Motor-Assisted Steering Feedback for Lash Compensation
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Solution Overview
Problem
Modern vehicles lack the ability to detect steering lash and provide countermeasures, leading to inconsistent steering feel and reduced vehicle control, which compromises safety and driver predictability.
Innovation Solution
A computer system estimates steering lash level by determining the relationship between motor angle and torque, and adjusts motor torque to provide consistent steering feedback independent of lash, using electric motors and sensors to correlate wheel movement with steering feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydraulic power-assisted steering systems are used, then driver effort is reduced, but the system is difficult to tune and cannot detect steering lash
Solution Approach 1:
The system uses feedback from the electric motor's torque and angle sensors to detect steering lash conditions. The control unit continuously monitors the relationship between motor torque and angle, comparing it against predetermined relationships to identify lash levels, and adjusts motor torque accordingly to compensate for detected lash.
Solution Approach 2:
The patent replaces the purely hydraulic steering system with an electrically-operated actuator that can be controlled by a computer system. This substitution enables electronic sensing and control capabilities that were not present in traditional hydraulic systems, allowing for detection and compensation of steering lash through software-based algorithms.
2Reliability
If steering lash develops over time, then vehicle control is compromised, but the system lacks ability to detect or provide countermeasures
Solution Approach 1:
The system continuously monitors steering system conditions through feedback from torque and angle sensors. The control unit compares actual motor torque-angle relationships against predetermined relationships to detect changes in steering lash over time, enabling real-time identification of deteriorating vehicle control conditions.
Solution Approach 2:
The system performs preliminary detection of steering lash conditions by continuously monitoring motor torque and angle relationships. By identifying lash development early in its progression, the system can take preemptive corrective action through motor torque adjustment before steering lash severely compromises vehicle control.
3Ease of operation
If different drivers react differently to steering lash, then predictability is reduced, but the system cannot adapt to individual driver preferences
Solution Approach 1:
The system adjusts motor torque parameters dynamically based on detected steering lash conditions. By modifying the torque output in response to measured lash levels, the system standardizes steering feedback across different driving conditions and drivers, creating more predictable steering characteristics regardless of individual driver reactions or preferences.
Data Source
AI summary
A computer system includes processing circuitry configured to obtain motor angle and estimate motor toque of an electric motor of a steering system of a vehicle in motion, determine a relationship between the estimated motor torque and the obtained motor angle, estimate a steering lash level by comparing the determined relationship to predetermined relationships indicative of lash level, and modify motor torque based on the estimated steering lash level to adjust steering feedback supplied by the electric motor to a steering wheel of the vehicle. Adjustment of steering feedback responsive to the estimated steering lash level permits torque build-up to a driver of a vehicle to be applied independent of steering lash.