Abstract
A method of quantifying the response of a vehicle to steering wheel inputs is examined. The technique will aid designers to adapt a prototype vehicle to give a desired response or 'feel'. Also it may be used to investigate the steering performance of current vehicles to make comparison between vehicles, or to examine the effect of changes in a single vehicle such as tyre types, pressures and load distribution. A model driver/vehicle simulation is set up and it is postulated that a vehicle's steering qualities may be rated by assessing the contribution the model driver needs to make to place the closed loop response in an acceptable area on the pole/zero diagram. For a single vehicle it is shown that a better steering response is achieved with the car fitted with radial ply tyres than with cross-ply tyres.