Restrained and Unrestrained Driver Reach Barriers

Design and packaging of automotive interiors and airplane cockpits has become a science in itself, particularly in recent years where safety is paramount. There are various methods for restraining operators in their seats, including fitting an operator, such as a race car driver or pilot, with two seat belts, one for each side of the body, a three point restraining system as in commercial vehicles, and a lap belt as in some trucks and other types of vehicles. Moreover, significant experimental efforts have been made to study driver reach and barriers since they directly affect performance and safety. This paper presents a rigorous formulation for addressing the reach envelope and barriers therein of a 3-point restrained driver compared with a lap-belt-restrained driver. The formulation is based on a kinematic model of the driver, which characterizes the upper body and arm as 7 degrees of freedom (DOF) for an unrestrained and 4DOF for a 3-point restrained driver. These kinematic equations are further developed to address crossability analysis, a concept that is based on a quadratic form of the acceleration of the hand as it moves across a barrier. Visualization of such barriers and their crossability results within the reach envelope provides significant insight into driver performance and reach zones.