ORSIS – News and further developments

The paper deals with the simulation program Off Road Systems Interactive Simulation (ORSIS) which is the w,orldwide leading simulation tool for off road driving of wheeled vehicles. Even though the present state of development allows a very realistic simulation of the man–vehicle–terrain system, there is continuous further improvement in the computer program’s detail. Some of the recent innovations integrated into the program are presented in this paper. These examples were chosen in a way that the scope of the further developments can be demonstrated. They represent three main directions of the work carried out: the refining of the tire–soil-model, the integration of new technologies and subsystems into the vehicle model and the improvement of the man–machine–interface especially in driving simulators.The first part of the paper describes a further development of the tire–soil-model. A significant improvement has been achieved to include the influence of slippery surfaces on traction in combination with the tire tread pattern. Results from finite element method (FEM) as well as real measurements were used to build up an approach, which qualitatively allows the influence of the positive–negative portion of the tire tread and the lug height of the tire tread on traction to be considered. The basic idea is very simple and straightforward. Moreover the calculation costs are very low, so the enhancement does not affect real time operation.In the second part a physical model for the central tire inflation system (CTIS) is presented. With this model it is possible to simulate the complete pneumatic system of a CTIS, including the air compressor with an accumulator, the pressure line and the wheel valves. The components are modelled by their physical parameters, so an adaptation to different existing tire-pressure-control-systems (TPC) can be made. The paper presents a short review of the modelling and a first validation using real measurements. Furthermore the influence of each parameter, e.g. the discharge flow of the compressor on the inflation time, is presented.The third part of the paper describes a further development of the visualization system. The ORSIS OpenGL graphic engine was separated from the main ORSIS simulation and can be run on different PCs controlled via a network. It is therefore possible to build up very cheap multi-channel visualization systems using consumer PCs running under LinuX. The fact that ORSIS itself is running on a normal PC allows the assembly of comparatively cheap driving simulators of a high end simulation quality.