Automobile Directional Characteristics and Driver Steering Performance

Sensitivity of Driver-Vehicle Performance to Vehicle Characteristics Revealed in Open-loop Tests

“…Ratings of both 'responsiveness' and 'steering gain' indicated an acceptable region for (r/S,,),, between 0.2 and 0.4s-' at 80 kmlh, with a preference for higher gains as the yaw rate lead time constant T, increased (or, equivalently, as the directional mode natural frequency o, decreased). This trend is in accord with Sweatman and Joubert's [66] finding that the optimum steering sensitivity increased with increasing vehicle response time. It is also interesting to note that in another experiment with a VCC, Sweatman and Joubert [65] found that driver heart rates (a measure of stress or level of task demand) remained constant, in a task requiring precise control of lateral position and heading, only if the steering sensitivity increased as the vehicle response time increased.…”

“…Thus, for a given response time, decreasing the damping degrades performance, as does increasing the response time with a given percentage overshoot. This is in qualitative agreement with Sweatman and Joubert's [66] finding that the optimum stability factor decreases with increased response time: If K is decreased, 5, increases, so that t,/leff should decrease. This composite parameter, which combines the effects of w,, 5, and T,, shows great promise as a measure of vehicle transient response which is relevant to the driver's needs.…”

“…In an experiment employing a variable characteristic car (VCC), Sweatman and Joubert [66] investigated the interaction effects of 1 / G l (referred to as 'steering sensitivity' by the authors) with other vehicle characteristics (response time and stability factor) and with task variables (vehicle speed and the width of the 35 m radius circular driving lane). Only low speeds (23-35 kmlh) could be used.…”

Understanding and Modeling the Human Driver

“…The parameter t was an effective transport time delay. More specific studies aimed at understanding the human as an automobile driver [16,[19][20][21][22][23][24][25][26][27][28][29][30][31] followed from or paralleled this type of manual control work. One example is a series of publications by Rashevsky in the late 1950s and early 1960s that addressed the topic of ''Mathematical Biology of Automobile Driving'' [25] wherein the basic model of the driver as a steering controller was treated in a purely geometric/ kinematic manner.…”

“…More complete treatments of the driver modeling effort and associated measurements of driver-vehicle system responses were also emerging in this same time frame, particularly with the increased use of computers and driving simulators. Example works that studied driver control behavior and accounted for the dynamics of the vehicle include studies by Wierwille [19], McRuer [22], Weir [18,[29][30][31], Kondo [17], Yoshimoto [20] as well as many others [16,[26][27][28][34][35][36][37]. Key findings from these studies and others that followed are discussed further in subsequent sections of the paper.…”