SAE 840069 中间位置操纵性评价4444444概要1.doc

SAE 840069 Objective Evaluation of On-Center Handling Performance 中间位置操纵性评价目标 ABSTRACT A test was developed to quantify automobile handling characteristics for the performance region encountered in freeway driving. Steering wheel angle and torque ,vehicle speed and yaw rate are recorded during a low frequency sinusoidal steer maneuver. The data is reduced to steering hysteresis, on-center and off-center steering sensitivities and torque gradients ,and a steering work parameter. This paper describes the test procedure and parameters. Test results are presented comparing the general attributes of foreign versus domestic cars,manual versus power steering ,and rear versus front wheel drive. The study of driver automobile interaction during steering maneuvers has been widely addressed in the technical literature. However, it remains an area of vehicle handling where there is much to be learned. The “road feel” of automobiles in the low lateral acceleration or “on-center” region is of particular interest in evaluating handling for highway driving. Optimization of steering characteristics for easier controllability and driving comfort was studied at least as early as 1964 when Segel examined the effect of varying steering torque gradient() on drivers’ perception of the ease and precision of driving (1)*. He found drivers preferred a steering torque gradient of 23N.m/g to steering torque gradients of 6.4 or 41N.m/g in lane change and 0.2g steady state turning tasks. In his paper, Segel explained that driving situations demanding precise path control require the driver to be more attentive to vehicle response. This attentiveness is the gain of the response-feedback loop in Segel’s driver-vehicle control system block diagram. *Numbers in parentheses designate references at end of paper The more attention needed, the tighter the loop. When less attention is needed, the driving strategy tends toward open-loop control. Segel postulated that a driver relies more on steering whee