A dynamic idle trolley cruising method

Abstract

The present application relates to a kind of dynamic idle trolley cruising methods, for material handling system, comprising the following steps: when a work area has new idle trolley, it is judged whether the new idle trolley is the only potential idle trolley of current work area;If new idle trolley is not the only potential idle trolley of current work area, it is judged whether there is work area without potential idle trolley in system;If there is work area without potential idle trolley in system, it is selected as target work area according to the priority order of task amount from high to low without potential idle trolley;And make the idle trolley that stays in current work area longest as mobile idle trolley, and drive to target work area.The present application optimizes the flowability of idle trolley in overall system.

Description

TECHNICAL FIELD

[0001] The present application relates to material handling scheduling technology, in particular to a dynamic idle overhead traveling crane (OHT) tour method. BACKGROUND

[0002] Through the control and scheduling of a software system, according to the instructions of a production system, automatic material handling and buffer storage between production line processes are realized, which is a common requirement in the production process.

[0003] Taking an automated material handling system (AMHS) as an example, the automated material handling system (AMHS) is an important technology in the development of the semiconductor industry. In the material handling and storage system, a plurality of machines and tracks form a work area (intrabay), and a high-speed transport track (interbay) is arranged in the center of the work area. The overhead traveling crane (OHT) is responsible for the handling work in the AMHS. To realize a safe and efficient handling function, each link needs to be controlled. The working state of the overhead traveling crane mainly includes a receiving task state, a delivering task state, and an idle state. Generally, after completing the delivery task, the overhead traveling crane will enter the idle state until it receives a task request again. How to arrange the tour scheme of the idle overhead traveling crane has a great influence on the efficiency of the overhead traveling crane receiving tasks and the smooth transportation of the working vehicles.

[0004] In the scheme for controlling the tour of the idle overhead traveling crane, a side lane or a fixed parking area is assumed to store the idle overhead traveling crane. This way will cause uneven distribution of idle overhead traveling cranes as the system runs, and the average receiving time is long. Further, such a scheme must set a large number of side lanes for parking idle overhead traveling cranes. Other schemes propose that, in the case of no parking area, the idle overhead traveling crane tours in the current work area or stays in place after completing the task. However, during the system operation, the generation and distribution of tasks are not uniform. Such a scheme will cause poor mobility of the idle overhead traveling crane.

[0005] In other production fields, if material handling and vehicle storage are required, similar technical problems will also exist. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application discloses a dynamic idle overhead traveling crane tour method.

[0007] The technical scheme adopted by the present application is as follows:

[0008] A dynamic idle overhead traveling crane tour method is used in a material handling system, the material handling system includes a plurality of work areas; there are idle overhead traveling cranes, delivery overhead traveling cranes, and / or receiving overhead traveling cranes in the work areas; the tour method includes the following steps:

[0009] When a new idle crane is added in a work area, it is determined whether the new idle crane is the only potential idle crane in the current work area; the potential idle crane is an idle crane and a put-away crane; if the new idle crane is the only potential idle crane in the current work area, the original state is maintained.

[0010] If the new idle crane is not the only potential idle crane in the current work area, it is determined whether there is a work area without a potential idle crane in the system; if there is a work area without a potential idle crane in the system, a target work area is selected in order of priority from high to low according to the task amount; and the idle crane with the longest stay time in the current work area is used as a mobile idle crane to move to the target work area.

[0011] Further technical solutions thereof are that when the mobile idle crane reaches the entrance of a passing work area during the movement to the target work area, it is determined whether the current passing work area is the target work area; if the current passing work area is the target work area, the mobile idle crane enters the target work area to patrol; if the current passing work area is not the target work area, the mobile idle crane continues to run to the next passing work area and determines whether it is the target work area.

[0012] Further technical solutions thereof are that the upper limit of the stay time of the idle crane in the work area is set to ;

[0013] When the mobile idle crane reaches the entrance of a passing work area, if it is determined that the current passing work area is not the target work area, it is determined whether there is a replaceable idle crane with a patrol time exceeding in the current passing work area; if there is a replaceable idle crane with a patrol time exceeding in the current passing work area, the mobile idle crane enters the current passing work area to replace the replaceable idle crane, and the replaceable idle crane continues to run to the next passing work area as a new mobile idle crane and determines whether it is the target work area; if there is no replaceable idle crane with a patrol time exceeding in the current passing work area, the mobile idle crane continues to run to the next passing work area and determines whether it is the target work area.

[0014] Further technical solutions thereof are that if there is no work area without potential idle cranes in the system, then in order of priority from high to low according to the task amount, it is judged in turn whether there is an idle crane position in the current highest priority work area category; if there is a work area with an idle crane position in the current highest priority work area category, then the work area with the least idle cranes is selected as the target work area, and if there is no work area with an idle crane position in the current highest priority work area category, then it is continued to judge whether there is an idle crane position in the next highest priority work area; if there is no idle crane position in all work area categories, then the original state is maintained.

[0015] Further technical solutions thereof are that the number of vehicles in the jth work area is recorded as , and the upper limit of potential idle cranes in the jth work area is .

[0016] After the mobile idle crane enters the target work area for cruising, it is judged whether the number of potential idle cranes in the target work area is greater than ; if the number of potential idle cranes in the target work area is greater than , then the idle cranes outside the target work area are prohibited from entering.

[0017] Further technical solutions thereof are that if the number of potential idle cranes in the target work area is greater than , then the idle cranes outside the current work area are allowed to be replaced with the idle cranes in the current work area, and after the put-away crane enters the current work area, the idle crane with the longest cruising time is designated as an out-of-limit condition state; and the crane in the out-of-limit condition state is taken as a new idle crane.

[0018] Further technical solutions thereof are that the maximum number of vehicles allowed to exist simultaneously in the jth work area is set as ; if the number of potential idle cranes in the target work area is not greater than , then it is judged whether the total number of vehicles in the target work area is greater than ; if the total number of vehicles in the target work area is greater than , then it is judged whether there is an idle crane in the target work area; if there is an idle crane in the target work area, then the idle crane with the longest cruising time is designated as an out-of-limit condition state; and the crane in the out-of-limit condition state is taken as a new idle crane; and if there is no idle crane in the target work area, then the original state is maintained.

[0019] Further technical solutions thereof are that the upper limit of the stay time of the idle crane in the work area is set as ; if it is judged that the total number of vehicles in the target work area is not greater than , then it is judged whether the stay time of the idle crane in the target work area is greater than If yes, the idle crane exceeding the upper limit of the stay time is designated as an exceeding limit condition state; and the crane in the exceeding limit condition state is added as an idle crane.

[0020] A further technical solution is that, in the step of maintaining the original state, if a new idle crane or a task crane enters the work area, the following steps are directly performed: judging whether the number of potential idle cranes in the target work area is greater than , judging whether the total number of cranes in the target work area is greater than , and / or judging whether the stay time of the moving idle crane in the target work area is greater than ; the task crane is a receiving crane or a delivery crane.

[0021] A further technical solution is that the system adjustable parameters can be adjusted to reduce the average receiving time without affecting the overall average delivery time; the system adjustable parameters are the upper limit of the potential idle cranes and the upper limit of the stay time of the idle crane in the work area ; the adjustment method is as follows:

[0022] The initial value of the system adjustable parameter is set, the average receiving time of the idle crane in the work area is counted, and the variance and average value are calculated;

[0023] The initial value is increased to obtain an adjusted value, and the variance and average value of the average receiving time are observed;

[0024] When the variance and average value are both reduced, it is determined that the adjusted value is better than the initial value;

[0025] When the variance and average value are both increased, the adjusted value is reduced, and the variance and average value of the average receiving time of the idle crane in each work area are observed again.

[0026] The beneficial effects of the embodiment of the present application are as follows:

[0027] The embodiment of the present application is designed for the cruising scheme of the idle crane, mainly optimizes the flowability of the idle crane in the overall system, sets the priority to allocate the idle crane by classifying the work areas according to the task amount, and sets some conditions to drive the idle crane to cruise in the overall system. It aims to reduce the receiving time of the idle crane, reduce the influence on the task crane, and improve the operation efficiency of the overall system. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a schematic diagram of the material handling system in the embodiment of the present application.

[0029] Figure 2This is a flowchart of the dynamic idle crane patrol method in an embodiment of the present invention. Detailed Implementation

[0030] Taking the semiconductor field as an example, most existing research on idle crane handling assumes the existence of side aisles or fixed parking areas for idle cranes. This approach not only leads to uneven distribution of idle cranes as the system operates, but also ignores the benefits of idle crane patrols in shortening the overall average receiving time. Furthermore, many crane system designs do not include a large number of side aisles for parking idle cranes.

[0031] Therefore, some other solutions address the issue of no parking areas by having idle cranes patrol the current work area after completing their tasks, or remain stationary while other task-carrying cranes push them forward. However, during system operation, task generation and distribution are not uniform. This can lead to situations where, in a patrol strategy, idle cranes tend to concentrate in certain work areas with high task loads, while in a push strategy, once a task-carrying crane completes its task, it may remain stationary and stop pushing the previous idle crane, causing an accumulation of idle cranes. Alternatively, the previous crane may pick up a task nearby, preventing subsequent idle cranes from reaching the task location.

[0032] Moreover, all of the above solutions for handling idle overhead cranes have neglected the liquidity of idle overhead cranes in the entire system.

[0033] This technical solution designs a patrol scheme for idle overhead cranes, primarily to optimize the mobility of idle cranes in the overall system. By classifying various work areas according to task volume, priority is set to allocate idle vehicles, and conditions are set to drive idle cranes to patrol throughout the system. The aim is to reduce the receiving time of idle cranes, minimize the impact on tasked cranes, and improve the overall system's operational efficiency.

[0034] Those skilled in the art will understand that although the embodiments of the present invention take a material handling system in the semiconductor industry as an example, the technical solution of the present invention can also be applied to similar material handling scenarios in other production fields.

[0035] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0036] Figure 1 This is a schematic diagram of a material handling system according to an embodiment of the present invention. The dynamic idle crane patrol method is used to control and schedule cranes in the material handling system. Figure 1 As shown, the material handling system comprises multiple intrabays, with a transport channel (interbay) located between two sets of intrabays. The intrabays are as follows: Figure 1a(1), a(2), b(1), etc. identified in the middle.

[0037] According to the task amount of the work area, the work area is classified into different area categories. At least one work area is included in each area category. The number of area categories can be determined according to the number of designed work areas. If the number of work areas is too small, no area category can be set. If the number of work areas is too large, more than two area categories can be divided. Figure 1 In the middle, the work area is divided into a class area and a b class area. The task amount of the work area in the a class area is more than that in the b class area. There are 4 work areas in the a class area, and 4 work areas in the b class area.

[0038] There are idle cranes, loading cranes and receiving cranes in the work area. Of course, during the operation of the system, due to the different receiving and loading states of the cranes, there may be only one or two of the idle cranes, the loading cranes and the receiving cranes in the work area.

[0039] Figure 2 The flow chart of the dynamic idle crane patrol method in the embodiment of the application is shown in FIG. 1. Figure 1 、 Figure 2 The number of vehicles in the jth work area is denoted as , the maximum number of vehicles allowed to exist simultaneously in the work area is , the upper limit of potential idle vehicles is , and the number of potential idle vehicles is the sum of the number of idle cranes and the number of loading cranes. Then The maximum number of vehicles and the upper limit of potential idle vehicles in different work areas can be set to different values. The upper limit of the idle crane staying time in the work area is T.

[0040] The maximum number of vehicles is the maximum number of cranes that can be accommodated in the work area according to the track length in the work area and the maximum speed allowed for the crane to travel. The upper limit of potential idle vehicles is the initial value set for each area category at the beginning of the system operation, which can be adjusted according to the actual operation in the future. The upper limit T of the idle crane staying time in the work area can also be adjusted according to the actual operation in the future. The purpose of adjustment is to reduce the average receiving time without affecting the overall average delivery time.

[0041] Further, the adjustment method of the upper limit of potential idle vehicles is as follows:

[0042] Set the initial , and calculate the variance and average value of the average receiving time of the idle cranes in each work area;

[0043] Increase the initial and get the adjusted Observe the variance and mean;

[0044] When both variance and mean decrease, the adjusted value is determined. Better than the initial and take it as a new ;

[0045] When both variance and mean increase, the adjusted... Decrease the variance and mean, and then observe them again.

[0046] Furthermore, examine whether the shorter receiving time in the work area is the cause. If the value is too high, the receiving time in the work area will increase. Therefore, adjustments will be made to individual work areas accordingly.

[0047] Furthermore, the method for adjusting the maximum dwell time T of an idle overhead crane in the work area is as follows:

[0048] Setting initial The average receiving time of idle overhead cranes in each work area was statistically analyzed, and the variance and mean were calculated.

[0049] Increase the initial And after adjustment Observe the variance and mean;

[0050] When both variance and mean decrease, the adjusted value is determined. Better than the initial and take it as a new ;

[0051] When both variance and mean increase, the adjusted... Decrease the variance and mean, and then observe them again.

[0052] Similarly, examine whether the work area has a shorter receiving time. If the value is too high, the receiving time in the work area will increase. Therefore, adjustments will be made to individual work areas accordingly.

[0053] If a parking area is provided within the work area, the idle overhead crane will patrol the work area for a predetermined time and then wait in the parking area. If there is no parking area, the idle overhead crane will patrol the work area for a predetermined time and then remain in the transport corridor, ready to be propelled by other task overhead cranes. Task overhead cranes include receiving overhead cranes and releasing overhead cranes. Based on this, the system executes... Figure 2 The diagram illustrates the dynamic idle crane traversal method. During the execution of this traversal method, when an idle crane receives a task assignment, such as a cargo receiving task, the task assignment is executed first.

[0054] like Figure 2 As shown, the dynamic idle crane patrol method includes the following steps:

[0055] S0, the system starts running, all cranes enter the track. And set the maximum number of vehicles in each work area , the upper limit of potential idle vehicles and the upper limit of the time of idle cranes in the work area T.

[0056] S1, when a new idle crane is added to a work area, determine whether the new idle crane is the only potential idle crane in the current work area. The potential idle crane is the idle crane and the put-away crane. The new idle crane also includes the case where it is designated as a new idle crane due to exceeding the limit condition in the subsequent step.

[0057] If the new idle crane is the only potential idle crane in the current work area, the new idle crane remains in the current work area and maintains its original state. At this time, if a new idle crane or a task crane enters the work area, proceed to step S5. The task crane refers to a pick-up crane or a put-away crane.

[0058] If the new idle crane is not the only potential idle crane in the current work area, proceed to step S2.

[0059] S2, determine whether there is a work area in the system that has no potential idle crane.

[0060] If there is a work area in the system that has no potential idle crane, in order of priority from high to low according to the task amount of the area category to which the work area belongs, investigate whether there is a work area that has no potential idle crane, and select the work area with the highest task amount that has no potential idle crane as the target work area. In this embodiment, the work areas are divided into a class a region and a class b region according to the task amount from high to low, the task amount of the class a region is greater than that of the class b region, then according to the order of the class a region first and the class b region second, select the work area that has no potential idle crane as the target work area. And make the idle crane that stays in the current work area the longest as the moving idle crane, and drive it to the target work area, proceed to step S3.

[0061] If there is no work area in the system that has no potential idle crane, proceed to step S8.

[0062] S3, when the moving idle crane drives to the target work area, it arrives at the entrance of a passing work area, and determines whether the current passing work area is the target work area.

[0063] If the current passing work area is the target work area, the moving idle crane enters the target work area and patrols, and proceeds to step S5.

[0064] If the current passing work area is not the target work area, proceed to step S4.

[0065] S4, judging whether there is a replaceable idle trolley with a cruising time over .

[0066] If there is a replaceable idle trolley in the current passing work area, the idle trolley is moved into the current passing work area, and the replaceable idle trolley is replaced. The replaceable idle trolley continues to run to the next passing work area as a new idle trolley, and it is judged whether it is the target work area.

[0067] If there is no replaceable idle trolley in the current passing work area, the idle trolley directly continues to run to the next passing work area, and step S3 is entered.

[0068] S5, judging whether the number of potential idle trolleys in the target work area is greater than .

[0069] If the number of potential idle trolleys in the target work area is greater than , the idle trolley outside the target work area is prohibited from entering. The idle trolley outside the current work area is allowed to replace the idle trolley inside the current work area, and after the delivery trolley enters the current work area, the idle trolley with the longest cruising time is designated as an out-of-limit condition state. The trolley in the out-of-limit condition state is taken as a new idle trolley, and step S1 is entered.

[0070] If the number of potential idle trolleys in the target work area is not greater than , step S6 is entered.

[0071] In this paragraph or other places in this article, "not greater than" means less than or equal to. "Greater than" does not include the case of being equal.

[0072] S6, judging whether the total number of trolleys in the target work area is greater than .

[0073] If the total number of trolleys in the target work area is greater than , it is judged whether there is an idle trolley in the target work area. If there is an idle trolley in the target work area, the idle trolley with the longest cruising time is designated as an out-of-limit condition state. The trolley in the out-of-limit condition state is taken as a new idle trolley, and step S1 is entered. If there is no idle trolley in the target work area, the original state is maintained, and if a new idle trolley or task trolley enters the work area, step S5 is entered.

[0074] If the total number of trolleys in the target work area is not greater than , step S7 is entered.

[0075] S7, judging whether the stay time of the moving idle trolley in the target work area is greater than .

[0076] If the mobile idle crane stays in the target work area for a longer period of time than If the condition is not met, the idle crane will be designated as being in an "exceeding the limit" state. The crane in the "exceeding the limit" state will then be added as a new idle crane, and the process will proceed to step S1.

[0077] If the time the mobile idle overhead crane spends in the target work area is no greater than If the current state remains unchanged, and a new idle crane or task crane enters the work area, then proceed to step S5.

[0078] S8. Determine if there are any vacant overhead crane positions in the work area of ​​type a region.

[0079] If there are available overhead crane locations in a work area within a Class A region, the moved available overhead crane will be assigned to the work area within Class A region with the fewest potential available overhead crane locations. If all work areas within a Class A region have the same available overhead crane location, the nearest work area will be selected.

[0080] If there are no available overhead crane positions in any work area of ​​type a region, proceed to step S9.

[0081] S9. Determine whether there are any vacant overhead crane positions in the work area of ​​type b region.

[0082] If there are available overhead crane locations in a work area of ​​type b, the available overhead crane will be assigned to the work area in type b with the fewest potential available overhead crane locations. If all work areas in type b have the same available overhead crane locations, the nearest work area will be selected.

[0083] If there are no available overhead crane positions in all work areas of type b, then maintain the original state. If a new available overhead crane or a task overhead crane enters the work area, then proceed to step S5.

[0084] The above steps S8 and S9 are because in the present embodiment, the work area is divided into a type a region and a type b region. Of course, when the number of work areas in the system is large, there can be more classifications of work areas. At this time, if there is no work area without a potential idle crane in the system, in step S8 and the steps after S8, it is judged whether there is a work area with an idle crane position in the current highest priority work area category in the order of priority from high to low according to the task amount. If there is a work area with an idle crane position in the current highest priority work area category, the work area with the least potential idle crane in the current highest priority work area category is selected as the target work area, and if the number of potential idle cranes in all work areas is the same, a work area is selected as the target work area. If all work areas in the current highest priority work area category do not have an idle crane position, it is continued to judge whether there is a work area with an idle crane position in the next highest priority work area category. If there is no work area with an idle crane position in all work area categories, the original state is maintained.

[0085] In the process of executing steps S1-S9, the idle crane at any stage receives a task instruction, and the process ends, and the task instruction is executed preferentially.

[0086] Figure 2 The flowchart shown is a preferred embodiment of the dynamic idle crane patrol method in the present application. In the present embodiment, the scheme divides the region categories according to the task amount of different work areas, so that the idle crane can be preferentially allocated to the work area with a large task amount. The maximum number of vehicles in each work area , the upper limit of the potential idle crane , and the upper limit T of the idle crane staying time in the work area are set to drive the idle crane to dynamically patrol in the entire system.

[0087] In this process, a step of exchanging the patrol task of the idle crane in the work area according to time is also set, which further improves the mobility of the idle crane.

[0088] However Figure 2 The embodiment shown is a preferred embodiment, and is not a limitation on the present technology. Those skilled in the art can understand that in actual work, only part of the steps in Figure 2 may be implemented according to needs, which can also optimize the patrol method of the idle crane to a certain extent and obtain corresponding technical effects relative to the prior art. As long as the implemented part of the steps is relatively complete, logically closed, and can ensure normal operation of the system.

[0089] For example, in one embodiment, only steps S1, S2 and S3 are used, that is, the region categories are divided according to the task amount of different work areas, so that the idle overhead hoists can be preferentially allocated to the work areas with large task amount, thereby improving the operation efficiency of the system to a certain extent.

[0090] For example, in one embodiment, only steps S1 to S5 are used, by setting the upper limit of the potential idle hoists and adding the replacement step of the idle overhead hoist with excessively long cruising time, the mobility of the idle overhead hoists can be improved to a certain extent, and the operation efficiency of the system can be improved.

[0091] The technical solutions of the present application will be further described below through a specific embodiment.

[0092] Please refer to Figure 1 and Figure 2 . In Figure 1 , there are 8 work areas, which are divided into a-class regions and b-class regions according to the task amount. The work areas in each region are represented by the numbers in the brackets. For example, the work areas in the a-class regions include a(1), a(2), a(3) and a(4).

[0093] The initial setting of the upper limit of the potential idle hoists in the a-class regions is 2, and the upper limit of the potential idle hoists in the b-class regions is 1. Different colors are used to represent different states of the overhead hoists, yellow for the hoists receiving goods, red for the hoists delivering goods, and blue for the idle hoists. In this embodiment, the dynamic idle hoist cruising method includes:

[0094] S1a, there is a new idle hoist OHT8 in the work area b(1), and it is judged that the new idle hoist OHT8 is not the only potential idle hoist in the work area b(1), so step S2a is entered.

[0095] S2a, it is judged that there is a work area b(4) without potential idle hoists in the system, and the work area b(4) is taken as the target work area. And the idle hoist OHT21 with the longest residence time in the work area b(1) is taken as the mobile idle hoist, and drives to the target work area b(4).

[0096] S3a, the mobile idle hoist OHT21 arrives at the entrance of the work area a(3), and it is judged that the work area a(3) is not the target work area.

[0097] S4a, it is judged that there is a replaceable idle hoist OHT20 in the work area a(3) with cruising time exceeding . OHT21 and OHT20 exchange tasks, and OHT20 goes to the work area b(4) as a new mobile idle hoist.

[0098] The technical solutions of the present application will be further described below through another specific embodiment. Please refer to Figure 1 and Figure 2 In the present embodiment, the dynamic idle overhead traveling method comprises:

[0099] S1b, there is a new idle overhead OHT 24 in the work area b (3), and it is determined that the new idle overhead OHT 24 is not the only potential idle overhead in the work area b (3), and step S2b is entered.

[0100] S2b, it is determined that there is no work area without a potential idle overhead in the system. At this time, step S8b is entered.

[0101] S8b, it is determined that there is no idle overhead position in the a-type area. Step S9b is entered.

[0102] S9b, it is determined that there is no idle overhead position in the b-type area, and the original state is maintained. The overhead OHT 24 and the overhead OHT 23 are both maintained to travel in the work area b (3). At this time, if a new demand, i.e. a task, appears, the task is preferentially executed, and the overhead OHT 23 with a longer traveling time is allocated to the work area with the demand.

[0103] The above description is an explanation of the present application, not a limitation of the application. The scope of the present application is defined in the claims. The present application can be modified in any form without departing from the basic structure of the present application.

Claims

1. A method for dynamic idle crane patrol, characterized in that, For a material handling system, the material handling system includes multiple work areas; within each work area are idle overhead cranes, unloading overhead cranes, and / or receiving overhead cranes; the patrol method includes the following steps: When a new idle overhead crane is added in a work area, it is determined whether the newly added idle overhead crane is the only potential idle overhead crane in the current work area; the potential idle overhead crane is an idle overhead crane and a cargo release overhead crane; if the newly added idle overhead crane is the only potential idle overhead crane in the current work area, the original state is maintained. If the newly added idle crane is not the only potentially idle crane in the current work area, then it is determined whether there is a work area in the system without potentially idle cranes. If there is a work area in the system without potentially idle cranes, then work areas without potentially idle cranes are examined in descending order of task volume and selected as target work areas. The idle crane with the longest dwell time in the current work area is then designated as a mobile idle crane and driven towards the target work area. When the mobile idle crane reaches the entrance of a work area it passes by on its way to the target work area, it is determined whether the currently passed work area is the target work area. If the currently passed work area is the target work area, the mobile idle crane enters the target work area for patrol. If the currently passed work area is not the target work area, it continues to the next passed work area and determines whether it is the target work area. The upper limit for the dwell time of an idle crane in a work area is set to [value missing]. When the mobile idle crane arrives at the entrance of a passing work area, if it determines that the currently passing work area is not the target work area, it then determines whether there is a work area in the currently passing work area where the patrol time has exceeded the limit. Available idle overhead cranes can be replaced if there are cranes in the work area that have been in transit for more than [time period missing]. If a replaceable idle overhead crane is found, the moving idle overhead crane enters the currently passing work area and swaps with the replaceable idle overhead crane. The replaceable idle overhead crane then becomes the new moving idle overhead crane and continues to the next passing work area, determining whether it is the target work area. If there is no work area in the currently passing work area where the patrol time has exceeded [a certain threshold], [the text continues with further steps]. If a replaceable idle crane is found, the idle crane will continue to run to the next passing work area and determine whether it is the target work area.

2. The dynamic idle crane patrol method according to claim 1, characterized in that: If there is no work area in the system without potential idle overhead cranes, then in order of priority from high to low task volume, check whether there are any idle overhead crane positions in the current highest priority work area category. If there is a work area with available overhead crane positions in the current highest priority work area category, then the work area with the fewest available overhead crane positions is selected as the target work area. If there is no work area with available overhead crane positions in the current highest priority work area category, then the next second highest priority work area is checked for available overhead crane positions. If there are no available overhead crane positions in all work area categories, then the original state is maintained.

3. The dynamic idle crane patrol method according to claim 1, characterized in that: The number of vehicles in the j-th work area is denoted as The upper limit of potential idle overhead cranes in the j-th work area is ; After the mobile idle crane enters and patrols the target work area, determine whether the number of potential idle cranes in the target work area is greater than [the number of cranes]. If the number of potentially idle overhead cranes in the target work area is greater than If so, then idle overhead cranes outside the target work area are prohibited from entering.

4. The dynamic idle crane patrol method according to claim 3, characterized in that: If the number of potentially idle overhead cranes in the target work area is greater than It allows idle overhead cranes outside the current work area to be swapped with idle overhead cranes within the current work area, and after a cargo-delivery overhead crane enters the current work area, the idle overhead crane with the longest patrol time is designated as exceeding the restriction condition state; and the crane in the exceeding the restriction condition state is designated as a newly added idle overhead crane.

5. The dynamic idle crane patrol method according to claim 3, characterized in that: Let the maximum number of vehicles allowed to exist simultaneously in the j-th work area be . If the number of potentially idle overhead cranes in the target work area is no greater than Then determine whether the total number of vehicles in the target work area is greater than If the total number of vehicles in the target work area is greater than If there is an idle overhead crane in the target work area, then determine whether there is an idle overhead crane. If there is an idle overhead crane in the target work area, then designate the idle overhead crane with the longest patrol time as the one that exceeds the limit condition. Then, add the crane that exceeds the limit condition as a new idle overhead crane. If there is no idle overhead crane in the target work area, then keep the original state.

6. The dynamic idle crane patrol method according to claim 4, characterized in that: Set the maximum time that an idle overhead crane can stay in the work area to be [specified value]. If the total number of vehicles in the target work area is determined to be no greater than Then determine whether the idle crane stays in the target work area for more than [time value missing]. If so, it will exceed the maximum stay time limit. Idle overhead cranes are designated as being in an out-of-limits state; and cranes in the out-of-limits state are added as new idle overhead cranes.

7. The dynamic idle crane patrol method according to any one of claims 1 to 6, characterized in that: If, during the process of maintaining the original state, a new idle crane or task crane enters the work area, then a direct check is performed to determine whether the number of potential idle cranes in the target work area is greater than [the number of cranes in the target work area]. Determine whether the total number of vehicles in the target work area is greater than 1. And / or determine whether the dwell time of the mobile idle crane in the target work area is greater than The steps are as follows; the overhead crane in question is either a receiving overhead crane or a releasing overhead crane.

8. The dynamic idle crane patrol method according to claim 3, 5, or 6, characterized in that: The system's adjustable parameters can be adjusted to reduce the average receiving time without affecting the overall average delivery time; these adjustable parameters represent the potential idle crane upper limit. The maximum time that an idle overhead crane can stay in the work area. The adjustment method is as follows: Set initial values ​​for the system's adjustable parameters, and calculate the average receiving time of idle overhead cranes in the work area, as well as the variance and average. Increase the initial value and obtain the adjusted value, then observe the variance and mean of the average receiving time; When both variance and mean decrease, the adjusted value is considered to be better than the initial value. When both variance and mean increase, the adjusted values ​​are decreased, and the variance and mean of the average receiving time of idle overhead cranes in each work area are observed again.

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