Large-flow circular shuttle vehicle dynamic control method based on closed three-branch grid framework

Abstract

The invention discloses a large-flow circular shuttle vehicle dynamic control method based on a closed three-branch grid framework, which comprises the following steps: establishing a road three-branch grid model of a circular shuttle vehicle, the model comprises a shunting turnout and a converging turnout which are respectively provided with three line segments, and the shunting turnout and the converging turnout are used for representing a fork; the line segment represents a channel of the circular shuttle vehicle; based on a three-branch grid model, the method for dynamically managing the shuttle vehicle through a control system comprises the steps that a main control unit distributes a control unit of an area to which the shuttle vehicle belongs and a current line segment to the shuttle vehicle in real time according to the destination of the shuttle vehicle and the current real-time traffic condition; the area control unit calculates the maximum limiting speed of the vehicle according to a nearest distance dynamic algorithm based on the vehicle task target position, the line segment end point and the front vehicle distance; and when the distance between the front vehicle and the vehicle is suddenly changed, the vehicle control unit performs amplitude limiting and compensation on the suddenly changed original control speed of the vehicle in the line segment according to a natural constant exponentiation speed curve control method, so that the running efficiency and the stability of the shuttle vehicle are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of logistics and transportation automation, and specifically relates to a dynamic control method for a large-flow circular shuttle vehicle based on a closed three-way grid architecture. Background Art

[0002] In automated logistics systems, it is often necessary to achieve efficient, reliable, and large-scale material handling between multiple areas. The circular shuttle system equipped with a switch mechanism and track switching capability can meet the needs of large-scale, multi-regional large-volume material handling operations due to its variable paths and flexible operations. It is an important automated equipment for solving material transportation in large logistics systems. The current mainstream large-volume circular shuttle system's loop layout is mostly composed of a varying number of three-way intersections and the closed line segments between them. The number of diverging forks is the same as the number of converging forks, and the distribution of vehicles in these segments is dynamically changing. This system has a flexible and diverse path combination, which makes it very complicated to uniformly communicate and dispatch vehicles. How to efficiently and reliably control the shuttle to automatically run between the entire loop area is the key control technology of this type of circular shuttle system. At present, the centralized control mode based on the warehouse control system (WCS) is mainly used to control such systems. The main dispatching control module of the system is responsible for the communication, location, task scheduling and other controls of vehicles in all areas of the entire system. When facing a large system with a large number of vehicles and turnout nodes, the computing and communication load of the entire system is large, and the system flexibility is insufficient. When the process layout is adjusted, the adaptability is low and the system transformation is difficult. The reason for centralized control also means that all vehicle operations need to consider global factors, which is not conducive to the flexible switching of vehicle target positions, the vehicle spacing control is complex, and the efficiency of following vehicle control in the system is not high.

[0003] In addition, in such large-volume circular shuttle systems, the order and position of vehicles are always in a process of random change, and the vehicle running speed will undergo a short mutation due to these changes, which has a certain impact on the mechanical structure of the vehicle and the material posture. The current vehicle speed control method of the circular shuttle control system is basically based on the control technology of the target remaining distance. In a large-volume multi-turnout system with complex track path changes and variable front vehicle conditions, the adaptability is insufficient and the control efficiency is low. At present, the mainstream treatment method for the above-mentioned speed mutation problem is to rely on motion controllers such as inverters to perform secondary compensation for speed mutations, but the processing effect varies due to hardware differences, and the vehicle control debugging is complex and the implementation workload is large.

[0004] With the rapid development of computer control technology, the computing power of programmable controllers in the current industrial control field has been greatly improved. The Boolean and floating-point computing capabilities of the current mainstream programmable controllers have reached the ns level, and the industrial communication bus has also reached a gigabit rate and ms response time; the powerful controller computing power and high-bandwidth, short-delay multi-node communication capabilities have created conditions for the decentralized dynamic control of large-scale systems, thereby optimizing the control method of the original large-flow transfer circular shuttle system, solving the shortcomings of the original control technology, and realizing the efficient and reliable operation of such automated logistics systems. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, in view of the above technical background, the present invention proposes the following solutions:

[0006] The present invention provides a dynamic control method for a large-flow circular shuttle vehicle based on a closed three-way grid architecture, comprising:

[0007] S10, establishing a three-way grid model of the road for the circular shuttle, wherein the three-way grid model includes an equal number of diverging turnouts and merging turnouts, each diverging turnout is provided with three line segments, each merging turnout is provided with three line segments, and the three-way grid model is further provided with a starting line segment and an ending line segment, wherein the diverging turnouts and the merging turnouts are used to represent the forks of the circular shuttle, and the line segments are used to represent the passages of the circular shuttle;

[0008] S20, based on the three-way grid model, dynamically manage the shuttle through the control system, including:

[0009] S201, the main control unit allocates the regional control unit and the current line segment to the shuttle in real time according to the shuttle destination and the current real-time traffic conditions;

[0010] S202, the regional control unit establishes a dynamic vehicle container for each line segment, and dynamically controls the vehicle queue within the line segment;

[0011] S203, the regional control unit calculates the maximum speed limit of the vehicle according to the shortest distance dynamic algorithm based on the vehicle mission target position, the end point of the line segment and the distance to the preceding vehicle;

[0012] S204. When the distance between the current vehicles suddenly changes, the vehicle control unit limits and compensates for the sudden change in the original control speed of the vehicles in the line segment according to the speed curve control method based on the natural constant power operation, wherein the control system includes a main control unit, a regional control unit and a vehicle control unit, wherein the vehicle control unit manages the vehicles in the line segment with the line segment as the management unit, and the regional control unit manages the vehicle control units on the line segment in the area pre-divided by the main control unit, the main control unit is connected to the regional control unit where the vehicles are running in the line segment, and the main control unit is also directly connected to the vehicle control unit located in the turnout range, and the vehicle control unit located in the line segment is only connected to the regional control unit that manages the line segment, and the shuttle vehicle is the vehicle.

[0013] In one embodiment of the present invention, S201, the main control unit allocates the regional control unit and the current line segment to the shuttle in real time according to the shuttle destination and the current real-time traffic conditions, including:

[0014] The main control unit splits and formulates the vehicle route in real time according to the current real-time traffic conditions, the current position of the vehicle and the vehicle's mission destination, with the time to pass the current segment as the splitting period and the segment as the splitting unit, and assigns the shuttle vehicle to the corresponding area control unit and the current segment until the vehicle reaches the segment to which the vehicle's mission destination belongs.

[0015] In one embodiment of the present invention, S202, the regional control unit establishes a dynamic vehicle container for each line segment and dynamically controls the vehicle queue in the line segment, including:

[0016] The regional control unit performs communication and dispatch control based on line segments, and establishes a dynamic vehicle container pool for each line segment. The vehicle container pool scans the vehicle tasks and vehicle position sorting queues within the line segment in real time.

[0017] In one embodiment of the present invention, S203, the regional control unit calculates the maximum speed limit of the vehicle based on the vehicle mission target position, the end point of the line segment and the distance to the preceding vehicle according to the shortest distance dynamic algorithm, including:

[0018] Step 1, the regional control unit dynamically determines the vehicle's current running target on the current line segment based on the vehicle's mission target position until the vehicle reaches the vehicle's mission target position;

[0019] Step 2: Based on the current running target of the vehicle on the current line segment, the maximum speed limit of the vehicle is calculated according to the preset safety time interval;

[0020] Step 3: When there is a speed limit area on a curve in the line segment, a preset speed limit ratio is added to the maximum speed limit in step 2.

[0021] In one embodiment of the present invention, step 1, the regional control unit dynamically determines the vehicle current running target of the vehicle in the current line segment based on the vehicle mission target position until the vehicle reaches the vehicle mission target position, including:

[0022] When the vehicle's mission target position is outside the current line segment and there is no preceding vehicle, the end point of the current line segment is used as the vehicle's current running target;

[0023] When the vehicle's mission target position is outside the current line segment and there is a preceding vehicle, the position of the preceding vehicle's rear end is used as the vehicle's current running target;

[0024] When the vehicle mission target position is within the current line segment and there is no preceding vehicle, the vehicle mission target position is used as the current running target of the vehicle;

[0025] When the vehicle mission target position is within the current line segment and there is a preceding vehicle, the position closer to the vehicle between the vehicle mission target position and the rear of the preceding vehicle is selected in real time as the vehicle's current running target;

[0026] For vehicles located at a three-way intersection, the starting point of the next line segment after the vehicle passes the fork is used as the vehicle's current running target.

[0027] In one embodiment of the present invention, step 2, based on the current running target of the vehicle on the current line segment, calculating the maximum speed limit of the vehicle according to the preset safety time interval, includes:

[0028] The distance between the current running target of the vehicle and the current position of the vehicle in step 1 is used to find the quotient with the preset safety time distance in real time; or the distance between the current running target of the vehicle and the current position of the vehicle in step 1 and the preset safety distance are used to obtain the dynamic maximum speed limit of the vehicle.

[0029] In one embodiment of the present invention, S204, when the distance between the front vehicle and the vehicle suddenly changes, the vehicle control unit limits and compensates the original control speed sudden change of the vehicle in the line segment according to the speed curve control method based on the natural constant power operation, including:

[0030] According to the original control speed v that causes the vehicle speed mutation f The absolute difference v between the actual speed v0 of the current vehicle Δ The size determines whether to start the variable speed smooth speed control. Δ If it is greater than the judgment threshold, the speed regulation is started, and the speed value v at the end of each calculation cycle is calculated according to the following formula s :

[0031]

[0032] v sIndicates the speed value calculated in the current calculation cycle, v (s-1) Indicates the speed value calculated in the previous calculation cycle; T s represents the calculation cycle interval of each program preset in the speed controller in the vehicle control unit; T0 represents the control start time; T f represents the control end time; e is a natural constant; k is a speed change smoothing coefficient, and the original control speed is the vehicle control speed obtained based on the maximum speed limit of the vehicle in the line segment.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The dynamic control method for a large-volume circular shuttle vehicle with a closed three-way grid structure provided by the present invention establishes a three-way grid model of a circular shuttle vehicle, simplifies the circular line system into a microscopic environment in which all vehicles are dynamically controlled in each line segment and each three-way intersection in the entire system circular line, establishes a three-level control system to simplify the entire complex vehicle control management into a distributed control for regional management of a single or several line segments, all regional control units operate in parallel, the calculation time is short, the control real-time performance is high, the management load of the entire system is reduced, and the operation efficiency of the large-volume circular shuttle vehicle system is improved. When the distance between the front vehicles suddenly changes, the vehicle control unit limits and compensates for the original control speed mutation of the vehicle in the line segment according to the speed curve control method based on the natural constant power operation, so that the vehicle runs smoothly and the stability of the vehicle operation is improved.

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flow chart of a method for dynamically controlling a large-flow circular shuttle vehicle based on a closed three-branch grid architecture provided by an embodiment of the present invention;

[0037] Figure 2 (a) is a schematic diagram of the layout of a large flow circular shuttle vehicle according to an embodiment of the present invention. Figure 2 (b) is a method for dynamically controlling a large flow circular shuttle vehicle according to an embodiment of the present invention. Figure 2 (a) Simplified structural diagram using the three-branch grid model;

[0038] Figure 3 It is a schematic diagram of the structure of a control system in a dynamic control method for a large-flow circular shuttle vehicle based on a closed three-way grid architecture provided by an embodiment of the present invention;

[0039] Figure 4 It is a schematic diagram of the interaction between three levels of the control system in a dynamic control method for a large-flow circular shuttle vehicle based on a closed three-way grid architecture provided by an embodiment of the present invention;

[0040] Figure 5 It is a flow chart of the regional control unit dynamically determining the current operation target of the vehicle in the current line segment based on the vehicle mission target position;

[0041] Figure 6 It is a schematic diagram of a flow chart of limiting and compensating the original control speed of a vehicle based on a natural constant power operation speed curve control method provided by an embodiment of the present invention;

[0042] Figure 7 It is a curve diagram of calculating the smooth control speed based on the natural constant power operation speed curve control method in an embodiment of the present invention to limit and compensate for the original control speed mutation. DETAILED DESCRIPTION

[0043] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the scheme according to the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0044] The above and other technical contents, features and effects of the present invention are clearly presented in the following detailed description of the specific implementation modes in conjunction with the accompanying drawings. Through the description of the specific implementation modes, the technical means and effects adopted by the present invention to achieve the predetermined purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and explanation purposes and are not used to limit the technical solutions of the present invention.

[0045] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or equipment including a series of elements not only includes those elements, but also includes other elements that are not clearly listed. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the article or equipment including the elements. The term "and / or" is used to describe the association relationship of associated objects in this article, for example, it means that there can be three kinds of relationships between the front and back associated objects, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally represents that the front and back associated objects are in an "or" relationship.

[0046] Please refer to Figure 1 , Figure 11 is a flow chart of a method for dynamically controlling a large-flow circular shuttle vehicle based on a closed three-way grid architecture provided by an embodiment of the present invention. The method for dynamically controlling a large-flow circular shuttle vehicle based on a closed three-way grid architecture comprises the following steps:

[0047] S10, establishing a three-way grid model of the road for the circular shuttle vehicle;

[0048] The shuttle is a vehicle. The loop layout of the large-volume circular shuttle system is composed of three-way intersections of varying numbers and the line segments between them. These three-way intersections and line segments constitute a closed grid structure. The present invention uses the characteristics that the number of diverging forks in the three-way grid is the same as the number of merging forks, and the starting and ending points of the line segments are unique, to simplify the complex and large loop layout of the large-volume circular shuttle system into a closed three-way grid structure. A three-way grid model is established for the entire large-volume circular shuttle system with each three-way intersection as a node. The three-way grid model includes an equal number of diverging turnouts and merging turnouts. The diverging turnouts and merging turnouts are used to characterize the forks of the circular shuttle. Each diverging turnout is provided with three line segments, and each merging turnout is provided with three line segments. The line segments are used to characterize the channels of the circular shuttle. Specifically, the control of the large and complex loop system is simplified to relatively independent traffic control and task scheduling for all vehicles in the system in the microscopic environment of a single line segment and a three-way intersection in the entire loop. Formulate standard control logic for shuttle vehicles in a single line segment. The number of diverging turnouts and merging turnouts in the three-way grid is equal. Each line segment is defined by a unique starting point and end point, which are the confluence and bifurcation points of the three-way intersection. The position code of each line segment is unique in the entire loop, and the position of the vehicle in the entire loop is also non-repetitive. Furthermore, the three-way grid model is also set with a starting line segment and an ending line segment. Based on this logic, all vehicles in the entire system are positioned and sorted in each line segment and three-way intersection. The number of vehicles in a line segment is not limited and can be equal to the maximum number of vehicles in the system. The number of vehicles in a three-way intersection cannot be greater than 1. Please refer to Figure 2 , Figure 2 (a) is a schematic diagram of the layout of a large flow circular shuttle vehicle according to an embodiment of the present invention. Figure 2 (b) is a method for dynamically controlling a large flow circular shuttle vehicle according to an embodiment of the present invention. Figure 2 (a) is a simplified schematic diagram of the structure using the three-branch grid model. Figure 2 In (b), each gray circle represents a bifurcation point at a three-way intersection, each white circle represents a confluence point at a three-way intersection, the arrow is the direction of vehicle movement, and the current line segment number is marked in the middle of the arrow.

[0049] S20, based on the three-way grid model, dynamically manage the shuttle through the control system;

[0050] like Figure 3 As shown, the control system includes a main control unit, a regional control unit and a vehicle control unit. The vehicle control unit manages the vehicles in the line segment with the line segment as the management unit. The regional control unit manages the vehicle control units on the line segment in the area pre-divided by the main control unit. The main control unit is connected to the regional control unit where the vehicle is running in the line segment. The main control unit is also directly connected to the vehicle control unit located within the turnout range. The vehicle control unit located in the line segment is only connected to the regional control unit that manages the line segment. The regional control unit can be one or N, N is an integer greater than 1, and the vehicle control unit can be one or n, n is an integer greater than 1. In this embodiment, the regional control unit is 4, that is, N=4, and the vehicle control unit is 7, that is, n=7. Based on the three-way grid model, the shuttle vehicle is dynamically managed through the control system, which specifically includes:

[0051] S201, the main control unit allocates the regional control unit and the current line segment to the shuttle in real time according to the shuttle destination and the current real-time traffic conditions;

[0052] The dynamic control method of a large-flow circular shuttle vehicle based on a closed three-branch grid architecture uses a control system for dynamic control.

[0053] In the dynamic control method for a large-volume circular shuttle based on a closed three-way grid architecture provided in this embodiment, a main control unit interacts with a regional control unit with a vehicle in a line segment. The main control unit splits and formulates the vehicle route in real time according to the current real-time traffic conditions, the current position of the vehicle and the shuttle mission destination, with the time of passing the current line segment as the splitting period and the line segment as the splitting unit, and allocates the regional control unit and the current line segment to the shuttle until the vehicle reaches the line segment to which the vehicle mission destination belongs.

[0054] S202, the regional control unit establishes a dynamic vehicle container for each line segment, and dynamically controls the vehicle queue within the line segment;

[0055] The regional control unit performs communication and dispatch control based on line segments, and establishes a dynamic vehicle container pool for each line segment. The vehicle container pool scans the vehicle tasks and vehicle position sorting queues within the line segment in real time.

[0056] Each regional control unit performs dynamic sorting control management on a single or several segments in accordance with the standard control logic established above. Each segment is isolated at the control level and does not interact with each other. When the control system is running, the number of vehicles in the segment increases or decreases at any time, and the regional control unit dynamically adjusts the sequence of vehicles in the segment accordingly. The vehicle is controlled by the main control unit only when it is within the range of the three-way intersection, and is only controlled by the regional control unit when it is in each segment. This dynamic control method for high-flow circular shuttle vehicles based on a closed three-way grid architecture reduces the management load of the entire control system by simplifying the control logic of each regional control unit, and improves the operating efficiency of the high-flow circular shuttle vehicle system.

[0057] For details, please refer to Figure 4 , Figure 4 It is a schematic diagram of the interaction between the three levels of the control system in a dynamic control method for a large-flow circular shuttle vehicle based on a closed three-way grid architecture provided by an embodiment of the present invention, that is, a schematic diagram of the interaction between the main control unit, the regional control unit, and the vehicle control unit. Specifically, vehicles 01, 05, and 02 are the abbreviations of vehicles with vehicle serial numbers 01, 05, and 02, respectively, and so on, and the abbreviations are not repeated below. Vehicles 01, 05, and 02 are located in "Segment 01" between the curved track of "Turnout 01" and the straight track of "Turnout 02". Their vehicle control units interact with the regional control unit of "Segment 01" (the abbreviation of line segment 01, similar content will not be explained again), and the regional control unit of "Segment 01" interacts with the main control unit; vehicles 06 and 04 are located in "Segment 02" between the straight track of "Turnout 01" and the curved track of "Turnout 02", and their vehicle control units interact with the regional control unit of "Segment 02", and the regional control unit of "Segment 02" interacts with the main control unit; vehicle 03 is located in "Turnout 02", and its vehicle control unit interacts directly with the main control unit; there is no vehicle in "Segment n" between "Turnout 02" and "Turnout n", and the regional control unit of "Segment n" does not interact with the main control unit.

[0058] S203, the regional control unit calculates the maximum speed limit of the vehicle according to the shortest distance dynamic algorithm based on the vehicle mission target position, the end point of the line segment and the distance to the preceding vehicle;

[0059] For shuttles running in a large-volume circular shuttle system, their running targets may be located in various areas and segments of the system. The control logic of such vehicle targets is complex and requires a large amount of calculation. After using the above three-way grid model to simplify the system layout and establish a three-level control system architecture, the present invention simplifies the task target positions of all vehicles in each segment into two types: located inside the current segment and located outside the current segment.

[0060] Furthermore, the regional control unit calculates the maximum speed limit of the vehicle based on the vehicle mission target position, the end point of the line segment and the distance to the preceding vehicle according to the shortest distance dynamic algorithm, including:

[0061] Step 1: The regional control unit dynamically determines the vehicle's current running target on the current line segment based on the vehicle's mission target position until the vehicle reaches the vehicle's mission target position, such as Figure 5 As shown, including:

[0062] For vehicles at a three-way intersection, the starting point of the next line segment after the vehicle passes the fork is taken as the vehicle's current running target;

[0063] When the vehicle's mission target position is outside the current line segment and there is no preceding vehicle, the end point of the current line segment is used as the vehicle's current running target;

[0064] When the vehicle's mission target position is outside the current line segment and there is a preceding vehicle, the position of the preceding vehicle's rear end is used as the vehicle's current running target;

[0065] When the vehicle mission target position is within the current line segment and there is no preceding vehicle, the vehicle mission target position is used as the current running target of the vehicle;

[0066] When the vehicle mission target position is within the current line segment and there is a preceding vehicle, the position closer to the vehicle between the vehicle mission target position and the rear of the preceding vehicle is selected in real time as the vehicle's current running target.

[0067] Step 2: Based on the current running target of the vehicle on the current line segment, the maximum speed limit of the vehicle is calculated according to the preset safety time interval.

[0068] Specifically, the distance between the current running target of the vehicle and the current position of the vehicle in step 1 is used to find the quotient with the preset safety time distance in real time; or the distance between the current running target of the vehicle and the current position of the vehicle in step 1 and the preset safety distance are used to obtain the maximum dynamic speed limit of the vehicle.

[0069] Step 3: When there is a curve speed limit area in the line segment, a preset speed limit ratio instruction is superimposed on the operation control of the single vehicle in step 2, that is, the preset speed limit ratio is superimposed on the maximum speed limit in step 2.

[0070] Specifically, when the vehicle enters a speed limit area on a curve within a line segment, the vehicle's maximum speed limit is controlled in proportion to the speed limit. When the vehicle leaves the speed limit area on the curve within the line segment, the speed limit control is released and the vehicle resumes the maximum speed limit, thereby achieving smooth and controllable control of the vehicle entering and exiting the curve.

[0071] Furthermore, on this basis, for multiple vehicles within a line segment, the dynamic vehicle spacing control based on the vehicle sorting within the segment is fully adopted to control the safe position of the rear vehicle. The rear vehicle adopts following control with the rear position of the front vehicle as the target to ensure the safety of the vehicle spacing, without the need to configure a vehicle spacing sensor to judge the distance to the front vehicle.

[0072] The dynamic control method for a large-flow circular shuttle vehicle based on a closed three-way grid architecture provided in this embodiment, for all vehicles in a single line segment, the regional control unit of each line segment judges the changes of the three variables in real time based on the ternary logic operation of the three dynamic variables, namely, the vehicle mission target position, the line segment end position, and the front vehicle rear position, and dynamically calculates the vehicle's maximum speed limit based on the closest distance between the three variables and the vehicle, thereby achieving high-speed, efficient and safe operation of the vehicle.

[0073] S204: When the distance between the vehicles in front suddenly changes, the vehicle control unit limits and compensates for the sudden change in the original controlled speed of the vehicles in the line segment according to a speed curve control method based on a natural constant power operation.

[0074] The original control speed is the vehicle control speed obtained based on the maximum speed limit of the vehicle in the line segment. When the vehicle enters and exits the three-way intersection, the original control speed of the vehicle changes suddenly due to the random changes in the increase or decrease of the vehicles in front, which easily causes the vehicle's running posture to be abnormal in a short time. The present invention adopts the S-curve algorithm theory based on natural constants, and monitors the changes of the original control speed of the vehicle in real time through the speed controller in the vehicle control unit based on the natural constant power operation speed curve control method. The speed curve control method based on the natural constant power operation uses the time period as an index, and the time period is the accumulation of each operation cycle pre-set in the speed controller. And through the speed controller, the limit and compensation of the original control speed mutation are dynamically calculated to achieve tracking and smooth control of the original control speed of the vehicle, and improve the vehicle running impact caused by the speed mutation. According to the trend of the speed mutation, the control strategy includes the following two situations:

[0075] When a vehicle enters a new line segment where existing vehicles are running from a three-way intersection, causing the distance to the vehicle in front to suddenly decrease, resulting in a sudden drop in the original control speed of the vehicle, a natural constant deceleration curve with the original control speed as the target and the deceleration time as the exponent is calculated based on parameters such as the difference between the current vehicle speed and the original control speed and the vehicle deceleration value, and smooth compensation control is performed on the vehicle control speed.

[0076] When the vehicle in front of the vehicle leaves the line from the three-way intersection, causing the distance to the vehicle in front to suddenly increase, causing the original control speed of the vehicle to suddenly increase, a natural constant acceleration curve with the original control speed as the target and the acceleration time as the exponent is calculated based on parameters such as the difference between the current speed of the vehicle and the original control speed, and the acceleration value of the vehicle, and the original control speed of the vehicle is smoothly limited.

[0077] Through the above control, the speed change between the smooth control speed and the original control speed gradually tends to 0 within the control cycle. The smooth control speed is the calculated limit and compensation for the sudden change of the original control speed, and finally the smooth control speed dynamically follows the original control speed to achieve fast and smooth response.

[0078] For further information, please refer to Figure 6 , Figure 6 The present invention provides a flow chart of limiting and compensating the original control speed of a vehicle based on a natural constant power operation speed curve control method. The present invention provides a flow chart of limiting and compensating the original control speed of a vehicle based on a natural constant power operation speed curve control method to achieve a smooth transition of the vehicle speed, which specifically includes the following steps:

[0079] According to the original control speed v that causes the vehicle speed mutation f The absolute difference v between the actual speed v0 of the current vehicle Δ The size determines whether to start the variable speed smooth speed control. Δ If it is greater than the judgment threshold, the speed regulation is started, and the speed value v at the end of each calculation cycle is calculated according to the following formula s :

[0080]

[0081] v s Indicates the speed value calculated in the current calculation cycle, v (s-1) Indicates the speed value calculated in the previous calculation cycle; v f Indicates the original control speed value; T s represents the calculation cycle interval of each program preset in the speed controller in the vehicle control unit; T0 represents the control start time; T f Indicates the control end time; e is a natural constant; k is the speed change smoothing coefficient.

[0082] Then use this value as the speed value v of the previous cycle (s-1) Substitute it into the next calculation cycle for calculation, and iterate in this way to obtain a natural constant power operation curve with the integral of the control time as the exponent. This speed curve always smoothly tends to the original control speed value, which is an effective and reliable control method to suppress speed mutation. When the difference between the smooth speed value and the original control speed value vΔ If the speed is less than a certain range, the smooth speed control is judged to be over, the operation is terminated, and the speed change is smooth. This smooth speed control is not used when the vehicle is docked at the mission target location.

[0083] The dynamic control method of a large-flow circular shuttle vehicle with a closed three-branch grid structure provided by the present invention, the speed controller in the vehicle control unit calculates the smooth control speed based on the natural constant power operation speed curve control method to limit and compensate the original control speed mutation, so that the output speed is relatively smooth in the first half of the speed regulation stage when the original control speed mutation occurs, and the equipment impact is small. After that, the output speed gradually accelerates to the original control speed, and the output speed curve is asymmetrically distributed before and after the speed regulation control time. The distribution trend of the speed change curve before and after the time can be adjusted by adjusting the speed change smoothing coefficient k, so that the control efficiency is high, the speed change trend of the entire curve is controlled by the speed change smoothing coefficient k, and the variable can be set according to the vehicle position. The entire smooth speed change control has good adjustability, and the real-time monitoring of the original control speed change of the vehicle is realized to realize smooth speed control. The speed controller designed in the vehicle control unit completes the smooth speed regulation calculation and control of the original control speed value based on the natural constant power operation speed curve control method, which is not affected by specific hardware conditions and is easy to be applied and implemented in most industrial control systems.

[0084] Please refer to Figure 7 , Figure 7 The present invention is a curve diagram of calculating the smooth control speed based on the natural constant power operation speed curve control method to limit and compensate for the original control speed mutation. The horizontal axis of the smooth control curve diagram represents the running time (unit: s), and the vertical axis represents the speed (unit: m / s). The blue curve in the figure represents the smooth control speed curve obtained after limiting and compensating the original control speed, that is, the output speed curve. The red curve represents the original control speed curve. The first half of the blue curve is the smooth control speed curve obtained by limiting the acceleration mutation of the original control speed, and the second half is the smooth control speed curve obtained by compensating for the deceleration mutation of the original control speed. The smooth speed change speed value has a gentle speed change in the first half cycle of limiting and compensating control, which can better absorb the impact of the speed mutation on the vehicle structure, while the speed curve in the second half cycle has a stronger fitting trend with the original control speed. The smooth control speed curve is asymmetrically distributed in the front and back sections of time. The distribution trend of the speed change curve in the front and back sections of time can be adjusted by adjusting the speed change smoothing coefficient k. The control efficiency of actual application is relatively high. The uniform speed stage of the above curve diagram shows the uniform speed running state of the vehicle without speed mutation and after the speed smoothing control is completed.

[0085] The closed three-way grid architecture dynamic control method for a large-volume circular shuttle vehicle provided in this embodiment establishes a three-way grid model of a circular shuttle road, simplifies the circular system into a system where all vehicles are dynamically controlled in the micro-environment of each line segment and each three-way intersection in the entire system circular line, and establishes a three-level control system to simplify the entire complex vehicle control management into a distributed control for regional management of a single or several line segments. All regional control units operate in parallel, with short calculation time and high real-time control, thereby reducing the management load of the entire system and improving the operating efficiency of the large-volume circular shuttle vehicle system.

[0086] For the control of large-volume circular shuttle vehicles, industrial control equipment such as programmable controllers are basically used as control platforms in actual engineering applications. In order to be suitable for programmable controller operations and program writing, and to maintain the control efficiency of the shuttle vehicles to the greatest extent, the present invention adjusts and optimizes the relevant calculation methods and operation sequences based on the program writing characteristics and ideas of the mainstream programmable controllers in the current automation system, and adjusts the data units according to the actual engineering needs, tries to use integer data for operations, reduces the amount of floating-point operations, and minimizes program judgment and loop operations, which is very suitable for the current mainstream automation control system applications.

[0087] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A dynamic control method for a large-flow circular shuttle vehicle based on a closed three-way grid architecture, characterized in that: include: S10, establishing a three-way grid model of the road for the circular shuttle, wherein the three-way grid model includes an equal number of diverging turnouts and merging turnouts, each diverging turnout is provided with three line segments, each merging turnout is provided with three line segments, and the three-way grid model is further provided with a starting line segment and an ending line segment, wherein the diverging turnouts and the merging turnouts are used to represent the forks of the circular shuttle, and the line segments are used to represent the passages of the circular shuttle; S20, based on the three-way grid model, dynamically manage the shuttle through the control system, including: S201, the main control unit allocates the regional control unit and the current line segment to the shuttle in real time according to the shuttle destination and the current real-time traffic conditions; S202, the regional control unit establishes a dynamic vehicle container for each line segment, and dynamically controls the vehicle queue within the line segment; S203, the regional control unit calculates the maximum speed limit of the vehicle according to the shortest distance dynamic algorithm based on the vehicle mission target position, the end point of the line segment and the distance to the preceding vehicle; S204: When the distance between the vehicles in front suddenly changes, the vehicle control unit limits and compensates the sudden change in the original control speed of the vehicles in the line segment according to the speed curve control method based on the natural constant power operation. The control system includes a main control unit, an area control unit and a vehicle control unit, wherein the vehicle control unit manages the vehicles in the line segment with the line segment as the management unit, and the area control unit manages the vehicle control units on the line segment in the area according to the area pre-divided by the main control unit. The main control unit is connected to the area control unit where the vehicle is running in the line segment, and the main control unit is also directly connected to the vehicle control unit located within the turnout range. The vehicle control unit located in the line segment is only connected to the area control unit that manages the line segment, and the shuttle vehicle is the vehicle.

2. The method for dynamic control of a large flow circular shuttle vehicle based on a closed three-way grid architecture according to claim 1 is characterized in that: S201, the main control unit allocates the regional control unit and the current line segment to the shuttle in real time according to the shuttle destination and the current real-time traffic conditions, including: The main control unit splits and formulates the vehicle route in real time according to the current real-time traffic conditions, the current position of the vehicle and the vehicle's mission destination, with the time to pass the current segment as the splitting period and the segment as the splitting unit, and assigns the shuttle vehicle to the corresponding area control unit and the current segment until the vehicle reaches the segment to which the vehicle's mission destination belongs.

3. The dynamic control method of a large flow circular shuttle vehicle based on a closed three-way grid architecture according to claim 1 is characterized in that: S202, the regional control unit establishes a dynamic vehicle container for each line segment and dynamically controls the vehicle queue within the line segment, including: The regional control unit performs communication and dispatch control based on line segments, and establishes a dynamic vehicle container pool for each line segment. The vehicle container pool scans the vehicle tasks and vehicle position sorting queues within the line segment in real time.

4. The method for dynamic control of a large flow circular shuttle vehicle based on a closed three-way grid architecture according to claim 1 is characterized in that: S203, the regional control unit calculates the maximum speed limit of the vehicle based on the vehicle mission target position, the end point of the line segment and the distance to the preceding vehicle according to the shortest distance dynamic algorithm, including: Step 1, the regional control unit dynamically determines the vehicle's current running target on the current line segment based on the vehicle's mission target position until the vehicle reaches the vehicle's mission target position; Step 2: Based on the current running target of the vehicle on the current line segment, the maximum speed limit of the vehicle is calculated according to the preset safety time interval; Step 3: When there is a speed limit area on a curve in the line segment, a preset speed limit ratio is added to the maximum speed limit in step 2.

5. The method for dynamic control of a large flow circular shuttle vehicle based on a closed three-way grid architecture according to claim 4 is characterized in that: Step 1: The regional control unit dynamically determines the current running target of the vehicle in the current line segment based on the vehicle mission target position until the vehicle reaches the vehicle mission target position, including: When the vehicle's mission target position is outside the current line segment and there is no preceding vehicle, the end point of the current line segment is used as the vehicle's current running target; When the vehicle's mission target position is outside the current line segment and there is a preceding vehicle, the position of the preceding vehicle's rear end is used as the vehicle's current running target; When the vehicle mission target position is within the current line segment and there is no preceding vehicle, the vehicle mission target position is used as the current running target of the vehicle; When the vehicle mission target position is within the current line segment and there is a preceding vehicle, the position closer to the vehicle between the vehicle mission target position and the rear of the preceding vehicle is selected in real time as the vehicle's current running target; For vehicles located at a three-way intersection, the starting point of the next line segment after the vehicle passes the fork is used as the vehicle's current running target.

6. The method for dynamic control of a large flow circular shuttle vehicle based on a closed three-way grid architecture according to claim 4 is characterized in that: Step 2: Based on the current running target of the vehicle on the current line segment, the maximum speed limit of the vehicle is calculated according to the preset safety time interval, including: The distance between the current running target of the vehicle and the current position of the vehicle in step 1 is used to find the quotient with the preset safety time distance in real time; or the distance between the current running target of the vehicle and the current position of the vehicle in step 1 and the preset safety distance are used to obtain the dynamic maximum speed limit of the vehicle.

7. The method for dynamic control of a large flow circular shuttle vehicle based on a closed three-way grid architecture according to claim 6 is characterized in that: S204: When the distance between the front vehicle and the rear vehicle suddenly changes, the vehicle control unit limits and compensates the sudden change of the original control speed of the vehicle in the line segment according to the speed curve control method based on the natural constant power operation, including: According to the original control speed v that causes the vehicle speed mutation f The absolute difference v between the actual speed v0 of the current vehicle Δ The size determines whether to start the variable speed smooth speed control. Δ If it is greater than the judgment threshold, the speed regulation is started, and the speed value v at the end of each calculation cycle is calculated according to the following formula s : v s Indicates the speed value calculated in the current calculation cycle, v (s-1) Indicates the speed value calculated in the previous calculation cycle; T s represents the calculation cycle interval of each program preset in the speed controller in the vehicle control unit; T0 represents the control start time; T f represents the control end time; e is a natural constant; k is a speed change smoothing coefficient, and the original control speed is the vehicle control speed obtained based on the maximum speed limit of the vehicle in the line segment.

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