Evaluation On Automobile Pedals Layout Considering The Musculoskeletal Information

Handling comfort of automobile pedals affects automobile comfort to some extent,and further impact user's driving experience.Driving discomfort makes muscle prone to muscle fatigue,causes muscle soreness and even increases the occurrence of traffic accidents.There are many factors affecting pedals' handling comfort,including pedal travel,dimensional design and spatial arrangement et al.It's the driver who evaluates comfort.Therefore,it is necessary to consider not only the mechanical design,but also human factors engineering and man-machine interaction in the process of pedals design.The final design can be achieved by trial error and optimization.The existing evaluation of the driver's comfort is mainly from the statistical analysis of foreign scholars,therefore,there is still a lack of Chinese characteristics of the driver's comfort evaluation methods.In this paper,from the point of view of the mechanical properties of the driver's skeletal muscle,the simulation analysis and the real vehicle test are combined to evaluate the comfort of the pedal arrangement.The quantitative indicators are used to predict the comfort of pedal.The main research contents of this paper includes the following three aspects:First,based on the driver's skeletal muscle dynamics model,the steering wheel and pedals were introduced into the model.The effect of various pedal positions was analyzed to human's lower extremity joints and leg muscles.Extract the feature parameters such as joint forces,joint torques and muscles' activities and then put the most significant parameters as the main research object in the test.Second,it has collected real drivers' electromyography data through real vehicle test under various working conditions.The test conditions are divided into two parts: the driver's heel on the ground and the heel off the ground,and each of the major conditions include the operation of the 10 pedals.Then carried on denoise processing,full-wave rectifier and linear processing.Activities of muscles were calculated according to the root mean square of electromyography while muscles' maximum contraction gathered before the test and the root mean square of electromyography acquired in these cases.Thus,the influence of various vehicles and different pedal space arrangements on the activation degree of each muscle was verified.Finally,using analytic hierarchy process method,the middle layer is the lower leg and thigh,and the schematic layer is tibialis anterior muscle,gastrocnemius,rectus femoris and hamstring muscles' activities,according to table 1 to 9 scale degrees scoring middle layer and schematic layer to determine the weight of each muscles' activities.A function using these factors was proposed to evaluate pedal layout discomfort.Then the conclusion got by the above function using simulation data is consistent with that of the real vehicle test.