A control system method for an RGV vehicle

Abstract

The present invention discloses a control system method for an RGV vehicle, which includes a central PLC, an RGV vehicle PLC controller, a frequency converter, a relay, a traveling motor, a lifting motor, a track, a battery, a carbon brush, and a pantograph. Among them, the central PLC is a computer cluster or a computer terminal, and the central PLC uniformly manages the PLC controllers of each RGV vehicle. In the present invention, the central PLC is divided into site data, scheduling algorithm, and path algorithm, all of which are independently set to meet different adaptability problems. It is not necessary to rewrite the program every time a new site is added. Only the site data and path data need to be updated, and the scheduling and path algorithms are universal. This rule can be executed for any route, whether it is a straight line or a circular line, etc.

Description

Technical Field

[0001] The present invention relates to the field of RGV trolley equipment, and particularly to a control system method for an RGV trolley. Background Art

[0002] RGV is the English abbreviation of Rail Guided Vehicle, also known as a rail shuttle trolley. RGV trolleys can be used in warehouses with various high-density storage methods. The trolley channels can be designed to be arbitrarily long, which can increase the storage capacity of the entire warehouse. And when operating, there is no need for a forklift to drive into the aisle, making it safer. During the driving and operation of the RGV trolley, it is necessary to control each RGV trolley on the track so that the RGV trolley can operate normally without errors. Moreover, the RGV needs to draw power from the pantograph line and travel on the track. It is relatively difficult to modify the route once it is determined. Therefore, its adaptability to the use place is poor. For this reason, a control system method for an RGV trolley is proposed herein. Summary of the Invention

[0003] The purpose of the present invention is to provide a control system method for an RGV trolley to solve the above deficiencies in the technology.

[0004] To achieve the above purpose, the present invention provides the following technical solutions: including the following control methods:

[0005] Step 1: The central PLC first receives the task requirements, performs scheduling algorithm calculations, determines the designated RGV for transportation, and sends a path instruction.

[0006] Step 2: After the RGV trolley obtains the path instruction, the carbon brush on the RGV trolley intercepts the current on the pantograph line, and at the same time, the traveling motor and the lifting motor on the RGV trolley will be in an energized state.

[0007] Step 3: After the traveling motor and the lifting motor are energized, the central PLC sends the traveling speed of each RGV trolley to the PLC controller of each RGV trolley. After the RGV trolley obtains the traveling speed information, the frequency converter will control the traveling motor to start and travel at the set speed. The RGV also feeds back the current path to the PLC in real time during transportation.

[0008] Step 4: After the RGV trolley travels to the set position, the relay will control the lifting motor to pick up the item on the shelf. After the RGV trolley picks up the item, the relay will control the lifting motor to retract, and the frequency converter will restart the traveling motor to make the RGV trolley travel along the track to the position where the item is to be put down. After the RGV trolley puts the item in the designated position, it sends its own position from the PLC controller to the central PLC through the communication module. At this time, the central PLC will reassign tasks for the RGV trolley.

[0009] As a preferred embodiment of the present invention, the specific steps of Step 1 are as follows:

[0010] A: The central PLC first collects site data from the site data terminal. Assuming there are N stations, the route of each RGV has N*(N - 1)*(N - 1) stations;

[0011] B: The scheduling algorithms are divided into single RGV corresponding to a single site, single RGV corresponding to multiple sites, and multiple RGVs corresponding to multiple sites.

[0012] Specific scheduling principles:

[0013] ①. Single RGV corresponding to a single site: Whoever issues the task first will execute it first (first come, first served);

[0014] ②. Single RGV corresponding to multiple sites: Whoever issues the task first will execute it first (first come, first served);

[0015] ③. Multiple RGVs corresponding to a single site: If each RGV has only one site task, perform speed adjustment and move forward at a constant speed;

[0016] ④. Multiple RGVs corresponding to multiple sites: Queuing principle:

[0017] When there are two or more RGVs waiting for tasks, sort the process durations of each RGV's site separately, select the two RGVs with the minimum and maximum process times among all RGVs. If it is the same vehicle, select the vehicle with the second largest process duration as the other one, and so on. The others are sorted according to the average process duration, and the process durations close to the average process duration are placed in the first position and sorted in sequence. The maximum process duration is followed by the minimum process duration and sorted in sequence. Calculate the queue for each RGV separately, and the replacement principle is that the one with the longer process time is replaced first until the routes do not interfere. After all RGVs have completed transportation, continue with unified scheduling. The specific operation is as follows: Suppose there are 3 RGVs receiving tasks. Each RGV separately finds the minimum and maximum process durations for comparison, selects the RGVs with the minimum and maximum process durations. One of them is sorted according to the average process duration. After determining the path order of each RGV, judge whether the routes of the three times interfere. If they interfere, judge which route interferes. If all three routes interfere, replace the routes with the second largest and the largest process durations based on the times of the 3 RGVs in this comparison until the routes do not interfere; if two routes interfere, replace the one with the longer process time first until the routes do not interfere.

[0018] As a preferred embodiment of the present invention, it includes a central PLC, an RGV car PLC controller, an inverter, a relay, a walking motor, a lifting motor, a track, a battery, a carbon brush, and a trolley wire;

[0019] Among them, the central PLC is a computer cluster or a computer terminal, and the central PLC uniformly manages the PLC controllers of each RGV cart;

[0020] The RGV cart PLC controller consists of a controller, an arithmetic unit, and a register, and the circuits of the above components are all integrated on a single chip and are connected to the input / output interface circuit of the memory through an address bus and a control bus;

[0021] The main circuit of the frequency converter is the power conversion part that provides a voltage-regulated and frequency-modulated power supply for the traveling motor, and converts the power frequency power supply into DC power, and absorbs the "smoothing circuit" of the voltage pulsations generated in the converter and the inverter;

[0022] The relay has an interactive relationship between a control system (also known as an input circuit) and a controlled system (also known as an output circuit), and is an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays roles such as automatic regulation, safety protection, and circuit conversion for the lifting motor.

[0023] As a preferred solution of the present invention, the RGV cart PLC controller includes any one of Siemens PLC, Schneider PLC, Rockwell PLC, Delta PLC, and Galishi PLC.

[0024] As a preferred solution of the present invention, the traveling motor includes a traveling motor with model RT-XZ300 or a YR355 traveling motor.

[0025] As a preferred solution of the present invention, the communication module includes a local area network or a WLAN network.

[0026] In the above technical solution, the technical effects and advantages provided by the present invention:

[0027] In the present invention, the central PLC is divided into site data, scheduling algorithm, and path algorithm, all of which are independently set to meet different adaptability problems. It is not necessary to rewrite the program every time a new site is added. Only the site data and path data need to be updated, and the scheduling and path algorithms are universal. This rule can be executed for any route, whether it is a straight line or a circular line. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0029] Figure 1Schematic diagram of the framework structure of a control system method for an RGV vehicle proposed by the present invention. Detailed implementation manners

[0030] In order to make a clearer explanation and illustration of the technical solution and implementation manner of the present invention, several preferred specific embodiments for implementing the technical solution of the present invention are introduced below.

[0031] The following description is essentially exemplary only and is not intended to limit the present disclosure, application, and uses. It should be understood that in all these drawings, the same or similar reference numerals indicate the same or similar parts and features. Each drawing only schematically shows the concept and principle of the implementation manner of the present disclosure, and does not necessarily show the specific dimensions and their ratios of each implementation manner of the present disclosure. In a specific part of a specific drawing, the relevant details or structures of the implementation manner of the present disclosure may be illustrated in an exaggerated manner. The disclosed contents of various publications, patents, and published patent specifications cited herein are incorporated herein by reference in their entirety. Below, in conjunction with the embodiments of the present invention, the technical solution of the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention.

[0032] In the description of the present invention, unless otherwise clearly specified and defined, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; unless otherwise specified or stated, the term "plurality" means two or more; the terms "connection", "fixation", etc. should all be understood in a broad sense. For example, "connection" can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the description of this specification, it should be understood that the orientation terms such as "upper", "lower", "left", "right", etc. described in the embodiments of the present application are described from the angles shown in the drawings and should not be construed as limiting the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that one element is connected "on" or "under" another element, it can not only be directly connected "on" or "under" another element, but also be indirectly connected "on" or "under" another element through an intermediate element.

[0034] Embodiment 1

[0035] Referring to the attached drawings of the specification Figure 1 , the PLC controller of the RGV vehicle uses a Siemens PLC, the traveling motor uses a traveling motor with the model RT-XZ300, the communication module uses a local area network, and a control system method for an RGV vehicle:

[0036] The central PLC is a computer cluster, and the central PLC uniformly manages the Siemens PLC controllers of each RGV car. The RGV car PLC controller consists of a controller, an arithmetic unit, and a register, and the circuits of the above components are all integrated on one chip, and are connected to the input / output interface circuit of the memory through the address bus and the control bus. The main circuit of the frequency converter is the power conversion part that provides the voltage-regulated and frequency-modulated power supply for the traveling motor, and converts the power frequency power supply into DC power, and absorbs the "smoothing circuit" of the voltage pulsation generated in the converter and the inverter. The relay has an interactive relationship between the control system (also known as the input circuit) and the controlled system (also known as the output circuit), and is an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays roles such as automatic regulation, safety protection, and circuit conversion for the lifting motor.

[0037] The central PLC first collects site data from the site data terminal. Assume there are N stations, and each RGV route has N*(N - 1)*(N - 1) stations. The scheduling algorithms are divided into a single RGV corresponding to a single station, a single RGV corresponding to multiple stations, and multiple RGVs corresponding to multiple stations. The specific scheduling principles are as follows: - When a single RGV corresponds to a single station: The one that issues the task first will execute first (first come, first served). - When a single RGV corresponds to multiple stations: The one that issues the task first will execute first (first come, first served). - When multiple RGVs correspond to a single station: If each RGV has only one station task, speed adjustment is carried out and they move forward at a constant speed. - When multiple RGVs correspond to multiple stations: Queuing principle: When two or more RGVs are waiting for tasks, sort the process durations of each RGV's stations respectively. Select the two RGVs with the smallest and largest process times among all RGVs. If it is the same trolley, select the trolley with the second largest process duration as the other one, and so on. The others are sorted according to the average process duration. The process durations close to the average process duration are placed in the first position and sorted in sequence. The largest process duration is followed by the smallest process duration and sorted in sequence. Calculate the queue for each RGV respectively. The replacement principle is that the one with the longer process time is replaced first until the routes do not interfere. After all RGVs have completed transportation, continue with unified scheduling. The specific operation is as follows: Assume there are 3 RGVs receiving tasks. Each RGV finds the smallest and largest process durations respectively and compares them. Select the RGV trolleys with the smallest and largest process durations. One of them is sorted according to the average process duration. After the path order of each RGV is determined, judge whether the routes of the three times interfere. If they interfere, judge which route interferes. If all three routes interfere, replace the routes with the second largest process duration and the largest process duration respectively according to the times of the 3 RGVs in this comparison until the routes do not interfere. If two routes interfere, replace the one with the longer process time first until the routes do not interfere. After the RGV trolley obtains the path instruction, the current on the contact wire is intercepted through the carbon brush on the RGV trolley. At the same time, the traveling motor and the lifting motor on the RGV trolley will be powered on. After the traveling motor and the lifting motor are powered on, the central PLC sends the traveling speed of each RGV trolley to the PLC controller of each RGV trolley. After the RGV trolley obtains the traveling speed information, the frequency converter will control the traveling motor to start and travel at the set speed. The RGV also feeds back the current path to the PLC in real time during transportation. After the RGV trolley travels to the set position, the relay will control the lifting motor to pick up the items on the shelf. After the RGV trolley picks up the items, the relay will control the lifting motor to retract, and the frequency converter will restart the traveling motor to make the RGV trolley travel along the track to the position where the items are to be put down. After the RGV trolley puts the items in the designated position, it sends its own position from the PLC controller to the central PLC through the communication module. At this time, the central PLC will reassign tasks to the RGV trolley.

[0038] Embodiment 2

[0039] Refer to the attached Figure 1 For the RGV cart PLC controller, a Schneider PLC is adopted; for the traveling motor, a traveling motor with the model RT-XZ300 is used; for the communication module, a local area network is adopted. A control system method for the RGV cart is as follows:

[0040] The central PLC is a computer cluster, and the central PLC uniformly manages the Schneider PLC controllers of each RGV cart. The RGV cart PLC controller consists of a controller, an arithmetic unit, and a register, and the circuits of the above components are all integrated on one chip, and are connected to the input / output interface circuit of the memory through the address bus and the control bus. The main circuit of the frequency converter is the power conversion part that provides a voltage-regulated and frequency-modulated power supply for the traveling motor, and converts the industrial frequency power supply into DC power, and the "smoothing circuit" that absorbs the voltage pulsations generated in the converter and the inverter. The relay has an interactive relationship between the control system (also known as the input circuit) and the controlled system (also known as the output circuit), and is an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays roles such as automatic regulation, safety protection, and circuit conversion for the lifting motor.

[0041] The central PLC transmits the instruction signal for picking up goods to the Schneider PLC controllers of each RGV car via the local area network. After the RGV car receives the instruction, the current on the sliding contact line is intercepted by the carbon brush on the RGV car. At the same time, the traveling motor and the lifting motor on the RGV car will be powered on. After the traveling motor and the lifting motor are powered on, the central PLC sends the traveling speed of each RGV car to the Schneider PLC controller of each RGV car. The central PLC first collects site data from the site data terminal. Assuming there are N stations, the route of each RGV has N*(N - 1)*(N - 1) stations. The scheduling algorithms are divided into a single RGV corresponding to a single site, a single RGV corresponding to multiple sites, and multiple RGVs corresponding to multiple sites. The specific scheduling principles are as follows: A single RGV corresponding to a single site: Whoever issues the task first will execute it first (first come, first served); A single RGV corresponding to multiple sites: Whoever issues the task first will execute it first (first come, first served); Multiple RGVs corresponding to a single site: If each RGV has only one site task, speed adjustment will be carried out and they will move forward at a uniform speed; Multiple RGVs corresponding to multiple sites: Queuing principle: When two or more RGVs are waiting for tasks, the operation process durations of each RGV site are sorted respectively, and the two RGVs with the minimum and maximum operation process times among all RGV sites are selected. If it is the same car, select the car with the second largest operation process duration as the other one, and so on. The others are sorted according to the average operation process duration. The operation process duration close to the average operation process duration is placed in the first position and sorted in sequence. The largest operation process duration is followed by the smallest operation process duration and sorted in sequence. Queue calculations are performed on each RGV respectively, and the replacement principle is that the one with a longer operation process time is replaced first until the routes do not interfere. After all RGVs have completed transportation, unified scheduling continues.The specific operations are as follows: Suppose there are 3 RGVs receiving tasks. Each RGV separately finds the minimum and maximum process durations for comparison, selects the RGV carts with the minimum and maximum process durations. One of them is sorted according to the average process duration. After the path order of each RGV is determined, it is judged whether the routes of the three times interfere. If they interfere, it is judged which route interferes. If all three routes interfere, the routes with the second-largest process duration and the largest process duration are respectively replaced according to the times of the 3 RGVs in this comparison until the routes do not interfere; if two routes interfere, the one with the longer process time is preferentially replaced until the routes do not interfere. After the RGV cart obtains the path instruction, the current on the pantograph line is intercepted through the carbon brush on the RGV cart. At the same time, the traveling motor and the lifting motor on the RGV cart will be powered on. After the traveling motor and the lifting motor are powered on, the central PLC sends the traveling speed of each RGV cart to the PLC controller of each RGV cart. After the RGV cart obtains the traveling speed information, the frequency converter will control the traveling motor to start and travel at the set speed. The RGV also real-time feedbacks the current path to the PLC during transportation. After the RGV cart travels to the set position, the relay will control the lifting motor to pick up the item on the shelf. After the RGV cart picks up the item, the relay will control the lifting motor to retract, and the frequency converter will restart the traveling motor to let the RGV cart travel along the track to the position where the item is to be put down. After the RGV cart puts the item in the designated position, its position is sent from the PLC controller to the central PLC through the communication module. At this time, the central PLC will reassign tasks to the RGV cart.

[0042] Embodiment III

[0043] Refer to the attached instruction manual Figure 1 , the RGV cart PLC controller uses Rockwell PLC, the traveling motor uses a traveling motor with the model RT-XZ300, the communication module uses a WLAN network, and a method for the RGV cart control system:

[0044] The central PLC is a computer cluster, and the central PLC uniformly manages the Schneider PLC controllers of each RGV cart. The RGV cart PLC controller consists of a controller, an arithmetic unit, and a register, and the circuits of the above components are all integrated on one chip and are connected to the input / output interface circuit of the memory through the address bus and the control bus. The main circuit of the frequency converter is the power conversion part that provides the voltage and frequency regulated power supply for the traveling motor, and converts the power frequency power supply into DC power, and the "smoothing circuit" that absorbs the voltage pulsations generated in the converter and the inverter. The relay has an interactive relationship between the control system (also known as the input circuit) and the controlled system (also known as the output circuit), and is an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays roles such as automatic regulation, safety protection, and circuit conversion for the lifting motor;

[0045] The central PLC transmits the instruction signal for picking up goods to the Rockwell PLC controllers of each RGV vehicle through the WLAN network. After the RGV vehicle obtains the instruction, the current on the pantograph line is intercepted through the carbon brush on the RGV vehicle. At the same time, the traveling motor and the lifting motor on the RGV vehicle will be powered on. After the traveling motor and the lifting motor are powered on, the central PLC sends the traveling speed of each RGV vehicle to the Schneider PLC controller of each RGV vehicle. The central PLC first collects site data from the site data terminal. Assuming there are N stations, the route of each RGV has N*(N - 1)*(N - 1) stations. The scheduling algorithms are divided into a single RGV corresponding to a single site, a single RGV corresponding to multiple sites, and multiple RGVs corresponding to multiple sites. The specific scheduling principles are as follows: A single RGV corresponding to a single site: Whoever issues the task first will execute it first (first come, first served); A single RGV corresponding to multiple sites: Whoever issues the task first will execute it first (first come, first served); Multiple RGVs corresponding to a single site: If each RGV has only one site task, speed adjustment is carried out and they move forward at a constant speed; Multiple RGVs corresponding to multiple sites: Queuing principle: When two or more RGVs are waiting for tasks, the operation process durations of each RGV site are sorted respectively. Select the two RGVs with the minimum and maximum operation process times among all RGV sites. If it is the same vehicle, select the vehicle with the second largest operation process duration as the other vehicle, and so on. The others are sorted according to the average operation process duration. The operation process duration close to the average operation process duration is placed in the first position and sorted in sequence. The largest operation process duration is followed by the smallest operation process duration and continues to be sorted in sequence. The RGVs are queued and calculated respectively. The replacement principle is that the one with a longer operation process time is replaced first until the routes do not interfere. After all RGVs have completed transportation, unified scheduling continues.The specific operations are as follows: Suppose there are 3 RGVs receiving tasks. Each RGV respectively finds the minimum and maximum process durations and compares them. Select the RGVs with the minimum and maximum process durations. One of them is sorted according to the average process duration. After the path order of each RGV is determined, judge whether the routes of the three times interfere. If they interfere, judge which route interferes. If all three routes interfere, replace the routes with the second-longest process duration and the longest process duration respectively according to the times of the three RGVs in this comparison until the routes do not interfere. If two routes interfere, replace the one with the longer process time first until the routes do not interfere. After the RGV obtains the path instruction, the current on the pantograph line is intercepted through the carbon brush on the RGV. At the same time, the traveling motor and the lifting motor on the RGV will be powered on. After the traveling motor and the lifting motor are powered on, the central PLC sends the traveling speed of each RGV to the PLC controller of each RGV. After the RGV obtains the traveling speed information, the frequency converter will control the traveling motor to start and travel at the set speed. The RGV also feeds back the current path to the PLC in real time during transportation. After the RGV travels to the set position, the relay will control the lifting motor to pick up the items on the shelf. After the RGV picks up the items, the relay will control the lifting motor to retract, and the frequency converter will restart the traveling motor to make the RGV travel along the track to the position where the items are put down. After the RGV puts the items in the designated position, its position is sent from the PLC controller to the central PLC through the communication module. At this time, the central PLC will reassign tasks to the RGV.

[0046] Only some exemplary embodiments of the present invention have been described in an illustrative manner above. Undoubtedly, for those of ordinary skill in the art, without departing from the spirit and scope of the present invention, the described embodiments can be modified in various different ways. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the protection scope of the claims of the present invention.

Claims

1. A control system method for an RGV vehicle, characterized in that: it includes a central PLC, an RGV vehicle PLC controller, an inverter, a relay, a traveling motor, a lifting motor, a track, a battery, a carbon brush, and a pantograph; wherein, the central PLC is a computer cluster or a computer terminal, and the central PLC uniformly manages the PLC controllers of each RGV vehicle; the RGV vehicle PLC controller is composed of a controller, an arithmetic unit, and a register, and the circuits of the controller, the arithmetic unit, and the register are all integrated on one chip and are connected to the input / output interface circuit of the memory through an address bus and a control bus; the main circuit of the inverter is a power conversion part that provides a voltage-regulated and frequency-modulated power supply for the traveling motor, converts the power frequency power supply into DC power, and absorbs the "smoothing circuit" of the voltage pulsation generated in the converter and the inverter; the RGV vehicle PLC controller includes any one of Siemens PLC, Schneider PLC, Rockwell PLC, Delta PLC, and Galishi PLC, and the traveling motor includes a traveling motor with model RT-XZ300 or a YR355 traveling motor; it also includes the following control method: Step 1: The central PLC first receives a task requirement, performs scheduling algorithm calculation, determines the specified RGV for transportation, and sends a path instruction; A. The site data terminal performs site collection. Assuming there are N stations, the route of each RGV has N*(N - 1)*(N - 1) stations; B. The scheduling algorithm is divided into a single RGV corresponding to a single site, a single RGV corresponding to multiple sites, and multiple RGVs corresponding to multiple sites; Specific scheduling principles: First: A single RGV corresponding to a single site: Whoever issues the task first executes it first; Second: A single RGV corresponding to multiple sites: Whoever issues the task first executes it first; Third: Multiple RGVs corresponding to multiple sites: Queuing principle: When there are two or more RGVs waiting for tasks, queue calculations are performed on the RGVs in turn, which are divided into: calculating the process duration of each site according to the site information, sorting from small to large, and finding the shortest process duration; calculating the process duration of each site according to the site information, sorting from the average time from small to large, and replacing the smallest time with the time behind the largest time in the time sequence to find the intermediate process duration; calculating the process duration of each site according to the site information, sorting from large to small in time, and finding the longest process; after the process durations of each RGV are clear, judge whether the routes of the three times interfere. If they interfere, judge which route interferes. If all three routes interfere, replace them with the second-largest time and the route with the second-largest average number respectively until the routes do not interfere; if two routes interfere, replace the longer time first until the routes do not interfere; Step 2: After the RGV vehicle obtains the path instruction, the current on the pantograph is intercepted by the carbon brush on the RGV vehicle, and at the same time, the traveling motor and the lifting motor on the RGV vehicle will be in an energized state; Step 3: After the walking motor and the lifting motor are powered on, the central PLC sends the driving speed of each RGV car to each RGV car PLC controller. After the RGV car obtains the driving speed information, the frequency converter will control the walking motor to start and drive at the set speed. The RGV also feeds back the current path to the PLC in real time during transportation; Step 4: After the RGV car travels to the set position, the relay will control the lifting motor to pick up the items on the shelf at the same time. After the RGV car picks up the items, the relay will control the lifting motor to retract, and the frequency converter will restart the walking motor to let the RGV car travel along the track to the position where the items are to be put down. After the RGV car puts the items in the designated position, it will send its own position from the PLC controller to the central PLC through the communication module. At this time, the central PLC will reassign tasks to the RGV car.

2. A method for controlling an RGV car system according to claim 1, characterized in that: The communication module includes a local area network or a WLAN network.

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