Study On Driving Comfort Based On Biological Response

With the development of society, comfort is increasingly playing an important role in driving, especially in taxi divers who always work at least 8 hours a day. Recent research reveals that uncomfortable driving posture not only can produce physical pathological changes such as spine and skeleton system, digestive system, heart and vascular system, especially low back pain, but also traffic accidents. Car interior with comfort and good design can decrease awkward posture and occupational diseases, but activate optimal operating performance. Many countries in the world have take steps on the study of driving comfort, especially in western countries which are deeper and wider.Comfort is a subjective feeling, which results from psychology and physiology. From physiology and biophysics, this paper studies driving comfort with questionnaire, protocol analysis, sEMG and image scale, et al..The study is composed of three main experiments. Experiment One investigated the comfort influencing factors with a series of sub-experiments. The results reveal that:(1) The subjective influencing factors includes sleep, driving time, mood, physical status and fatigue, and the objective influencing factors includes seat comfort, seat adjustability, vibration, noise, machine appearance, driving space, climate control, view, display and panel, control and control method, and fatigue.(2) The results of operating comfort study accords with the objective influencing factors study. Seat comfort, vibration, control and control method, noise are the main factors that influence driving comfort. Normally, the total comfort evaluation of driving is at "normal" but second to not comfort.(3) The total seat comfort evaluation is at "normal" but second to not comfort. The factors that influence seat comfort mainly include seat back shape, low support and upper support, especially low support.Experiment Two measured the human joint angle at static comfort driving situation and investigated the comfort space. The results reveal that the angle ranges are embodied in the area measured in simulated driving situation at lab.With taxi drivers as subjects, Experiment Three investigated the comfort at dynamic driving situation by the eEMG tests of neck extensors, erector spinae muscle, multifidus muscle and biceps femoris muscle through maximum back expansion and Biering-Sorensen Testing (BST). The results reveal that:(1) With the driving time extended, the BST time continually falls and the back expansion decreases.(2) There is little difference between the whole AEMG and MPF, which is possibly influenced by subjective factors such as willpower, endurance, et al. To the analysis of sEMG, we find that the signal and data in the preliminary 20 seconds are useful to the study.(3) By the odd variance analysis to the average of AEMG, MPF and slope of MPF in the preliminary 20 seconds, we find that the falling slopes of MPF of the left multifidus muscle and the right multifidus muscle are remarkably influenced by driving time, not so other muscles. The experiment ulteriorly indicates that the multifidus muscle possibly is the main problem that causes low back pain.(4) The human subjective comfort feelings are accordant with the objective experimental data.(5) With the integrated analysis of subjective comfort function and objective comfort function, we defined and prescribed low back comfort exponent and obtained low back comfort exponent function so as to put it in driving evaluation.After the experiments, we proposed a framework of computer-aided ergonomics evaluation system and investigated the key technologies. Then a computer-aided ergonomics evaluation system based on comfort was developed based on CAXA and the experimental data were built in so as to support virtual design, product innovation and workspace design.At last, we summarize all the works of the whole paper in chapter seven and indicate the parts that need further research in next steps.