Pepperl+Fuchs Blog

Position Guided Vision for Automatic Guided Vehicle (AGV) Control

Posted by Gerry Paci on Fri, Mar 10, 2017

Automated guided vehicles (AGVs) are used to move product throughout the factory or warehouse floor. Speed and precision are key when moving materials— if you've seen AGVs zipping around in a warehouse, you want to ensure that they stay on track and that they go exactly where they need to, with materials and AGV intact.

The video below discusses the key features and general applications for our PGV absolute positioning system for automatic guided vehicles. The PGV follows Data Matrix codes or colored lines with sub-millimeter precision and is ideal for guidance of AGVs.

From control codes to initiate starts, stops, and turns, to the user-friendly software Vision Configurator, the PGV is packed with the tools you need for any AGV application.

Position Guided Vision for Automatic Guided Vehicle (AGV) Control



Video transcript:

The PGV is the only product on the market offering a distinctive combination of navigation, tracking, and absolute positioning feedback all in one device. This is the optimal solution for AGV control.  

Hello everyone! This is Gerry Paci, Product Manager at Pepperl+Fuchs. Today I want to discuss why the PGV is the best all-in-one device for tracking automated guided vehicles or AGVs.

The PGV uses an advanced industrial 2-D camera to guide an AGV along its coded or colored path. By scanning Data Matrix codes, the PGV can output precise absolute position information. In combination with Data Matrix technology, the PGV can also navigate using a color path.

For configuration of several parameters with the click of a mouse, the vision configurator software allows the user to fine tune settings. With this software and a simple connection between the PGV and a PC, live images, device optimization, and various functions can be set. These are just a few of the features that make the PGV the ideal choice for AGV control.

Let's first talk about the absolute positioning information that is provided by the PGV and the Data Matrix codes. Data Matrix codes encompass a large amount of digital information in a small 15 mm by 15 mm square. Using our Data Matrix code tape, the PGV can achieve .2 mm resolution and track up to 6 miles. These codes contain position information for dual axis as well as providing X and Y data.

In many AGV applications, the route of travel is rarely a straight line. This is no problem for the PGV, because in addition to the X and Y data, 360 degrees of angular feedback is continuously delivered.

Installation is quick and simple, too. Our Data Matrix code tape has a self-adhesive backing, allowing the user to easily install on a factory floor. The code tape is also very durable, made out of polyester laminate. For the more challenging AGV applications, the user can install two rows of code tape for multiple lane tracking. These are often referred to as "branches."

In addition, the user may want to initiate a stop, start, or turn. An easy solution for this is by using our control codes. These are similar to the Data Matrix code squares in size, but function slightly differently. Control codes are 1 meter in length and laid in parallel with both the Data Matrix codes and colored lines. There are 1000 unique codes available, which can initiate different user-specified actions.

Now that we have discussed the Data Matrix code tape and control codes, let's talk about the PGV's ability to track colored lines. The PGV is designed to track colored lines. The PGV is designed to track the standard red, blue, green, or yellow tape in widths up to 40 mm. Accurate angular feedback and Y axis positional information is provided from the colored lines. Readability of the lines is unaffected by background color or reflectivity. This is because the PGV is tuned to focus directly on the region of interest, ignoring outside influences like light or glossy floors in the background. Not only will it track colored tape, but painted lines will also work fine. This makes the installation very flexible and cost-effective. When using paint, the same width and color rules apply as with the colored tape. Sometimes, using painted lines in a rugged environment is best for durability and ease of repair. While the PGV can evaluate a damaged or dirty colored line to a certain degree, installing new tape, or painting over the marked area is typically simple. If there are colors outside of the standard, for example, a specific orange, we can quickly test it to determine how well it will work.

Similar to the Data Matrix code tape is the ability to have two rows of colored lines. This will allow lane control for a more complex AGV application. Another similarity shared with the code tape is that colored lines can utilize the control codes to initiate an action, but the limitation of distance is removed. The PGV can track colored lines as far as they can be installed.

The last guidance method the PGV uses is the Data Matrix tag. These tags have a total of 16 Data Matrix codes all in one 85 mm x 85 mm square. They are unique, because this is the only tracking method that provides all of the positional information the PGV offers. You will receive sub-millimeter absolute positional information on the X and Y axes, 360 degrees of angular feedback, and also, a unique identifier.

Data Matrix tags share the same durability features as the code tape and are also adhesive, so installation is simple. They can also be used in combination with colored lines, allowing the user to have full control of their AGV. Due to the amount of code squares in one 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 helps for redundancy, if some of the code squares become damaged or unreadable.

One of the most important features of PGV is that for absolute position, only one legible Data Matrix code square is required. This level of redundancy from the code squares coupled with the large reading window ensure that the PGV will keep the vehicle on track at all times.

High speeds are also no issue for the PGV. It can handle speeds up to 17 MPH with no loss of information. Its size is also beneficial for the smallest AGVs. The PGV read head is nearly able to fit inside the palm of your hand!

As mentioned earlier, the PGV is fully configurable with vision configurator software. This software is free of charge, and is available directly from Pepperl+Fuchs website. All that is needed is a PC, the PGV read head, and the USB converter kit.

For specific information on the vision configurator software, please refer to the video 'Automatic Guided Vehicle PGV Demo Case.'  In this video, all of the how-to features are demonstrated.

As an overview, the software will allow several parameter changes to occur with the PGV. Adjusting the resolution, assigning inputs or outputs, taking a live picture in image view, or looking at the real-time feedback information are just a few of the features with the vision configurator.

The PGV is also available in several popular industrial protocols with plug-and-play connectivity.

The last topic I want to touch on is related to the environment of an AGV. Many AGVs are installed in automotive or manufacturing plants. Sometimes the floor will have dirt, debris, or heavy foot traffic. This can really put the durability of the code tape, tags, or colored lines to the test. This is why for all installations, we recommend using our protective laminate cover. The cover is self-adhesive, just like the code tape, but it is thin and clear. It is installed over the top in order to protect it from the sometimes harsh environment of the factory floor. When affixed on top of the code tape or tags, there is no loss of readability. It is always a good idea to add a layer of protection without losing any functionality.

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Topics: Software, Positioning Systems

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