• A Fast Realtime Simulation of a Complex Mechanical System on a Parallel Hardware Architecture

      Oertel, C.-H.; Gelhaar, B.; Institute for Flight Research (International Foundation for Telemetering, 1992-10)
      Real-time computation speed is an additional requirement for simulations. It is necessary for 'man-in-the-loop' systems like flight simulators and for 'hardware-in-the-loop' systems where real components like new closed loop controllers are tested under realistic conditions. In the past a lot of companies have designed and built special purpose simulation computers which are very powerful but expensive and not handy enough for 'in-the-field-tests'. The progress in computer science shows a trend to distributed systems where multiple processors are running in parallel to improve the performance dramatically. At the DLR Institute for Flight Mechanics a computer system, based on the transputer, was designed to achieve the real-time simulation capabilities for the ROTEST model rotor. This four-bladed rotor is a 2.5 scale of the BO105 main rotor, equipped with elastic blades, operating at 1050 rpm. After an introduction to the ROTEST rotor, including the demands upon the simulation, a short introduction to transputers and the associated philosophy is given. The next part of the paper presents the characteristics of the simulation model, its mathematical description and the transputer architecture on which it is running. In the last part of the paper the input and output processes to the simulation are described. This includes a real-time representation of the rotor and an oscilloscope like output device, as well as analogue input and output devices to a controller.
    • A Transputer Based 3D-Graphics System

      Alvermann, Klaus; Institute for Flight Research (International Foundation for Telemetering, 1992-10)
      The Institute for Flight Mechanics operates the flying simulators ATTAS (a wing aircraft) and ATTHeS (a helicopter), their respective ground based simulators and uses realtime and offline simulations for system identification and other purposes. Based on a parallel transputer architecture, a 3D-graphics tool for visualization and view simulation to be used with the simulations has been developed. The tool uses data received by telemetry, realtime data from a simulation, or recorded data to show the movement and orientation of an aircraft in realtime 3D-graphics. The aircraft or scene may be observed from any point of view. Placing the camera in the cockpit of the aircraft and showing the environment results in a view simulation. The use of a parallel transputer architecture allows a modular and scalable structure, i.e. the system may be adapted to the needs of the application. By adding software modules and transputers we may include 24 bit colour, shadowing, a higher resolution, a better shading algorithm or other things which are required by an application. On the other hand we may remove transputers to get a small and cheap system if the requirements are low. A small system may consist of only 8 transputers, whereas a big system may include 50 or 60 transputers.