Common AGV navigation guidance methods:
1. Magnetic nail navigation
The navigation method still uses the magnetic navigation sensor to detect the magnetic signal of the magnetic nails to find the travel path, but it changes the continuous induction of the magnetic stripe when the magnetic stripe navigation is used to intermittent induction, so the distance between the magnetic nails cannot be exceeded. Large, and the AGV between the two magnetic nails is in a state of distance measurement. In this state, an encoder is required to measure the distance traveled. Secondly, the control module used for magnetic nail navigation is the same as the magnetic stripe navigation control module.
2. Magnetic stripe navigation
Magnetic stripe navigation is considered to be a very mature technology, mainly by measuring the magnetic field signal on the path to obtain the position deviation between the vehicle itself and the target tracking path, so as to realize the control and navigation of the vehicle. Magnetic stripe navigation has high measurement accuracy and good repeatability. Magnetic navigation is not easily affected by changes in light. During operation, the magnetic sensor system has high reliability and robustness. Once the magnetic strip is laid, the maintenance cost is very low, the service life is long, and it is easy to add and change the path.
Laser navigation is to install a laser reflector around the AGV's driving path. The AGV determines its current position and direction by emitting a laser beam and collecting the laser beam reflected by the reflector, and realizes the AGV through continuous triangular geometric operations. navigation. Laser navigation technology is accurate in positioning, and the driving path on the ground can be flexible and changeable without other positioning facilities. It can be suitable for a variety of on-site environments. It is currently the advanced navigation method preferred by many domestic and foreign AGV manufacturers.
4. Electromagnetic navigation
Electromagnetic navigation is one of the more traditional navigation methods, and it is still being used. It embeds metal wires in the driving path of the AGV, and loads the guiding frequency on the metal wires, and realizes the navigation function of the AGV by identifying the guiding frequency . The navigation technology is similar to the magnetic stripe navigation. Due to the shortcomings of the navigation technology, such as lack of beauty and difficulty in path changes, the technical solution is gradually abandoned by AGV manufacturers. However, the navigation technology is also more suitable for specific occasions, depending on the requirements of the AGV working environment. For example, under high temperature environment, strict requirements such as line straightness are required.
5. QR code guide
The two-dimensional code guidance method is to lay QR two-dimensional codes discretely, and obtain real-time coordinates by scanning and analyzing the two-dimensional codes through the AGV vehicle camera. The two-dimensional code guidance method is also the most common AGV guidance method on the market. The composite navigation form of two-dimensional code guidance + inertial navigation is also widely used. Amazon's KIVA robot realizes autonomous movement through this navigation method. This method is relatively flexible, and it is also convenient to lay and change paths, and requires regular maintenance.
6. Inertial navigation
Inertial navigation is to install a gyroscope on the AGV. The gyroscope can be used to obtain the three-axis angular velocity and acceleration of the AGV. The AGV can be navigated and positioned through integral operations. The advantages of inertial navigation are low cost and high accuracy in a short time, but this navigation method The shortcomings are also particularly obvious. As the gyroscope itself grows over time, the error will accumulate and increase until it loses its position, which can be called an "absolute flaw." Inertial navigation is usually used as an aid to other navigation methods.
7. SLAM laser navigation (natural navigation)
SLAM laser navigation is a natural navigation method that does not require the use of reflectors. It no longer needs to use auxiliary navigation signs (QR codes, reflectors, etc.), but through the natural environment in the work scene, such as: pillars in the warehouse , Wall, etc. as positioning reference objects to achieve positioning and navigation.
8. Visual navigation
Visual navigation is also a navigation method based on the SLAM algorithm. This navigation method collects image information of the operating area through the on-board vision camera, and performs positioning and navigation through image information processing. Visual navigation has the advantages of high flexibility, wide application range and low cost. However, the current technology maturity is average, and the technology of quickly and accurately realizing road sign recognition using on-board vision system is still in the bottleneck stage.
