A Preventive Evaluation of Perceived Postural Comfort in Car-Cockpit Design: Differences between the Postural Approach and the Accurate Muscular Simulation under Different Load Conditions in the Case of Steering-Wheel Usage

The evaluation of perceived comfort inside a car during the early stages of the design process is still an open issue. Modern technologies like CAE (Computer Aided Engineering) and DHM (Digital Human Modeling) already offer several tools for a preventive evaluation of ergonomic parameters for car drivers using detailed CAD (Computer Aided Design) models of car interiors and by a MBS (multi-body-system) solver for evaluating movements and interactions. Such evaluations are, nonetheless, not sufficient because the subjectivity of comfort perception is due to factors that are very difficult to evaluate in the early stage of design. Physical prototypes are needed and these are often too expensive to be realized. In the last 30 years, several researchers have tried to develop methods to objectivize comfort performance but most of these methods are based on questionnaires, market research, or physiological and biomechanical analyses, and need devices or interactions that modify perceived comfort. Recently, the authors of this study developed a software tool named CaMAN® for postural comfort evaluations of upper limbs. The software employs a static analysis of human joints in a working environment (the car cockpit is assumed to be a working environment). Some software, like AnyBody™, allows evaluations of the muscular efforts made during body actions. In the literature, it is possible to find several papers such as Na et al. [26] and Telfer et al. [40] that demonstrate a correlation between muscular effort and perceived comfort. Empirical evidence suggests that better comfort is related to lower muscular activity. This paper shows the results obtained from numerical and experimental analyses using AnyBody™ and CaMAN®. Simulations of the static and dynamic behaviors of a car driver using a steering wheel are performed. The results show the differences between preventive analyses of perceived comfort that are made with and without an applied load for a subject in the fiftieth percentile. This paper shows the results obtained from numerical and experimental analyses using AnyBody™ and CaMAN®. Simulations of the static and dynamic behaviors of a car driver using a steering wheel are performed. The results show the differences between preventive analyses of perceived comfort that are made with and without an applied load for a subject in the fiftieth percentile.