Modelling take-over hand trajectories using linear mixed effects models

Automated driving is currently one of the most important research areas in the automotive industry. If automation reaches its system limits, the driver is obliged to take over the driving of the vehicle again. In that scenario, the driver first has to put his hands on the steering wheel again if he was occupied with a non-driving task. This work shows a method to precisely model these hand movements from a specific task back to the steering wheel. These movements are analyzed depending on the individual parameters of each person, such as age, gender, body height. For this purpose, a test stand was developed and assembled, on which a study with 52 participants was carried out. It can be observed that the hand trajectories are lying in a plane in the three-dimensional space, with orthogonal deviation from the plane smaller than 10 mm. This finding allows to model the trajectory as a combination of a polynomial and the orientation of the individual plane. The results show that the trajectory of the hand movement only averaged about 2 mm from their main movement plane. The trajectories from this study were fitted using polynomials. Trajectories were parametrized and fitted to a linear mixed effects model using the 'lmer' [1] and 'afex' [2] R-packages.