Steering Control Device Nonlinear Reaction Force

Solution Overview

Problem

Conventional steering devices for vehicles, particularly in steer-by-wire systems, face challenges in transmitting appropriate reaction forces to the driver during tire slip conditions, leading to excessive steering operations and reduced vehicle stability.

Innovation Solution

A steering control device that increases reaction force in nonlinear regions where the cornering force characteristic becomes nonlinear, using a microcontroller to calculate and adjust the reaction force actuator's torque based on lateral acceleration and turning torque, thereby enhancing driver feedback and vehicle stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the reaction force is increased in nonlinear region where cornering force characteristic becomes nonlinear, then the vehicle stability is improved and excessive steering operation is prevented, but the device complexity increases due to region determination logic

Engineering Contradiction:

Improvevehicle stabilityVSAvoidcontrol logic complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of reaction force magnitude based on the determined region (linear or nonlinear). When nonlinear region is detected, the reaction force is increased compared to the linear region, thereby improving vehicle stability while using a simple region-based parameter change approach

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The cornering force characteristic is segmented into two distinct regions: linear region and nonlinear region. This segmentation allows the control system to apply different reaction force strategies for each region, simplifying the control logic while effectively addressing vehicle stability in different operating conditions

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the reaction force actuator is controlled based on cornering force characteristic region, then appropriate reaction force is transmitted to driver, but the measurement precision requirement increases for detecting slip angle and lateral force

Engineering Contradiction:

Improvedriver feedback qualityVSAvoidslip angle and lateral force detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The cornering force characteristic is segmented into two distinct regions: linear region and nonlinear region. This segmentation allows the control system to apply different reaction force strategies for each region, simplifying the control logic while effectively addressing vehicle stability in different operating conditions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of reaction force magnitude based on the determined region (linear or nonlinear). When nonlinear region is detected, the reaction force is increased compared to the linear region, thereby improving vehicle stability while using a simple region-based parameter change approach

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12110072B2Steering control device

Publication Date: 2024.10.08 ASTEMO LTD

AI summary

The present disclosure provides a steering control device capable of transmitting an appropriate reaction force by a driver via a steering wheel and improving the stability of a vehicle. Provided is a steering control device 100 for controlling a reaction force actuator 16 that generates a reaction force against an operation of a driver in a steering wheel 13 of a vehicle 10. The steering control device 100 increases the reaction force in a nonlinear region where a cornering force characteristic that is the relationship between the slip angle and the lateral force of tires 11 of the vehicle 10 becomes nonlinear, more than the reaction force in a linear region where the cornering force characteristic becomes linear.