Autonomous Vehicle Position Estimation via Dynamics Model Correction
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Solution Overview
Problem
Automated driving systems face challenges in accurately determining vehicle position, especially in conditions where primary positioning sensors like GNSS are unavailable, leading to impaired navigation and path-following capabilities.
Innovation Solution
A vehicle control system that includes an actuator for steering, sensors for yaw rate and longitudinal velocity, and a controller using a vehicle dynamics model and PID controller to estimate vehicle position and correct model discrepancies, allowing for automatic control without human intervention, even when primary sensors are unavailable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vehicle dynamics model with PID controller is used to estimate vehicle position, then measurement precision and reliability are improved when GNSS is unavailable, but device complexity increases
Solution Approach 1:
The patent introduces a vehicle dynamics model as an intermediary system that mediates between available sensors (wheel angles, longitudinal velocity) and the required output (vehicle position). This model acts as a virtual sensor, translating measurable quantities into position estimates through mathematical relationships, thereby resolving the contradiction by providing accurate position estimation without direct GNSS measurement.
Solution Approach 2:
The PID controller implements feedback by continuously comparing the estimated position with the desired position and adjusting control inputs accordingly. The controller uses feedback from measured wheel angles and longitudinal velocity to correct position estimates, improving measurement precision while managing system complexity through established control theory frameworks.
2Reliability
If model correction using PID controller is applied, then reliability is improved under sensor impairment, but computational requirements and device complexity increase
Solution Approach 1:
The patent applies dynamic model correction where the vehicle dynamics model parameters are continuously adjusted based on real-time sensor measurements and PID control outputs. This dynamic adaptation allows the system to maintain reliability under varying conditions and sensor impairments, balancing computational requirements with improved navigation reliability through time-varying parameter adjustment.
3Adaptability or versatility
If vehicle dynamics model estimation is used instead of primary sensors, then adaptability is improved for operation without GNSS, but measurement precision may be compromised
Solution Approach 1:
The patent segments the positioning system into multiple independent components: primary GNSS-based positioning and secondary vehicle dynamics model-based estimation. This segmentation allows the system to switch between or combine different positioning methods depending on availability, improving adaptability while maintaining measurement precision through the use of multiple independent estimation pathways rather than relying on a single method.
Data Source
AI summary
An automotive vehicle includes an actuator configured to control vehicle steering, a sensor configured to detect a yaw rate of the vehicle, and a controller. The controller is configured to estimate a yaw rate and lateral velocity of the vehicle via a vehicle dynamics model based on a measured longitudinal velocity of the vehicle, calculated road wheel angles of the vehicle, and estimated tire slip angles of the vehicle. The controller is configured to receive a measured yaw rate from the sensor, and to calculate a difference between the measured yaw rate and the estimated yaw rate. The controller is configured to apply a model correction to the vehicle dynamics model using a PID controller based on the difference, and to estimate a vehicle position based on the estimated lateral velocity and the measured longitudinal velocity. The controller is configured to automatically control the actuator based on the vehicle position.