This paper describes a driving simulator with moving base system that is just being built at the National Swedish Road and Traffic Research Institute. The description deals mainly with the theoretical model and its validation from certain aspects. The simulator is primarily intended for vehicle handling studies and the simulation program has been used to study the transient reeponse of a medium-sized passenger car to a sinusoidal steering input for validation. The test procedure follows the methods stated in a draft proposal from ISO TC22 SC9. Time lags of the lateral acceleration and yaw velocity in relation to the steering wheel angle are computed with cross-correlation techniques and plotted as functions of the severity of the manoeuvre. This is carried out at four different frequencies. The amount of lateral stiffness at the front is varied producing different degrees of under-over steering as expected and correlating well with field tests.

The theoretical model describes a car with four wheels, nonlinear tire characteristics and semistatic load transfer. An approximate representation of the engine data is also presented. The model has been successfully tried in real time applications with a human driver.