated into the docking area of ​​the autonomous vehicle chassis, and the position of its receiving coil is fixed with the vehicle's own positioning reference point. With this design, when the autonomous vehicle stops at the predetermined final position, the vertical distance between the on-board wireless charging receiver and the wireless charging transmitter at the charging pile can fall within the efficient energy transmission range of 2cm to 4cm, ensuring proper coil alignment and guaranteeing charging efficiency. The UWB positioning module communicates with the UWB base station via nanosecond-level narrow-pulse UWB signals, achieving an effective identification distance of at least 30 meters, a positioning accuracy exceeding 5 centimeters, and good penetration and multipath interference resistance. The UWB base station and its built-in multi-antenna array measure the vehicle's signal angle of arrival (TOA) and distance, combining distance and direction information to calculate the relative pose of the charging pile. Combined with dedicated algorithms, this allows for the calculation of the relative pose between the vehicle and the charging pile, achieving spatial three-dimensional positioning. The dedicated algorithms refer to a series of signal processing and position calculation methods designed specifically for the characteristics of UWB signals and the multi-antenna array hardware. These algorithms achieve high-precision spatial three-dimensional positioning of the vehicle and the charging pile by fusing distance (TOA / TDOA) and angle (AOA) information, combined with geometric calculations and dynamic filtering. As the autonomous vehicle approaches the charging station, it employs a tiered positioning and guidance strategy. First, the UWB system performs remote coarse positioning and guidance. Once the vehicle enters the effective recognition range of the vision system, it switches to vision-based positioning for final fine alignment. After fine alignment and stabilization in the final position, the wireless charging process is automatically initiated, completing a seamless transition from positioning to charging.

[0008] In summary, this utility model has the following beneficial effects: This invention achieves stable long-distance, coarse-precision perception and positioning unaffected by light and obstruction using UWB technology, reliably guiding vehicles into the visual recognition area and avoiding the problem of single visual positioning being easily affected by environmental interference at long distances. It also achieves millimeter-level high-precision positioning at close range using visual technology, overcoming the relative shortcomings of UWB in terms of blind spots and errors at close range. The two technologies complement each other. This integrated positioning method forms a positioning guidance chain covering the entire process from far to medium to near. It can ensure the stability and accuracy of positioning in complex obstructed environments or in scenarios with changing lighting, significantly improving the success rate of stakeout and the robustness of the system. Meanwhile, through the fusion positioning of UWB and vision, the vehicle can be directly controlled to park in a precise position, ensuring efficient alignment and appropriate spacing of the wireless charging coil without additional manual adjustment. This achieves seamless connection of the entire process of automatic charging for unmanned vehicles, improving the automation level and ease of use of unmanned vehicle operation. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the overall system structure and signal interaction of this utility model; Figure 2 Installation diagram of UWB positioning module, visual signage and wireless charging transmitter; Figure 3 A schematic diagram showing the installation locations of the UWB base station, visual positioning module, and wireless charging receiver for the unmanned vehicle. Figure 4 A schematic diagram of the hierarchical guidance process and control state switching for the entire process of wireless charging of unmanned vehicles; Figure 5 A schematic diagram illustrating the control logic and data interaction throughout the entire process of starting, running, and stopping a wireless charging system.

[0010] Reference numerals: 11, UWB base station; 21, visual positioning module; 31, wireless charging receiver; 12, UWB positioning module; 22, visual sign; 32, wireless charging transmitter. Detailed Implementation

[0011] The present invention will be further described in detail below with reference to the accompanying drawings.

[0012] As shown in Figure 1, the device of this utility model mainly includes a pile-end system and a vehicle-end system. The pile-end system consists of a UWB positioning module 12, a visual identifier 22, and a wireless charging transmitter 32; the vehicle-end system consists of a UWB base station 11, a visual positioning module 21, and a wireless charging receiver 31. The UWB system is responsible for initial positioning and guidance at medium and long distances, the visual system is responsible for final accurate positioning at close range, and the wireless charging system is responsible for power transmission after accurate alignment. The various systems work together to achieve automatic charging of the unmanned vehicle. As shown in Figure 2, the UWB positioning module 12 is fixed to the upper side of the charging pile, 1.8 meters above the ground. The distance between two UWB positioning modules 12 is 20cm. They are connected to the charging pile housing with bolts. The metal housing effectively protects against external impacts, dust, and rain. The visual identifier 22 is a QR code label, tightly affixed to the front of the charging pile. The horizontal distance between its center and the center of the wireless charging transmitter coil is 5cm, and the vertical distance is 3cm. This relative position is accurately measured using a laser rangefinder during installation and recorded into the vehicle control system. The wireless charging transmitter 32 panel is exposed on the surface of the charging pile, with no metal obstructions around it, ensuring efficient electromagnetic induction transmission. As shown in Figure 3, the UWB base station 11 is installed on the top center of the unmanned vehicle using a dedicated metal bracket. The bracket is 20cm high to ensure unobstructed UWB signal reception. The visual positioning module 21 uses an industrial-grade high-definition camera, installed 10cm to the left of the charging port at the front of the unmanned vehicle. The camera lens is horizontally facing forward with a field of view of 60 degrees to ensure stable capture of the visual marker 22 when the vehicle approaches the charging pile. The wireless charging receiver 31 is integrated into the docking area on the upper part of the unmanned vehicle chassis and is covered with a plastic protective cover. The relative position of the center of the receiving coil and the center point of the rear wheel axle of the unmanned vehicle is fixed. During installation, it is adjusted using a calibration tool to ensure that the receiving coil and the transmitting coil are aligned when the vehicle is parked in its final position. The hierarchical guidance and execution process for the entire wireless charging process of autonomous vehicles is as follows: Figure 4 As shown, it is divided into four stages: The first stage is remote charging station search. When the distance between the unmanned vehicle and the charging station is greater than 10 meters, the unmanned vehicle travels at a normal speed of 1 m / s and obtains coarse positioning information by relying solely on the UWB positioning module 12 signal received by the UWB base station 11. The vehicle control system performs global path planning based on this information and guides the vehicle to travel towards the charging station. The second stage is the mid-range approach. When the distance between the autonomous vehicle and the charging pile is within 5 to 10 meters, the vehicle control system reduces the vehicle speed to 0.5 m / s, integrates the UWB positioning data with the environmental perception data collected by the vehicle's lidar, corrects the driving path in real time, and initially aligns the vehicle with the charging pile. The visual marker 22 is also included in the field of view of the camera of the visual positioning module 12, preparing for subsequent visual recognition.

[0013] The third stage is precise docking. When the distance between the autonomous vehicle and the charging pile is less than 5 meters, the visual positioning module 21 is activated, beginning to identify and analyze the visual markers 22 to obtain the precise pose of the charging port relative to the vehicle, including lateral and angular deviations. The onboard control system integrates the absolute position information provided by UWB and the relative pose information provided by vision, controlling the vehicle to perform final pose fine-tuning at an extremely low speed of 0.1 m / s until the vehicle accurately stops at the predetermined final docking position. At this time, the wireless charging receiver 31 and the wireless charging transmitter 32 are directly opposite each other, with a vertical distance of 3 cm between them, which is within the efficient energy transmission range of 2 cm to 4 cm.

[0014] The fourth stage is wireless charging, the process is as follows: Figure 5 As shown. After the vehicle comes to a complete stop and reaches a precise relative position, the onboard control system sends a charging request signal to the charging pile controller. This signal includes parameters such as vehicle identity, current battery level, and battery capacity. Upon receiving the request signal, the charging pile controller verifies the vehicle's identity and, if successful, replies with a signal indicating successful handshake and readiness. Upon receiving the ready signal, the vehicle's battery management system enters the charging preparation state and reports the completion of preparation to the onboard control system. The onboard control system sends a charging start command to the charging station controller, which instructs the wireless charging transmitter to start power output, establishing a high-frequency alternating electromagnetic field between the transmitter coil and the receiver coil to achieve power transfer. During charging, the wireless charging receiver 31 collects charging data in real time, including charging voltage, charging current, and coil temperature, and feeds this data back to the battery management system. Based on the battery's current charging status, such as charging progress and battery temperature, the battery management system sends a request to the charging station controller to dynamically adjust the power output. The charging station controller then adjusts the transmitter's power output in real time according to the request, forming a closed-loop control system to ensure safe and efficient charging. When the battery management system detects that the battery has reached full charge, or detects an abnormality such as excessive coil temperature, it sends a stop charging signal to the vehicle control system. The vehicle control system then sends a stop charging command to the charging station controller, which immediately cuts off the power output of the transmitter, ending the wireless charging process.

[0015] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An unmanned vehicle automatic charging device based on UWB and visual fusion positioning, characterized in that, It includes a charging station-end system and a vehicle-end system installed on the autonomous vehicle; the charging station-end system includes a UWB positioning module, visual markers, and a wireless charging transmitter; the vehicle-end system includes a UWB base station, a visual positioning module, and a wireless charging receiver; the UWB positioning module is used to transmit UWB signals with identity and location information to achieve long-distance coarse positioning guidance; the visual positioning module is used to identify visual markers at close range to achieve precise positioning and docking; the wireless charging transmitter and wireless charging receiver charge the autonomous vehicle through electromagnetic induction after the vehicle is accurately aligned.

2. The unmanned vehicle automatic charging device based on UWB and vision fusion positioning according to claim 1, characterized in that, The UWB positioning module consists of two sets, each including a UWB signal transmitting unit, an encoding processing unit, a low-power control unit, and a metal casing. The casing and the fixing bracket are installed on the top or side of the charging pile.

3. The unmanned vehicle automatic charging device based on UWB and visual fusion positioning according to claim 1, characterized in that, The UWB base station includes a high-sensitivity receiving unit, a signal analysis unit, a filtering circuit, and a data transmission interface. It is installed on the center of the top of the unmanned vehicle using a dedicated bracket and is connected to the vehicle control system via a CAN bus or Ethernet.

4. The unmanned vehicle automatic charging device based on UWB and visual fusion positioning according to claim 1, characterized in that, The visual positioning module includes a high-definition vehicle-mounted camera with its viewpoint pointing directly in front of the vehicle.

5. The unmanned vehicle automatic charging device based on UWB and vision fusion positioning according to claim 1, characterized in that, The visual identifier is a QR code label affixed near the wireless charging transmitter of the charging station, with a fixed relative position to the center of the wireless charging transmitter.

6. The unmanned vehicle automatic charging device based on UWB and vision fusion positioning according to claim 1, characterized in that, The wireless charging transmitter is integrated inside or on the surface of the charging pile, and the positional relationship between the center of the transmitting coil of the wireless charging transmitter and the visual marker is precisely calibrated; the wireless charging receiver is integrated into the docking area of ​​the unmanned vehicle chassis, and the position of the receiving coil of the wireless charging receiver is fixed with the vehicle's own positioning reference point.

7. The unmanned vehicle automatic charging device based on UWB and vision fusion positioning according to claim 1, characterized in that, By using UWB and vision fusion positioning control, the unmanned vehicle is parked at the predetermined final position, so that the vertical distance between the on-board wireless charging receiver and the wireless charging transmitter at the charging station falls into the high-efficiency energy transmission range, and the coils are aligned.

8. The unmanned vehicle automatic charging device based on UWB and visual fusion positioning according to claim 1, characterized in that, The UWB positioning module communicates with the UWB base station via nanosecond-level narrow pulse UWB signals.

9. The unmanned vehicle automatic charging device based on UWB and visual fusion positioning according to claim 1, characterized in that, UWB base stations and their built-in multi-antenna arrays measure the angle of arrival and distance of signals at the vehicle end, and calculate the relative pose of the vehicle and the charging pile to achieve spatial three-dimensional positioning.

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