Xplanar streamlines drive systems for the modern era

The ground-breaking XPlanar system from Beckhoff offers boundless potential for streamlining production machines and plant design. It utilises planar movers that float freely over floors of planar tiles that can be arranged in any kind of pattern.

What characterises the new XPlanar drive system is that it is based on the principle of flying motion. Like the XTS linear transport system, XPlanar is much more than just a drive system – it’s a solution designed to make product transport flexible. Compared to XTS, XPlanar adds movement in a second dimension and allows the movers floating over floor tiles to overtake one another and to be held in buffer zones or to bypass them. The free-floating planar movers also have a further important advantage – because of the contactless drive principle, they are silent and completely wear-free.

So, what kind of functionality does this system provide for implementing transport tasks?
“Basically, a transport system simply moves products from one processing station to the next – from A to B, then from B to C, from C to D, and so on,” said Prüßmeier. “With XPlanar, these stations need neither to be in a linear arrangement, nor visited in a fixed sequence.

This means that a given product need only travel to those stations that are essential for processing it. By incorporating the second dimension, XPlanar opens up several other options, too, including the ability to discharge individual movers from the production flow, or to create special waiting zones in order to optimise processing sequences. Enabling faster movers to overtake slower movers is also important, as it allows sub-processes to be executed swiftly, in parallel. Not only is each planar mover controlled individually, as a single servo axis, it can also be synchronised precisely with other movers if necessary.”

The movers can also travel with six degrees of freedom. They not only travel to processing stations, they can also move into them. They can turn, rotating the payload they are carrying through all three axes so that it can be processed or inspected easily from any side. The movers can also be raised or lowered slightly and even tilted. For example, a little tilt can be useful to prevent spills when accelerating quickly while carrying a container full of liquid.

In spite of all the complex motion options that XPlanar supports, the system is simple to set up and deploy from a user standpoint.

“Right at the start of the development process, we decided it was important that the system should be highly integrated and that users would only have to plug in two cables – one for data communication over EtherCAT G and another for power supply,” said Prüßmeier. “As a result, all other functionality has been fully incorporated into the modules. Design-wise, they are also extremely compact – the distance between the working surface of each planar tile and the carrier frame beneath it is just 4cm.”

The system builds on one basic component – a planar tile measuring 24 x 24cm. The tiles can be arranged in any floor or track layout. In addition to this standard tile, there will be another version in the future, identical in shape and size, over which planar movers can rotate through a full 360 degrees – that is to say, infinitely. The movers available differ only in terms of their size and their load-carrying capacity. They currently range from 95mm x 95mm for payloads up to 0.4kg, through to 275mm x 275mm, for a maximum payload of 6kg.

The TwinCAT software also plays a key part in the system’s ease of use.

“Our main objective is to make sure that users find the planar motor system easy to manage,” said Prüßmeier. “In TwinCAT, the planar movers appear as simple servo axes, capable, in principle, of supporting all six degrees of freedom. However, given that the degree of flexibility available with six axes is not always needed from a practical perspective – or, at least, not throughout the XPlanar system – TwinCAT provides a way to reduce this complexity. It does this by representing each mover as a one-dimensional axis capable of optional additional movements in other dimensions – lifting, tilting and turning, for instance – that are available when it reaches a processing station. This means it’s enough, initially, to just set the desired route, or track, across the XPlanar floor. This simplifies operation significantly.”

And how important is TwinCAT Track Management when implementing complex motion sequences?

A key factor in XPlanar’s flexibility is that its ability to transport products is not confined to the aforementioned single tracks, according to Prüßmeier. Users can define additional tracks, and movers can switch between them. To keep things simple for users, even when operating multiple tracks, TwinCAT offers Track Management, a user-friendly tool designed to support complex motion sequences, including the ability to overtake slower movers on the same track, or to accumulate movers in waiting zones. To do this, it allows users to define parallel lanes, bypasses, or tracks to other plant areas on the XPlanar floor.

Track Management allows movers to switch smoothly from one track to another via a short parallel segment. All this takes is a “switch track” command, without users having to deal with the specifics of merging in and out of the flow, or avoiding collisions. Movers can also be positioned with freedom, without having to follow any preset tracks. Using Track Management, they are sent to specific coordinates within the defined XPlanar floor space – again, without any risk of colliding with other movers.

According to Prüßmeier, there are plenty of advantages for the users for building a XPlanar floor from individual tiles.

“Here, too, we put flexibility front and centre,” he said. “The tiles can be arranged in any shape – and even wall- or ceiling-mounted – so the XPlanar system can be configured to perfectly suit a given application’s requirements. For instance, you can leave gaps within the tiled floor to accommodate processing stations, or lay tracks around plant components. This means users can set up a transport system in a cost-optimised fashion and, at the same time, reduce machine size to a minimum. In addition, it’s easy to modify the planar motor system subsequently just by adding more tiles when necessary, that is, to accommodate new processing stations or gain extra space to optimise motion through curves.”

And how can users best exploit this innovation’s potential? According to Prüßmeier, XPlanar opens up new avenues in machine and system design. Users need, literally, to experience the system’s new possibilities hands-on in order to grasp them, so at market launch Beckhoff is offering easy-to-use starter kits, just as it did with XTS.

“These consist of 6 or 12 planar tiles installed on a carrier frame, along with 4 movers and a small control cabinet with an industrial PC, complete with preinstalled software, and the requisite electrical components,” said Prüßmeier. “This offers machine builders an ideal basic kit on which to trial XPlanar in their own environments and then go on to use later in real-life applications. In addition, offering this kind of preconfigured system makes it a lot easier for the Beckhoff support staff to answer any questions that might arise.

Prüßmeier also said that there are almost no limits on using it with production plants and machines. The only requirement is that a product’s weight and volume are within the limits of what the planar movers can carry. Where this applies, users can benefit from all the system’s flexible positioning capabilities. These are particularly interesting in sectors with special requirements in terms of hygiene and cleanability, zero emissions, or low noise.

This is the case in the food and pharmaceuticals industry, as well as in laboratory environments or processes that require a vacuum (in semiconductor production, for instance). The latter two sectors in particular can benefit from the fact that products are carried on floating movers, abrasion- and contamination-free. Depending on the needs of a given application, users can also apply plastic, stainless-steel foil or glass plates to the XPlanar surfaces to make them easy to clean without residue.

XPlanar was first exhibited at the SPS IPC Drives show in Nuremberg in November 2018, with the product attracting interest among visitors.

“It also spawned lots of ideas for possible applications, because many users have been looking for a flexible solution to solve specific transport problems in their production facilities for years now,” said Prüßmeier.

He gives an example from food processing.

“In the production of high-quality confectionery, there are always minor deviations in the colour of chocolate coatings,” he said. “This is not a problem as such, provided there’s no variance within individual boxes of chocolates. However, at a production rate of 100 chocolates per minute, selecting 10 individual chocolates with the same colour for each pack is difficult using conventional means. It would require using several pick-and-place robots to check and sort all the chocolates, which would be costly in terms of time, floor space and throughput rate. The problem can be solved much more efficiently using individually controlled planar movers operating on a single floor. Movers transporting individual chocolates could easily sort themselves at the end of the production line according to the chocolates’ particular shade of colour. Or, if movers were designed to carry an entire box at once, each mover could automatically travel to the system ejection point for the appropriate colour of chocolate to pick up the products. Both of these approaches could be implemented much faster and, importantly, with lower space requirements than, for example, the robot solution I mentioned.”

Beckhoff has already received specific inquiries from the laboratory automation sector, where there’s interest in maximising the flexibility of analyses. For the most part, samples are tested for the same substance content, but less common analyses also need to be carried out for the purpose of individualised diagnostics.

Even with mass analysis methods, XPlanar offers a way to extract individual samples; it also creates additional quality assurance advantages by making it easy to discharge or exchange particular samples. There’s similar demand in the cosmetics industry, too. For example, in one particular case, fragrances need to be filled into selectable, customer-specific bottles that are individually labelled and packaged.

“The main difference is that the XPlanar movers don’t need a mechanical guide rail, so the system offers greater flexibility in terms of movement,” said Prüßmeier. “At the same time, though, the mechanical guidance in XTS can be an advantage. Compared to the magnetic counterforce of the planar movers, a guide rail allows better dynamics and higher speeds in curves, especially in very tight curves, and even when carrying a payload. The specifics of a given application will ultimately determine which of the two systems is the better option. The bottom line is that XPlanar and XTS complement each other perfectly.”