Driver perception of steering feel

Abstract

Steering feel is optimized at a late stage of vehicle development, using prototype vehicles and expert opinion. An understanding of human perception may assist the development of a good ‘feel’ earlier in the design process. Three psychophysical experiments have been conducted to advance understanding of factors contributing to the feel of steering systems. The first experiment, which investigated the frames of reference for describing the feel (i.e. haptic properties) of a steering wheel, indicated that subjects focused on the steady state force that they applied to the wheel rather than the steady state torque, and on the angle that they turned the wheel rather than the displacement of their hands. In a second experiment, thresholds for detecting changes in both steady state steering-wheel force and steady state steering-wheel angle were determined as about 15 per cent. The rate of growth in the perception of steady state steering-wheel force and steady state steering-wheel angle were determined using magnitude estimation and magnitude production. It was found that, according to Stevens’ power law, the sensation of steady state steering-wheel force increases with a power of 1.39 with increased force, whereas the perception of steady state steering-wheel angle increases with a power of 0.93 with increased steering-wheel angle. The implications for steering systems are discussed.