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This paper proposed a path coordination strategy for autonomous parking based on independently designed parking lot topological map. The strategy merges two types of paths at the three stages of path planning, to determinate mode switching timing between low-speed automated driving and automated parking. Firstly, based on the principle that parking spaces should be parallel or vertical to a corresponding path, a topological parking lot map is designed by using the point cloud data collected by LiDAR sensor. This map is consist of road node coordinates, adjacent matrix and parking space information. Secondly, the direction and lateral distance of the parking space to the last node of global path are used to decide parking type and direction at parking planning stage. Finally, the parking space node is used to connect global path and parking path at path coordination stage.

The transient response characteristics of a vehicle under steering angle input are important evaluating indicators of vehicle handling stability. For a new developed vehicle, which was found that the transient response under steering angle input is too slow at high speed, a rigid-flexible coupling vehicle model is established in ADAMS/Car based on multi-body dynamics theory. Improvement measures are studied and put forward to improve the transient response characteristics of the vehicle. The sensitivities of transient response to various parameters are analyzed. The optimization method of adjusting the tire cornering stiffness and moving forward the mass center is adopted. The test data after improvement show that the response time of yaw velocity is shortened obviously. Meanwhile, the value of evaluation index in other tests remains basically unchanged.