Intralogistics AGVs: Which navigation technology for which application?

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Leuze electronic GmbH & Co. KG

FAULHABER Drive Systems

Wuxi InfiMotion Technology Co., Ltd.

Automated Guided Vehicles (AGVs) navigate with different technologies. This includes sensor technology, which must fit the intralogistics within the company. Only then can material transport be made as efficient as possible. The article provides an overview of the different navigation technologies.

Automated Guided Vehicles (AGVs) navigate with different technologies. Each has its own strengths and weaknesses. The technical requirements and local conditions are decisive for choosing the optimal solution. Sensor technology also plays a role in reliable navigation. The specialist for innovative and efficient sensor and safety solutions in automation technology Leuze assists decision-makers in choosing the optimal solution.

Particularly position accurate: laser navigation

For particularly precise and flexible navigation of AGVs, laser navigation, also known as contour navigation or natural navigation, is recommended. This is based on laser scanners or Lidar (Light Detection and Ranging). The AGV initially travels through its environment in "learning mode," capturing fixed points using a rotating laser beam and creating a map from them. Using this map, the AGV autonomously orients itself in the space. Obstacles can be safely detected and, if necessary, bypassed. Compared to camera-based systems, laser navigation works even in dark environments and poor lighting conditions. Note: Dust or dirt can affect the precision of the system. Regular maintenance and cleaning are therefore required. Additionally, the range of the laser beams is limited. Therefore, laser navigation is better suited for work areas with clearly defined contours than for wide, contourless environments.

In dynamic environments: laser triangulation

Laser triangulation uses reflectors in the room to determine the AGV's position with a laser scanner. The scanner requires line of sight to at least three reflectors installed several meters high. This enables very precise positioning and navigation of the AGV. This technology is useful in dynamic, frequently changing environments. Cost-wise, it should be noted that the sensor on the AGV must be mounted at reflector height. Additionally, the installation of reflectors in the room is necessary. These must be recognizable at all times for reliable positioning of the AGV. Note: Additional sensors are required to secure the travel path.

The optical or inductive lane guidance

Another type of AGV navigation is optical or inductive track guidance. With inductive track guidance, the AGV follows a magnetic tape or induction cable laid in the ground, and with optical track guidance, it follows a track applied to the floor. Sensors installed on the AGV detect the path, allowing precise vehicle alignment. The advantage is manageable acquisition and installation costs for the sensors. This technology is particularly suitable for environments with clear and predictable paths. It is independent of the vehicle type: The sensor is simply mounted on the AGV with a short distance to the ground. Disadvantages include the construction effort if a magnetic tape or induction cable needs to be laid. In this case, vehicles are also fixed to the previously defined track. This limits flexibility for new layouts or routes. Additionally, navigation in environments with many curves or narrow passages can be less precise compared to Lidar or camera technologies.

Navigation by structure: grid navigation

Grid navigation is based on a coordinate system. It consists of 2D codes on the floor or transponders embedded in the ground. These are arranged in a grid-like pattern and serve as reference points for the AGV to determine its position. The AGV moves on predefined grid paths. This technology is easy to implement. The coordinate system allows for precise positioning and high navigation accuracy. Grid navigation is particularly useful in environments with predictable and structured paths, such as warehouses or production facilities with clear lanes. A disadvantage is the low flexibility for new routes or frequently changing environments. Installing transponders also requires physical interventions in the ground.

Flexible driving: camera-based navigation

In camera-based navigation or vision guidance, cameras capture markers or patterns in the environment. The navigation software uses this data for positioning and navigating the AGV. The main advantage is the high flexibility when paths change frequently. However, camera-based systems often work only limitedly in poor lighting or low contrast conditions. Furthermore, their range is limited, and objects at greater distances cannot always be accurately detected. Compared to other navigation methods, implementing camera-based systems into the overall system can be more complex. The acquisition costs are often higher, requiring investment in high-quality cameras and image processing technology.

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