Simulated effect of driver and vehicle interaction on vehicle interior layout Burak Ozsoy a , Xuewu Ji b , James Yang a, * , Jared Gragg a , Bradley Howard a a Human-Centric Design Research Laboratory, Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, USA b State Key Lab of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China article info Article history: Received 16 November 2013 Received in revised form 3 December 2014 Accepted 4 May 2015 Available online Keywords: Physics-based posture prediction Optimization Seat adjustment range Digital human model abstract Digital human modeling is an essential tool to reduce cost and to save time in a design process where humans take the part of users of the design. Considering this phenomenon for a vehicle interior, the importance of the seat track location and adjustment ranges become important. This paper presents the effect of driver and vehicle interaction on vehicle interior layout based on simulation approach. This simulation method includes two optimizations. The first optimization problem is the physics-based seated posture prediction. In order to represent physical drivers, 4,500 virtual drivers are generated based on an anthropometric database-ANSUR. Interaction forces between the digital human and pedal, seat, ground, and steering wheel are incorporated in the physics-based posture prediction. Three different pedal reaction moments (0, 20, and 40 N m) are implemented into the formulation to examine the effect of pedal reaction moment on driver seat location and adjustment ranges. To study the effect of shear forces, the physics-based posture prediction is compared to kinematics-based posture prediction. After posture predictions are completed, individuals' preferred seat locations are used in a second optimization problem to predict the seat track location and adjustment ranges. For a specific vehicle with 20 N m pedal reaction moment, adjustment ranges are predicted as 223 mm and 82 mm in horizontal and vertical directions, respectively. Also, it was shown that shear force due to the interaction between the driver and the seat pan and the pedal reaction moment are both influential to the seat track location and adjustment ranges. Relevance to industry: The simulation model presented in this paper is useful in vehicle and seat design and can be easily used for virtual design assessment in vehicle design. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Variance in human anthropometry is a primary concern and challenge of vehicle interior design. Positioning of the vehicle interior components (seat track, controls, displays, steering wheel, gear shift, pedals, etc.) should be determined according to a target population's driving postures and reach zones. For this design problem, one of the main issues is the location and size of the adjustment ranges. If the sizes of adjustment ranges were large enough to accommodate the entire population, it would increase cost excessively. Also, correct seat positioning has a major effect on driver response time (Scott et al., 1996). These design consider- ations should be determined for diverse users in a population where a target percentage is accommodated without any dissatisfaction. From reviewing the literature on seat and occupant interaction studies, it is clear that interaction forces play an important role in seated postures besides the legroom (Cascioli et al., 2011) and lumber spine stiffness (De Carvalho and Callaghan, 2011). In literature, there is no study considering the interactions (interaction forces) between the human and the vehicle for determining the seat track location and adjustment ranges although some studies (Bush and Hubbard, 2007; Rasmussen et al., 2009; Grujicic et al., 2010; Hobson, 1992; Olesen, 2012; Majid et al., 2011) have focused on the physical in- teractions between the design and the user for seated applications. The motivation of this study is to test two hypothesizes: The shear forces due to the interaction between the seat pan and the driver are influential in determining the seat track location and adjust- ment ranges; and the pedal moment influences the seat track location and adjustment ranges. Two methods for vehicle interior design have been reported in the literature. The first method is the usage of the standardized * Corresponding author. E-mail address: james.yang@ttu.edu (J. Yang). Contents lists available at ScienceDirect International Journal of Industrial Ergonomics journal homepage: www.elsevier.com/locate/ergon http://dx.doi.org/10.1016/j.ergon.2015.05.004 0169-8141/© 2015 Elsevier B.V. All rights reserved. International Journal of Industrial Ergonomics 49 (2015) 11e20