Steering Control Device Curvature Offset
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Solution Overview
Problem
Existing steering control devices cause discomfort to drivers due to changes in steering reaction force characteristics related to self-aligning torque, especially during curved driving.
Innovation Solution
A steering control device that calculates an increasing offset amount with curvature and sets a steering reaction force characteristic with coordinate axes of self-aligning torque and steering reaction force, offsetting the characteristic in the same direction as the self-aligning torque to maintain the steering reaction force, thereby reducing discomfort by minimizing changes in steering torque during curved driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the steering reaction force characteristic is changed with respect to the self-aligning torque to reduce steering load during curved driving, then the steering ease is improved, but the driver experiences discomfort due to unnatural steering feedback
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the steering reaction force characteristic based on curvature. Specifically, the steering reaction force characteristic is offset by an offset amount that increases as curvature increases, transforming the fixed characteristic into a dynamically adjustable one that adapts to driving conditions, thereby reducing steering load while maintaining natural feedback
Solution Approach 2:
The patent implements dynamics by making the steering reaction force characteristic variable rather than fixed. The characteristic changes dynamically according to the vehicle's curvature, with the offset amount being adjusted in real-time based on curvature detection, allowing the system to adapt to different driving scenarios and maintain optimal steering feel
2Speed
If the steering reaction force is reduced during curved driving to improve steering responsiveness, then the steering sensitivity is improved, but the steering stability deteriorates
Solution Approach 1:
The patent uses parameter changes to dynamically adjust the steering reaction force characteristic based on curvature. By offsetting the characteristic by an amount that increases with curvature, the system achieves faster steering response during turns while maintaining stability through the structured relationship between offset amount and curvature
Solution Approach 2:
The patent implements feedback by continuously monitoring curvature and adjusting the steering reaction force characteristic accordingly. The system detects curvature, calculates the appropriate offset amount, and applies it to the steering reaction force characteristic, creating a closed-loop control that maintains both responsiveness and stability
Data Source
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AI summary
The present invention comprises a steering unit 1 that receives steering input from a driver and is mechanically separated from a turning unit 2 that turns a left and a right front wheel (5FL, 5FR) (the turnable wheels); a steering reaction force control unit 20 that sets a steering reaction force characteristic to coordinates, of which the coordinate axes are the self-aligning torque and the steering reaction force, so that the self-aligning torque increases as the steering reaction force increases, and the control unit applies the steering reaction force to the steering unit 1 based on the steering reaction force characteristic; a curvature calculation unit 34a that detects the curvature of a white line; a lateral force offset unit 34 (an offset means) that calculates an offset amount that increases as the detected curvature increases and offsets the steering reaction force characteristic at the coordinates only by the offset amount in the same coding direction as the self-aligning torque; a lateral acceleration inference unit 342 (a lateral acceleration detection means) that detects the lateral acceleration of a vehicle; and a limiter processing unit 34e (an offset suppression means) that suppresses a change in the lateral force offset amount more as the detected steering torque in the curve direction increases.