Vehicle Design Method and Ingress/Egress Motion Analysis to Minimize Door Trim Scuff and Soil

Abstract

Human factors design is becoming increasingly important in the automobile industry. However, if the interior materials of a car are not maintained, human sensibility is affected. Although the maintenance of the interior materials of vehicles is a chronic problem according to J.D. Power, existing solutions have been limited to surface treatment and materials. Thus, to prevent scuff and soil, an ergonomic solution using human ingress/egress motion is proposed. Specifically, automotive design parameters were studied to determine their influence on maintenance defined as contact with the pressure pad located on the front door trim. In this research, door trim is a major concern. Ingress/egress experiments were performed 3 times with a customized and parameterized vehicle mock-up, validated as similar environment as a real automobile by an inertial motion capture device. A 6-parameter experiment was conducted at first and each one parameter was screened for each experiment by half normal probability plot. As a result, 4 vehicle parameters plus vehicle types were analyzed by ANOVA. Each experiment was based on the design of experiments. Low and high levels of parameters were determined within a range of mock-up covers but were sufficiently apart. Three parameters were selected as the most influential factors: A-pillar to H-point, H-point to sill, and Door open angle. Other minor parameters were rejected: H-point to ground, Sill height, and Door trim extrusion. An optical motion capture was performed in 3rd experiment. With motion capture data, informative joints to classify motion that made scuff and soil, were selected by recursive feature elimination. K-nearest neighbors algorithm was used as classification. Hip, knee, and subtalar were selected as the most influential joints to scuff and soil. Therefore, parameters and motion analysis would make vehicle designers understand ingress/egress motion causing interior scuff and soil and introduce vehicle design method to solve the problem.