Hahlbrock manufactured the largest substructure of the new driving simulation system, the testing room made of carbon fiber reinforced plastic.

The simulator dome can accommodate a complete Mercedes vehicle (not just mock-ups); The 360° projection screen provides a realistic representation of road traffic. This testing room is housed as a hexapod with six movable supports.

To simulate highly dynamic driving processes, the goal was to develop a very light and at the same time stiff simulator dome.

CONSTRUCTION

• Round support platform with an attached spherical section as a projection surface
• Top end with a roof in the shape of a flat cone
• The roof supports the eight high-performance image projectors
• Door opening for bringing cars into the cathedral

GEOMETRY AND WEIGHT

• Spherical diameter, outside: 7.67m
• Spherical diameter, inside: 7.52m
• Spherical height: 3.00m
• Dome height with roof: 4.52m
• Dome width with gate: 7.81m
• Gate width: 2.68m
• Gate height: 2.49m
• Weight (without car): approx. 5.5t

MATERIALS

• Platform: Central cast aluminum element with radially attached molded parts made of carbon fiber reinforced plastic (CFRP)
• Dome jacket (spherical section): Fiber composite sandwich material, consisting of a core made of lightweight PVC foam and thin cover layers made of CFRP on both sides
• Dome roof: Roof cap also made of fiber composite sandwich material, radially stiffened with ribs and struts made of CFRP

MANUFACTURING PROCESS

The CFRP parts were manufactured using a vacuum-assisted resin injection process. Flat fabrics made of carbon fibers were placed in several dry layers in a mold and then impregnated with epoxy resin under vacuum. The composite of carbon fibers and the synthetic resin then hardened at temperatures of up to approx. 80°. After removing the hardened CFRP raw parts from the molding tools, the edges of the moldings were milled into their final contour using NC-controlled machines and, if necessary, drilled.

ASSEMBLY

The individual CFRP molded parts were glued together using an epoxy resin adhesive and riveted with around 24,000 special titanium rivets. The arrangement and alignment of the over 200 individual CFRP parts was carried out in NC-milled assembly devices, with individual parts being precisely adjusted using distance lasers. The accuracy of the spherical shells of the dome mantle was determined by laser scanning.

PROJECT IMAGES

The Berlin Institute is a facility of the Federal Environment Agency. The task of the test facility is to investigate the influence of pollutants on aquatic life forms.

16 channel systems with a total flow length of 1,632 meters were manufactured, consisting of modularly interconnectable channel shells, basins, elbows, mixing containers and special parts made of GRP. All surfaces in contact with water were equipped with a low-migration and wear-resistant gelcoat – the suitability of which was checked through abrasion tests by the MPA Hannover.

The design of the channel connections allows individual components to be replaced without having to completely dismantle a channel assembly.

The channel seals are designed in such a way that no relevant migration of substances into the water of the system takes place and deformations of the channel structure exposed to temperature and vibrations do not cause leaks.

PROJECT IMAGES

After the simulator dome was mounted on the movement system and the entire system was technically established, the Institute for Motor Vehicles IKA at RWTH Aachen University was able to start trial operations with its new, highly dynamic driving simulator.

This innovative tool for researching new vehicle systems and autonomous driving was designed by the simulator specialist Imtec-Innovative Maschinentechnik and implemented at IKA, with financial support from the BMBF.

Despite the goal of minimal mass, the new IKA driving simulator is so large that even large, complete cars can be accommodated on a rail system in the dome. The spherical projection surface surrounds the vehicle 360° and thus offers the test driver or test person the most realistic representation of the driving simulation possible.

Maintaining the exact spherical geometry in the seamless joints between the 10 individual FRP cathedral wall elements was a challenge not only in the CNC-supported production of the molds and component processing, but also in joining the FRP components to form a simulator dome that was closed on all sides.

Manufacturing process of the simulator dome

For the spherical shell elements manufactured in sandwich construction, Hahlbrock decided to use a special fiberglass prepreg, which harmonizes the unique character of the simulator dome and the cost-effectiveness of its production. This prepreg gives the large-format FRP components with relatively thin laminates the rigidity required for correct image projection, even at higher accelerations of the simulator dome, and generates sufficiently constant material thicknesses. The curing temperature of the prepreg below 100 °C allowed the use of standard PVC rigid foams for the sandwich cores. Before the FRP manufacturing process, these were thermally formed into the desired spherical shell geometry, glued together and provided with the necessary recesses. Also the elements of the roof cone, which houses the image projectors and the base plate were manufactured in a sandwich construction with the same core material. All fiber composite components were trimmed, drilled and joined with CNC support based on the 3D CAD model of the driving simulator.

Press release for the opening

PROJECT IMAGES

The challenge in producing covering shells made of GRP is to transfer the porous asphalt grain from the plane to a cylindrical surface that is as gap-free as possible.

The surface structure of an asphalt test track is first molded with an elastic matrix and in a second special manufacturing process transferred to several part-circular, usually thick-walled shells made of GRP. These are then assembled into a full circle on a tire manufacturer’s drum and represent a short section of the original test road with high dimensional accuracy.

The fiber composite material gives the road shells, which are rotating with the test drum, their high mechanical strength. The road shells are hardened on the embossed surface in a multi-stage process and thus very resistant against abrasion for synthetic resin-bonded materials, even under high contact loads from truck tires.

PROJECT IMAGES

The Department of Vehicle Technology at TU Darmstadt (FZD/TUD) is conducting research into alternative driving simulator concepts (MORPHEUS project).

The suitability of a tire-based approach for displaying driver accelerations of road-based means of transport is being examined, which can be used, among other things, to secure automated driving functions in the future.

On behalf of the TU, Hahlbrock designed and manufactured the cabin of a highly dynamic, tire-mounted, mobile driving simulator that is suitable for initial test subject studies.

Structure and materials

The requirements for the necessary dynamics of the cabin on the hexapod and the movement platform have been taken into account by using a lightweight composite construction. The cabin was designed as a cylinder with a flat roof and floor plate made of glass fiber reinforced plastic (GF-EP) in a sandwich construction, using the SPRINT ^® process. The flat, two-leaf sliding door through which the test subject/user enters the cabin was also designed as a composite sandwich.

PROJECT IMAGES