Due to increasingly complex processes, an automotive supplier needed to reorganize its safety systems for factory traffic. Working with Still, the company optimized safety precautions with intelligent driver assistance systems, AI-supported cameras, and projection warning signs.

In the fall of 1964, the Rehau plant in Brake was established with 15 employees on 2,750 square meters. Initially manufacturing pipe systems, Rehau Automotive specialized in injection molding, painting, and assembly of polymer systems for body components for cars from renowned manufacturers. Matthias Blum, Production Logistics Supervisor: "Every day, around 180 trucks arrive at the receiving department and deliver our bumper systems and exterior components to the shipping department.

For this purpose, up to 6,000 transport orders are triggered each day for internal transport alone, which are processed using 91 industrial trucks from Still's electric forklift fleet." Due to steady growth, the Rehau plant now employs more than 1,000 people across 80,000 square meters of indoor space and 234,000 square meters of outdoor space.

Sophisticated warning functions

Over the years, the wide range of products has also made production logistics workflows increasingly complex. Consequently, faulty processes in production supply chain management jeopardized safety in plant traffic. Michael Dänekas, Still's Regional Service Manager for Safety & Energy Solutions, explains: "To minimize the risk of accidents and injuries, our Safety Assist functions support forklift drivers with sophisticated warning systems and automated intervention processes."

Today, the optimized safety system for transportation reduces the risk of accidents in factory traffic to virtually zero. Thanks to radio-based zone detection functions, collision damage to hall doors is virtually nonexistent. The resulting vehicle speed limits also significantly reduce the risk of accidents. At dangerous intersections, stop signs projected onto the ground suddenly protect pedestrians from approaching vehicles.

AI camera systems for person detection warn the driver of danger both visually and acoustically in multiple stages and slow the vehicle down until it comes to a stop.

The hall doors are controlled by motion detectors. Blum: "Due to the increased traffic volume, vehicles occasionally came to a standstill in the middle of the gate area."

Together with Still, the gate zones, driving speeds, and lift mast heights of the forklifts were analyzed, and the collected data was stored in Safety Assist. Furthermore, 36 vehicles in the forklift fleet were pre-equipped with radio antennas and connected to the driver interface with the vehicle control system. Corresponding reception sensors for radio data transmission were installed on 26 hall doors.

Complex transport processes

If a vehicle now drives into the danger zone of a hall door, it transmits via radio to both door modules, which are mounted parallel to the roadway at a certain distance, all information for activating the predefined safety functions, such as reducing the driving speed and switching on the warning lights for pedestrians.

By means of the continuous triangulation measurement via radio, i.e. the angle measurement in the triangle between the forklift, gate module 1 and gate module 2, the hall door is opened at the right time and remains reliably open until the vehicle leaves the danger zone behind the door again.

“With radio-based zone detection, there is now virtually no collision damage to the hall doors,” explains Blum.

The ultra-wideband (UWB) range used here, which is highly susceptible to interference in industrial environments, allows objects to be located with an accuracy of up to ten centimeters. "Due to the stable UWB radio signal, a single active antenna on the forklift roof is sufficient. The same radio signal is used to control both the hall doors and the projector lighting technology. The acquisition costs for UWB radio are lower than for other technologies," explains Michael Dänekas. This means that the radio-based zone detection can be quickly adapted to changes in the structural conditions. If, for example, a hazard point in plant traffic changes, the projector for the lighting technology with the integrated radio module can be quickly and flexibly relocated. The advantages of the zoning technology were decisive criteria when awarding the contract, according to the Still project manager.

Accident risk drastically reduced

The speed parameters of the zone detection also allow for limiting the maximum driving speeds in the halls and on the open-air grounds. Matthias Blum explains: "This significantly reduces the risk of accidents. Due to the high pedestrian traffic in the halls, the requirement was to limit the maximum forklift speed to 10 km/h without reducing productivity or requiring additional personnel. In the open-air grounds, however, we set the speed limit at 16 km/h due to the long transport distances and lower pedestrian traffic."

The "Easy Control" display and control unit monitors all safety and performance functions. An additional LED installed in the cockpit, which illuminates red when activated, visually highlights the speed limit.

All photos: G.Knehr

The new AI-supported camera system detects people and person-like objects in real time. Thanks to the integrated AI processor, no additional hardware for person detection is required. The camera can be mounted not only on the rear of the vehicle but also on the front and sides of the forklift where potential hazards may occur during the work process. The camera operates smoothly even under extreme conditions ranging from -40°C to +85°C.

The camera system can be expanded to include multiple cameras. The driver is warned in two stages, both with the camera image and an acoustic signal via a loudspeaker inside the vehicle. In the detection zone, an acoustic signal is triggered at a moderate frequency, the person is outlined in yellow on the monitor, and the vehicle's speed is optionally reduced. Finally, in the warning zone, a continuous alarm tone sounds with a person outlined in red. With the optional stop function, the risk of an accident is minimized. Detection zones and warning mechanisms can be customized.

Plant Manager Thomas Köhle: "Every euro we invest in preventative measures brings at least twice the added value on average. Furthermore, the image of our Brake plant improves both among our own employees and our clients."

The optimized safety system not only minimizes the risk of accidents but also reduces energy costs, as previously defective hall doors remained open for extended periods. With 6,000 transport orders per day, the automated assistance functions significantly reduce the workload for drivers.

Gerd Knehr

www.still.de