An Emission-free Modular Vehicle Concept for Inner Urban Transportation in Near Future Megacities (Urban MoVe-T)

As the demands for fast and sustainable transportation in megacities are growing, new transportation concepts with full electric vehicles for the distribution of goods are needed. Not only the “last mile” is important for the delivery of small goods, but also the distribution from the big logistic centres in the outskirts to the inner city has a big influence on the volume of traffic. A new concept for a zero emission vehicle, the “Urban MoVe-T” (Urban Modular Vehicle for Transportation) has been developed within the Institute of Vehicle Concepts to meet these new requirements It consists of two parts, the “Ultra Mobility Tractor” (UMT) and secondly different “Intelligent Versatile Modules” (IVM). The concept of the one-axle-two-wheeled UMT is comparable to the well-known Segway© technology, but includes an additional driver cabin and an integrated safety cell for the driver. Moreover the UMT has an innovative wheel integrated bearing and chassis suspension system. This suspension system includes an innovative electric motor coupling, which enables to keep the unsprung masses low, while providing the unit compact. With the vehicle`s tractor module the driver has a high manoeuvrability, which is important, when used for delivery in historic city centres like Vienna. Coupled with the smallest Intelligent Versatile Module, the whole transportation vehicle has a total length of 2.5m and width of 1.7m, but is capable to carry two euro-pallets with a payload of 1t each. The vehicle has the highest payload per vehicle volume rate up to date. Due to its compact dimensions it enables the new concept to be integrated in existing infrastructures like into the commuter railway system. It can be parked transverse to the direction of travel of the train and can later on leave the train without changing the direction itself. The IVMs used for carrying the load all have 360° turn able wheels for manoeuvring on the spot to meet the requirements for the usage with the UMT. As all the IVMs have their own electric drive system, the load modules are able to drive independently when used on restricted sites like in distribution centres in the outskirts of the megacities. A bigger version of the IVM is able to carry six euro-pallets and has the dimensions of 3.5m length and 2.5m width; in total the tractor/load module combination has a total length as well as a turning radius of less than 5m, which is an unchallenged value for a vehicle in the sector of transportation. The big IVMs are also capable to be put autonomous onto the train for a fast and effective transportation from the distribution centre into the city centre. There the UMTs could fetch the IVMs and bring them to their destination. So a whole new effective distribution can be achieved with a significant reduction of the overall traffic on the streets of the big cities

Innovative design steps towards a safe active lightweight chassis for an electric vehicle

Lightweight design is still very important for an all-electric vehicle especially when used in urban areas. A new active chassis suspension designed for such an urban car is in development at the DLR. The first main component is a composite transverse leaf spring, where a new (partly) automated design and dimensioning process is in development. The second component is an orbital wheel bearing with an optional integrated electrical drive. The third component is an innovative wheel independent two axis steering actuator changing the toe and camber angle. This enables an increase of the active and passive safety of the occupants. First simulations proved the benefits of the concept regarding enhanced crashworthiness. The modular concept of the system allows to use the same wheel at each corner of the vehicle without changing a single part, thus reducing vehicle part variants and costs

Fibre Reinforced Plastic Concepts for Structural Chassis Components

FRP lightweight design in chassis suspension

Fibre Reinforced Plastic Concepts for Structural Chassis Parts

Abstract Fibre reinforced plastics (FRP) have a high potential for reducing masses of automotive parts, but are seldom used for structural parts in the chassis. If the whole chassis concept is adapted to the new material, then a high weight saving potential can be gained and new body concepts can result. DLR Institute of Vehicle Concepts designed and dimensioned a highly stressed structural part in FRP. A topology optimisation of a defined working space with the estimated loads was performed. The results were analysed and fibre reinforced part concepts derived, detailed and evaluated. Especially by the use of the new FRP material system in the chassis area, a weight saving of more than 30% compared to the steel reference was realised. With the help of those concepts it is shown, that there is also a great weight saving potential in the field of chassis design, if the design fits with the material properties. The existing concepts still have to be detailed further, simulated and validated to gain the full lightweight potential

Lightweight Design by Functional Integration Using Magnesium Castings

The history of terrestrial transport systems on the road has always been influenced by material-related developments. These developments gave rise to various construction methods, taking into account the different requirements that transport systems had to fulfil and provides new approaches. A major motivation for the development of new vehicle structures apart from the reduction of fuel consumption is to decrease emissions which affect the climate. The urgency of the CO2 problem will result in alternative power trains also establishing themselves on the market, in turn giving rise to new requirements and possibilities in the field of vehicle construction over and above the established light weight design

Design approach for automated transverse leaf spring composite structures in a suspension system

Developing sustainable products using high persistent and durable materials is challenging. Associated processes to mature innovations in industrial development are often inflexible due to safety reasons and economic requirements. A possible approach to solve these challenges can be found in digitalized development processes. By using optimization techniques for automated evaluation, a high number of structural concepts can be created. The introduced optimization approach focuses on a virtual process chain for the automated design of glass fiber reinforced transverse leaf springs. Composite materials have the potential to reduce weight by functional integration and improved fatigue performance. As reference suspension system an innovative McPherson-like front suspension system is used. The control arms, coil springs and stabilizer bar are substituted by a composite leaf spring with the main goal to integrate wheel controlling functionalities into the structure. Parameters for wheel control are shape, fiber orientations and laminate lay-up. Designing composite transverse leaf springs with wheel controlling functionalities is extremely challenging due to obtained high number of design parameters. Large deflections due to wheel travel by preserving longitudinal and lateral stiffness and strength also complicate the identification of solutions in the design space. Therefore automation in modelling and evaluation is essential for using the required optimization algorithms. Meta-model-based, evolutionary or gradient optimization methods can be used to identify solutions in the obtained complex design space. The process chain connects CAD, finite element and multi body simulation software within the developed process chain. To ensure elastic behavior and durability, the Puck criterion is applied as an optimization constraint. The first results show that the investigated optimization approaches have high potential for finding appropriate composite structures with wheel controlling functionalities

Methodology for automated designing of composite structures in suspension systems

Composite materials in automotive structures have the potential to reduce CO2 emissions by simultaneously saving weight and improving fatigue performance. Further weight reduction potential can be obtained by integrating additional functions into composite structures. Regarding a suspension system, the control arms and coil springs in a McPherson front axle can be substituted by a transverse composite leaf spring. Designing this composite leaf spring structure with wheel controlling functionality is extremely challenging due to the high number of design parameters influencing the geometry and the laminate layer setup. In particular, large deformations due to bending of the control arm during wheel travel while preserving longitudinal and lateral stiffness and strength complicates the finding of solutions. Meta-model-based optimization methods can be used to identify solutions in the complex design space. Therefore, automation in the modelling process is essential. In the Next Generation Car project (NGC) of the German Aerospace Center (DLR), new development methods are investigated for automated designing and dimensioning by using optimization algorithms. The programmed process chain is connecting CAD, finite element and multi body simulation software is controlled by optimization software. All obtained displacements are cross-checked with the reference trajectory. The parametric CAD model and layer setup is controlled by meta-model-based optimization software. The resulting geometry is meshed and an implicit finite element model is created to directly identify the structural response. The design space of the optimizer includes different geometric designs of the composite structure and each layer of the laminate which are sized according to the load cases. To ensure elastic deformation, the Tsai-Wu criterion is applied as an optimization constraint. The first results show that the selected optimization approach has a high potential for finding structures which can achieve the desired wheel travel. The investigated process chain creates transverse leaf spring geometries with reasonable layer sequences

Strukturintegrierte Kunststoff- und Sandwichbauteile am Beispiel der Next Generation Car Technologieplattform für ein leichtes Nutzfahrzeugkonzept im urbanen Bereich

Das Großforschungsprojekt Next Generation Car bündelt die Aktivitäten und Infrastruktur des DLR im Bereich der Straßenfahrzeuge. Dabei werden Methoden und Technologien für die ganzheitliche Entwicklung von Straßenfahrzeugen für morgen und übermorgen an unterschiedlichen Innovationsträgern wie dem NGC Urban oder dem NGC Interurban entwickelt und dargestellt. Ein Teil dieser Arbeiten beinhaltet auch Entwicklungen für strukturintegrierte Kunststoff- und Sandwichbauteile wie sie anhand eines leichten Nutzfahrzeugkonzepts für den urbanen Bereich durchgeführt im folgenden Beitrag dargestellt werden

Mobility of Tomorrow; Research Topics of DLR-FK

Das DLR-FK erarbeitet für Straßen- und Schienenfahrzeuge neuartige und anwendungsorientierte Lösungen. Dazu zählen Konzeption, Konstruktion, Berechnung und Simulation bis zur Darstellung von Forschungsdemonstratoren, -komponenten und -fahrzeugen

An innovative and safe active light weight design chassis concept

Important for an all-electric vehicle, especially when used in an urban area, is still lightweight design. Simple chassis systems for small urban vehicles covering those weight limitations often lack an acceptable drive comfort and driving stabil-ity in extreme situations. A new active chassis suspension designed for such an urban car is in development at the DLR Institute for Vehicle Concepts in the founded project Next Generation Car (NGC) Urban Modular Vehicle (UMV). This concept even provides active safety measurements regarding the demanding small overlap crash scenario. The main components are a composite transverse leaf spring, an orbital wheel bearing optional with an integrated electrical drive and an innovative wheel independent two axis steering actuator changing the toe and camber angle. For the realisation of this innovative concept a (partly) auto-mated design and dimensioning process is going to be established