Application design of the hottest RFID technology

Application design of RFID technology in automated three-dimensional warehouse

according to the management of automated three-dimensional warehouse in modern logistics system, the basic principle of RFID technology and RFID technology have the characteristics of wireless transmission of information, large amount of information transmission and convenient and accurate information transmission. Combined with the working situation of automated three-dimensional warehouse, RFID technology is applied to automated three-dimensional warehouse, Build an automated three-dimensional warehouse based on RFID technology. Through practice, the speed of information processing in this system is more than 10 times higher than that in the traditional way. At the same time, it can process data information in real time, which meets the needs of modern logistics system

preface

with the gradual maturity of the production technology of automated three-dimensional warehouse system equipment and the gradual popularization of its application, the traditional

management method based on manual records can no longer meet the current needs of enterprises, while the magnetic card, bar code and other technologies are not suitable for the development of logistics industry in the future due to their own shortcomings. These models have exposed many shortcomings in the development process of modern enterprises, which has greatly affected the process of enterprise information automation

rfid technology is a new and advanced automatic identification technology. Its broad development prospects in various industries have attracted widespread attention of countries and enterprises all over the world. RFID technology has the advantages of waterproof, antimagnetic, high temperature resistance, long service life, long reading distance, convenient and fast reading, encryption of data on the label, larger storage capacity, free change of storage information, diversification of shape and so on, which other identification technologies do not have. The emergence of RFID technology solves the problem of automatic data identification, processes information more quickly and accurately, reduces manual intervention, avoids cumbersome manual input and other processes, and thus reduces production costs. Therefore, this paper proposes a design of applying RFID technology to the three-dimensional warehouse system, which can not only realize the normal operation of the automatic warehouse with 80 storage locations with high precision and speed, but also adapt to the production management of modern factories and enterprises

1 radio frequency identification (RFID) technology

1.1 introduction to RFID technology

radio frequency identification (RFID) is a technology that uses radio frequency signals to realize contactless information transmission through spatial coupling (alternating magnetic field or electromagnetic field) and achieves the purpose of identification through the transmitted information. The basic RFID system is generally composed of electronic tags, antennas, readers, etc

(1) electronic tag. It is composed of coupled components and chips. Each electronic tag has a global identification number (ID), which cannot be modified or imitated, providing security. Electronic labels should be attached to objects to mark the target object. Generally, electronic data in the agreed format is stored in the electronic label, such as the type, production batch, quantity of the object to be identified, and the location number of the shelf

(2) antenna. The RF signal is transmitted between the tag and the reader, that is, the data information of the tag and the command information sent by the reader

(3) reader. Devices for reading or writing electronic label information, including handheld and fixed. The reader can read and recognize the electronic data stored in the electronic tag without contact, so as to achieve the purpose of automatic object recognition. It is connected with the computer to process the read label information. The composition of RFID system is shown in Figure 1

Figure 1 Composition of RFID system

compared with traditional identification technology, RFID has the following advantages: fast processing speed; Small size and diversified shape; Strong pollution resistance and durability; Reusable; It has strong penetrability and can realize barrier free reading; Large memory capacity of data; High safety

1.2 working principle of RFID technology

the reader writer emits energy in a certain area through its antenna to form an electromagnetic field, and the size of the area depends on the transmission power, working frequency and antenna size. When the tag enters this area, it receives the RF pulse of the reader writer, charges the capacitor after bridge rectification, and uses it as the working voltage after voltage stabilization. At the same time, the data demodulation part demodulates the command and data from the received RF pulse and sends them to the control logic. The control logic receives the command and sends the product information (passive tag, passive tag or passive tag) stored in the tag, or the tag actively sends a signal of a certain frequency (active tag, active tag or active tag). After receiving the returned data, the reader/writer decodes and performs error verification to determine the validity of the data, and then sends it to the central information system for relevant data processing

2 overall design of automated three-dimensional warehouse based on RFID technology

2.1 composition of automated three-dimensional warehouse system

the main body of automated three-dimensional warehouse system is automated three-dimensional warehouse. In order to realize the automatic storage and removal of materials, corresponding management and monitoring system is also required. Therefore, the composition of the system is shown in Figure 2

Figure 2 composition of the automated three-dimensional warehouse system used to ensure safety protection in the process of the experiment

2.2 the automated three-dimensional warehouse system mainly consists of

(1) main controller. The main controller used in this design adopts the small PLC of Siemens, which has the processing capacity of 40 digital i/o points, and has two communication/programming ports, which can realize the network control function of multiple stations in the system

(2) detection device. The detection of the system includes warehouse location detection, state judgment of each actuator of the system, etc. the detection devices used include contact position sensor, photoelectric sensor (Omron cx-24), rotary encoder (Omron e6a2-cw5c), etc

(3) stacker. The main executive mechanism in the automated three-dimensional warehouse system is the stacker, whose function is to automatically access goods from the shelves. The stacker designed in this system is mainly composed of three-axis motion mechanism composed of stepping motor. The selected motor adopts HS series high torque square hybrid stepping motor, which has small volume and high precision. The stacker composed of it and PLC controller can meet the requirements of accurate positioning

(4) conveying system. Its function is to transport goods to or remove goods from the stacker. Common conveyors include chain conveyor, belt conveyor, etc

(5) RFID system. The system selects V600 series produced by OMRON in changsanjiao region and zhusanjiao region, which are currently flame retardant PP manufacturers in Japan, as RFID system. The device adopts electromagnetic coupling mode, and the oscillation frequency is 530khz. It mainly includes read-write head, ID controller and passive electronic tag

① read write head, model v600 H11, which is the bridge between the electronic tag and the ID controller, belongs to the amplifier built-in type. Through the read-write head, the command of the host can be sent to the electronic tag within a certain range through the ID controller, and the response information of the electronic tag can be transmitted to the ID controller at the same time. ② The ID controller, model v600-ca5d02, is used to connect with the read-write head of v600-h series, execute the command of the host to read and write the electronic tag, and return the response signal of the electronic tag to the host at the same time. ③ Electronic label, model v600 D23p66n, a battery free data carrier in Omron V600 series, belongs to passive electronic tags

2.3 system process analysis

according to the flow direction of goods, the main process of the system is divided into two parts: the warehousing operation process and the outbound operation process with a square level leaning against the vertical and horizontal positions on the outer surface of the oil cylinder, as shown in Figure 3 and Figure 4

(1) warehousing process

① warehousing preparation. The warehousing preparation of the system includes the initialization of the system state and data initialization. At this time, the stacker is in the initial state, and the ID controller is ready to detect the goods. ② The warehousing order is released. The warehousing order can be delivered to the main controller manually or electronically. The main controller identifies the type of goods according to the information of the warehousing order. At the same time, it also needs to process the ID information of the detected goods fed back by the read-write head, and compare the two information. When the goods information is consistent with the warehousing order, the system automatically assigns a warehouse location number to the warehousing goods, which is written into the electronic label by the read-write head. ③ Warehouse in. Warehousing refers to the transfer of the stacker from the warehousing port to the picking platform. The system assigns a space coordinate point to the stacker according to the warehouse number assigned by the goods. At this time, the stacker operates from the initial state to the storage port, and the goods are transferred from the loading platform to the picking platform of the stacker to prepare for the next shelf. ④ Put into storage and put on shelves. Warehousing and shelving is the last operation step of warehouse warehousing. The stacker puts the goods on the picking table into the designated warehouse location. According to the space coordinate points allocated by the system, the stacker automatically finds an optimal track to deliver the goods from the storage port to the three-dimensional warehouse. ⑤ End of warehousing. After the goods are put on the shelf, the stacker returns to the standby state, and the system updates the location data and completes the corresponding records

(2) outbound operation process

① outbound preparation. The delivery standard of the system greatly meets the needs of customers, and the preparation is similar to the warehousing preparation. ② Release the delivery order. The delivery order can be delivered to the main controller manually or electronically. The main controller identifies the type of goods according to the information of the delivery order. At the same time, it also needs to process the ID information of the detected goods fed back by the read-write head, and compare the two information. When the goods information is consistent with the delivery order, the system is ready to deliver. ③ Exit and enter. After the system confirms the delivery operation, the stacker will obtain a certain spatial coordinate point according to the location information determined by the delivery order. Under the operation of the main controller, the stacker will arrive at the designated bin from the current position along the optimal path. ④ Out of the warehouse and off the shelf. In the warehouse area, the stacker removes the goods from the designated bin, and the read-write head reads the goods ID information and feeds it back to the main controller. The main controller determines whether the information of the outbound goods is consistent with the information of the outbound order. When the information is confirmed, it performs the picking operation and transports the goods to the outbound port. At the same time, the electronic tag system writes the outbound information into the electronic tag and updates the stored data. ⑤ End of delivery. The stacker returns to the standby state, the system data is updated, and the corresponding records are completed

3 program design

in the operation process of the whole system, the core control technology includes two aspects: one is the automatic track finding and spatial positioning of the stacker in the automated warehouse; On the other hand, RFID system automatically detects and updates data information

it can be seen from the system flow chart (see Figure 3 and Figure 4) that the RFID system is mainly divided into two parts in application, namely, read information operation and write information operation. For the reading and writing operation of electronic labels, there are corresponding fixed communication formats in the corresponding system. Users can complete the corresponding control only according to the communication format

commands such as read and write operations can be realized by changing the command code in the communication format. Next, the main controller controls the reader to complete the read operation as an example to illustrate the program design

in order to complete the PLC control of the ID controller, the PLC controller needs to send the correct command to the ID controller, so the free VI instructions XMT (data sending instruction) and RCV (data receiving instruction) of the controller are used to complete the purpose of operating the ID controller

when the goods arrive at the storage port, the switching signal of the photoelectric sensor is triggered. At this time, the PLC executes the port sending instruction XMT, and the port sends the automatic reading