Evaluation and Optimization of Driver Steering Override Strategy for LKAS Based on Driver’s Acceptability 2018-01-1631

In order to satisfy design requirements of Lane Keeping Assistance System (LKAS), a Driver Steering Override (DSO) strategy is necessary for driver’s interaction with the assistance system. The assistance system can be overridden by the strategy in case of lane change, obstacle avoidance and other emergency situations. However, evaluation and optimization of the DSO strategy for LKAS cannot easily be completed quantitatively considering driver’s acceptability. In this research, firstly subjective and objective evaluation experiment is designed. Secondly, correlations between the subjective and the objective evaluation results are established by using regression analysis. Finally, based on the correlations established previously, the optimal performance of DSO strategy is obtained by setting the desired comprehensive evaluation ratings as the optimized goal. Except for the whole process of the research, there are some details of the subjective and objective evaluation experiment design to be introduced. For the objective evaluation experiment, several objective characteristic indices (CI) are extracted, which are unrelated to controller. As for the subjective evaluation experiment, a questionnaire consisting of 7 questions is initially designed. Then, based on pre-experiment results, it is simplified by correlation analysis among its questions to eliminate information redundancy. Additionally, proper weights are given to different questions of the questionnaire by using Analytic Hierarchy Process (AHP), and the driver’s comprehensive evaluation of DSO strategy is added on by this method. Overall, with the conduct of the newly designed experiment, it would be possible to achieve the following five advantages. The first one is a generic objective evaluation regardless of controller types. The second one is a more simplified subjective evaluation experiment. The third one is a reliable comprehensive subjective evaluation. The forth one is the optimization of DSO strategy for LKAS based on the driver’s acceptability. The last one is the obtained target objective CI can be used for different types of controller design.