The Knapsack AGV Handling Trolley is a series of products developed for automated production lines and automated logistics. It is a gentle handling intelligent trolley developed according to the tight needs of the current industrial production material industry. It is specially designed for industrial material handling. It is a handling equipment that can easily carry workshop materials , Load the goods on the knapsack AGV trolley, which can realize the easy handling of the goods. When multiple AGV unmanned trucks are used together, they can form an assembly line instead of an assembly line to form a flexible production system. Using the role of magnetic strip guidance, the AGV trolley selects the destination by identifying the landmark, and the AGV trolley can place materials at will according to the set site. Place a material rack or a turnover box on the car body for reciprocating motion, identify landmarks through magnetic strip guidance, and make selective stops. This car can also be used as a one-way AGV, with a minimum turning radius of 300mm, which is very suitable for use in venues with insufficient space and frequent handling.
The trolley adopts a four-wheel structure in which the two rear wheels independently drive differential steering, and the two front wheels are universal wheels. The stepper motor provides driving force through the drive wheel after the reducer, and differential steering can be realized when the two wheels move at different speeds.
AGV automatic guided vehicle consists of body system, power system, drive device, steering device, precise parking device, vehicle control system, walking system, safety and auxiliary system, motion controller, communication device, transfer system, and navigation system, etc. composition.
1. Vehicle control system
The vehicle-mounted control system is the core part of the AGV. It is generally composed of a computer control system, a navigation system, a communication system, an operation panel and a motor driver. The computer control system can use PLC, single-chip microcomputer and industrial computer. The navigation system can be divided into different forms such as electromagnetic navigation, magnetic stripe navigation, laser navigation and inertial navigation according to different navigation methods. Through the navigation system, the AGV can determine its own position and walk along the correct path. The communication system is a bridge for exchanging information and commands between the AGV and the console. Since radio communication is not blocked by obstacles, radio communication is generally used between the console and the AGV, and between the AGV and the transfer equipment in order to Optical communication is used for accurate positioning. The function of the operation panel is mainly to input commands during AGV debugging, display relevant information, and connect with the computer through the RS232 interface. The energy on the AGV is the battery, so the action elements of the AGV generally use DC motors, stepper motors and DC servo motors.
2. Body system
It includes chassis, frame, shell and controller, battery mounting frame, etc. It is the body of AGV and has the structural characteristics of electric vehicles.
①The car body consists of the chassis, frame, shell and control room and the corresponding mechanical and electrical structures such as gearboxes, motors, wheels, etc. It is the basic part of the AGV automatic guided vehicle. It has the structural characteristics of electric vehicles and special requirements for unmanned automatic operation. The frame is usually welded with steel components, and the lower the center of gravity is, the more conducive it is to resist overturning. Transfer devices, electronic control systems, buttons, display screens, etc. are often placed on the board.
② Frame The frame is the body part of the entire AGV automatic guided vehicle, which is mainly used to install wheels, light sensors, servo motors and reducers. The servo motor driver, PCD board and battery are installed on the frame. For the design of the frame, there must be sufficient strength and hardness requirements, so the frame material is cast aluminum alloy, and the grade is 6061. Among them, 6061 is relatively light in weight and has good weldability.
③ Wheels The wheels are made of solid rubber tires. The two driving wheels at the rear of the car body are fixed driving wheels, which are connected with the hub-type motor. The front two follower wheels are rotary follower wheels, which play the role of supporting and balancing the trolley.
3. Walking system
It generally consists of a driving wheel, a driven wheel and a steering mechanism. There are three-wheel, four-wheel, six-wheel and multi-wheel, etc. The three-wheel structure generally adopts the front wheel steering and driving, and the four-wheel or six-wheel generally adopts two-wheel drive, differential speed Steering or independent steering.
4. Transfer system
It is an executive mechanism used to complete tasks. Under different tasks and site environments, different transfer systems can be selected. Commonly used are raceway type, forklift type, manipulator type, etc.
5. Safety and auxiliary systems
In order to avoid the collision of the AGV when the system fails or when people pass the AGV working route, the AGV generally has devices such as obstacle detection and collision avoidance, alarm sound, police vision, and emergency stop. In addition, there are auxiliary devices such as automatic charging.
The console can use an ordinary IBM-PC machine, or an industrial control computer when the conditions are bad. The console accepts the AGV conveying task issued by the main control computer through the computer network, and collects the status information of each AGV in real time through the wireless communication system. According to the demand and the current operation of each AGV, the scheduling command is delivered to the selected AGV. After the AGV completes a transportation task, it waits for the next task at the standby station. How to efficiently and quickly schedule multi-tasking and multi-AGV, as well as a series of problems such as collision avoidance in complex terrain, need software to complete. Since all kinds of smart devices in the whole system have their own properties, it is a good choice to use the object-oriented design C++ language to program. When programming, it should be noted that the AGV system has strong real-time performance. In order to speed up the wireless communication between the console and the AGV and the AGV scheduling based on this, it is best to use a multi-threaded mode in programming to enable communication and scheduling, etc. Each functional module does not affect each other, which speeds up the system.
7. Communication system
On the one hand, the communication system accepts the command of the monitoring system and transmits it to other corresponding subsystems in a timely and accurate manner to complete the actions specified by the monitoring system; on the other hand, it receives the feedback information of each subsystem and sends it back to the monitoring system as a monitoring The basis for system coordination, management and control.
Since the position of the AGV is not fixed and there are many devices in the whole system, the communication between the console and the AGV is most suitable for wireless communication. The console and each AGV form a point-to-multipoint wireless local area network. Two issues should be paid attention to in the design process:
①The modulation problem of radio
In radio communication, signal modulation can be done in two ways: amplitude modulation and frequency modulation. In the working environment of the system, the electromagnetic interference is serious, the signal frequency range of the AM mode is large, and it is easy to be interfered, while the frequency range of the FM signal is very narrow, so it is difficult to be interfered, so the frequency modulation mode should be given priority. Moreover, the baud rate of AM mode is relatively low, generally less than 3200Kbit/s, and the baud rate of FM can reach more than 9600K bit/s.
②The problem of communication protocol
In communication, the communication protocol is an important issue. The formulation of the protocol should follow the principles of simplicity and reliability. A concise and effective protocol can reduce the time for the controller to process signals and increase the speed of the system.
8. Navigation system
The function of the AGV navigation system is to ensure that the AGV trolley walks along the correct path and to ensure a certain walking accuracy. The guidance methods of AGV are divided into three types according to the presence or absence of guided routes: one is the method with a fixed route; the other is the semi-fixed route method, including the marking tracking method and the magnetic guidance method; the third is the route-free method, including ground-assisted guidance. method, use the route instruction guidance method on the map and search the shortest path guidance method on the map.
The guidance methods of the fixed route include electromagnetic guidance, optical control belt guidance, laser guidance and ultrasonic guidance.
①Electromagnetic guidance method
②Optical control belt guide method
③Laser guidance method
④Ultrasonic guidance method
9. Load transfer device
The load transfer device of the AGV is a flat plate, which is used to transport the box-like parts to the designated station. Mainly used to load box parts, transport materials, etc.
10. Drive device
The subsystem that drives the AGV to operate and has speed control and braking capabilities. It mainly includes motors, reducers, drivers, control and drive circuits, etc. The drive system is generally closed-loop and open-loop. The former is mainly based on servo DC motors, and the latter is mainly based on stepper motors.
11. Power system
The battery is the only power source currently used by the AGV automatic guided vehicle. It is used to drive the car body and accessories on the car, such as control, communication, security, etc. The surrounding facilities of the AGV automatic guided vehicle use general industrial power, and have different requirements according to the purpose. Such as frequency generators in charging rooms, automatic doors, computer rooms, communication devices, and the power of devices required in the working environment. According to the model, operation and load, different power storage devices are used, and they are generally battery assemblies. Common DC voltages are 12 volts, 24 volts, 48 volts and 72 volts.
AGV is an intelligent mobile robot and the main equipment of modern industrial automation logistics system.