Once you understand how AGVs navigate, you'll realize how and why they are a safer option than traditional transportation.
AGV Navigation
AGVs need to know their location within the manufacturing plant or assembly line in order to navigate effectively. There are two methods for determining location: relative and absolute. Absolute position measurement uses an absolute position because it is mapped. In relative positioning methods, the position is calculated relative to a defined reference point within the factory. With this basic information, we can examine the different navigation methods employed by AGVs and how safety is ensured when working alongside humans.
Magnetic navigation
Here's an example illustrating how magnetic tape can be used to control AGVs. The magnetic tape, being self-adhesive and easy to install, is laid on a track. The AGV then moves solely along the magnetic tape.
The advantage here is the low implementation cost. It is also easy to transfer operations from one area to another. To add additional areas to cover, the system only requires additional tapes; the rest can be expanded in the software, with minimal disruption during implementation.
Safety of magnetic navigation
The magnetic strips will be clearly visible on the factory floor. AGVs move only along tracks filled with magnetic strips. People can easily avoid the tracks and prevent collisions with the vehicles. These vehicles will also be equipped with proximity sensors. The proximity sensors detect any objects in their path by emitting magnetic radiation. There should be no objects in the AGV's path because it has a dedicated track. The controls are coded so that if any object is detected in its path, the AGV will stop moving.
Optical navigation
It is very similar to optical navigation. Ordinary magnetic tape, painted or brightly colored, is used instead of magnetic tape. The vision sensor system can detect the tape with a clear contrast to the factory ground and center the vehicle on the tape. Another implementation uses barcoded tape. This is particularly helpful for implementing branching and converging tracks. The path can be easily changed with this system.
Safety of optical navigation
AGVs equipped with optical navigation can also utilize proximity sensors. Once an object is detected in the path, it automatically stops. Another approach is to use optical sensors equipped on the AGV to detect people and obstacles. Depending on the capabilities of the optical sensor and the associated software, it can be used to detect obstacles in the path. Proximity sensors are a simpler and cheaper option because sensing obstacles with optical sensors requires more advanced software and processing power.
Light detection and ranging
LiDAR (Light Detection and Ranging) is a relatively new technology that has been widely adopted in autonomous vehicles. It functions similarly to sonar or sound navigation and ranging. Instead of sound waves, laser pulses are sent in every direction of the AGV (Automated Guided Vehicle). LiDAR sensors detect these laser pulses reflected from surrounding objects and walls. This is used to construct a useful 3D map of the environment. This map is updated in real time. Because lasers travel much faster than sound, the map of the area is created very quickly, updating multiple times per second.
Safety of LiDAR (laser) navigation
As mentioned earlier, LiDAR uses laser technology to obtain a 3D map of its environment. It clearly shows surrounding obstacles and other objects. This can be used to map paths. Unlike previous navigation modes, LiDAR-enabled AGVs do not rely on tracks for navigation. They can traverse any path with great flexibility. When it detects an object in its path, it can redetermine its route in such a way that it can avoid obstacles.
Fast lasers are used to update the environment model multiple times per second. This helps detect moving objects, their direction of movement, and their speed. Sophisticated algorithms can calculate the trajectory of moving objects and plot a path to avoid them. In this way, LiDAR provides a dynamic safety mechanism.
Other security features
AGVs can use a combination of the aforementioned safety functions. In addition, they can use sound and light signals to alert users to their presence.
Sound-based AGVs can be equipped with an audible system to warn people of their approach. This can involve continuous beeping during operation or only beeping when an obstacle is detected in the path. Proximity sensors or other existing object detection technologies can be used to trigger the warning sound. This helps to clear the path.
Illuminated AGVs can be equipped with normal lights or strobe lights to indicate their presence. Strobe lights attract the attention of those nearby, who will naturally make way. Lights can also be used to indicate various states of the AGV or the manufacturing process.
Changing routes. Here, AGVs change their routes to adapt to objects in their path. A combination of sensors and computer algorithms can be used to change paths to avoid obstacles. Compared to traditional assembly lines, AGVs not only offer operational efficiency but also superior protection for those around them. AGVs can be used to eliminate the hazards of traditional assembly line conveying.
