ERL seat design and digital human models

ERL is a computer program and technical process that evaluates or designs seating in vehicle interiors. The computer program uses an optimization algorithm, digital human body models (DHMs), biomechanical model of seated weight distribution, force–deflection model of the seat, and digital models of the seat trimmed surface and vehicle controls for driving. Numerical results describe positions and orientations of drivers, seat, steering wheel, and accelerator. These results are used to calculate driver comfort scores. Unigraphics NX displays drivers sitting in the seat with their hands on the steering wheel, foot on the accelerator, and eye in position to see the road. To demonstrate, 41 vehicles from Europe, North America, and Asia have been analyzed for this chapter. Bivariate relationships between dimensions of seat positions (fore/aft and up/down), joint angles (elbow, torso, hip, and neck), seat adjustments (cushion tilt and back recliner), head restraint backset, and comfort demonstrate how seats affect driver comfort, ergonomics, and safety. Using the same anatomical landmarks in the same sample of DHMs creates an angular description of seat shape that shows high variability in seating. This analysis demonstrates how small women are least comfortable and medium size men are most comfortable in these vehicles.