CN116400618A - An Intelligent Control Method Based on Time Synchronization Used in Logistics System - Google Patents

Abstract

The invention provides an intelligent control method based on time synchronization applied to a logistics system. The method realizes intelligent control by system initialization, path planning and control of the driving equipment, and can ensure that goods are transported to a designated destination according to the planned path under a control instruction preset by each node, so that the algorithm can effectively improve the working efficiency of the conveying system. The intelligent control method based on time synchronization provided by the invention has the advantages that in a logistics warehouse center with wide occupied area, large cargo quantity and high time efficiency and accuracy, the cargo can be transported to a designated place in a short time with extremely high accuracy, and the transport efficiency of the cargo is effectively improved.

Description

An Intelligent Control Method Based on Time Synchronization Used in Logistics System

technical field

The invention belongs to the technical field of artificial intelligence, in particular to an intelligent control method based on time synchronization applied to a logistics system.

Background technique

At present, the existing logistics control system mainly uses the sensor-server method to sense and locate items, and realizes motion control through the server-edge device-control device. Connected, able to efficiently control objects for transport.

But this system has the disadvantage of communication delay. This problem mainly exists in the communication between the sensor and the host computer, and the communication between the host computer and distributed edge devices. Due to the existence of time delay, there are huge uncertainties in the multi-directional logistics control at high speed, and it is difficult to meet the accuracy required by the system.

At the same time, when the control device of the system expands to a certain extent, the message queue will be blocked in the communication: when the instruction does not arrive at the specified time node, the messages will accumulate in the transmission queue and cause congestion, but when the system arrives After the specified time node is specified, multiple data packets will be transmitted at the same time, which will cause problems such as data coverage or queuing delay, which will further aggravate the negative effects of time delay.

Contents of the invention

The purpose of the present invention is to solve the problems in the prior art, and propose an intelligent control method based on time synchronization applied to the logistics system.

The present invention is achieved through the following technical solutions. The present invention proposes an intelligent control method based on time synchronization applied to a logistics system. The method is specifically:

Based on the time of the upper computer, synchronize the distributed edge devices with it and unify the time to complete the initialization preparation of the control method. Time synchronization between distributed edge devices needs to be re-synchronized at regular intervals to ensure high-precision accuracy;

Predict the time when the goods enter the logistics system, and use this time as a reference, call the A* algorithm to plan the route of the goods, and predict the trajectory of the object according to the linear speed and the feedback of the drive control, and calculate the arrival of the goods at each node The time required, and the control commands that the node needs to issue;

Design a message queue with priority. The format of the message content is: priority, running time, and control instruction; the message content is sent according to the time when the goods enter the logistics system. After the distributed edge device receives the data, it All commands are sorted according to the set priority-running time, and control commands are issued to the drive equipment at the specified running time.

Furthermore, when the visual sensor detects a cargo collision, the host computer will call the RVO algorithm to recalculate the trajectory of the cargo, and raise the priority of the current instruction to the highest, insert it into the front of the queue for delivery, and the distributed edge device receives After the content of the message with higher priority, the same drive device or the same time, it will overwrite the command that has been sent to the machine.

Furthermore, PTPd is selected to obtain the time of the network driver layer to synchronize the time of distributed edge devices.

Further, the PTPd moves the generation position of the time stamp from the physical layer to the network driver layer, and the formula for calculating the time deviation is:

Further, the distributed edge device and the upper computer are connected through a high-speed real-time bus, and the sensor and the upper computer use POWERLINK or EtherCAT real-time industrial Ethernet.

Further, in the path planning process:

When the transportation starts, the goods are placed at the starting point of the logistics system. After the visual or pressure sensor confirms the condition of the goods, it will notify the host computer to start calculation;

The upper computer uses the A* algorithm for path planning to meet the planning requirements for the goods to arrive at any destination from any starting point according to the optimal path. After completing the path planning, the upper computer will calculate the goods according to the planned path and the set cargo transportation speed. The acceleration required to be provided by the driving device when passing through each node, and the estimated time for the goods to pass through the node;

After the calculation is completed, the upper computer will combine the calculated control commands of each node with the time node to synthesize a message in a specified format, and send it to the edge device to which each node belongs. The edge device judges the existing control command and the issued Whether the command will conflict, if so, report the conflict to the host computer, and the host computer calls the RVO algorithm to recalculate the corresponding data; if there is no conflict, the edge device needs to issue the control command when it reaches the recorded time node to the specified driver.

The present invention proposes an intelligent control system based on time synchronization applied to a logistics system. The system is specifically:

Initialization module: It is used to synchronize the distributed edge devices with the time of the upper computer and unify the time to complete the initialization preparation of the control method. Time synchronization between distributed edge devices needs to be re-synchronized regularly to ensure high precision accuracy;

Prediction module: used to predict the time when the goods enter the logistics system, and use this time as a reference, call the A* algorithm to plan the route of the goods, and predict the trajectory of the object according to the linear speed and the feedback of the drive control, and calculate the The time it takes for the goods to arrive at each node, and the control instructions that need to be issued by the node;

Control module: used to design a message queue with priority, the format of the message content is: priority, running time, control instruction; the message content is sent according to the time when the goods enter the logistics system, and the distributed edge device receives it After collecting the data, sort all current commands according to the set priority-running time, and issue control commands to the drive equipment at the specified running time.

Furthermore, once new goods enter the logistics system, or the visual sensor detects a collision, the upper computer will be notified in real time to re-plan the path using the RVO algorithm. After the upper computer re-plans, it will synthesize a higher priority report. document and distribute it.

The present invention also proposes an electronic device, including a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the intelligent control method based on time synchronization applied to the logistics system is realized A step of.

The present invention also proposes a computer-readable storage medium for storing computer instructions, and when the computer instructions are executed by a processor, the steps of the intelligent control method based on time synchronization applied to the logistics system are realized.

Beneficial effects of the present invention:

The present invention proposes an intelligent control method based on time synchronization applied to the logistics system. With the increase of the amount of goods, the logistics transportation system is gradually increasing the transmission speed, but the current control algorithm has certain limitations in this environment. An effective intelligent control algorithm is urgently needed to ensure the stability of transmission. The intelligent control method based on time synchronization proposed by the present invention can transport the goods to the designated place with a very high accuracy rate in the logistics warehouse center that covers a large area, has a large quantity of goods, and has high requirements for timeliness and accuracy. , Effectively improve the transportation efficiency of goods. In particular, the intelligent control method can also be applied to similar systems that require predictive control, such as factory robotic arms and smart cars.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is the basic flowchart of intelligent control method;

Fig. 2 is the flowchart of PTP algorithm;

Figure 3 is a schematic diagram of the client selecting the eth0 port to connect to the network cable without clock synchronization;

Figure 4 is a schematic diagram of the client selecting the eth0 port to connect to the network cable and performing clock synchronization.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention proposes an intelligent control method based on the technology of time synchronization and path planning, which can be directly applied to the cargo transportation of the logistics system.

In combination with Fig. 1-Fig. 4, the present invention proposes an intelligent control method based on time synchronization applied to the logistics system. The method is specifically:

Based on the time of the upper computer, synchronize the distributed edge devices with it and unify the time to complete the initialization preparation of the control method. Time synchronization between distributed edge devices needs to be re-synchronized at regular intervals to ensure high-precision accuracy;

Predict the time when the goods enter the logistics system, and use this time as a reference, call the A* algorithm to plan the route of the goods, and predict the trajectory of the object according to the linear speed and the feedback of the drive control, and calculate the arrival of the goods at each node The time required, and the control commands that the node needs to issue;

Design a message queue with priority, the format of the message content is: priority, running time, control instruction; among them, the running time and control instruction are the data calculated above, and the message content is according to the time when the goods enter the logistics system After the distributed edge device receives the data, it sorts all current commands according to the set priority-running time, and sends control commands to the drive device at the specified running time.

In particular, when the visual sensor detects a cargo collision, the host computer will call the RVO algorithm to recalculate the trajectory of the cargo, and raise the priority of the current instruction to the highest, insert it into the front of the queue for delivery, and the distributed edge device receives After the content of the message with higher priority, the same drive device or the same time, it will overwrite the command that has been sent to the machine.

1. Time synchronization of distributed edge devices:

Use PTPd to obtain the time of the network driver layer to synchronize the time of distributed edge devices.

In different control systems, there is a big difference in the selection of distributed edge devices. Considering that not all devices support the hardware-accurate PTP protocol, in order to improve the compatibility of the control algorithm, in this invention, the choice that can obtain The PTPd protocol of the network driver layer.

PTPd (Precision Time Protocol daemon) is based on the implementation of the PTP protocol defined by the IEEE1588 standard, which can provide precise time coordination for computers connected by Ethernet.

In this intelligent control algorithm, when the device is started, the time of the upper computer is used as the reference, and all distributed edge devices are synchronized using the PTPd protocol to complete the initialization preparation of the algorithm. And it needs to re-synchronize the edge device regularly (1-2s) to ensure the accuracy of the accuracy.

PTPd is based on the implementation of the PTP protocol, and the implementation process of PTP is shown in Figure 2.

Compared with PTP, the difference between PTPd and PTP is mainly that the generation position of the time stamp is moved from the physical layer to the network driver layer, and its calculation method still uses the formula of PTP. The formula for calculating the time deviation is:

2. Network communication under time synchronization:

In order to reduce the negative effects caused by network delay as much as possible, the distributed edge devices and the host computer are connected through a high-speed real-time bus. In particular, real-time industrial Ethernet such as POWERLINK or EtherCAT can be considered for sensors and host computers. In order to reduce the delay of message sending and ensure the real-time performance of the system.

Based on the intelligent control method proposed by the present invention, message scheduling is only composed of messages required to complete system clock synchronization and necessary control instruction messages, and the sending time of all messages can be configured in advance, which can effectively avoid The blocking of the message queue improves the utilization rate of the bus and ensures the real-time performance of the system.

3. Intelligent control method based on path planning:

During path planning:

When the transportation starts, the goods are placed at the starting point of the logistics system. After the visual or pressure sensor confirms the condition of the goods, it will notify the host computer to start calculation;

The upper computer uses the A* algorithm for path planning, which can meet the planning requirements for goods to arrive at any destination according to the optimal path from any starting point. After completing the path planning, the upper computer will calculate according to the planned path and the set cargo transportation speed The acceleration required by the driving device when the goods pass through each node, and the estimated time for the goods to pass through the node;

After the calculation is completed, the upper computer will combine the calculated control commands of each node with the time node to synthesize a message in a specified format, and send it to the edge device to which each node belongs. The edge device judges the existing control command and the issued Whether the command will conflict, if so, report the conflict to the host computer, and the host computer calls the RVO algorithm to recalculate the corresponding data; if there is no conflict, the edge device needs to issue the control command when it reaches the recorded time node to the specified driver.

The present invention proposes an intelligent control system based on time synchronization applied to a logistics system. The system is specifically:

Initialization module: It is used to synchronize the distributed edge devices with the time of the upper computer and unify the time to complete the initialization preparation of the control method. Time synchronization between distributed edge devices needs to be re-synchronized regularly to ensure high precision accuracy;

Prediction module: used to predict the time when the goods enter the logistics system, and use this time as a reference, call the A* algorithm to plan the route of the goods, and predict the trajectory of the object according to the linear speed and the feedback of the drive control, and calculate the The time it takes for the goods to arrive at each node, and the control instructions that need to be issued by the node;

Control module: used to design a message queue with priority, the format of the message content is: priority, running time, control instruction; the message content is sent according to the time when the goods enter the logistics system, and the distributed edge device receives it After collecting the data, sort all current commands according to the set priority-running time, and issue control commands to the drive equipment at the specified running time.

In particular, once new goods enter the logistics system, or the visual sensor detects a collision, the upper computer will be notified in real time to re-plan the path using the RVO algorithm. After the upper computer re-plans, it will synthesize a higher priority report. document and distribute it.

The method and system of the present invention can ensure that the goods can be transported to the designated destination according to the planned route under the preset control instructions of each node, and such an algorithm can effectively improve the working efficiency of the transmission system.

The invention mainly solves a series of problems caused by time delay in the logistics transportation system, and in particular, experiments verify the necessity of time synchronization.

In the experiment, the server was selected as the upper computer, and the Raspberry Pi was used as the edge device, and the transmission delay between the server and the client was tested with or without time synchronization and whether the bus was selected for connection. Figures 3 and 4 prove that in the case of time synchronization, selecting the bus can effectively reduce the delay to the millisecond level, which meets the precision requirement required by the present invention.

The present invention also proposes an electronic device, including a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the intelligent control method based on time synchronization applied to the logistics system is realized A step of.

The present invention also proposes a computer-readable storage medium for storing computer instructions, and when the computer instructions are executed by a processor, the steps of the intelligent control method based on time synchronization applied to the logistics system are realized.

The memory in the embodiments of the present application may be a volatile memory or a nonvolatile memory, or may include both volatile and nonvolatile memories. Among them, the non-volatile memory can be read only memory (read only memory, ROM), programmable read only memory (programmable ROM, PROM), erasable programmable read only memory (erasable PROM, EPROM), electrically erasable Programmable read-only memory (electrically EPROM, EEPROM) or flash memory. Volatile memory can be random access memory (RAM), which acts as external cache memory. By way of illustration and not limitation, many forms of RAM are available, such as static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM ), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDRSDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous connection dynamic random access memory (synchlink DRAM, SLDRAM) and Direct memory bus random access memory (direct rambusRAM, DRRAM). It should be noted that the memory of the methods described herein is intended to include, but not be limited to, these and any other suitable types of memory.

In the above embodiments, all or part of them may be implemented by software, hardware, firmware or any combination thereof. When implemented using software, it may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on the computer, the processes or functions according to the embodiments of the present application will be generated in whole or in part. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website, computer, server or data center Transmission to another website site, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server or a data center integrated with one or more available media. The available medium may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a high-density digital video disc (digital video disc, DVD)), or a semiconductor medium (for example, a solid state disk (solid state disc, SSD)) etc.

In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the methods disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the field such as random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, register. The storage medium is located in the memory, and the processor reads the information in the memory, and completes the steps of the above method in combination with its hardware. To avoid repetition, no detailed description is given here.

It should be noted that the processor in the embodiment of the present application may be an integrated circuit chip, which has a signal processing capability. In the implementation process, each step of the above-mentioned method embodiments may be completed by an integrated logic circuit of hardware in a processor or instructions in the form of software. The above-mentioned processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components . Various methods, steps, and logic block diagrams disclosed in the embodiments of the present application may be implemented or executed. A general-purpose processor may be a microprocessor, or the processor may be any conventional processor, or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the field such as random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, register. The storage medium is located in the memory, and the processor reads the information in the memory, and completes the steps of the above method in combination with its hardware.

The above is a detailed introduction of a time-synchronized intelligent control method applied to the logistics system proposed by the present invention. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used To help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, this specification The content should not be construed as a limitation of the invention.

Claims (10)

1. An intelligent control method based on time synchronization applied to a logistics system is characterized by comprising the following steps of: the method specifically comprises the following steps:

synchronizing the distributed edge equipment with the distributed edge equipment by taking the time of the upper computer as a reference, unifying the time to finish initialization preparation of a control method, and carrying out time synchronization between the distributed edge equipment at regular time again to ensure high-precision accuracy;

predicting the time of goods entering a logistics system, calling an A-type algorithm to carry out path planning on the running route of the goods by taking the time as a reference, predicting the movement track of an object according to the linear speed and feedback of drive control, and calculating the time required by the goods to reach each node and the control instruction required by the node;

designing a message queue with priority, wherein the format of the message content is as follows: priority, run time, control instructions; the message content is issued according to the time when the goods enter the logistics system, after the distributed edge equipment receives the data, all the current instructions are ordered according to the set priority-running time, and the control instructions are issued to the driving equipment at the specified running time.

2. The method according to claim 1, characterized in that: when the visual sensor monitors the collision of goods, the upper computer calls the RVO algorithm to recalculate the motion trail of the goods, and the priority of the current instruction is raised to be the highest, the current instruction is inserted into the forefront end of the queue to be issued, and after the distributed edge equipment receives the message content of the same driving device or the same time with higher priority, the instruction issued to the upper computer is covered.

3. The method according to claim 1, characterized in that: and selecting PTPd to acquire network driving layer time, and performing time synchronization of distributed edge equipment.

4. A method according to claim 3, characterized in that: the PTPd moves the generation position of the timestamp from the physical layer to the network driving layer, and the formula for calculating the time offset is:

5. the method according to claim 2, characterized in that: the distributed edge equipment is connected with the upper computer through a high-speed real-time bus, and the sensor and the upper computer adopt POWERLINK or EtherCAT real-time industrial Ethernet.

6. The method according to claim 1, characterized in that: in the path planning process:

when the transportation starts, goods are placed at the starting point of the logistics system, and after the visual or pressure sensor confirms the condition of the goods, the upper computer is informed to start operation;

the upper computer adopts an A algorithm to carry out path planning, meets the planning requirement that goods reach any end point from any initial point according to an optimal path, and calculates the acceleration required by the driving device when the goods pass through each node and the estimated time when the goods pass through the node according to the planned path and the set goods transportation speed after the path planning is completed;

after the calculation is completed, the upper computer synthesizes the calculated control instructions of all the nodes and the time nodes into a message with a specified format, and transmits the message to the edge equipment to which all the nodes belong, the edge equipment judges whether the existing control instructions and the issued instructions conflict or not, if so, the conflict is reported to the upper computer, and the upper computer calls an RVO algorithm to recalculate corresponding data; if no conflict occurs, the edge device needs to issue a control instruction to the designated driving device when reaching the recorded time node.

7. An intelligent control system based on time synchronization applied to a logistics system is characterized in that: the system specifically comprises the following steps:

an initialization module: the method is used for synchronizing the distributed edge equipment with the distributed edge equipment by taking the time of the upper computer as a reference, unifying the time to finish initialization preparation of a control method, and the time synchronization is needed to be carried out between the distributed edge equipment again at fixed time so as to ensure high-precision accuracy;

and a prediction module: the method comprises the steps of predicting the time of goods entering a logistics system, calling an A algorithm to conduct path planning on the running route of the goods by taking the time as a reference, predicting the movement track of an object according to the linear speed and feedback of drive control, and calculating the time required by the goods to reach each node and the control instruction required by the node;

and the control module is used for: for designing a message queue with priority, the format of message content is as follows: priority, run time, control instructions; the message content is issued according to the time when the goods enter the logistics system, after the distributed edge equipment receives the data, all the current instructions are ordered according to the set priority-running time, and the control instructions are issued to the driving equipment at the specified running time.

8. The system according to claim 7, wherein: once new goods enter the logistics system or the visual sensor detects collision, the upper computer is informed to carry out path planning again by using the RVO algorithm in real time, and after the upper computer completes planning again, the messages with higher priority are synthesized and sent down.

9. An electronic device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any of claims 1-6 when the computer program is executed.

10. A computer readable storage medium storing computer instructions which, when executed by a processor, implement the steps of the method of any one of claims 1-6.

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