Curved-Section Information Supply for Real-Time Vehicle Control
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Solution Overview
Problem
Existing road-shape estimating apparatuses require significant time to calculate clothoid curves and radius of curvature at each traveling position in a clothoid section, making them unsuitable for real-time vehicle control applications.
Innovation Solution
A curved-section-information supplying apparatus that identifies clothoid sections, obtains clothoid coefficients, and calculates radius of curvature based on travel distance, using tables to efficiently derive necessary parameters without determining the entire clothoid curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the known apparatus calculates coordinate values of a large number of points representing the clothoid curve to determine the clothoid curve, then the accuracy of the curved section information is improved, but the calculation time increases significantly
Solution Approach 1:
The patent extracts only the essential parameters (clothoid coefficient A and curve length L) needed to calculate radius of curvature, rather than computing the entire clothoid curve with many coordinate points. This selective extraction of necessary information dramatically reduces calculation time while maintaining the accuracy needed for vehicle control applications.
Solution Approach 2:
The patent performs partial calculation by directly computing radius of curvature at specific traveling positions using the formula R=A²/L, rather than calculating all intermediate points of the clothoid curve. This partial action approach provides sufficient accuracy for control purposes without the excessive computation of the complete curve geometry.
2Reliability
If the known apparatus calculates radius of curvature at each traveling position based on the obtained clothoid curve information, then the usefulness of the information for vehicle control is improved, but the overall processing time increases
Solution Approach 1:
The patent makes the system self-sufficient by directly calculating radius of curvature from the clothoid coefficient and curve length without requiring external curve determination processes. The apparatus generates control-relevant information on-demand using the efficient formula R=A²/L, eliminating the need for time-consuming pre-computation of complete curve data.
Solution Approach 2:
The patent replaces the mechanical process of determining complete clothoid curves with coordinate points with a direct mathematical computation method. By substituting the geometric construction approach with an algebraic formula (R=A²/L), the system achieves both speed and accuracy for real-time vehicle control applications.
Data Source
AI summary
A curved-section-information supplying apparatus includes: a clothoid-section identifying unit that identifies a clothoid section included in a curved section of a road; a clothoid-coefficient obtaining unit that obtains a clothoid coefficient for a clothoid curve representing a shape of the clothoid section identified by the clothoid-section identifying unit; and a radius-of-curvature calculating unit that calculates a radius of curvature at a position at a travel distance in the clothoid section, based on the clothoid coefficient and a curve length from a start point of the clothoid curve, the curve length corresponding to the travel distance from a start point of the clothoid section, to supply curved-section information based on the radius of curvature at the position at the travel distance in the clothoid section.