Safety encoders make AMRs productive and safe

STILL has built a strong reputation in intralogistics. Its forklift trucks, pallet trucks, reach trucks, stackers, ... are in great demand in the industry. From the Belgian site, in co-creation with Colruyt Smart Technics, an autonomous pallet truck has now been added to that range with all the gadgets the pallet truck needs to navigate autonomously through a warehouse, but composed of standard components. A game-changer in the world of AMRs, but totally reliable thanks to TR-Electronic's safety encoders.

Even before corona, Colruyt was looking for an intralogistics solution for its warehouse. The retail chain looked to AGVs to deal with labor shortages on the one hand and still safely move pallets across a crowded shop floor on the other. No supplier could meet Colruyt's requirements with its AMRs. So with its Smart Technics department, it decided to design its own Self Driving Vehicle (SDV). "A first prototype was delivered, but it had to be even more robust and performant. It therefore chose STILL as its partner to provide the hardware, scale up production and market the SDV," says Jasper Van Gool who is pulling the project for STILL. The software remains in the hands of Colruyt.

Standardization

The basis for the SDV became a standard pallet truck from STILL's range. "That immediately makes the cost price very interesting. AMRs are now often built for specific applications. We want to go the way of standardization, so that we can offer customers a more cost-efficient solution with a shorter lead time. Moreover, this allows us to scale up quickly ourselves." This approach allows customers to order state-of-the-art AMRs off the shelf. For gadgets to allow the SDVs to navigate safely and autonomously through warehouses have by no means been skimped on. Advanced SLAM technology maps the environment in 3D so that the SDVs can quickly navigate their way through it. Obstacle detection cameras, safety scanners and ultrasonic sensors on the forks ensure that they don't come into contact with anything and can detect and position pallets very accurately. "Productivity and safety at the top," says Van Gool enthusiastically. "Thanks to the presence of this technology in combination with TR-Electronic's safety encoders, we can even achieve SIL3 PL e, although SIL2 PL d is sufficient for this application."

Three encoders for absolute reliability

Each SDV is thus given three, specifically the CDV582M type. One of them is paired with the drive motor to ensure speed, while the other two check that the commands given to the steering motor receive correct execution. They then share their information with the safety PLC. "This allows us to be sure that if the software calculates that a 15° turn is needed to avoid an obstacle, it is done exactly, with no deviation. Not a degree more or less. What appealed to us about TR-Electronic's encoders is that redundancy is built in. Before, you needed two to confirm the proper operation of the encoder itself. Now you still have two signals for absolute reliability, but they are built into one encoder, which makes for a compact solution. Important, because we want to come up with an even more compact SDV model in the next version." 

The relationship is also correct

A second important point is the numerous interface options offered by the encoders. "We needed a Powerlink compatible solution. As a result, the safety encoders communicate seamlessly with the safety PLC." Not only did the product have to be right, by the way; more important was the relationship. "This started as a prototype. Then you need a partner who thinks with you more than a supplier who supplies you with components. If we encountered problems, René Verbruggen's team always got them out in no time. And they could also provide us with the complete package - cable, connector and encoder. That eased the learning curve," Van Gool laughs. 

To be continued

Meanwhile, several devices are already driving around at Colruyt. Other companies also already showed interest and this will only grow. To be continued, no doubt.