Abstract
The importance of off-road mobility is inversely proportional to the density of the network of hard surface roads. Not only in developing countries, but also in industrialised countries there is a need for terrain vehicles. Off-road vehicles are used in large numbers for example in:
- agriculture
- military applications
- construction
- rescue
- expedition, and for
- recreational purposes
The author describes the state of art and the developing trends of off-road vehicles with respect to:
- modelling
- design
- components
- environmental impact
Off-road vehicles, too, are influenced by general developments in automotive technology. Off-road vehicles share many components with commercial vehicles. But to operate in terrain, these vehicles need different considerations, a new or modified layout of the whole vehicle or only of some components. The author describes the different design principals of off-road vehicles and their components, as well as aspects for the future.
The challenging competition on the global automobile market calls for a short development time. Due to this requirement, simulation programs have become indispensable tools for planning, design and production. This trend also applies to off-road vehicles and is described in this paper.
But the modelling of off-road vehicles is somewhat different and more complicated than for road vehicles. The surface of rigid roads is defined. In contrast, the interaction between the running gear (wheels or tracks ) of off-road vehicles and the terrain is very complicated. In the last decades many theories have been developed to describe their mutual interaction and influence and are used to predict the mobility of terrain vehicles in models. The several interaction models act side-by-side and cannot be mixed. Some of these theories are presented. The driver and the passengers too must be taken in consideration. A general overview of simulation models is given.
Electrical drives and electronics have increasingly become design elements of terrain vehicles.
Active suspension and hybrid vehicles especially for military use in wheeled and tracked versions show a trend for the future.
The situation for a driver is more dangerous in terrain than under road conditions. Automation of the drive line, as gear box, all-wheel drive, and engaging and disengaging the differential locks allows the driver to concentrate more on steering, braking and observing the terrain, which leads a safer off-road ride.
The author gives an overview and some examples of automation in off-road vehicles.
Environmental considerations become more important in the minds of producers and users of vehicles and in the decisions of politicians. The desire for clean air applies to all vehicles with combustion engines.
In addition to this, off-road vehicles should protect the ground as much as possible.
These two aspects are discussed.
The summary provides an outlook for new developments.