Steering Control Device for Impact Suppression

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Solution Overview

Problem

Existing turning control systems fail to effectively suppress impact and abnormal noise due to end-abutting at high turning velocities without compromising the minimum turning radius, leading to uncomfortable driving experiences.

Innovation Solution

A turning control device with a first steering angle detection unit, a first actuator, a second steering angle detection unit, a target steering angle calculation unit, a steering angular displacement calculation unit, a steering angle correction value calculation unit, a steering angle correction value limiting unit, and a steering angle control unit, which calculates and adjusts the steering angle correction values based on the steering state and angular velocity to prevent excessive turning angle increases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If steering reaction force is rapidly generated to suppress end-abutting, then impact and abnormal noise are reduced, but the minimum turning radius increases and handling deteriorates

Engineering Contradiction:
Improveimpact and abnormal noiseVSAvoidhandling
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the steering angle correction value variable based on steering state and angular velocity. The correction value is dynamically adjusted: when the driver further turns the steering wheel, a larger correction value is applied to suppress end-abutting impact, while when the driver returns the steering wheel, a smaller correction value is applied to maintain responsive handling and minimum turning radius.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by adjusting the steering angle correction value based on steering angular velocity and steering state. The correction value is modified according to the magnitude of angular velocity and the direction of steering operation, allowing the system to optimize between impact suppression and handling performance under different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If steering angle correction value is increased to suppress end-abutting impact, then abnormal noise is reduced, but the steering responsiveness decreases

Engineering Contradiction:
Improveabnormal noiseVSAvoidsteering responsiveness
Core Design Contradiction:
Object-generated harmful factorsVSSpeed

Solution Approach 1:

The system dynamically adjusts the steering angle correction value based on real-time steering angular velocity and steering state detection. When abnormal noise occurs during further turning, a larger correction value is applied to suppress the noise. When the steering wheel is being returned, a smaller correction value maintains steering responsiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent detects steering state and angular velocity in advance to determine the appropriate correction value before end-abutting occurs. By preliminarily identifying the steering condition, the system can apply the suitable correction value to prevent abnormal noise while maintaining responsiveness.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3858719B1Steering control device
Publication Date: 2022.11.16 NSK LTD
  • EP3858719B1 patent drawingFigure 1
  • EP3858719B1 patent drawingFigure 2
  • EP3858719B1 patent drawingFigure 3~4

AI summary

A turning control device includes: a target steering angle calculation unit (30) configured to calculate a target steering angle (θsr0) of a turning mechanism, based on at least a second steering angle (θh) of a steering mechanism; a steering angular displacement calculation unit (31) configured to, when a third steering angle that is either a first steering angle (θs) of the turning mechanism or the second steering angle (θh), is in an angular range from a maximum steering angle that the third steering angle can take to a first threshold steering angle, calculate a steering angular displacement (θr) of the third steering angle with the first threshold steering angle used as a reference; a steering angle correction value calculation unit (32) configured to calculate a steering angle correction value (Δθ) according to at least the steering angular displacement (θr); a steering angle correction value limiting unit (43) configured to limit the steering angle correction value (Δθ) according to at least a steering state, angular velocity (ω) of the third steering angle, and the third steering angle; a corrected target steering angle calculation unit (33) configured to correct the target steering angle (θsr0) with a limited steering angle correction value (Δθa).