Limit handling in a driving simulator.

The purpose of the work reported in R861A has been to investigate how the driving simulator performs at the handling limit of a vehicle. The purpose was also to improve its function so that the simulator feels and behaves more like a real vehicle when driving on the limit. This study has helped in understanding how the current vehicle model could be improved for simulating on-the-limit driving, although the method has not yet been fully developed. It was shown that the derived vehicle model closer captures the understeer and time lag properties of a real Volvo S40 compared to the original model. Still, additional improvements needs to be made before the model can be regarded as fully useful for on-the-limit driving situations. Open loop track tests were performed with a test vehicle that is very similar to the one that is modelled in the simulator. Based on these test results the vehicle model currently used in VTI's driving simulator III was modified in order to better simulate vehicle characteristics when driving on the handling limit. In addition to the original version of the vehicle model, two candidate models were created. The method uses the double lane change manoeuvre, with test drivers performing the manoeuvre first on the test track and then in the driving simulator. The method was divided into a subjective and objective part. The subjective evaluation used questionnaires filled out by the test drivers, while the objective relied on measurements of driver inputs and vehicle response. The validation tests showed that the original vehicle model is more neutral and stable than the real vehicle, and has a too fast response, while resulting in excessive yaw rate. It also lacks the nuances of the real vehicle during the manoeuvre. In comparison, the new models exhibit some of the nuances of the real vehicle during the manoeuvre, especially for steering response. The yaw rate is also comparable to the real vehicle. However, the vehicle response was too slow during the latter part of the manoeuvre, making the models harder to drive compared to the real vehicle. (Author/publisher)