Automatic Guided Vehicle - AGV
Automatic Guided Vehicle (AGV) is a type of unmanned wheel-driven robot. Under the instructions given by monitoring system, it is able to find the specified destination through predetermined route by utilizing automatic guide devices and on-board sensors and then complete assigned tasks. Due to advantages of agility and intelligence, AGV is mainly used in applications such as flexible manufacturing systems and smart warehouses.
An AGV device is composed of a variety of modules for navigation, movement, obstacle detection, loading/unloading, communication and power supply. Navigation is certainly the key function. Nowadays, navigation methods adopted in AGV include electromagnetic, magnetic stripe, optical, infrared, laser and visual navigation. Laser navigation is a popular method used in AGV due to its high agility and accurate control. To implement laser navigation, a great number of rectangular prisms that can reflect laser back to vehicles are required to be fixed on walls and obstacles, and laser transceivers that can rotate horizontally should be mounted on top of vehicles. When vehicles are moving, the real-time location can be calculated based on incident angle and prisms’ positions, and then compared with the predetermined route stored in memory to accurately adjust vehicles’ movement.
The movement module of an AGV is made up of motors, motor control units and driving circuits. Vehicles’ speed is controlled by processor. The moving direction of vehicles changes when the motors on both sides are rotating at different speed. During movement, AGV needs an ultrasonic or infrared sensor to detect obstacles standing in its way. Furthermore, an accelerometer is used to detect the inclination of ground in order to prevent fall of loaded goods. AGV’s loading/unloading module is used to load and unload goods by driving a motor to control forklift. Battery is used as power supply of AGV. When low power is detected, monitoring system gives vehicles an instruction to go to a specific position to charge automatically.
With the development of sensor technology, multiple navigation and obstacle detection methods could be combined together to realize AGVs with more intelligence and accuracy.