Abstract:

It is necessary to conduct studies of driver seated reach with consideration of difficulty rating. Literature research shows that at present, no corresponding researches have been done about reaching difficulty and its mechanism, as well as about the reach capability considering the difficulty ratings. Based on the UMTRI test data, a computer program is developed to process the data, in which the target marker positions, the anthropometry dimensions of the participants, the coordinates of joint centers of the subjects, and subjective difficulty ratings are extracted. A kinematics model of human body is created based on the coordinates of joint centers. Posture angle variables are defined. Factors are analyzed about the reaching capability considering the difficulty rating, and the binary Logistic regression is used to model the reach capability at different difficulty ratings. The regression models are validated with perfect qualities. Based on the reach capability models and the package parameters of a mini-van, and with consideration of the seating positions of drivers, the reach envelope surfaces are established and compared with corresponding SAE J287 control reach envelope. Four human body biomechanics models are created based on the anthropometry data distributed near the boundary of the participants, and are used to conduct the biomechanical calculations and analyses of the terminal frame data of the reaching process, from which the relationships of the difficulty rating and the biomechanics loads of the human body are acquired, as well as the influences of the subject stature on the biomechanics loads and difficulty ratings. Another main point of this study is that a modeling method of reach capability is established for different target populations considering the difficulty rating and based on the terminal reaching data and vehicle packaging parameters.

Key words: binary logistic regression, biomechanics loads, difficulty, reach capability, reach envelope, seated reach