The effects of joint angle variability and different driving load scenarios on maximum muscle activity – A driving posture simulation study

Abstract

To date, no studies have been conducted on the main and interaction effects of joint angles on maximum muscle activity in different driving load scenarios. To investigate the influence of joint angle variability on the muscular system, this study calculated maximum muscle activity during three static driving load scenarios through the use of musculoskeletal inverse dynamic simulation. Six joint angles in sagittal plane were varied with reference to reported driving posture angles in the literature. A digital manikin with a height of 180 cm and weight of 70 kg was used with simple muscles and a minimum fatigue criterion for muscle activation optimization. Three static driving load scenarios were simulated: sitting with no external forces except gravity, steering, and pedaling operation. Prediction models were developed for each driving load scenario using Least Squares Support Vector Machine. Finally, the Pareto optimization method was applied for multi-objective optimization combining the three developed models.The results indicate that the developed models can be used for the prediction of simulated maximum muscle activity. The six joint angles explain a higher percentage of maximum muscle activity variance in the steering and pedaling operation scenarios compared to the sitting scenario. The six joint angles differ in their main and interaction effects on maximum muscle activity depending on the driving load scenario. The optimum joint angle values of the driving posture depend on the driving load scenarios. The different driving postures based on minimum maximum muscle activity are presented for the three driving load scenarios. Relevance to industryThe results of this study can be utilized in establishing driving posture simulation models to improve vehicle interiors during the early development stage. Furthermore, the results of this study can provide base data for the development of a tool for real driving posture evaluation of maximum muscle activity.