Clothoid Path Planning Using Precomputed Lookup Tables
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Solution Overview
Problem
Current methods for generating clothoid curves in autonomous vehicle path planning are computationally expensive and inefficient, making it difficult to calculate the required parameters for smooth transitions between start and end points, especially when vehicle orientation changes.
Innovation Solution
A method involving an initialization stage where unique clothoid curves are generated with calculated center points, followed by a curve-fitting technique to create a closed-form expression that relates center point values to clothoid parameters, allowing for efficient calculation of clothoid curves connecting start and end points using a path planning system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional methods are used to generate clothoid curves for path planning, then smooth transitions between start and end points are achieved, but computational cost becomes excessively high and real-time processing is not feasible
Solution Approach 1:
The patent pre-calculates and stores a lookup table of clothoid parameters (a-values) corresponding to different center point distances during an initialization phase. This preliminary action eliminates the need for complex real-time calculations during actual path planning, allowing the system to simply query the pre-computed table for immediate results.
Solution Approach 2:
The patent creates a simplified computational model by copying essential clothoid parameters into a lookup table structure. Instead of performing full clothoid calculations, the system copies relevant parameters (a-values) that can be directly retrieved and applied, significantly reducing computational burden while maintaining path planning accuracy.
2Ease of operation
If clothoid curves are used to provide smooth transitions for passenger comfort, then path quality is improved, but the computational complexity increases making real-time implementation difficult
Solution Approach 1:
The patent pre-calculates clothoid parameters during an initialization phase and stores them in a lookup table. This preliminary computation of the parameter a = sqrt(R*L) for various center point distances eliminates complex real-time calculations, allowing the system to maintain high path quality for passenger comfort while reducing computational complexity during actual operation.
Solution Approach 2:
The patent uses a simple lookup table structure that requires minimal computational resources compared to full clothoid calculations. This disposable-like approach of using pre-computed values instead of complex algorithms maintains path quality while dramatically simplifying the computational requirements for real-time implementation.
3Measurement precision
If exact clothoid parameters are calculated to connect start and end points with specific orientations, then path planning accuracy is improved, but computational expense becomes prohibitive for real-time applications
Solution Approach 1:
The patent pre-computes the relationship between center point distance and clothoid parameter a during initialization, storing these precise values in a lookup table. This preliminary action allows the system to retrieve accurate path planning parameters without performing energy-intensive calculations during real-time operation, thus maintaining precision while reducing computational energy consumption.
Solution Approach 2:
The patent copies pre-calculated clothoid parameters into a readily accessible lookup table structure. This copying approach preserves the precision of exact clothoid calculations while eliminating the need to re-compute them, significantly reducing computational energy requirements for real-time path planning applications.
Data Source
AI summary
A system and method of path planning utilizing a clothoid curve to connect a start point and an end point is provided. The method includes receiving at a path planning system inputs including the start point and the end point of a desired path. The method further includes calculating clothoid parameters for a clothoid curve connecting the start point and the end point based the received start point, the received end point, and a closed-form expression, wherein the closed-form expression is generated based on a relationship between a plurality of unique center point values associated with a plurality of unique clothoid curves and the clothoid parameters associated with each of the plurality of unique clothoid curves. A clothoid curve is generated based on the determined clothoid parameters, wherein the generated clothoid curve represents a planned path from the start point to the end point.