Autonomous Vehicle Motion Control Using NMPC Based on Orthogonal Collocation Method: Integration Stability Study

Nonlinear model predictive control (NMPC) has gained increasing interest in motion control of autonomous driving. Integration stability is one of the crucial factors influencing the effectiveness of NMPC, which has not been considered much for the applications of autonomous driving. Orthogonal collocation method is utilized in this study to address the integration stability problem. Compared with two explicit integration methods which are commonly used, the proposed method is A -stable and thus provides a much wider stable region. By integrating orthogonal collocation method into the framework of NMPC, the integration stability problem at low velocity motion can be settled. The simulation under a small turning radius U-turn maneuver at a low vehicle velocity is performed and the results also show that the stability problem at low vehicle speeds is successfully resolved.