AGV navigation systems

LGVs are equipped with a 2-dimensional AGV LiDAR Navigation Sensor, also referred to as a laser emitter. The navigational laser emits a continuous beam of modulated laser light in a 360-degree pattern. That laser beam interacts with reflectors, also called targets, positioned in the area where the AGV is operational.

Depending on the laser device manufacturer, LGVs calculate and correct their positioning between 30-40 times per second, making these devices incredibly accurate. Once the laser hits the target, the beam is sent back to the navigation laser that calculates the laser’s traveling time together with radial coordinates. This data allows us to calculate the X,Y coordinates of the reflectors and the AGV. The center of the target must be positioned at the same height as the navigation device and a maximum of 30 meters from the AGV.

When it comes to magnetic tape navigation, automated guided vehicles are equipped with magnetic sensors and follow a defined track made by magnetic tape that is placed on the floor surface. The AGV magnetic sensor detects the magnetic field from the tape and drives the AGV following the path.

Magnetic Tape is easy to install. The high-bond adhesive is used for laying the magnetic tracks. Standard dimensions are 1 mm thick and 5 cm wide, which makes the tape non-invasive.

In general, AGVs with natural navigation are able to navigate autonomously by identifying and mapping the surrounding area. Natural navigation, also commonly referred to as free navigation, is the most evolved AGV navigation method.

Driverless robots with natural navigation can identify a defined wall and navigate at a given distance from it. There are in fact several technologies under the “natural navigation” umbrella such as contour recognition which is the most typical technology.  The vehicles with this technology navigate by identifying and mapping the surrounding area with different types of sensors used by mobile robots.

It is also important to note that the type of self-driving robot that performs natural navigation is called Autonomous Mobile Robot (AMR) rather than Automated Guided Vehicle (AGV).

AGVs can navigate with the help of small cylindrical magnetic spots embedded on the floor. Magnetic spots are commonly cylindrical magnets with dimensions close to 20×10 mm and are installed every 250-500 mm creating a virtual path.

The AGVs goes from one spot to the next using sensors and controls sensors, encoders, and counters to calibrate against steering angle errors. The vehicle follows a CAD drawing previously loaded on the AGV management system while the magnetic spots provide a reference in accordance with the map.