Infrastructure sensors for safe, automated forklifts

When it comes to logistics, people and robots often work together closely. But this collaboration is only truly efficient if there is no need to separate the machines from workers and they instead operate in the same area and at the same time. This requires that the safety of the people is ensured at all times. For instance, robots such as driverless transport systems must be able to adapt their speed to the situation to avoid collisions. However, people are currently most often responsible for avoiding collisions.

Sensors can be used to monitor the environment so that safety distances are always maintained. The Fraunhofer Institute for Cognitive Systems IKS worked with Hitachi on a simulation to investigate whether this solution can improve the situation in warehouses.

Simulation of the movements of automated forklifts

Screenshot of the simulation from Fraunhofer IKS: An automated forklift next to high shelves with goods in a warehouse.
© Fraunhofer IKS
Shelves and goods can occlude the view in warehouses.

Heavy loads are usually lifted by forklifts. But if driverless transport systems are used as such in mixed areas of warehouses, critical situations may arise primarily as a result of two conditions:

  • Confusing intersections: People and machines can only detect each other as they enter the intersection and must reduce their speed accordingly to react in time if necessary.
  • Poor visibility due to goods: As goods are being moved, visibility and the position of blind spots may change over time.

Infrastructure sensors dynamically adjusting the behavior of transportation systems can be helpful to improve safety in warehouses. The Fraunhofer Institute for Cognitive Systems IKS investigated the impact of such sensors on the performance and safety of automated forklifts in collaboration with Hitachi in order to assess their potential benefits and risks. To do so, the researchers constructed a simulation framework for the movements of driverless transportation systems in warehouses using Webots.

First, a model warehouse was created. Models of workers and of manned as well as driverless forklifts were imported, equipped with actuators and sensors, and programmed to perform simple tasks. The virtual workers follow certain paths and either let the forklifts pass or ignore them. The automated forklifts follow a dynamically calculated path using information from the infrastructure sensors and the forklifts themselves. This allows simulations of different configurations as well as scenarios and testing the reliability of the algorithms in different contexts.

Example: simulation of driverless forklift and human at a blind corner

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Simulation designed by Fraunhofer IKS

A simulation designed by Fraunhofer IKS paves the way for robots and humans to interact safely — without reducing efficiency. Here, a blind corner of the warehouse was selected and scenes where a human worker and an automated forklift want to cross at similar times were examined.

More performance and fewer collisions

The performance of forklifts is dependent on multiple factors: The allocation of tasks, navigation, path planning, motion planning, and other aspects influence their performance. To only investigate the effects of different strategies for collaboration, the simulation included different scenes in which people and machines tried to cross the same area at similar times. This also allowed estimating the residual risk of people overlooking the forklift. The simulation from the Fraunhofer Institute for Cognitive Systems IKS demonstrated that automated forklifts in warehouses with infrastructure sensors need on average 30% less time to cross the intersection and can simultaneously avoid all collisions. Furthermore, different strategies for dealing with blind spots were investigated.

Additional simulations of collaboration across the warehouse also identified unexpected hazards. Hitachi can use this new information to develop methods for improving safety in the warehouse even further.

The constructed simulation framework from the Fraunhofer Institute for Cognitive Systems IKS allows further refinement of safety concepts and comparing them with other concepts. This includes the ability to assess the effects of various infrastructure sensors. The Fraunhofer Institute for Cognitive Systems IKS will gladly assist you in choosing the best safety concept for your application. Do not hesitate to contact the person mentioned on the right for further information.


Safe interaction of automated forklifts and humans at blind corners in a warehouse with infrastructure sensors

Read the paper on the project here, which was presented at SafeComp in September 2021.


How robots in warehouses operate safely and efficiently

A simulation designed by Fraunhofer IKS paves the way for robots and humans to interact safely — without reducing efficiency. Read more on our blog.


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