Human emotional response to automotive steering wheel vibration: development of a driver emotional semantic scale

Abstract

The 21st century automobile has become more than just a simple tool for transportation and more of a brand image or a way for drivers to express their personal taste. This has made it increasingly important for automotive manufacturers to design the driver experience and driver feeling so as to tailor their preferences and interests. Currently there is not enough information on how to design or brand the communication of meaningful feedback from the automobile to the driver. With the development of new advanced technologies such as electric steer-by-wire systems or electric automobiles, the need to provide meaningful feedback to the driver plays a central role in the experience of using the new driving technology. Thus it is important to understand how to assess the emotional response to the stimuli reaching the driver so to be able to optimise at later stage the perceived experience. Steering wheel vibration feedback plays an important role for the driver’s control input when driving. There is currently a lack of research on the formal assessment criteria of driver emotional response used to define automotive steering wheel vibration feedback, therefore this thesis proposes a newly Driver Emotional Semantic (DES) Scale to answer the research question: “How can the emotional response to steering wheel vibration be assessed?”. This study starts with a comparison of a questionnaire survey (Exp.1) and a laboratory test (Exp.2) to identify if a correlation exists between the emotional ratings measured from the expected driver’s perception of the vibration and the experienced emotional feeling of steering wheel vibration. The work then defines a semantic scale to capture the vibrational vocabulary used by the driver to express their feeling of perceived vibration during real-road driving scenarios. Experiment 3 was therefore carried out to gather the underlying semantic descriptors used by drivers during driving scenarios. To test the reliability of the descriptive pairs of the DES rating scale developed, two evaluations of the assessment criteria were carried out: in real road scenarios (Exp.4) and laboratory test setting (Exp.5). Current research findings of this thesis suggest that the consistency of the scale dimensions found in the field study has captured with greater accuracy the driver semantic experience of automotive steering wheel vibration character as compared to the laboratory experiment dimensionality. Results suggest that the main vibrotactile semantic descriptors to assess the human emotional response to automotive steering wheel vibration were found to be four: pleasant, smooth, sharp and powerful. The final proposed DES scale could help automotive research and industry determine and customise the aspects of the automobile towards drivers’ preferences of felt experience.