Research On The Automotive Handling Discomfort Based On Joint Torque

With the development of technology and the improving of people’s living standard, requirements for vehicle handling comfort has been increasingly improved. Early studies on the discomfort are mainly based on evaluating the driver joint angles. This kind of method requires a lot of statistics to reduce the impact of subjective feeling, and it is difficult to explain the deep problems like driving fatigue and sports injuries. Aiming at that kind of problem, this paper studies the joint torque of human body during the steering and pedal process from the perspective of biomechanics. After that, the relationship between joint torque and discomfort is analyzed to provide reference about vehicle cabin design.Firstly the human body size is predicted. Due to the difference of human body size, the accurate and typical human body size is the precondition of product design. The prediction of human body size is that picking up the body size of specific human from total population to make the evaluation model of discomfort can meet certain fitness. In this paper,10000 samples are generated by using the Monte Carlo simulation as data source of the human body sizes for driver’s posture prediction. Through principal component analysis (PCA) to reduce dimension of the body size variates, three biggest principal component data that can exactly explain raw data are extracted. On the basis of results, confidence bounding sphere with confidence interval of 0.95 is built, and three typical model of the human body are selected as sample in this paper.Secondly driving posture is predicted. Accurate driving posture is the basis of man-machine engineering checking. In this paper, the virtual cap is established by CATIA, which can set different cabin layout parameters. Specific percentage of the human body is selected and the RAMSIS is used to predict the posture. After that, the posture of upper limbs and lower limbs are simulated in the process of manipulation, and the comfortable driving angle is obtained under different cabin layout parameters to study the influence on joint angle.On that basis, combining with the measurement of force in the process of steering and pedal controlling, a kind of method to evaluate discomfort during handling process based on joint torque is presented. Through the construction of upper limbs and lower limbs dynamical model to calculate the joint torque of human body, and combining with the research achievement of joint torque to put forward an evaluation method for local discomfort and overall discomfort. At last, comparing with the discomfort model in RAMSIS to verify the rationality and availability of this research.The research results offer some ideas to the objective evaluation on the handling discomfort, and also provides reference for the optimization of the cab arrangement.