A Low Cost PC Based Driving Simulator for Prototyping and Hardware-In-The-Loop Applications 980222

This paper describes a low cost, PC based driving simulation that includes a complete vehicle dynamics model (VDM), photo realistic visual display, torque feedback for steering feel and realistic sound generation. The VDM runs in real-time on Intel based PCs. The model, referred to as VDANL (Vehicle Dynamics Analysis, Non-Linear) has been developed and validated for a range of vehicles over the last decade and has been previously used for computer simulation analysis. The model's lateral and longitudinal dynamics have 17 degrees of freedom for a single unit vehicle and 33 degrees of freedom for an articulated vehicle. The model also includes a complete drive train including engine, transmission and front and rear drive differentials, and complete, power assisted braking and steering systems. A comprehensive tire model (STIREMOD) generates lateral and longitudinal forces and aligning torque based on normal load, camber angle and horizontal (lateral and longitudinal) slip. The tire model correctly simulates saturation and can represent off-road behavior including plowing in soft soil at high sideslip angles. The articulated vehicle can simulate tractor/trailer rigs, articulated buses and recreational/utility trailer setups.

The visual system image generator (IG) is composed of a high speed graphics accelerator and Intel Pentium processor. The IG is capable of 800x600-pixel resolution, and three screens can be combined to give up to a 135-degree field of view. A head-mounted display can also be used to give an unlimited field of view. The visual scene rendering includes full texturing, Goraud shading, and dynamic lighting effects. The update rate is 30-60 Hz depending on scene complexity, and the IG can render at a rate of 1 million polygons/second. The time delay for display presentation is less than 100 msec., which presents minimal interference with driver closed loop control. Tire model aligning torque and a steering system model are used to compute steering torque commands which are then displayed to the driver with a torque motor applied to the simulator steering column

The simulator VDM provides all outputs needed for driver cueing, including inertial outputs for commanding the IG, steering torque commands, various instrument commands, and auditory feedback. This paper summarizes the basic IG and VDM, means for generating and presenting cueing feedback to the driver, and a unique approach for easily creating and presenting driving scenarios. Several PC based driving simulation applications are also described, including a hardware-in-the-loop steering simulation, and desk top and cab simulations for use in research, rehabilitation, training and prototyping.