Steering-Pull Compensation Device for Asymmetrical Drive Trains

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Solution Overview

Problem

Vehicles with asymmetrical drive trains experience undesirable skewing effects due to gimbal reaction torques from unequal deflection angles of drive shafts, causing steering issues, especially noticeable during quick starts.

Innovation Solution

A device that compensates for skewing effects by using existing vehicle parameters, such as engine torque, deflection angles, and steering wheel variables, to generate a correction signal that adjusts the steering torque or angle, eliminating the need for additional sensors and continuous operation evaluation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a transverse engine with asymmetrical drive train is used, then the engine layout is compact and efficient, but gimbal reaction torques cause unwanted steering effects

Engineering Contradiction:
Improveengine layout compactnessVSAvoidgimbal reaction torque steering effects
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The control device calculates a compensating steering torque based on engine torque and deflection angle difference before the steering effect occurs, then applies this compensating torque through the steering actuator to counteract the harmful gimbal reaction torques on the wheel carriers

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention introduces a control device as an intermediary that receives engine torque signals and deflection angle information, processes them to calculate compensating torque, and transmits control signals to the steering actuator to mediate between the engine's asymmetrical drive and the steering system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If additional sensors are added to measure skewing effects, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improveskewing effect detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses existing vehicle sensors (engine torque sensors and deflection angle sensors already present for other functions) to provide the necessary measurement data for skewing effect compensation, eliminating the need for additional dedicated sensors and maintaining system self-sufficiency

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention makes existing sensors serve multiple functions: engine torque sensors originally for power management now also provide data for skewing compensation, and deflection angle sensors originally for suspension control now also enable steering torque calculation, achieving multi-functionality without additional hardware

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If continuous driving operation evaluation is implemented, then correction accuracy improves, but processing time and energy consumption increase

Engineering Contradiction:
Improvecorrection signal accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The control device continuously monitors and evaluates driving operation parameters (engine torque, deflection angles) in advance to determine when skewing effects are likely to occur, preparing compensating torque calculations before actual steering corrections are needed, thus reducing real-time processing delays

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP1767437B1Steering-pull compensation device for motor vehicle
Publication Date: 2011.09.14 VOLKSWAGEN AG
  • EP1767437B1 patent drawingFigure 1
  • EP1767437B1 patent drawingFigure 2

AI summary

The device computes a correction signal (S k) from a parameter (K m), which represents a driving torque of a vehicle, a parameter (K k), which represents deflection state of driven vehicle wheels, and a steering-wheel parameter (K l), where the wheel parameter is a function of a steering wheel angle, an angular speed steering wheel and a steering wheel torque. The correction signal compensates an asymmetrical deflection behavior of drive shafts of drive strand, and superposes an input signal (S l) of an electromechanical steering system (1), where the shafts are guided to vehicle wheels.