Begin with the fact that there are several methods of robot navigation in space, each of which has its advantages and disadvantages, depending on which ones are more or less popular.
In connection with the history of AGV robots, everyone knows how to follow the induction, magnetic or color line. The latter is still very popular, because it is an extremely flexible method, fast to implement and with a good price-performance ratio. In addition to the line, the route is usually marked with QR codes or RFID tags informing the robot about stations and characteristic points.
However, the most interesting thing is surely laser navigation , which ensures independence of the robot in space. The WObit company has developed its own LMS laser navigation system (Laser Mapping System) and will give you an approximation of its principles.
The principle of laser navigation
In contrast to conventional methods, the LMS system does not need any additional components mounted in the environment (such as codes, reflectors, etc.). Natural objects are used for navigation, such as walls, machines, gates, etc., which are measured using a mobile robot's laser scanner. This information is used to create a coordinate system in which the AGV robot will move along the virtual line. This way of creating a map, unlike the SLAM system (Simultaneous localization and mapping), in which the robot is currently located on the basis of previously accumulated experience, ensures significantly higher predictability and repeatability. After creating the map, the robot will move deterministically on it, covering the route always in the same way, unless the environment conditions change significantly (eg changing the location of a large machine). Such a method of laser navigation works especially in factories, where there is a lot of traffic of different objects (eg fork-lift trucks) occurring on the robot's route, especially compared to navigation with a colored / magnetic line that can be used. dirty or destroyed
A mobile robot using the LMS navigation system is fast in implementation. In order to prepare a route of traffic, a robot's initial travel is required, during which he scans the surroundings using laser scanners with the measurement function. The data is transferred to the software on the PC to generate the initial map, then after making the necessary correction, it can be sent to the LMS system installed on the robot. After downloading the data to the software, under the supervision of a man, the map is imprinted and deleted errors arise as a result of slips or incorrect odometry *. The final stage of the map creation process is verification of the correctness of navigation, after which the robot is ready to work. It takes anywhere from a few to several hours depending on the size of the route and the surroundings. Positioning accuracy is based on environmental conditions and in the worst case is Â± 1 cm.
* Odometry is a measure that deals with the measurement of distances. To measure the road, we use, among others information from encoders placed on robot wheels. They allow the robot to change the position of the robot relative to the initial position in time.