Travel Path Filtering for Small-Radius Curve Suppression
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Solution Overview
Problem
Existing travel path generation techniques in autonomous driving fail to effectively remove curves with small radii of curvature, leading to increased lateral acceleration, vibrational behavior, and power consumption due to steering angle overload.
Innovation Solution
A travel path generation apparatus and method that determine a cutoff frequency based on the spacing between points and a radius of curvature threshold, using low-pass filtering to remove curves with small radii, thereby generating a smoother travel path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polynomial approximation filtering is used on lane shape, then general lane shape is preserved, but curves with small radius of curvature remain causing increased lateral acceleration and vibrational behavior
Solution Approach 1:
The patent changes the filtering parameters by introducing a cutoff frequency parameter and using low-pass filtering instead of polynomial approximation. This allows selective removal of high-frequency components (small radius curves) while preserving the general lane shape, thus resolving the contradiction between maintaining lane shape accuracy and eliminating harmful vibrations.
Solution Approach 2:
The patent introduces an intermediary processing step that converts the lane shape into a frequency domain representation, applies low-pass filtering to remove harmful high-frequency components, and then converts back to time domain. This intermediary frequency domain processing acts as a mediator between the original lane shape and the final filtered path, eliminating small radius curves while preserving overall shape.
2Device complexity
If polynomial approximation filtering is used on lane shape, then processing is simple, but curves with small radius of curvature cause EPS motor overload and power consumption
Solution Approach 1:
The patent changes the filtering approach from polynomial approximation to low-pass filtering with a cutoff frequency parameter. This parameter change enables effective removal of small radius curves that cause EPS motor overload, reducing power consumption and heating while maintaining acceptable processing complexity through standard digital signal processing techniques.
3Manufacturing precision
If polynomial approximation filtering is used on lane shape, then minor variations are removed, but the filtered path still contains curves with small radius of curvature
Solution Approach 1:
The patent introduces frequency domain analysis as an intermediary step that transforms the lane shape data, allowing selective filtering of high-frequency components corresponding to small radius curves. This intermediary transformation enables more effective separation of desirable lane shape features from harmful variations, improving travel path smoothness and reliability.
Solution Approach 2:
The patent changes the filtering methodology from polynomial approximation to low-pass filtering with adjustable cutoff frequency. This parameter change provides better control over which frequency components are removed, enabling more effective elimination of small radius curves while preserving the essential lane shape characteristics, thus improving both filtering accuracy and path smoothness.
Data Source
AI summary
It is an object of the present disclosure to provide a travel path generation apparatus and a travel path generation method enabling generation of a travel path not including a curve having a small radius of curvature. A travel path generation apparatus according to the present disclosure includes: a parameter determination unit to determine a cutoff frequency based on spacing between points of a sequence of points each having location information and a predetermined threshold of a radius of curvature, the sequence of points representing a shape of a lane in which a vehicle travels in a two-dimensional or three-dimensional Cartesian coordinate system; and a filtering unit to perform low-pass filtering using the cutoff frequency determined by the parameter determination unit on the location information of each of the points of the sequence of points.