A New Approach to Modeling Driver Reach

Abstract

The reach capability of drivers is currently represented in vehicle design practice in two ways. The SAE Recommended Practice J287 presents maximum reach capability surfaces for selected percentiles of a generic driving population. Driver reach is also simulated using digital human figure models. In typical applications, a family of figure models that span a large range of the target driver population with respect to body dimensions is positioned within a digital mockup of the driver's workstation. The articulated segments of the figure model are exercised to simulate reaching motions and driver capabilities are calculated from the constraints of the kinematic model. Both of these current methods for representing driver reach are substantially limited. The J287 surfaces are not configurable for population characteristics, do not provide the user with the ability to adjust accommodation percentiles, and do not provide any guidance on the difficulty of reaches that are attainable. The figure model method is strongly dependent on the quality of the models used for posturing and range of motion, and, in any case, cannot reliably generate population distributions of either reach capability or difficulty. A new method of modeling driver reach capability is presented. The method is based on a unified model of reach difficulty and capability in which a maximum reach is a maximally difficult reach. The new approach is made possible by new measurement methods that allow detailed and efficient sampling of an individual's reachdifficulty function. This paper summarizes the experimental approach and presents the structure of the new integrated model of population reach difficulty and capability.

Human motion simulation for vehicle and workplace design

“…What they found was that the soft tissue around the greater trochanterion of the hip appears to provide the maximum excursion limit for the center of pressure during lateral reaches. This is a much larger excursion than normally assumed in Figure 3 Illustrations of the complex pelvic orientations and spinal column curvatures associated with four different arm-reaching tasks in a seated posture (from Reed et al, 2003).…”

“…The torso often is geometrically modeled with a large number of links, sometimes mimicking the vertebral column, but the underlying kinematics model that predicts the relative motions of these segments is a highly reduced model, often using simple proportionality rules for each segment's movements relative to the motion of the entire column. Reed, Parkinson, and Chaffin (2003) discuss this issue and propose a much more sophisticated model, one that is based on careful observations of the curvature changes in the spinal column and rotations of the pelvis of people reaching around a seated workplace. Some results of this study are illustrated in Figure 3. …”

Human reach envelope and zone differentiation for ergonomic design

“…accommodation percentiles, and do not provide any guidance on the difficulty of reaches that are attainable. Reed et al (2003) demonstrated the experiment approach to obtain human reach envelopes. It entails three steps:…”

“…The first method involves experimental-based methods using a large number of subjects to visualize human reach (Badler, 1997;Chaffin, 2002;Hammond & Roe, 1972;Ottaviano, Lanni, & Ceccarelli, 2001;Parkinson, Reed, & Klinkenberger, 2003;Reed, Parkinson, & Chaffin, 2003). The second one is the voxel-based method (Troy & Guerin, 2004), and the third one is the closed-form solution (Abdel-Malek, Yang, Brand, & Tanbour, 2001;Lenarcic & Umek, 1994;Sharma et al, 2004;Yang, 2003;Yang, Abdel-Malek, & Nebel 2005a, 2005b.…”

Workspace zone differentiation tool for visualization of seated postural comfort

“…The first one is the data-driven method (Hammond and Roe, 1972;Badler, 1997;Chaffin, 2002;Reed et al, 2003;Parkinson et al, 2003). It needs to collect thousands of subjects to do the experiment and visualize the collected data in the form of isosurfaces.…”