Part of the smart factory are production environments that organize themselves and are based on intelligent units: Machines coordinate production processes independently, collaborative robots in assembly work hand in hand with people and driverless transport systems complete logistics orders autonomously. More and more of these mobile units are transporting material or goods from point A to point B in the field of intralogistics. Their contribution to value creation in production is the smooth flow of goods. As with other machines, it is therefore important to avoid downtimes as far as possible.

Track-guided systems such as classic driverless transport systems are similar to trains or streetcars that follow predefined paths. There are also freely navigating vehicles, so-called Autonomous Mobile Robots (AMRs), which are flexible in their route finding without exception. However, both types of driverless transport systems (AGVs) have one thing in common: they must be safe in their dynamically changing environment, which they share with humans, other AGVs and machines. But how can productivity and safety be optimally combined in mobile robotics?

Follow markings - but safely

Simple AGVs follow markings on the ground on their way, for example from a machine to the warehouse. According to ISO 3691-4 (Industrial trucks - Safety requirements and verification - Part 4: Driverless industrial trucks and their systems), if there are obstacles such as pallets in this path, the AGVs must comply with defined warning and safety zones according to their speed, which can lead to the AGV stopping, for example.

The 'PSENscan' safety laser scanner from Pilz, for example, provides this type of protection - and therefore also productive area monitoring for collision protection. If required, it can switch to standby mode with an automated autoreset function, which guarantees a time-saving restart of the AGV. The safety laser scanner also logs error lists to enable rapid diagnosis.

If further safety functions, such as emergency stop, are to be covered in addition to safe standstill, a flexible solution consisting of the safety laser scanner and the modular safety relay 'myPNOZ', also from Pilz, which consists of a head module with up to eight freely combinable extension modules, is available. Users can put together an individual safety solution to suit their needs, which can be expanded as required if the functions need to be extended in the future.

Safe sensor technology in the open field

Freely navigating mobile platforms (AMRs) can avoid obstacles or people. For this reason, the required safety functions are more complex: on the one hand, this means that safe sensor technology such as laser scanners must permanently record the surroundings for free navigation. 'PSENscan' can read out the data via the UDP interface, the C++ library or the ROS (Robot Operating System) packets so that users can use them for their own SLAM algorithm (Simultaneous Localization and Mapping). In this way, environment maps can be created for navigation. Up to 70 protective fields can be set up with the safety laser scanner, creating a dynamic protective field adjustment around the AGV.

At high speeds, the protective zones cover a larger radius in order to detect obstacles at an early stage, and a correspondingly smaller radius at slower speeds in order to avoid standstills as far as possible. This allows the AGV to move efficiently. The configurable small controller 'PNOZmulti' with an expansion module for drive monitoring selects the corresponding safety zone of the safety laser scanner. Together with the 'PITreader' access authorization system, the 'PITestop' emergency stop button and the 'PITsign' muting lamp, Pilz offers a complete solution package for efficient and safe monitoring of mobile applications.