Design and evaluation of a Fuzzy comfort-oriented speed profile generator for autonomous passenger cars

During the past twenty years, autonomous driving has moved from the realm of science fiction to a very real possibility. With the growing interest in self-employed vehicles, the problem of motion sickness may be so important that not addressing it may limit the users’ acceptance, reducing the safety and environmental impact of autonomous vehicles. The comfort of an autonomous vehicle is largely determined by its control algorithm. An autonomous vehicle’s control consists mainly of three interconnected modules: environment perception, path planning and vehicle control. In view of this, the current study presents a method based on a Fuzzy Logic Controller aiming to compute a suitable reference speed profile in order to optimize the passenger comforts and control performances. To this end, the amount of vibration transmitted to the passengers and the probability to experience motion sickness are evaluated considering two comfort indexes extracted by ISO 2631. This thesis work can be divided into four parts. After a deep analysis of the state of art and an investigation of the main modules that constitute the overall architecture of an autonomous vehicle, in the first part of the thesis the Fuzzy Logic Controller is designed. In the second part of the thesis work, a 3 degrees of freedom vehicle model is used to model the vehicle dynamics and simulations are conducted in virtual scenarios created using Automated Driving Scenario Toolbox® on MATLAB® and Simulink®. In the third part of the thesis work, the simulated experiments are performed on Simscape Vehicle Template where the vehicle dynamics are modeled using a complete vehicle model with 15 degrees of freedom. In the last part, the comfort indexes of driver and passengers are evaluated. The study focuses on three different scenarios; an highway scenario where the path is straight and the maximum speed is set to 130 km/h, an interurban scenario with fairly straight road and slight curves with maximum speed set to 70 km/h and a competition race track with sharp curves and maximum speed set to 70km/h. The effectiveness of the comfort optimization method results in a lower percentage of people who may experience nausea and in a lower value of equivalent acceleration perceived by the passengers compared with the classical approach.