Steering Assist System Transient Steady-State Compensation
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Solution Overview
Problem
Existing steering systems struggle to maintain directional stability in vehicles due to transient conditions like road crowns and crosswinds, as well as steady-state factors such as chassis misalignment and inconsistent tire inflation, requiring drivers to make continuous corrections and compromising steering feel.
Innovation Solution
A steering assist system with separate modules for transient and steady-state compensation, using a baseline assistance force to determine and apply counter-torques, along with a steering-feel module for consistent haptic feedback, to reduce steering effort and maintain a straight path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single power assist unit is used to compensate for all directional instability, then steering effort is reduced, but steering feel consistency deteriorates due to mixing transient and steady-state disturbances
Solution Approach 1:
The patent segments the directional instability compensation into two separate modules: a transient disturbance compensation module for rapidly changing conditions (road crown, crosswinds) and a steady-state disturbance compensation module for persistent conditions (chassis misalignment, tire inflation). This segmentation allows each module to be optimized for its specific disturbance type, maintaining consistent steering feel while reducing overall steering effort.
2Reliability
If power steering systems apply steering assist force to eliminate drift and pull, then directional stability improves, but system complexity increases
Solution Approach 1:
The patent divides the steering assist system into distinct functional modules: a baseline assistance module for normal steering support, a transient disturbance compensation module for temporary road/environmental conditions, and a steady-state disturbance compensation module for persistent mechanical issues. This modular segmentation improves directional stability while keeping each module's complexity manageable and independent.
Solution Approach 2:
The patent introduces a controller as an intermediary that receives inputs from multiple sensors (steering wheel angle sensor, lateral acceleration sensor, yaw rate sensor) and coordinates the output of different compensation modules. This intermediary manages the complexity by centralizing the integration logic and simplifying the interaction between modules.
3Reliability
If steering assist systems compensate for all directional instability, then path maintenance improves, but unnecessary assist force application occurs reducing driver control
Solution Approach 1:
The patent applies different compensation strategies to different types of disturbances based on their local characteristics. The transient disturbance compensation module actively compensates for rapidly changing conditions to maintain path, while the steady-state disturbance compensation module provides subtle corrections for persistent issues. This localized approach to different disturbance types maintains path accuracy while preserving appropriate driver control.
Solution Approach 2:
The patent employs multiple sensors providing feedback about vehicle state (steering wheel angle, lateral acceleration, yaw rate) to the controller. This feedback mechanism allows the system to distinguish between driver-intended steering inputs and actual disturbances requiring compensation, ensuring path maintenance without unnecessary assist force that would interfere with driver control.
Data Source
AI summary
A steering assist system for a vehicle comprises a steering assist module configured to determine a baseline assistance force to be applied to a steering system of the vehicle, and a transient disturbance compensation module configured to determine a transient compensation force to compensate for transient conditions that urge the vehicle to deviate from a straight path. The transient compensation force is based at least partially on the determined baseline assistance force. The system also includes a steady-state disturbance compensation module configured to determine a steady-state compensation force to compensate for steady-state conditions that urge the vehicle to deviate from the straight path, the steady-state compensation force being based at least partially on the determined baseline assistance force. Methods relate to controlling steering systems.