Currently, the main navigation methods are:
Electromagnetic guidance is a relatively traditional guidance method. The realization form is to bury a metal wire in the driving path of the automatic guided vehicle, and load a low-frequency and low-voltage current on the metal wire to generate a magnetic field. The magnetic field is guided through the on-board electromagnetic sensor. The identification and tracking of the strength and weakness realize the navigation, and the task is completely specified by reading the pre-embedded RFID card.
Electromagnetic guidance has a relatively simple route and requires 24 hours of continuous operation in manufacturing (such as automobile manufacturing).
The principle of magnetic tape guidance is similar to that of electromagnetic guidance. Tape is also laid on the path of the automatic guided vehicle, and the guidance method is realized through the recognition of magnetic field signals by the on-board electromagnetic sensor.
Magnetic stripe guidance is suitable for ground-embedded, light-load traction, and can be used in non-metallic ground and non-demagnetized indoor environments, and can work stably and lastingly.
Two-dimensional code guidance, coordinate marking is realized by two-dimensional code on the ground. Two-dimensional code guidance is similar to magnetic nail guidance, but the coordinate markers are different. The principle of the two-dimensional code navigation is to automatically guide the car to scan the ground QR code through the camera, and obtain the current position information by analyzing the two-dimensional code information. Two-dimensional code navigation is usually combined with inertial navigation to achieve precise positioning.
The laser navigation method enables the AGV to flexibly plan the route, accurately locate, the driving route is flexible and changeable, the construction is more convenient and can adapt to various practical environments. Because the reflector of laser navigation is in a higher physical position, it is not easy to be damaged. The reflector cannot be shielded during normal operation, otherwise it will affect its positioning. Due to the high cost of laser navigation, the occupancy rate in the current AGV market is not very high, but due to its superiority, it will gradually replace some traditional navigation guidance methods.
The method of navigation is achieved by obtaining image information around the operating area by the on-board vision sensor of the automatic guided vehicle. The hardware needs down-view camera, fill light and hood to support the realization of this kind of navigation method. Rich ground texture information can be used, and the displacement and rotation between the two images can be calculated based on the phase correlation method, and then obtained by integration current location.
Vision navigation AGV currently has fewer applications in the market. The advantages of visual texture navigation are lower hardware costs and precise positioning. The disadvantage is that the running ground requires texture information. When the running site is large, the time to draw the navigation map is longer than that of laser navigation.
A single navigation method can adapt to a limited number of scenarios. The multi-navigation fusion method allows agv to have more than two navigation characteristics to meet the needs of more complex scenarios. The development of smart storage has made integrated navigation a trend.
