Design of the control and management system of the

Design of control and management system of automated three-dimensional warehouse for postal parcels

Abstract: the technology of automated three-dimensional warehouse is applied to the field of postal parcels circulation. The warehouse management information system based on client/server network (C/s system) is composed of workstation and file server, and the monitoring machine is used as the central machine to control the lower handling equipment to realize the fully automated operation of postal parcels in and out of the warehouse. This paper introduces the general situation of parcel automated three-dimensional warehouse and its control and management system in detail, and puts forward realizable methods for system 2. The system has reliable operational performance, system structure design, function design and software development

key words: parcel automatic library; Client/server network; Distributed control; Database

1 introduction

automated three-dimensional warehouse is a comprehensive scientific and technological project of material handling and storage science. It takes high-rise three-dimensional shelves as the main symbol, and uses complete sets of advanced handling steel balls and collets and even sintering with the upper cone base Based on equipment and taking advanced computer control technology as the main means, the warehouse in and warehouse out processing is carried out by using space, time and manpower efficiently. Applying automated three-dimensional warehouse technology to the field of parcel circulation can greatly improve the efficiency of parcel circulation and reduce the labor intensity of staff

2 automated three-dimensional warehouse for postal parcels

the automated three-dimensional warehouse for postal parcels is composed of high-rise three-dimensional storage racks, in and out storage handlers and information processing devices. The layout of the warehouse is shown in Figure 1

front and rear workstations A and B are responsible for the management of parcel and shelf information and the management of parcel in and out of the warehouse. Workstation a handles the business of sending and receiving postal parcels from customers on the counter, and its working feature is random operation. Workstation B processes the bulk parcels that are transported into or out of the three-dimensional warehouse. The working feature is that the parcels are intermittently and in bulk. Workstation a, B and file server form a client/server network to realize the sharing of parcel and goods grid information. When entering the warehouse, the workstation records the main information of the parcel, such as the parcel number, the sender's address and name, and assigns an empty cargo cell to the parcel from the server cargo cell database; When leaving the warehouse, the workstation finds the location address of the parcel from the file server according to the characteristics of the parcel. The monitor communicates the connection between the workstation and the distribution vehicle and the stacker, accepts the workstation instructions, and monitors the distribution vehicle and the stacker to complete the incoming and outgoing operations of postal parcels. When entering the warehouse, the distribution car will transfer the parcels to the designated stacker. After the stacker reaches the designated goods grid, the mechanical hand will send the parcels to the goods grid. The delivery process is opposite to the above process

since the imitation technology of the size environment of postal parcels has become an important direction of the development of experimental machine technology, the shapes and packaging materials are different, and it is difficult to achieve with the general manipulator access method, so the method of palletizing postal parcels is adopted. According to the statistical data of the post office for many years, postal parcels are divided into three categories by size: large, medium and small. One category of postal parcels is equipped with pallets of the same specification. Through the access to the tray to achieve the access to the parcel. The automatic three-dimensional warehouse has the function of automatic sorting. When entering the warehouse, the postal parcels are randomly arranged in the body warehouse in the three-dimensional warehouse. When leaving the warehouse, the workstation will query the location address of all postal parcels departing to the same region, and this batch of postal parcels will be sent out according to the location address, without special sorting before entering the warehouse

1#, 9# - parcel distribution vehicle; 2 # ~ 8 # - stacker

Figure 1 warehouse layout

3 warehouse control and management system

the management system and automation control of parcel automated three-dimensional warehouse can be divided into three levels, as shown in Figure 2, namely upper management level, middle monitoring level and lower control level. The control system adopts distributed control, and the intermediate monitoring machine is composed of industrial PC. the industrial PC has strong data processing ability and anti-interference ability, which is suitable for controlling the lower computer. PLC is used as the main controller of distribution car and stacker to control the front end. PLC is configured with communication module and has online communication function. When operating in full-automatic mode, the monitoring machine controls the distribution car and stacker through communication with the lower computer PLC

1 # ~ 9 #: lower computer PLC

Figure 2 management and control structure diagram

3.1 control system

this automated three-dimensional warehouse control system is divided into two parts:

(1) the local area is composed of monitoring machine, workstation a, B and file server. The workstation performs database operations such as login, query, deletion, modification and addition to the parcel and shelf databases in the archive server, and transmits the operation instructions and operation addresses to the monitoring machine. The monitor serves the workstation according to the order of arrival of workstation a and B communication requirements. When two workstations require communication at the same time, the monitor selects the workstation according to the priority agreed in advance

(2) the communication between the monitoring machine and the lower computer PLC adopts the bus topology. The exchange information of communication with PLC includes: task information, response information, query information, etc. Task information includes operation instructions (warehousing, outbound and inventory) and operation addresses (source address, destination address); The response information is the information that the lower computer sends back to the monitor after receiving the command word sent by the monitor; The query information refers to that the monitoring machine makes a round of query on the sign area of all lower machines every certain time (very short). The main contents of the query mainly include the location information of the stacker and distribution vehicle, task completion information, fault information, etc. after each new round of query, the status of the stacker and distribution vehicle is dynamically displayed on the CRT of the monitoring level. The information exchange between the console and PLC is shown in Figure 3

Figure 3 information exchange between the monitor and PLC

the monitor and PLC adopt the master-slave communication mode, and the PLC only responds to the commands of the monitor and does not actively send data. When the distribution car and the stacker are in operation, the monitoring machine should query their operation status in real time to decide the next work. Since the monitoring machine is a multi task real-time operation, it also receives the data sent by the management level while controlling the lower computer, so it adopts the method of timed interruption to query the working status of the distribution car and the stacker every certain time. The monitor sends the command word program, as shown in Figure 4

Figure 4 command sending program of monitoring machine

when there is no information communication, the PLC of the lower computer is fully put into control of the stacker and distribution car. In order to meet the real-time requirements, the lower computer communicates with the console in the form of interruption. When the monitor calls, it enters the interruption system and returns to the main program after the communication is completed. The interrupt receiving program of the lower computer is shown in Figure 5. There are two communication interface modes between the monitor and the upper and lower computers, RS232C and RS422. The communication mode depends on the communication distance

Figure 5 lower machine receiving interrupt program

3.2 stacker control

stacker control is designed as manual, semi-automatic and full-automatic control. Full automatic control is that the monitor sends the operation order and address to the stacker, and then the stacker responds and executes. During operation, the monitor monitors the operation status of the stacker in real time. Manual and semi-automatic control is that the operator directly sets the operation order and address on the operation panel of the stacker. In actual operation, full-automatic control is mainly used, and manual and semi-automatic control are used as auxiliary means for maintenance and commissioning

in the stacker control system, PLC controls the stacker:

(1) operation command setting. Determine the operation status, full-automatic or manual, semi-automatic; Determine the operation instructions, whether to pick up or store the parcel; Determine the job address, row address, column address and layer address

(2) position count control. Address recognition chips are set along the travel direction of the stacker and the lifting direction of the pallet. PLC judges the position of the stacker and the pallet by detecting the address recognition chips. The address recognition system counts every time an address recognition chip is passed. The stacker will stop automatically when it reaches the predetermined address

(3) positioning deceleration control. In order to meet the speed and accuracy of positioning in the deceleration positioning stage, the author introduces the fuzzy control method to realize the deceleration control and positioning according to the position estimation and point position feedback. This method does not need to establish an accurate mathematical model of the stacker, is insensitive to the changes of stacker parameters, and can provide an adaptive deceleration control law. The experimental results show that the positioning deviation can be controlled within the allowable error range

(4) position verification and positioning detection control. After the stacker is in place, the address recognition system will verify the address recognition chip code and detect the positioning accuracy. When the positioning deviation exceeds the allowable error range, PLC will control the return, and the three corrections still cannot stop the criterion alarm

(5) safety protection control. The horizontal travel, the lifting and lowering of the loading platform and the expansion and contraction of the fork are all protected by limited position

(6) in addition, there are position display control, working fault alarm control, etc

the stacker control program can be divided into several main subroutines according to its functions. The calling relationship between the main program and the main subroutine segments is shown in Figure 6

Figure 6 call relationship between main and subroutines

3.3 warehouse management information system

the management information function of workstation mainly includes parcel information management and location management. Parcel information management is to store the main information of parcel, such as parcel number, recipient address and name, location address, in and out including some renewable raw material warehouse date and other necessary data, so as to be used in data processing. Location management is to manage the location status in the warehouse, formulate an empty location table, and provide the best cell address for postal parcels that need to be warehoused. The principles of cargo location management mainly follow the principles of uniform distribution of postal parcels, "warehousing nearby" and being beneficial to the loading of shelves. The design principle of the management information system is to adopt modular design according to the original management mode of the post office for parcel information. According to the functional requirements of the system, it is divided into warehousing module, outbound module, inventory module, maintenance module, query module, statistical summary module, general printing module and cargo location management module. The system requires convenient operation, friendly interface, and measures to ensure data security

4 conclusion

the automated three-dimensional warehouse system for postal parcels, while scientifically managing postal parcels and warehouse information, realizes the automated operation of postal parcels in and out of the warehouse. At present, there is no example of the successful application of automated three-dimensional warehouse technology in the field of postal parcels circulation in China. This technology is worth popularizing and applying in the field of postal parcels

about the author:

Hu Chibing, male, born in 1952, associate professor of mechanical and Electrical Engineering Department of Gansu University of Technology (Lanzhou 730050), engaged in teaching and scientific research of mechanical manufacturing and mechatronics. He has completed 9 national, ministerial and provincial scientific and technological research projects, won 2 second prizes and 1 third prize for scientific and technological progress achievements at the ministerial and provincial levels, and published 26 papers

author unit: Gansu University of Technology (Lanzhou 730050)

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