Abstract:

To address the challenges of abrupt curvature changes, high collision risks, and repeated adjustments in parallel parking within narrow urban passages, this study proposes a three-segment one-step path planning method integrating curve combinations and numerical optimization to enhance vehicle steering performance and dynamic obstacle avoidance capabilities. Firstly, based on the curvature characteristics of arcs and spiral curves, two types of curve combinations, namely CAC (clothoid-arc-clothoid) and CC (clothoid-clothoid), are designed. Secondly, the parking process is reversed, the CAC curve combination is used to design the path of the end section. Then, the constrained optimization model of the CC curve combination is constructed to plan the path of the starting section. The middle section path is designed by introducing the fivetic polynomial curve. Finally, multi-condition simulation tests are carried out in the quasi-feasible area through Matlab. The results show that this method can plan a collision-free and continuously curved feasible path in a narrow scene with a channel width of only 3 meters, and it occupies a relatively narrow channel width. Comparative analysis reveals significant advantages over quintic polynomial and arc-clothoid-straight methods in path smoothness, obstacle avoidance, and space utilization efficiency. Model Predictive Control (MPC) validation confirms precise path tracking with continuous front-wheel steering angle changes. This method provides an efficient and safe solution for narrow-space parallel parking, effectively alleviating road congestion caused by roadside parking operations and advancing urban traffic efficiency.

Key words: automatic parking, path planning, clothoid curve, numerical optimization