Rack Force Observer Diagnostics for Autonomous Steering Accuracy
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Solution Overview
Problem
Existing autonomous vehicle steering systems face challenges in accurately compensating for external disturbances and internal component failures that affect steering accuracy and safety, particularly in dynamic driving conditions.
Innovation Solution
An electronic steering system with a rack force observer and diagnostic module that measures and compensates for steering rack forces using sensors and actuators, integrating data from various vehicle systems to estimate and adjust steering angles for improved safety and maintenance signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional steering systems are used in autonomous vehicles, then the system structure is simple, but steering accuracy deteriorates under external disturbances and internal failures
Solution Approach 1:
The patent introduces a rack force observer as an intermediary component that estimates rack force using motor current and position data without requiring direct force sensors. This mediator enables accurate disturbance detection while avoiding the complexity of direct measurement systems
Solution Approach 2:
The patent replaces direct mechanical force measurement with an observer-based estimation system that uses electrical and positional data to infer mechanical rack force, substituting complex mechanical sensing with computational estimation
2Reliability
If no rack force monitoring is implemented, then the system is simple to operate, but reliability deteriorates due to inability to detect disturbances and failures
Solution Approach 1:
The rack force observer performs self-diagnosis by monitoring motor current and position data to detect disturbances and failures automatically, enabling the system to monitor its own health without requiring external intervention or complex operator procedures
Solution Approach 2:
The patent implements continuous feedback through the rack force observer that monitors steering behavior and provides real-time detection of disturbances and failures, enabling proactive safety responses without complicating system operation
3Measurement precision
If comprehensive sensor integration is implemented for disturbance detection, then measurement precision improves, but device complexity increases
Solution Approach 1:
The rack force observer serves multiple functions simultaneously: it estimates rack force for disturbance detection, monitors system health for failure detection, and provides diagnostic information, allowing one component to perform multiple measurement tasks without requiring separate dedicated sensors for each function
Data Source
AI summary
A number of illustrative variations may include a method for use in a vehicle having an electronic steering system, a position control module, an electronic steering system rack force observer, and a rack force observer vehicle diagnostic, wherein the method includes the steps of providing a vehicle that may include an electronic steering system, a position control module, an electronic steering system rack force observer, and a rack force observer vehicle diagnostic; measuring the steering angle and steering velocity of the vehicle; communicating a steering angle of the vehicle to the position control module and the electronic steering system rack force observer; communicating a steering velocity of the vehicle to the electronic steering system rack force observer; communicating electronic steering system motor commands to the electronic steering system rack force observer; and estimating rack force data and communicating the rack force data to the rack force observer vehicle diagnostic; and determining a compensated target steering angle.