自動(dòng)化立體倉(cāng)庫(kù)系統(tǒng)設(shè)計(jì)——堆垛機(jī)以及貨架系統(tǒng)等設(shè)計(jì)含6張CAD圖,自動(dòng)化,立體倉(cāng)庫(kù),系統(tǒng),設(shè)計(jì),堆垛,以及,貨架,CAD Optimization of Storage Location Assignment in Automated Warehouse Dong Yang, Yaohua Wu* ,Wenkai Ma School of Control Science and Engineering,Shandong University, Jinan, Shandong 250061, China * Corresponding author:Yaohua Wu, Email: Yangdong0205@163.com Abstract: To effectively manage the automated warehouse, aiming at the optimization of goods location assignment, an optimization function for the assignment of storage location was established with the shelf stability and access efficiency as the goal according to the principle of storage space allocation. To optimize the picking location of the roadway stacker when exiting the warehouse, a mathematical function model was established by analyzing the picking strategy of the warehouse delivery operation. The research results showed that the optimization of the cargo space and the optimization of the stacker crane operation route can improve the overall operating efficiency. It is concluded that the model can reduce the cost of goods handling and storage, the time lost in the storage process and handling process, thereby decreasing logistics costs and increasing revenue. Key words: Automated warehouse, location optimization, picking route, scheduling strategy 1. Introduction The automated stereo warehouse is called automatic storage/ retrieval system (AS/RS).It is a new type of storage technology and an integrated science and technology project in materials handling and storage science [1]. Automated warehouse stage can automatically store and export materials. It is composed of multi- storage rack, conveyor system, computer-aided system and communication system. It is an integrated system that integrates information automation technology, automated guided car technology, robotics, and automated storage technology [2]. At the same time, the development of AS/RS is closely related to the development of warehousing. The development of AS/RS is one of the obvious signs of the warehousing development stage, while the advances in warehousing technology can significantly drive the development of AS/RS technology. It is known that after entering the automation stage, warehousing has further developed toward the integrated storage phase and the intelligent storage phase [3]. The current management of automated warehouses is chaotic, and management efficiency is low, so it is necessary to improve its management efficiency through scientific methods.In this paper, the storage strategy and principle of distribution location are analyzed. Taking the carrying capacity of shelves and the efficiency of stacker as the goal, a model of cargo location optimization in automated warehouse is established. Taking the automated warehouse of a household electrical appliance logistics center in Shanghai as object, a multiobjective genetic algorithm is applied to solve it [4]. By analyzing the picking strategy of warehouse operations, the mathematical function model is established with the goal of minimizing the distance traveled by the warehouse stacker. Taking the automated warehouse of a home appliance logistics center in Shanghai as the research object, an ant colony algorithm is used to solve the problem. 2. Theories 2.1 Automated warehouse system The automated warehouse system introduces modern intelligent technology on the basis of traditional warehouse management, and carries out all-round changes to the warehouse structure and management. It is the development direction of modern warehouse management.The composition of the home automation warehouse system is the same as that of most automated warehouse systems. It is an integrated system that combines mechanical, electrical, high-power control and weak current control [5]. As shown in figure 1, it consists of the following four parts. The composition of the three-dimensional warehouse system Management and control system Home appliance transportation system Home selection and selection system Home appliance storage system Figure 1. The composition of the automatic warehouse system for household electrical appliances In the transportation process, different stacking methods also play different roles in product protection. The packaging of electrical products is mainly based on the shape of a rectangular box, and the feasibility of transportation costs must be considered. Therefore, there are mainly two stacking methods in the transportation process: overlapping and interleaving. At the same time, the interleaving is also divided into three types: crisscross, rotary interleaving and positive and negative interleaving [6]. The overlapping type is also called the straight stacking method. It is a stacking method in which pieces are piled up one by one, stacked up one by one, and pressed one by one. That is, the layer stacking method is the same and corresponds to the top and bottom. This method is convenient for operation and counting, but its stability is poor. Because of the lack of friction between the layers and the poor stability, the stack is easy to collapse. Therefore, the overlapping type is only applicable to boxed items. Export products generally use containers to ship goods. Containers need to consider the full use of space. The internal structure is compact and they are generally stacked by overlapping. Interleaving means that each item is stacked upwards and is suitable for long boxes. This method is relatively stable but it is inconvenient to operate. In more spacious places such as warehouses, crisscrossing can be used to enhance stacking stability. When using small trucks to transport goods, if there are no fences or the surrounding fences are shorter, crisscross can be considered for shipping to enhance stability. 2.2 Automated warehouse management system The automated warehouse management system is the intelligent management of the automated warehouse in the form of a system,AS/RS is a comprehensive application system based on modern information technology, modern control technology, and computer communication technology. It is a combination of modern logistics technology and computer automation technology. In different companies and different industries, the structure of the AS/RS management and control system has different characteristics. From the functional level, the structure of the automated warehouse management and control system is basically the same. Therefore, it can be divided into three levels: management layer, monitoring layer and execution layer [7]. For different levels of function, the requirements for automated warehouse management and control systems vary. For management, the management and control system require that it must have certain intelligence and certain data processing capabilities [8]. For example, when detecting abnormal information in the inventory, this abnormal information can be alarmed, and dispatch operations and logistics system information can be processed. For the monitoring layer, the management and control system does not necessarily require that its data processing capability is strong, but it must be required to have a very high realtime nature and a relatively strong data processing speed. Also, it is required to be able to pass various instructions to the execution layer at any time and monitor the execution status of the execution layer at any time. For the execution layer, the management and control system require them to have higher reliability. In this way, the failure rate of the logistics system can be reduced, and the logistics system can be healthy for a long time. 2.3 Automated warehouse management technology Automated warehouse management technology is an intelligent technology for automated warehouses, and is the basis for improving the operation of automated warehouses.For the allocation of storage space of home appliances, the allocation of the storage space is to allocate the home appliances to the best location in accordance with certain standards or guidelines. There may be more than one free space in the warehouse at the same time. Through rational allocation of space, it is possible to shorten the work cycle, improve the work flow and the efficiency of delivery[9]. The basic standard for the allocation of storage space is generally based on the principle of export, turnover rate and cargo-related principle. Therefore, the issue of storage space allocation is a multi-objective combination decision problem. Its solution is generally more complicated. There are also more commonly used solving methods, such as particle swarm optimization, simulated annealing fusion algorithm and ant colony algorithm. The MATLAB-based genetic algorithm is used in this paper. The delivery operation is an important operation process of the three-dimensional warehouse. Reasonably arranging the sequencing of the operations can shorten the time for delivery tasks, which is the key to meeting the real-time requirements of the logistics system. A complete delivery picking process is shown in figure 2. The optimization problem of picking location for delivery operations is also a combination of multiple objective optimization problems. The solution is relatively complex, and the technical method used under normal circumstances is the delivery job scheduling algorithm. The most classic delivery job scheduling algorithms include the earliest relative deadline date first algorithm, the minimum task priority first algorithm, and the shortest free time first algorithm[10]. Stacker starts Receive an instruction from a task NO Current task information Start running Run to take the goods fork pallet picking YES Return to run to the picking table Job completion YES Send the information and accept the new task There are new tasks End: the stacker returns to the starting point NO Figure 2. Out of Library sorting process 2.4 Automated warehouse operation process Stereoscopic warehouse is an intermediate link between suppliers and consumers and an important part of the company's supply chain. It mainly serves as a buffer and balance. As a subsystem of the logistics system, the three-dimensional warehouse generally includes four main processes: receiving goods, storing goods, picking goods and distributing goods. Each operation process includes different operations. As shown in figure 3, the receiving cargo operation includes handling and inventory operations, and the picking operation includes replenishment operations[11]. Order processing Purchase Deliver goods Distribution Pick up the Treasury and pick up the goods Storage storage Replenishment Inventory Figure 3. Automated warehouse operation flow chart In this paper, two of the major job flows are studied: the inbound storage operations (shown in figure 4) and the outbound picking operations[12] (shown in figure 5). If the process is intelligent in the system, the intelligent management of the warehouse can be carried out through the intelligent management system of this article, and the efficiency of warehouse operation can be improved. Scan the barcode to store the pallet, and display the destination area Get out of the mouth and sort out artificially Registry registration DATA Carry the tray to the storage conveyor Measurement of conveyor size Unqualified The storage information system automatically assigns the best repository Qualified Automatic stacker goods will be sent to the designated location The stacker will feed information into warehousing information system Completion of storage Figure 4. Flow chart for warehousing The warehouse information system sends out the outgoing instructions to the stacker Tug out of the Treasury conveyor size YES NO Move the tray to the collection area Select according to the number of display on display, then press Finish button Move the tray to the The stacker will be returned to the original location to save the remaining goods. Move the selected goods to the collection ar Pick up staff pick up the goods according to the quantity of the goods Feedback from outgoing information to computer storage information system Figure 5. Flow chart of goods out of warehouse 3. Methodology 3.1 Inbound principle of automated warehouse Whether or not a three-dimensional warehouse needs to be partitioned depends mainly on the actual conditions such as the form of the warehouse and the frequency of the warehouse. Under normal circumstances, for a long warehouse, the partition is necessary. It is also necessary to partition a material with a large amount of storage and a small inventory[13]. There are also special items that need to be partitioned because the inherent chemical nature of the items determines that they cannot be mixed with other items and must be stored separately from other items. In the actual operation of the warehouse, it is necessary to decide whether to partition according to the actual situation of the AS/RS. In practical applications, the specific methods include partitioning according to the characteristics of the goods, partitioning according to the priorities of the inbound and outbound storage, partitioning according to the frequency of the inbound and outbound storage, and partitioning according to the principle of gravity[14]. The warehouse needs to follow certain principles in the allocation process.the principle of uniform distribution is the most basic principle of location selection for automated warehouse management. Its purpose is to improve the efficiency of inbound while avoiding the emergence of certain items concentrated in a roadway. After a problem occurs in the roadway stacker, this type of item cannot exit the warehouse. Therefore, various items will be evenly distributed to each laneway. The principle of uniform distribution can basically be divided into three types, uniform distribution of location, uniform distribution of goods and uniform distribution of equipment load[15]. 3.2 Allocation principle There are many principles to consider when assigning locations. For the automated three-dimensional warehouse, the principle of location allocation is mainly the following: The first is uniform load-bearing shelf. Under normal circumstances, the heavier items are stored in the place near the ground, and the light weight items are stored in the place far away from the ground. Therefore, the upper part of the shelf is lighter and the bottom part is heavier. In this way, the shelf can be well stressed. The overall force of the shelf is uniform to ensure the stability of the shelf and avoid the uneven stress of the upper part of the shelf because of the goods storage[16]. As a result, the shelves cannot be collapsed and there is no accident. To speed up the turnover of materials, the principle of first in-first out is applied. That is, when the same materials are used for outbound operations, the goods with a longer storage time are prioritized for the outbound storage operation, which greatly speeds up the material turnover speed and avoids damage to the articles caused by the long-term stacking and backlog of the materials, resulting in unnecessary loss. When storing goods in the laneway, it is necessary to improve reliability. When the AS/RS has multiple lanes, the same kind of items are scattered and stored in different lanes to prevent the failure of a stacker from a roadway. As a result, the discharge of certain materials and production interruption are avoided. The aim is to improve the efficiency of inbound storage in light of the principle of inbound and outbound storage. In a three-dimensional warehouse, in order to ensure rapid response to a request for a warehouse, the material is generally placed near the outbound warehouse. For product relevance, product relevance is often ordered at the same time when ordering, so it should be stored as close as possible to the adjacent location[17]. The automated three-dimensional warehouse serves the logistics system. Therefore, the purpose of optimizing the three-dimensional storage space should satisfy the principles of speed, safety, reliability and low cost of the logistics system based on factors such as turnover rate and moving distance. 3.3 Stereo warehouse picking strategy Different from the plane warehouse, the picking of the three-dimensional warehouse has certain requirements on the picking principle and picking technology.Using the simplest division method, the picking operation can be divided into three ways: order picking, batch picking and compound picking. Order picking is picking each order individually[18]. The batch picking is a picking list that is formed by summing multiple orders together, and then picking up items at once. Finally, the captured goods are classified. Compound picking is to make full use of the above two picking methods and comprehensively apply it to picking operations[19] The object of the order picking is very clear and it is for each order. After the operator accepts the order, it travels in the warehouse according to the order entry of the customer's order. According to the goods and quantity information listed on the order, the goods ordered by the customer are taken out one by one from the storage place of the warehouse or other operating area, and then are gathered together. Its operation flow chart is shown in figure 6. The picking process is a conditional format process. In the system, this type of picking code is easier to be recognized by the system and easier to execute, effectively reducing the possibility of an infinite loop in the system picking. Accept orders Pick up the picking information according to the order information Inventory goods and storage information Pick up the goods according to the order information Packing in accordance with the order unit Shipment Figure 6. Orders without pick mode operation flow chart After accepting multiple orders, the operator assembles multiple orders into one batch, and then picks the goods according to the product category. After the picking operation is completed, the retrieved total goods are classified according to certain principles. The operation flow chart is shown in figure 7. Accept orders According to the order information combination Inventory goods and storage information According to the statistics of commodity varieties Picking list Pick up the goods according to the number of Statistics According to order classification Packing in accordance with the order unit Shipment Figure 7. Batch picking mode operation flow chart To overcome the disadvantages of order picking and batch picking, the logistics center can also adopt a compound picking method combining order picking and batch picking, that is, compound picking. It is based on the morphological characteristics of customer orders. First, it combines the order picking and batch picking to classify the order. According to the characteristics of the customer's orders, such as variety and quantity, the orders can be divided into a variety of forms with the appropriate picking strategy. The choices made by compound picking are based on the rules for inventory cir