Pepperl+Fuchs Blog

4 PGV Navigation Methods for AGVs

Posted by Gerry Paci on Thu, Jul 18, 2019

Moving from point A to B in a busy warehouse can be a challenge for even the most advanced AGVs. So, it is important that the right guidance system is in place to ensure material handling tasks can be performed accurately and reliably.

With the compact position guided vision (PGV) positioning system from Pepperl+Fuchs, even the smallest AGVs can navigate without error. The PGV works in conjunction with the following four guidance options, all of which are available for our newest PGV EtherNet/IP version for more interoperability: Data Matrix code tape, colored lanes, control codes, and Data Matrix tags.

Data Matrix Code Tape

Data Matrix code tape is the most common means of AGV control for the PGV. It is used when detailed and continuous absolute positioning and guidance of an AGV is needed. The 2-D Data Matrix codes printed on the tape provide the PGV read head with sub-millimeter positional data. This data includes X, Y, and Z positions and 360° of angular feedback, which enable the PGV to track AGVs traveling along a variety of routes.

Our Data Matrix code tape is self-adhesive and can track position for up to 6 miles when combined with the PGV. The adhesive tape is easy to install on a factory floor, has high mechanical stability, and is resistant to high temperatures, chemicals, grease, and UV radiation. Since the tape is often located in high-traffic areas, Pepperl+Fuchs also offers a clear, protective laminate adhesive cover that can be installed on top of the code tape. This adds an extra level of protection without sacrificing code readability.

Colored Lanes

While Data Matrix code tape offers more position data, colored lanes are simpler to use, cost less, and are more flexible. The PGV is designed to track both colored tape and painted lines with widths up to 40 mm in the standard red, blue, green, and yellow. Users can quickly determine which color is best for the factory floor using Pepperl+Fuchs software.

The colored lines provide accurate angular feedback and Y-axis positional information, and the PGV can track colored lines as far as they can be installed. Line readability is unaffected by background color and reflectivity because the PGV focuses directly on the region of interest, ignoring outside influences like light and glossy floors.

Although the colored lanes are more flexible than Data Matrix code tape, they do not provide as much positional data. Colored lanes will only provide the PGV read head with Y-axis (offset) positional data and limited angular feedback. The user does not receive X-position, which is sufficient if they just want the AGV to get from point A to B. However, if users need to know exactly where the AGV is along its route, they need to use Data Matrix code tape. A combination of colored lanes and code tape can be used to enhance system availability.

Control Codes

Control codes are commonly used to initiate AGV actions like starts, turns, and stops. They are similar to the Data Matrix codes in size but function slightly differently. Control codes are 1 meter in length and are installed parallel to the Data Matrix codes and colored lines. Each of the 1000 unique codes available can initiate different user-specified actions.

Typically, control codes are installed directly next to Data Matrix code tape. This provides full positional information and outputs a user-specified number whenever a control code is scanned. Instead of using a specified position to initiate an action, the control codes (the number) can be programmed and installed in different places at different times. The AGV’s location can actually be changed or duplicated throughout the route—the number is the only constant identifier.

Data Matrix Tags

85 x 85 mm Data Matrix tags are made up of 16 Data Matrix squares and provide all of the positional information the PGV offers. This includes X, Y, and Z positions, 360° of angular feedback, and a unique tag number. Adhesive and just as durable as code tape, the tags are easy to install and are highly resistant to chemicals, abrasions, and heat.

Because of the high number of code squares in a single area, the tags offer the widest range of tolerance on the X and Y axes. Not only does this allow the PGV to stay on track, even with rapid movement, it provides redundancy if some of the code squares become damaged or unreadable.

AGVs that use Data Matrix tags are usually equipped with other guidance technologies, such as ultrasonic sensors or gyroscopes, to ensure they reach the next tag without incident. Since the PGV can automatically switch between tag mode and lane tracking, PGV users can decide to use colored lanes or code tape to guide AGVs from one Data Matrix tag grid to the other.

Learn More about the PGV

Topics: PGV, AGV

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