A multi-agv real-time synchronization method and system under low frequency communication

Abstract

This invention discloses a method for real-time synchronization of multiple AGVs under low-frequency communication, comprising: constructing a data structure containing AGV numbers, positions, and rotation angles; recording the time and initializing the AGV object upon initial data reception; calculating the time interval, movement distance, and real-time speed upon subsequent data receptions; smoothly updating the AGVs within the interval between two data receptions using frame-by-frame interpolation, wherein the displacement step size is the smaller of the product of the real-time speed and the frame interval and the remaining distance to the target point, while simultaneously using rotation interpolation to smoothly update the AGV orientation; repeating the above process for subsequent received data. This invention solves the problems of AGV state jumps, motion distortion, and poor visual continuity under low-frequency communication conditions, achieving continuous, accurate, and smooth multi-AGV motion trajectories on the digital twin without increasing communication bandwidth, significantly improving the system's synchronization accuracy and user experience.

Description

Technical Field

[0001] This invention relates to the field of digital twin technology, specifically to a method and system for real-time synchronization of multiple AGVs under low-frequency communication. Background Technology

[0002] With the rapid development of intelligent manufacturing and flexible logistics systems, the collaborative operation of multiple automated guided vehicles (AGVs) is increasingly widely used in warehousing, production lines, and other scenarios. Digital twin technology provides an efficient platform for the scheduling, monitoring, and collaboration of multiple AGVs by constructing a virtual mapping of the physical AGV system. Its core relies on real-time and accurate state synchronization between the AGVs and the twin system. However, in complex electromagnetic environments, limited network resources, or specific communication protocol limitations in industrial settings, communication between the AGVs and the digital twin platform often suffers from low frequency and unstable latency. This makes it difficult for the twin system to obtain continuous and accurate real-time operating status, resulting in significant deviations between the virtual model and the physical entity, affecting the accuracy of scheduling decisions and the collaborative efficiency of the system.

[0003] Currently, for high-frequency communication scenarios, periodic reporting or event-triggered mechanisms are typically used to achieve synchronization. However, under low-frequency communication conditions, existing methods are prone to problems such as data update lag, state jumps, or motion distortion, making it difficult to guarantee the continuity and synchronization accuracy of the operation of multiple AGVs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for real-time synchronization of multiple AGVs under low-frequency communication to address the shortcomings of the prior art. This method can solve the problems of AGV state jumps, motion distortion and poor visual continuity under low-frequency communication in the prior art.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for real-time synchronization of multiple AGVs under low-frequency communication is provided, applied to a digital twin platform, comprising the following steps: S1. Construct an AGV data structure, including AGV number, AGV position, and AGV rotation angle; S2. When the digital twin platform receives data reported by any AGV through low-frequency communication for the first time, it records the data arrival time, initializes the corresponding AGV object, and assigns values ​​to its position and rotation angle according to the received data. S3. When the digital twin platform receives data reported by the same AGV via low-frequency communication for the next time, record the arrival time of this data and calculate the time difference with the previous data; obtain the current position of the AGV according to the AGV number, and calculate the moving distance in combination with the initial position of the AGV; calculate the real-time speed of the AGV based on the moving distance and the time difference. S4. Set the time accumulation variable to an initial value of zero, and perform interpolation updates cyclically as long as the time accumulation variable is less than the time difference: increment by a fixed time interval in each frame, calculate the normalized direction vector from the current position to the target position, and take the smaller value between the product of the real-time speed and the fixed time interval and the remaining distance from the current position to the target position as the displacement step size; update the position of the AGV to the current position plus the product of the normalized direction vector and the displacement step size; at the same time, use a rotation interpolation method to smoothly update the orientation of the AGV. S5. For each subsequent data received by the AGV, repeat steps S3 and S4; independently perform data reception, motion parameter calculation and interpolation update operations on the remaining AGV data structures to achieve real-time smooth synchronization and visual coherent update of the motion states of multiple AGVs in the digital twin platform.

[0006] In the above scheme, step S4, during the cyclic interpolation update process, also includes an exit condition judgment: When the remaining distance is less than the preset distance threshold, and the difference between the current AGV's orientation angle and the target rotation angle is less than the preset angle threshold, the AGV's position and rotation angle are directly set to the target value, and the loop is exited.

[0007] In the above scheme, the preset distance threshold is 0.1 length units.

[0008] In the above scheme, the preset angle threshold is 5 degrees.

[0009] In the above scheme, step S5 includes: For subsequent AGV data with the same AGV number, steps S3 and S4 above are repeated; wherein, the data reported by the AGVs through low-frequency communication received by the digital twin platform is a set of data packets, which contain real-time status information of multiple AGVs. The digital twin platform traverses the data packets and performs motion parameter calculation and interpolation update operations for the corresponding AGV according to each AGV number, thereby realizing real-time smooth synchronization and visual coherent update of the motion status of multiple AGVs in the digital twin platform.

[0010] In the above scheme, step S4, the rotation interpolation method includes: Based on the difference between the current angle and the target angle, interpolation is used for a smooth transition; where the difference is the angle interpolation.

[0011] In the above scheme, the fixed time interval is set according to the rendering frame rate of the digital twin scene to ensure visual smoothness between adjacent interpolations.

[0012] In the above scheme, the low-frequency communication is a communication frequency of 2-4 seconds per communication.

[0013] In the above scheme, the method for calculating the real-time speed in step S3 is as follows: divide the moving distance by the time difference, and the result is the real-time speed.

[0014] In the above scheme, when the communication interruption exceeds a set threshold, the interpolation update of the corresponding AGV is suspended and an alarm signal is issued.

[0015] In the above scheme, the AGV data structure also includes the AGV's operating status identifier, which includes no load, full load, and power status.

[0016] Furthermore, to achieve the above objectives, this invention also proposes a real-time synchronization system for multiple AGVs under low-frequency communication, applied to a digital twin platform, comprising: The building module is used to construct the AGV data structure, which includes the AGV number, AGV position, and AGV rotation angle; The initialization module is used to record the data arrival time and initialize the corresponding AGV object when the digital twin platform first receives data reported by any AGV through low-frequency communication, and assign values ​​to its position and rotation angle according to the received data. The calculation module is used to record the arrival time of the data when the same AGV reports data via low-frequency communication for the next time it receives data from the same AGV on the digital twin platform, calculate the time difference between the data and the previous data, obtain the current position of the AGV according to the AGV number, calculate the moving distance in combination with the initial position of the AGV, and calculate the real-time speed of the AGV based on the moving distance and the time difference. The interpolation rendering module is used to set an initial value of zero for the time accumulation variable, and to perform interpolation updates cyclically as long as the time accumulation variable is less than the time difference: Incrementing by a fixed time interval in each frame, it calculates the normalized direction vector from the current position to the target position, and takes the smaller value between the product of the real-time speed and the fixed time interval, and the remaining distance from the current position to the target position, as the displacement step size; updates the AGV's position to the current position plus the product of the normalized direction vector and the displacement step size; simultaneously, it uses a rotational interpolation method to smoothly update the AGV's orientation. The update module is used to trigger the calculation module and the interpolation rendering module to perform corresponding operations for each subsequent data received by the AGV, so as to realize the real-time smooth synchronization and visual coherent update of the motion state of multiple AGVs in the digital twin platform.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) This invention provides a method for real-time synchronization of multiple AGVs under low-frequency communication. This method interpolates based on physical calculations between two consecutive discrete data reports, making the movement of AGVs in the digital twin virtual environment continuous and smooth, eliminating visual stuttering and distortion caused by state jumps, and improving the monitoring experience. This method does not rely on high-frequency data streams and can effectively maintain the approximate synchronization between the virtual model and the physical entity in industrial network environments with long communication intervals and unstable data packets. The interpolation algorithm of this invention has low complexity, and only performs a small number of vector and scalar operations per frame. It can be easily applied to complex scenarios containing dozens or even hundreds of AGVs and maintain the real-time rendering frame rate of the digital twin system. By taking the smaller value between the product of the real-time speed and the frame interval and the remaining distance as the displacement step size, it ensures that the AGV will not cross the endpoint when approaching the target point, thus ensuring positioning accuracy.

[0018] (2) The present invention provides a method for real-time synchronization of multiple AGVs under low-frequency communication, which effectively responds to abnormal situations by setting interpolation exit conditions and communication interruption alarms. Attached Figure Description

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart illustrating a method for real-time synchronization of multiple AGVs under low-frequency communication in Embodiment 1 of the present invention.

[0020] Figure 2 This is a flowchart illustrating a method for real-time synchronization of multiple AGVs under low-frequency communication in Embodiment 2 of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] It should be understood that the sequence number of each step in the embodiment 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 this application.

[0023] Example 1 This application provides a method for real-time synchronization of multiple AGVs under low-frequency communication conditions, applied to a digital twin platform. The aim is to achieve real-time smooth synchronization of the motion states of multiple AGVs under low-frequency communication conditions, enabling the virtual model of the digital twin platform to continuously reproduce the motion process of the physical AGVs, achieving visually coherent updates and improving the scheduling accuracy and collaborative efficiency of multi-AGV systems in low-frequency communication scenarios. This method is applied to a multi-floor material handling monitoring system in a large three-story factory. Due to the large warehouse area, numerous metal shelves, and severe wireless signal attenuation, communication between the AGVs and the server can only maintain a low-frequency reporting frequency of approximately once every three seconds. The image rendering frame rate of the digital twin platform in this embodiment is 60 frames per second. Please refer to... Figure 1 This embodiment provides a method for real-time synchronization of multiple AGVs under low-frequency communication, including: S1, construct the AGV data structure, which includes the AGV number, AGV position and AGV rotation angle.

[0024] In this embodiment, it is understood that the first step is to construct an AGV data structure. Specifically, this involves designing an AGV data structure that includes the AGV number, AGV position, and AGV rotation angle. The AGV number is used to distinguish different AGVs, enabling independent identification and status management of multiple AGVs. In this embodiment, it is a web-based 3D dashboard, which is actually a three-dimensional coordinate system, but the height is a fixed value (on the ground) during processing, which can be understood as a two-dimensional coordinate system. The AGV rotation angle is used to characterize the AGV's orientation. In addition, the AGV data structure also includes AGV operating status indicators, including whether the AGV is idle, fully loaded, or has sufficient power.

[0025] S2: When the digital twin platform receives data from any AGV for the first time, it records the data arrival time, initializes the corresponding AGV object, and assigns values ​​to its position and rotation angle based on the received data.

[0026] In this embodiment, when the digital twin platform receives AGV data corresponding to a certain AGV data structure for the first time, it first records the timestamp of the data arrival, then initializes the corresponding AGV virtual object according to the AGV number, and directly assigns initial values ​​to the position and rotation angle of the virtual object based on the received AGV data, thus completing the initial construction of the AGV virtual model.

[0027] S3. When the digital twin platform receives data from the same AGV for the next time, record the arrival time of this data and calculate the time difference with the previous data; obtain the current position of the AGV according to the AGV number, and calculate the moving distance in combination with the initial position of the AGV; calculate the real-time speed of the AGV based on the moving distance and the time difference.

[0028] In this embodiment, when AGV data with the same AGV number is received again, the timestamp of the data arrival is recorded again, and the time difference t between the arrival time of the current data and the previous data is calculated. The current position of the AGV virtual object is retrieved from the digital twin platform according to the AGV number, and the movement distance s of the AGV within the time difference is calculated by combining the received position data and the initial position of the AGV. The movement distance is further divided by the time difference to obtain the real-time movement speed v of the AGV.

[0029] S4. Set the time accumulation variable to zero initially. Under the condition that the time accumulation variable is less than the time difference, perform interpolation update cyclically: increment by a fixed time interval in each frame, calculate the normalized direction vector from the current position to the target position, and take the smaller value between the product of the real-time speed and the fixed time interval and the remaining distance from the current position to the target position as the displacement step size; update the position of the AGV to the current position plus the product of the normalized direction vector and the displacement step size; at the same time, use the rotation interpolation method to smoothly update the orientation of the AGV.

[0030] This embodiment also includes an exit condition judgment during the cyclic interpolation update process: When the remaining distance is less than the preset distance threshold, and the difference between the current AGV's orientation angle and the target rotation angle is less than the preset angle threshold, the AGV's position and rotation angle are directly set to the target value, and the loop is exited.

[0031] Specifically, in this embodiment, a time accumulation variable c is set and its initial value is set to zero. The interpolation update operation is performed cyclically as long as the time accumulation variable c is less than the aforementioned time difference t. Each frame increments the time accumulation variable by a fixed time interval a, where a is the image rendering frame interval of the digital twin platform. A normalized direction vector dir is calculated from the current position of the AGV to the target position corresponding to the current data, eliminating the influence of the position difference vector magnitude on displacement calculation. The product of the real-time speed v and the fixed time interval a, and the remaining distance from the current position to the target position are calculated respectively. The smaller of these two values ​​is taken as the displacement step size step to avoid position overshoot of the AGV virtual object. The current position of the AGV is superimposed with the product of the normalized direction vector dir and the displacement step size step to complete the AGV virtual object position update for each frame. Simultaneously, a rotation interpolation method is used to smoothly update the AGV's orientation. Specifically, the interpolation method used in this embodiment is angle interpolation, which is essentially linear interpolation, but the angle is normalized (mapped to [0, 360)) and the shortest rotation direction is calculated. In cases such as from 350° to 10°, which crosses the 0° / 360 boundary, the rotation is 20° instead of 340°, ensuring that the interpolation is along the shortest path.

[0032] In this embodiment, during the cyclic interpolation process, the remaining distance and angle difference are also judged in real time. When the remaining distance is less than 0.1 meters and the difference between the current AGV's orientation angle and the target rotation angle is less than five degrees, the position and rotation angle of the AGV virtual object are directly set as the target value, and the interpolation loop is exited to ensure that the AGV state ultimately matches the target state accurately.

[0033] S5. For each subsequent data received by the AGV, repeat steps S3 and S4 to achieve real-time smooth synchronization and visual coherent updates of the motion states of multiple AGVs in the digital twin platform.

[0034] In this embodiment, steps S3 and S4 are repeated for subsequent AGV data with the same AGV number. In this embodiment, the data reported by the AGVs via low-frequency communication received by the digital twin platform is a data packet containing real-time status information of multiple AGVs. The digital twin platform traverses the data packets and performs motion parameter calculation and interpolation update operations for the corresponding AGV based on each AGV number, achieving real-time smooth synchronization and visually coherent updates of the motion status of multiple AGVs in the digital twin platform. In summary, this embodiment provides a method for real-time synchronization of multiple AGVs under low-frequency communication, which can solve the problems of AGV state jumps, motion distortion and poor visual continuity in the prior art under low-frequency communication.

[0035] Example 2 This application provides a method for real-time synchronization of multiple AGVs under low-frequency communication. This method is basically the same as the method in embodiment 1, except that: In this embodiment of a method for real-time synchronization of multiple AGVs under low-frequency communication, the method further includes: when the communication interruption exceeds a set threshold, pausing the interpolation update of the corresponding AGV and issuing an alarm signal.

[0036] Specifically, such as Figure 2 As shown in this embodiment, if the digital twin platform does not receive new AGV data within a preset time (the threshold is set to 5s in this embodiment), it will trigger a data reception anomaly prompt and alarm, maintain the current motion state of the AGV virtual object and pause interpolation updates until new AGV data is received.

[0037] One embodiment of this application provides a real-time synchronization system for multiple AGVs under low-frequency communication, applied to a digital twin platform, including: The building module is used to construct the AGV data structure, which includes the AGV number, AGV position, and AGV rotation angle; The initialization module is used to record the data arrival time and initialize the corresponding AGV object when the digital twin platform first receives data reported by any AGV through low-frequency communication, and assign values ​​to its position and rotation angle according to the received data. The calculation module is used to record the arrival time of the data when the digital twin platform receives data reported by the same AGV through low-frequency communication, calculate the time difference with the previous data, obtain the current position of the AGV according to the AGV number, calculate the moving distance in combination with the initial position of the AGV, and calculate the real-time speed of the AGV based on the moving distance and the time difference. The interpolation rendering module is used to set the time accumulation variable to an initial value of zero. Under the condition that the time accumulation variable is less than the time difference, it performs interpolation updates cyclically: incrementing by a fixed time interval in each frame, calculating the normalized direction vector from the current position to the target position, and taking the smaller value between the product of the real-time speed and the fixed time interval and the remaining distance from the current position to the target position as the displacement step size; updating the position of the AGV to the current position plus the product of the normalized direction vector and the displacement step size; at the same time, using a rotation interpolation method to smoothly update the orientation of the AGV. The update module is used to trigger the calculation module and interpolation rendering module to perform corresponding operations for each subsequent data received by the AGV, so as to realize the real-time smooth synchronization and visual coherent update of the motion status of multiple AGVs in the digital twin platform.

[0038] It should be noted that, depending on the implementation needs, the various steps described in this application can be broken down into more steps, or two or more steps or parts of the steps can be combined into new steps to achieve the purpose of this invention.

[0039] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for real-time synchronization of multiple AGVs under low-frequency communication, applied to a digital twin platform, characterized in that, Includes the following steps: S1. Construct an AGV data structure, including AGV number, AGV position, and AGV rotation angle; S2. When the digital twin platform receives data reported by any AGV through low-frequency communication for the first time, it records the data arrival time, initializes the corresponding AGV object, and assigns values ​​to its position and rotation angle according to the received data. S3. When the digital twin platform receives data reported by the same AGV via low-frequency communication for the next time, record the arrival time of this data and calculate the time difference with the previous data; obtain the current position of the AGV according to the AGV number, and calculate the moving distance in combination with the initial position of the AGV; calculate the real-time speed of the AGV based on the moving distance and the time difference. S4. Set the time accumulation variable to an initial value of zero, and perform interpolation updates cyclically as long as the time accumulation variable is less than the time difference: increment by a fixed time interval in each frame, calculate the normalized direction vector from the current position to the target position, and take the smaller value between the product of the real-time speed and the fixed time interval and the remaining distance from the current position to the target position as the displacement step size; update the position of the AGV to the current position plus the product of the normalized direction vector and the displacement step size; at the same time, use a rotation interpolation method to smoothly update the orientation of the AGV. S5. For each subsequent data received by the AGV, repeat steps S3 and S4 to achieve real-time smooth synchronization and visual coherent updates of the motion states of multiple AGVs in the digital twin platform.

2. The method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 1, characterized in that, In step S4, during the cyclic interpolation update process, an exit condition check is also included: When the remaining distance is less than the preset distance threshold, and the difference between the current AGV's orientation angle and the target rotation angle is less than the preset angle threshold, the AGV's position and rotation angle are directly set to the target value, and the loop is exited.

3. The method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 2, characterized in that, The preset distance threshold is 0.1 length units; the preset angle threshold is 5 degrees.

4. The method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 1, characterized in that, Step S5 includes: For subsequent AGV data with the same AGV number, steps S3 and S4 above are repeated; wherein, the data reported by the AGVs through low-frequency communication received by the digital twin platform is a set of data packets, which contain real-time status information of multiple AGVs. The digital twin platform traverses the data packets and performs motion parameter calculation and interpolation update operations for the corresponding AGV according to each AGV number, thereby realizing real-time smooth synchronization and visual coherent update of the motion status of multiple AGVs in the digital twin platform.

5. The method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 1, characterized in that, In step S4, the rotation interpolation method includes: Based on the difference between the current angle and the target angle, interpolation is used to achieve a smooth transition; The difference is an angle interpolation.

6. The method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 1, characterized in that, The fixed time interval is set according to the rendering frame rate of the digital twin scene; The low-frequency communication refers to a communication frequency of 2-4 seconds per communication.

7. The method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 1, characterized in that, The method for calculating the real-time speed in step S3 is as follows: divide the moving distance by the time difference, and the result is the real-time speed.

8. The method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 1, characterized in that, When communication interruption exceeds a set threshold, the interpolation update of the corresponding AGV is suspended and an alarm signal is issued.

9. A method for real-time synchronization of multiple AGVs under low-frequency communication according to claim 1, characterized in that, The AGV data structure also includes the AGV's operating status identifier, which includes whether it is empty, fully loaded, or has a power level.

10. A real-time synchronization system for multiple AGVs under low-frequency communication, applied to a digital twin platform, characterized in that, include: The building module is used to construct the AGV data structure, which includes the AGV number, AGV position, and AGV rotation angle; The initialization module is used to record the data arrival time and initialize the corresponding AGV object when the digital twin platform first receives data reported by any AGV through low-frequency communication, and assign values ​​to its position and rotation angle according to the received data. The calculation module is used to record the arrival time of the data when the same AGV reports data via low-frequency communication for the next time it receives data from the same AGV on the digital twin platform, calculate the time difference between the data and the previous data, obtain the current position of the AGV according to the AGV number, calculate the moving distance in combination with the initial position of the AGV, and calculate the real-time speed of the AGV based on the moving distance and the time difference. The interpolation rendering module is used to set an initial value of zero for the time accumulation variable, and to perform interpolation updates cyclically as long as the time accumulation variable is less than the time difference: Incrementing by a fixed time interval in each frame, it calculates the normalized direction vector from the current position to the target position, and takes the smaller value between the product of the real-time speed and the fixed time interval, and the remaining distance from the current position to the target position, as the displacement step size; updates the AGV's position to the current position plus the product of the normalized direction vector and the displacement step size; simultaneously, it uses a rotational interpolation method to smoothly update the AGV's orientation. The update module is used to trigger the calculation module and the interpolation rendering module to perform corresponding operations for each subsequent data received by the AGV, so as to realize the real-time smooth synchronization and visual coherent update of the motion state of multiple AGVs in the digital twin platform.

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