Discussion on AGV technology and flexible manufact

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A brief discussion on the technology of automated guided vehicles (AGV) and its application in flexible manufacturing systems

1 overview of AGV

agv (automated guided vehicles), because of its high degree of automation, safety, flexibility and other characteristics, is widely used in automotive manufacturing, machining and other automated production and storage systems. It is one of the key equipment of modern logistics storage system such as flexible manufacturing production line and automated three-dimensional warehouse. At present, China has many robot industrialization bases, including Shenyang Xinsong Robot Automation Co., Ltd., the robot center of Beijing Institute of mechanical industry automation, Shanghai Mechatronics Engineering Co., Ltd., which has laid the foundation for the development of China's automated guided vehicle (AGV) industry. After years of unremitting efforts, China has been able to produce AGV series products with international advanced level, and some of them have achieved small batch production

2 AGV classification

2.1 according to the guidance technology classification

1) electromagnetic guided AGV. It is mainly to embed wires under the floor of the working area, and then apply a specific AC electromagnetic signal, which is detected by the sensor on the AGV to implement the running control

2) light stripes guide AGV. Draw or lay the route with specific color and shape on the floor of the working area, and AGV can detect the existence and offset position of pattern stripes by photoelectric probe

3) tape guided AGV. The tape is laid on the floor of the working section, and the AGV detects the tape signal through the magnetic field sensor to control the running

4) ultrasonic positioning AGV. More than three ultrasonic transmitters are installed at the fixed and known positions in the working range. The AGV receives the ultrasonic signals transmitted by it, calculates the distance between the AGV and each transmitter, obtains its own two-dimensional coordinates, and controls the vehicle movement accordingly

5) laser positioning AGV. The reflector is fixed at a known position in the working area, and a rotatable laser transmitter receiver is designed on the top of the AGV. Detect the included angle or distance between AGV and each reflector, and then calculate the two-dimensional coordinates and direction of AGV according to the coordinates of the reflector

6) visually guided AGV. There are many visual guidance methods, mainly through CCD camera to obtain the surrounding or ground image, and then identify the bionic image to determine its own coordinate position, and then guide the AGV

2.2 classification by purpose

1) handling AGV. It is widely used in warehousing and logistics systems in machinery, electronics, printing, home appliances, textiles, cigarettes and other industries

2) assembled AGV. Assembly type AGV is used in flexible production line of automobile assembly and other fields. For example, the assembly AGV of Xinsong company is mainly used in automobile production lines, which realizes the dynamic automatic assembly of engine, rear axle, fuel tank and other components. It is also used in the automatic assembly line of large screen color TV and other products, which greatly improves the production efficiency

3 introduction to AGV technology

3.1 AGV system composition

automatic guided vehicle (ACV) generally includes: vehicle body, control system, steering drive device, photoelectric guidance system, wireless communication system, power storage and charging device, safety device and other modules

the body part of AGV is composed of body and manipulator, which can perform telescoping, up and down, rotation and other operations. The control system is the center of the system, which integrates the functions of motor drive, sensor signal, positioning algorithm, manipulator action and wireless communication. Complete the control instructions of the upper computer for the motion direction, loading and unloading, parking and obstacle avoidance of the automatic guided vehicle (AGV). The steering driving device is composed of wheels, driving motors, photoelectric sensors and control circuits; The photoelectric guidance system uses the differential speed regulation of the left and right drive wheels to ensure that the automatic guided vehicle (ACV) runs along the correct track. The wireless communication system realizes the communication between the AGV and the main control computer (upper computer). The main control computer and the embedded industrial control computer on the AGV are equipped with wireless data communication cards. The battery adopts 48V DC storage to ensure continuous operation for 12h. The safety device uses some infrared sensors for collision avoidance and obstacle avoidance detection to protect people and equipment

3.2 AGV main technology

1) AGV navigation technology

agv navigation technology determines its motion direction and path mode. The commonly used methods are scheduled route outside the vehicle and non scheduled route. The way of predetermined route outside the vehicle refers to setting information media for navigation on the driving path. AGV obtains navigation information by identifying information media, such as tape guidance, electromagnetic guidance, optical guidance, etc. Unscheduled path means that the AGV recognizes the scheduling information and determines the driving path during the movement, such as laser guidance, GPS guidance, visual navigation, etc

2) AGV safety technology

agv safety collision avoidance is a good guarantee for its normal operation. AGV anti-collision safety devices are divided into contact type and non-contact type. Contact safety device mainly refers to the safety device installed around the edge of AGV. Such as buffer, pressure sensor, etc. Non contact device refers to the non-contact way to feel the unsafe factors around the AGV, so as to control the direction and speed of AGV movement and avoid collision. There are many types of non-contact devices, such as laser, ultrasonic, infrared and so on

3) AGV battery technology

in recent years, AGV has also developed with the development of battery technology, from using acid batteries, high-energy acid batteries to high-energy alkaline batteries, improving environmental protection performance, greatly improving the charge discharge ratio, from charging time/discharge time of 1:1 to 1:12, greatly shortening the standby charging time

4 application of AGV in flexible manufacturing system

at present, flexible manufacturing system has developed rapidly in automobile, manufacturing, motorcycle, tobacco and other industries. Among them, the three-dimensional warehouse module in flexible manufacturing system needs to carry out operations such as handling, warehousing and out of warehouse for blanks, semi-finished products and finished products. Automatic guided vehicle (AGV) can easily realize automatic access to loading and unloading stations, workbenches and shelves, and fully meet the requirements of high flexibility, large logistics volume, complex handling routes and so on. The main operation process of AGV in the flexible three-dimensional warehouse is as follows:

(1) warehousing: a station on the whole flexible manufacturing system puts forward clear requirements for warehousing to the system, which mainly include the name and quantity of parts. After the system responds, the upper computer sends instructions to the industrial control computer on the AGV through the wireless network to clearly inform the AGV to transport parts to the corresponding warehouse. AGV grabs the parts from the loading and unloading station, plans the motion path according to the current state, position, task, etc., runs to the corresponding bin, stops immediately, and then automatically places the parts into the corresponding bin according to the target position

109 ceramic bricks

(2) ex warehouse: the system notifies the automatic guided vehicle (how to maintain the technical indicators of AGV Jinan assay tensile testing machine) in the form of instructions to take out parts from a specific warehouse in the warehouse to the loading and unloading station. Grab the parts from the specific shelf of the warehouse, plan the motion path according to the current position, and run to the loading and unloading station, and stop immediately. Then, the parts are automatically placed in the loading dock buffer according to the target position. Then, the current position and status are sent to the upper computer through the wireless network. The upper computer updates the database according to the current state

in addition, the assembly type AGV in the automatic guided vehicle (AGV) enables the production system to run automatic assembly in multiple different tasks and test combinations. For example, in the automobile production line, AGV realizes the dynamic automation of automobile engine, rear axle, fuel tank and other components, and the testing and assembly of various physical and mechanical properties of plastic film, rubber, wire and cable, waterproof coiled material, metal wire and other materials. (end)

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