Terrestrial Vehicles

DLR possesses test benches and measuring equipment for examining novel power train concepts for road vehicles. Key subjects are the characterisation of (partially) electrified power trains and fuel cell drive systems. Rapid control prototyping is used to develop operating strategies. Closed-loop simulations replace individual components that are not yet available as hardware. Components for waste heat utilisation are developed and characterised on a hot-gas test bench.

DLR operates a four-wheel roller test bench with exhaust gas analysis and a climate chamber for passenger vehicles and light-duty trucks. The test bench simulates driving conditions for all single axle and four-wheel drive models in a variable temperature range of -25 to +50 degrees Celsius. Its explosion-proof design also allows hydrogen and natural gas vehicles to be examined on the test bench. The exhaust gas analysis enables measurements of untreated emissions to Euro 5-compliant accuracy.

The performance of fibre-reinforced plastic and composite materials is defined by the mechanical properties of the reinforcement fibre versus those of the matrix. In their application, important aspects besides the mechanical properties of the fibres are the optimisation of the entire fibre structure, the reproducibility of the properties and the cost of semi-finished products and processing. Numerous facilities seamlessly map the capacity to develop components from design to the finished prototype.

Joining technology is a central research area in modern multi-material design. To connect diverse materials requires the application of special joining technologies. Mechanical technologies, adhesive bonding and hybrid joining as a combination of both processes are the main focus of study.

A basic prerequisite for conclusive material simulation is the use of realistic material characteristics. Various testing machines are available for obtaining mechanical characteristics. Their measurement results are used in calculations, but also for developing and validating new numerical material and joining models. The focus of the research is on damage development and progression. In addition, mechanical stress tests or service life examinations are performed using a wide range of testing equipment.

In order to perform high-speed impact testing, DLR has installed a gas-gun test facility that allows the modelling of impact scenarios for high-speed trains and road vehicles. In addition to measuring projectile speed, the impact process is also recorded with analogue and digital high-speed cameras. DLR also has a drop-test bench that serves to examine the energy absorption behaviour of materials, structural concepts, components and structures.

Several wind tunnels and a water towing-tank are available for aerodynamic and aeroacoustic testing of terrestrial vehicles. In contrast to most other wind tunnels worldwide, the Cryogenic Wind Tunnel in Cologne allows Mach and Reynolds number to be adjusted independently of each other. In the water towing-tank, a model can be towed at variable or constant speed. Available measuring techniques include conventional force and pressure measuring procedures, hot wire and hot film processes and state-of-the-art laser-optical tools such as particle image velocimetry.

When high-speed trains pass through tunnels, they produce pressure waves that are perceived as unpleasant by passengers. All new tunnel constructions planned in Germany will be single- rather than double-track, resulting in smaller cross-sections and increased pressure gradients. The baro-chamber complex allows the study of their effects on humans by simulating a train compartment with six to eight test subjects and realistic, time dependent pressure changes.

The construction of CAD components and the CNC programming of the machine tools are carried out in DLR's Engineering Systems House. There are also production techniques such as CNC milling and turning, eroding and joining available, fibre composite materials can be processed and circuit boards produced. The experimental devices and system components are suitable for cryogenic use. Lightweight models and system components made of fibre composite materials, electronic systems and the design, production and integration of measurement technology all meet highest industrial standards.

DLR researchers have constructed a complete measuring and testing chain for analysing driver behaviour and developing and testing functional assistance systems. The ViewCar^® test vehicle is used to analyse drivers’ perception processes and behaviour on the road. It is equipped with sensors for measuring and recording traffic surroundings, driver workload and driver behaviour, including the driver's operation of the vehicle and the resulting vehicle behaviour. New driver assistance systems and functions can be evaluated quickly and flexibly with regard to their usability and acceptance in the Virtual Reality Laboratory. Stereo projection and head tracking provide three-dimensional simulations of the vehicle cockpit and the environment. The Dynamic Driving Simulator is used to test assistance functions at advanced stages of development. The realistic design of the simulation allows for a valid evaluation of the functions and therefore a safe transition to the test vehicle and real traffic. The driving simulator provides a realistic driving experience by means of a powerful motion system, a high-quality projection system and the integration of a complete vehicle. The FASCar experimental vehicle is used to test new, active assistance functions. Its 'road' operating mode meets the highest safety and security requirements for tests in real road traffic. The driver assistance system only actively intervenes to a limited extent. The systems can be overridden or deactivated at any time. All intervention options up to autonomous driving are available in ‘testing ground’ operating mode. The accelerator, brake and steering wheel are then controlled by a virtual co-pilot.

Traffic Management

Traffic data are collected for the purpose of planning, simulating and controlling transport systems. DLR operates two measuring vehicles, which are equipped with sensors and systems for data recording and processing, including video and radar systems, D-GPS and an extendable telescope mast, among other facilities. Speeds, vehicle accelerations and CAN-bus data can be recorded in mobile operation; when stationary, complete intersection data can be collected.

To record traffic data under realistic conditions and study sensor quality and dependability, DLR has constructed a 1.2 kilometre long Urban Road Research Laboratory, which is traversed by approximately 30 000 vehicles a day. Measuring and observation systems are installed on two accessible sign gantries or embedded in the roadway, among them video cameras, radar sensors, a visibility range measuring apparatus, a weather station and double induction loops. Their data are processed according to standards, transmitted to the data centre, visualised and archived.

In the Traffic Tower, DLR is developing and operating a fully functional virtual traffic management centre. Be it traffic monitoring during public mass events or evaluating traffic control algorithms, the Traffic Tower supports the work by virtually reproducing road traffic and traffic control systems. It is equipped with systems and functions for simulation, calculating transport demand and visualising traffic situations.

DLR operates extensive systems for receiving, processing, archiving and distributing satellite data, with both permanently installed antenna systems and mobile stations on all continents. The satellite data are archived via fully automated data libraries. Digital image evaluation accesses special centralised hardware and the robot archive, and facilitates the generation of video animations from satellite data and additional information.

The RailSiTe^® railway simulation and testing laboratory maps the entire chain from operation control centre operator, through track and train dynamics, all the way to the driver. The laboratory allows the analysis of systems, sub-systems and components of railway signalling and control systems as well as operating concepts. Therefore the interaction of system components produced by different manufacturers for ETCS for both operational and safety and security aspects can be validated, for example. In addition to software simulations, hardware-in-the-loop and cross-reference tests can also be performed. Following certification as a sub-contractor of Eisenbahn Cert (EBC), the 'Notified Body Interoperability' for Germany, DLR operates the world's only ETCS-certified laboratory in RailSiTe^®.

Modern rail transport operating procedures, with their high requirements for efficiency, safety and security, demand continuous, vehicle-based positioning information. The quality achieved by sensors can be evaluated in field tests using the RailDriVE^® experimental vehicle. Positioning and communication components, workstations for monitoring and initial online analysis of the measured data, a GPS module and a wireless modem are part of the extensive equipment of the two-mode, road and rail vehicle. RailDriVE^® is used for testing new positioning systems, as a test platform for positioning components, and for examining various sensor combinations.

Transport systems

DLR operates research aircraft, which are used as platforms for observing the Earth, ocean surfaces and the atmosphere. The German Civil Aviation Authority (Luftfahrt-Bundesamt) has approved DLR flight operations as an approved aeronautical workshop, authorised to independently perform maintenance work on its airplanes. DLR operates the largest civilian fleet of research aircraft in Europe.

Up to eight test subjects can be accommodated for several days or even weeks in the AMSAN Simulation Facility for Occupational Medicine Research. The 300 square meter facility can be operated as a closed system under controlled environmental conditions. It is fully air-conditioned, noise-protected, has only artificial lighting, and is predominantly used to examine the effect of night-time traffic noise on sleep and performance.

Planned facilities

DLR intends to create a separate development line that integrates materials research, component implementation and system demonstration as well as the qualification of high-temperature thermoelectric modules. This line will supplement the existing broad spectrum of thermoelectric materials characterisation and form the basis for high-powered and independent development activities. One core component consists of special compacting procedures that can produce dense thermoelectric materials with high mechanical strength from powders under reduced thermal load. Coating, connecting and sealing technologies required for the assembly of thermoelectric modules from individual semi-conductor pellets and metallic contact bridges complete the facility.

In view of the growing travel speed of long-distance trains, it is to be expected that the relevant aerodynamic characteristics will increasingly be dominated by their Mach number, in addition to the existing Reynolds number dependence. Low-turbulence wind tunnels, specially designed for high Reynolds number testing, are required to analyse the attendant issues. The Cryogenic Wind Tunnel in Cologne meets these basic requirements to a large extent. However, its optical measuring techniques must be adapted to facilitate studies at high Reynolds numbers, and a suitable ground simulation is required to allow transient effects to be observed to the extent required by safety considerations.

The expected reduction in the cross-sections of railway tunnels, resulting from the change to single-track tunnels, will lead to significantly increased pressure loads for passengers and train structures. Vehicle-specific prediction of these loads is currently neither numerically nor experimentally possible. DLR intends to build a Tunnel Simulation Facility that will eliminate the weaknesses of the few facilities of this type that currently exist worldwide. This facility will enable image-based, multi-dimensional field measurements for flow analysis and be capable of implementing the similarity parameters necessary for flow analysis. Its measuring equipment will have to be designed to permit the study of changeable loads.

For the described work on the Next Generation Train, a crosswind test facility and measurement technology that will allow measurement, testing, recording and analysis of transient and compressibility effects with high precision are required. There is currently no suitable experimental test facility to derive applicable physical models for future simulation procedures. Existing facilities that would be able to create even remotely approximate Reynolds and/or Mach number similarities or wind gust loads are limited to simple conventional measuring procedures and are not designed for the study of transient processes.

It has yet to be proven that high-quality components for the vehicle body of high-speed trains can be produced in large quantities. DLR is aiming for significant productivity increases by a factor of 10 to 100. For this purpose both a long fibre injection plant to produce two-dimensional, fibreglass-reinforced components for limited mechanical loads and a pultrusion facility for highly stressed and/or highly loaded structures are required. Both infrastructures are to be combined in a joint facility.