An Integrated, Modular Simulation System for Education ... - Cal Poly

Figure 11 BYOFS Original ScreenFigure 12 Snoopy Screenc++, so the integrators were recoded in c++. The simulator was modified by removing theoriginal equations of motion as well as all unused game code. Two setup files wereincluded to store the calibration for the game joysticks and to store the springing anddamping ratios for the numerical integrators. The graphics were simplified to increase thescreen display area and simulate a simple Heads up Display (HUD) (Figures 11 & 12).The new integrators were added to the simulators existing classes and the code modifiedto provide input to the integrators. The output from the integrators was sent to the baseclass while a linear airspeed was hard wired . State information was output to thegraphics and Heads Up Display. A second version of the code was modified by removingthe game joystick classes then combining graphics and equations of motion classes intothe stick and instrument classes in the PhEagle I c++ code. Modifications were thenmade to the timing classes to change from a floating time scheme where the integrationtime step is estimated from the length of the previous computational cycle to a fixed timestep were the length of the frame is hard coded and all of the computations must becompleted before the end of the frame. A fixed time scheme always involves unusedCPU time while the program waits to be released to the graphics. A fixed time step isrequired to guarantee a smooth, accurate and consistent visual simulation.26