Steering Torque Loss Correction Using Roll Rate Feedback
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Solution Overview
Problem
Existing steering control devices that apply assist or reaction torque to steering members often cause discomfort to drivers due to inadequate torque management.
Innovation Solution
A steering control device with a torque loss estimation unit and a correction amount calculation unit that estimates torque loss based on rack axial force and roll rate, allowing for the application of assist or reaction torque with reduced driver discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If assist torque or reaction torque is applied to steering member using conventional estimation methods, then steering assistance is provided, but driver discomfort occurs due to inaccurate torque loss estimation
Solution Approach 1:
The patent changes the parameters used for torque loss estimation from conventional methods (steering angle and vehicle speed only) to include roll rate as an additional parameter. The correction amount calculation unit calculates a correction value based on roll rate and applies it to the estimated torque loss, thereby improving estimation accuracy and reducing driver discomfort during steering operations.
2Device complexity
If simple torque estimation based on steering angle and vehicle speed is used, then device complexity is reduced, but torque loss estimation accuracy deteriorates
Solution Approach 1:
The patent adds roll rate as an additional parameter to the torque loss estimation without fundamentally changing the control system architecture. The correction amount calculation unit processes the roll rate data and applies a correction value to the existing estimation, achieving improved accuracy while maintaining relatively simple device complexity.
Data Source
AI summary
A steering control device which applies an assist torque or a reaction torque to a steering member operated by a driver, includes: a torque loss estimation unit which estimates torque loss; and a correction amount calculation unit which calculates a correction amount according to a rack axial force estimation value calculated based on a roll rate when the torque loss estimation unit estimates the torque loss.