Electric Power Steering Torque Steer Compensation

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Solution Overview

Problem

Torque steering in front-wheel drive vehicles with horizontally mounted engines causes steering issues due to engine torque affecting wheel grip, leading to vehicle deviation, and existing solutions like auxiliary drive shafts or suspension changes increase complexity and cost.

Innovation Solution

An electric power steering control method and system that measures vehicle and steering operation states to determine compensation torque based on wheel speed differences, outputting a signal to adjust steering to compensate for torque steering without adding parts, using sensors for engine torque, vehicle speed, steering angle, and wheel speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If auxiliary drive shaft or suspension structure changes are applied to suppress torque steering, then torque steering is suppressed, but device complexity and cost increase due to increased number of parts

Engineering Contradiction:

Improvetorque steering suppressionVSAvoidnumber of parts

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical solutions (auxiliary drive shaft, suspension structure changes) with an electronic control system. The controller detects wheel speed differences and generates compensation torque signals to the electric power steering, achieving torque steering suppression through electronic control rather than mechanical modifications.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary control system between the engine and the steering mechanism. The controller acts as a mediator that processes wheel speed sensor signals and generates compensation torque commands to the electric power steering motor, indirectly addressing the torque steering issue without direct mechanical intervention.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If auxiliary drive shaft or suspension structure changes are applied to suppress torque steering, then torque steering is suppressed, but cost and weight increase due to increased number of parts

Engineering Contradiction:

Improvetorque steering suppressionVSAvoidvehicle weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces heavy mechanical components (auxiliary drive shaft, modified suspension structures) with a lightweight electronic control system. The controller and sensors add minimal weight compared to the mechanical alternatives, while achieving the same torque steering suppression function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the torque steering suppression function from the mechanical domain and relocates it to the electronic control domain. By separating the detection function (wheel speed sensors) from the execution function (electric power steering motor), the system achieves weight reduction while maintaining effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

3Power

If excessive torque is transferred to driving wheel through large gear ratio, then engine torque is effectively transmitted, but torque steering becomes significant

Engineering Contradiction:

Improveengine torque transmissionVSAvoidtorque steering effect

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback control mechanism where wheel speed sensors continuously monitor the speeds of left and right front wheels. The controller compares these speeds, detects differences caused by torque steering, and generates compensation torque signals to counteract the effect, maintaining effective power transmission while suppressing harmful torque steering.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary anti-action by detecting wheel speed differences before they result in significant vehicle deviation. The controller generates compensation torque in advance to counteract the torque steering effect, preventing the harmful effect from fully manifesting rather than correcting it after the fact.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS10807634B2Control method for electric power steering and control system for electric power steering

Publication Date: 2020.10.20 HYUNDAI MOTOR CO LTD

AI summary

An electric power steering control method includes: measuring an operation state of a vehicle and determining whether the operation state of the vehicle corresponds to a sudden start-up condition; measuring a steering operation state and determining whether the steering operation state corresponds to a torque steer compensation control condition; determining a compensation torque according to a speed difference between left and right front wheels when the sudden start-up condition and the torque steer compensation control condition are satisfied; and outputting a compensation torque signal to an electric power steering according to the determined compensation torque.