Vehicle Curvature Estimation via Adaptive Yaw and Acceleration Fusion
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Solution Overview
Problem
Conventional methods for estimating a vehicle's radius of curvature are inaccurate when the vehicle decelerates or accelerates, as they do not consider slip, leading to a significant difference between estimated and actual curvature.
Innovation Solution
An apparatus and method that estimate the radius of curvature based on both yaw rate and lateral acceleration, with a curvature radius determining unit combining these estimates using weights adjusted by the magnitude of forward acceleration to account for slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the radius of curvature is estimated based on yaw rate and steering angle assuming constant velocity, then the estimation is simple and works well at constant speed, but the accuracy deteriorates greatly when the vehicle accelerates or decelerates due to slip
Solution Approach 1:
The patent applies dynamics by making the estimation method adaptive to changing vehicle conditions. The system dynamically selects between two estimation approaches based on the magnitude of longitudinal acceleration: using yaw rate-based estimation at constant speed and acceleration-based estimation during acceleration/deceleration. This dynamic adaptation resolves the contradiction by maintaining high accuracy across varying operating conditions without requiring a permanently complex system.
Solution Approach 2:
The patent changes the estimation parameters based on vehicle operating conditions. When longitudinal acceleration exceeds a threshold, the system switches from using yaw rate and steering angle to using lateral acceleration and longitudinal acceleration. This parameter change allows the system to maintain estimation accuracy during acceleration and deceleration while keeping the system relatively simple by only switching between two predefined estimation methods.
2Ease of manufacture
If the conventional estimation method is used that does not consider slip, then the system is simple to implement, but the difference between estimated and actual radius of curvature is large during acceleration and deceleration
Solution Approach 1:
The system dynamically adapts its estimation approach based on vehicle acceleration conditions. By monitoring longitudinal acceleration and switching between estimation methods, the system maintains ease of implementation through a clear decision logic while significantly improving accuracy during acceleration and deceleration events where slip occurs.
Solution Approach 2:
The patent introduces longitudinal acceleration as an intermediary parameter to detect slip conditions. This intermediary measurement allows the system to identify when the conventional estimation method becomes inaccurate and triggers a switch to the acceleration-based estimation method, thereby maintaining both simplicity and accuracy.
Data Source
AI summary
Disclosed is an apparatus and method for estimating a radius of curvature of a vehicle. An apparatus for estimating a radius of curvature of a vehicle includes a processor, a memory for storing a program to be executed in the processor. The program includes instructions for estimating a first radius of curvature of the vehicle based on a yaw rate of the vehicle, estimating a second radius of curvature of the vehicle based on a lateral acceleration of the vehicle, and determining a final radius of curvature of the vehicle by combining the first radius of curvature and the second radius of curvature.