Observer-based backstepping control method using reduced lateral dynamics for autonomous lane-keeping system

This paper presents a backstepping control method with an augmented observer for an autonomous lane-keeping system. A novel reduced second-order model is also derived for an autonomous lane-keeping system. The proposed reduced model of lateral vehicle motion has the following advantages: (1) The lateral motion of the vehicle can be controlled with only simple linear second-order dynamics via the backstepping procedure; (2) The state variable of the reduced model includes the look-ahead distance similar to that for a human driver; (3) The system functions with unknown parameters and external disturbances can be lumped in the disturbance. An augmented observer is designed to estimate the full state and lumped disturbance, including the system functions with unknown parameters and external disturbances. A backstepping control is developed for improving the lateral control and compensation of the disturbance. The stability of the closed-loop system is demonstrated using the input-to-state stable property. The lateral control performance of the proposed method is validated via numerical simulations using CarSim and MATLAB/Simulink.