关键词: 智能车辆；避障轨迹规划；分层优化；四阶 B 样条曲线；安全走廊

Abstract: To address the difficulty of simultaneously achieving trajectory smoothness and kinematic feasibility in single-layer planning methods for intelligent vehicle lane-changing scenarios, this paper proposes a hierarchical trajectory planning method based on fourth-order B-splines. The method adopts a hierarchical architecture of "geometric optimization, kinematic correction": first, a smooth reference trajectory is constructed using fourth-order B-spline curves, and the sequential least squares programming (SLSQP) algorithm is employed to optimize the control points, realizing spatial obstacle avoidance and geometric smoothness; subsequently, within the B-spline parameterization framework, multi-disk safety corridor constraints and a two-degree-of-freedom vehicle kinematic model are introduced to optimize the control sequence, ensuring that the trajectory satisfies vehicle kinematic constraints and comfort requirements. Building upon conventional hierarchical planning methods, the proposed approach converts the reference trajectory from the geometric layer into a bounded feasible region through a safety corridor generation mechanism, thereby endowing the motion layer with the ability to autonomously adjust the spatial trajectory within the corridor boundaries. Simulation results demonstrate that, compared with single-layer planning methods, the proposed method achieves superior trajectory smoothness and comfort performance in lane-changing obstacle-avoidance scenarios, while also improving computational efficiency by 61%, providing an effective technical solution for intelligent vehicle lane-changing and obstacle avoidance on structured roads.

Key words: intelligent vehicles; obstacle avoidance trajectory planning; hierarchical optimization; fourth-order B-spline curve; safety corridor