Further understanding of steering feedback and driver behaviour through the application of an instrumented steering wheel

Driver to steering dynamics are traditionally analysed with torque, angle and their differentiated signals in open loop manoeuvers. This is a recurrent task for vehicle calibration engineers and is increasingly gaining importance on the road to autonomous driving in order to create human-friendly hand and take over transitions. Understanding driver behaviour on closed loop condition becomes however complicated due to the limited amount of information channels. In this work we introduce an Instrumented Steering Wheel (ISW) which measures the grip force and the six components of force and moment for each hand, providing additional information of the driver control loop during manoeuvers. By analysing the trend of the forces during specific handling tasks and different vehicle chassis and steering configurations we identify force-based metrics closer to the human haptic feedback and action. These metrics not only take into consideration the effect of the manoeuvre on the vehicle dynamics, but also take into account the interaction of the driver's hands with the steering wheel, hence enabling a richer assessment of the handling qualities. This driver-in-the-loop approach has been extended from the proving ground measurements and has been put in use in the driving simulator environment. In such a way we can increase the cases of interest, add drivers of different skill to the experiments and ultimately enhance the fidelity of the hand wheel control loading system.