We can no longer do without a navigation system in our car, but inside the warehouse we have to make do without GPS. However, there are alternatives that are rapidly improving, partly due to the lightning-fast development of robots and drones. With these indoor positioning systems, we can avoid accidents and further simplify processes in the warehouse.
My attention for indoor positioning systems was caught by a report in last Saturday's Het Financieele Dagblad (FD): 'Forklifts can find their own way just fine'. The article featured the founder of US start-up 5D Robotics. He and a few colleagues have developed a positioning system that allows robots and drones to move independently inside buildings without colliding with each other. His first major customer is US rental company United Rentals, which will equip forklifts and other moving equipment with it.
Now, indoor positioning systems - usually referred to as real-time locating systems (RTLS) - are not new. In fact, they all work according to the same concept. At least three 'anchors' are hung at fixed positions in the premises. The object to be positioned receives a tag that continuously transmits a signal and measures the distance to the three anchors. This three-point measurement allows the position in the building to be determined. By including a fourth anchor, the height can also be determined.
What sets RTLS systems apart is the signal used to determine the distance to the anchors. In principle, the Wi-Fi network already present in many warehouses can be used for this purpose, but its accuracy is reportedly limited to 3 to 4 metres and its capacity is also limited. I myself remember talking to a supplier who marketed a system based on ultrasonic sound waves in 2007. This system had an accuracy of 30 centimetres, but at the time could not track more than five forklifts at a time. Moreover, the positioning took as much as half a second.
Modern RTLS systems therefore use ultra-wideband technology (UWB), which promises accuracy of up to 10 centimetres. An additional advantage of UWB is that the radio signal passes through walls and other objects, and both capacity and processing speed are much higher. In the article in the FD, 5D Robotics even claims to achieve an accuracy of 2 to 5 centimetres. With such accuracy, interesting applications of RTLS are increasingly within reach:
1 Preventing collisions
Accidents involving forklifts are still commonplace. By continuously determining and analysing the exact position of all moving objects in a room, the alarm can be triggered immediately if two objects get too close to each other. Not only collisions between forklifts can be prevented, but also collisions with pedestrians. This requires pedestrians to wear a tag that continuously transmits a signal, just like the forklifts. That tag can easily be sewn into any safety vest. The forklift can be programmed to stop immediately if a collision is imminent.
2 Order pickers follow
Order pickers are now forced to move through warehouses with an order picker truck or an order picker cart to collect the ordered items. When using an order-pick truck, this means frequently getting on and off the truck to put the machine back down, sometimes only a few metres away. Several forklift manufacturers have designed solutions for this, such as a button on the side of the truck or a remote control integrated into a glove. With an RTLS based on UWB technology, such features are not needed. The order picker truck or order picker cart - at least if it is equipped with a motor - can follow the order picker closely, whichever route through the warehouse he chooses.
3 Scanning superfluous
If positioning is possible to within 2 centimetres, forklift truck drivers no longer need to scan storage locations when putting away or picking up a pallet. If a tag is attached in the fork carriage, 3D positioning is sufficient to identify the exact storage location. At most, this requires the driver to press a button the moment he puts away or picks up a pallet, but this too can be automated with sensors.
4 No more need for drivers
Not only 5D Robotics, but also the Belgian start-up Pozyx are developing positioning systems based on UWB technology to allow robots and even drones to navigate independently through buildings. Obviously, this technology can also be applied to allow forklifts to do their work in warehouses unmanned. This is already possible, but until now has required each truck to 'learn' all possible routes. That seems soon to be unnecessary. You provide the coordinates of the final destination, and the machine then finds its own way.
Marcel te Lindert - Journalist logistics and supply chain
