Parking Trajectory Planning with Clothoid Transitions
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Solution Overview
Problem
Current driver assistance systems for parking face challenges in determining precise parking trajectories that can be followed by vehicles, often resulting in imprecise maneuvers due to sudden steering angle changes when transitioning between geometric sections like circular arcs and lines, leading to deviations from the planned path.
Innovation Solution
A method that determines a parking trajectory composed of circular arcs, lines, and clothoids by first defining an auxiliary trajectory with alternating sections, replacing transition areas between these sections with clothoids to smooth out steering angle changes, allowing for precise vehicle maneuvering within the parking space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the parking trajectory is composed of simple geometric segments (lines and circular arcs), then the calculation complexity is reduced, but the vehicle can only follow the trajectory very imprecisely due to sudden steering angle changes
Solution Approach 1:
The patent introduces clothoids as intermediary elements between lines and circular arcs in the parking trajectory. These clothoids serve as transition sections that smoothly connect the simple geometric segments, enabling continuous steering angle changes while maintaining calculation feasibility. The clothoids act as mediators that resolve the conflict between simplicity and precision by providing a mathematically tractable yet physically realizable transition curve.
Solution Approach 2:
The patent applies curvature variation through clothoid sections, where the curvature changes continuously rather than abruptly. By replacing the sharp transitions between lines and circular arcs with clothoids that have continuously varying curvature, the trajectory becomes followable by the vehicle's steering system while maintaining the overall simplicity of the geometric composition.
2Manufacturing precision
If the parking trajectory uses complex geometric sections (including clothoids), then the vehicle can follow the trajectory precisely, but the calculation complexity increases significantly
Solution Approach 1:
The patent segments the parking trajectory into distinct sections: simple geometric segments (lines and circular arcs) for the main path and clothoid transition segments for smooth connections. This segmentation allows the system to use simple geometry where possible while introducing complexity only where necessary for smooth transitions, thereby managing overall calculation complexity while achieving precise trajectory following.
Solution Approach 2:
The patent applies complex clothoid geometry locally only at the transition points between simple geometric segments, rather than throughout the entire trajectory. This local application of complexity minimizes the overall computational burden while achieving the necessary smooth transitions for precise vehicle following at the critical connection points.
3Reliability
If the number of obstacles and their detailed geometry are taken into account, then the parking trajectory can be planned to be obstacle-free, but the calculation complexity increases
Solution Approach 1:
The patent creates a simplified geometric model (copy) of the parking environment and vehicle constraints to plan the trajectory. By working with abstract geometric representations rather than detailed obstacle models, the system can efficiently calculate obstacle-free paths using simple geometric segments, then add clothoid transitions for smooth execution without reprocessing detailed obstacle geometry.
Data Source
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AI summary
The invention relates to a method for manoeuvring a motor vehicle (1) into a parking space, wherein a parking trajectory (9) is determined from a starting point (11) to a target point (12) in the parking space, wherein the parking trajectory (9) is composed of arcs (13, 13'), lines (14, 14') and clothoids (17), and the motor vehicle (1) is manoeuvred along the determined parking trajectory (9) into the parking space, wherein an auxiliary trajectory (10) with multiple sections is determined from the starting point (11) to the target point (12), wherein the auxiliary trajectory (10) has arcs (13, 13') and lines (14, 14') as the sections, a respective transition region (16) is defined for neighbouring sections and a clothoid (17) is determined for the respective transition regions (16), wherein the parking trajectory (9) is determined from the auxiliary trajectory (10) in which the respective transition regions (16) are replaced by the clothoids (17).