Motor Driven Power Steering Torque Offset Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Motor driven power steering systems experience temporary torque offsets due to magnetic fields generated by vehicle components like starter motors, leading to steering wheel vibrations, especially in vehicles with idle stop and go systems where engine frequent startups occur.
Innovation Solution
A system and method that includes a magnetic field detection module, a torque offset determination unit, and a correction unit to identify and correct torque offsets within a predetermined range, using sensors to detect the magnetic field, engine state, vehicle speed, and steering torque, thereby applying corrected torque to prevent vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic torque sensor is used to sense steering torque, then the torque sensing capability is improved, but the sensor signal becomes distorted by peripheral magnetic fields generated by electric parts like the starter motor
Solution Approach 1:
The patent introduces a magnetic field detection module as an intermediary to detect when magnetic fields are generated by electric parts. This mediator enables the system to identify distortion conditions and trigger correction mechanisms, resolving the contradiction between using magnetic torque sensors and avoiding their susceptibility to magnetic field interference.
Solution Approach 2:
The system implements feedback by continuously monitoring magnetic field conditions and torque sensor signals. When distortion is detected through the magnetic field detection module, the system feeds back this information to the controller, which then applies correction values to compensate for the distortion, maintaining accurate torque measurement despite the presence of magnetic fields.
2Productivity
If the starter motor operates to restart the engine in an idle stop and go system, then the engine can be restarted, but a magnetic field is generated that causes torque offset and steering wheel vibration
Solution Approach 1:
The system performs preliminary action by detecting magnetic field generation before torque offset fully develops. The magnetic field detection module identifies when the starter motor operates and generates a magnetic field, allowing the system to proactively apply correction values to the torque sensor signal, preventing steering wheel vibration before it occurs.
Solution Approach 2:
The patent applies preliminary anti-action by introducing correction values that counteract the expected torque offset caused by magnetic field generation. When the magnetic field detection module detects starter motor operation, the system preemptively applies compensation to neutralize the harmful torque offset effect, maintaining steering stability during engine restart operations.
3Reliability
If torque offset correction is applied to prevent steering wheel vibration, then steering stability is improved, but the system complexity increases due to additional detection and correction mechanisms
Solution Approach 1:
The controller is designed with multi-functionality, serving both as the primary steering control unit and as the magnetic field detection module. By integrating the magnetic field detection capability into the existing controller rather than adding a completely separate system, the patent reduces overall device complexity while still achieving torque offset correction and improved steering stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents steering wheel vibrations by automatically correcting torque offsets to the normal range, even when magnetic fields distort torque sensor signals, ensuring stable steering assistance in vehicles with idle stop and go systems.
Implementation Method 1
a magnetic field generation detection module configured to detect generation of a magnetic field
Implementation Method 2
when the starter motor of the vehicle operates, the magnetic field is generated
Data Source
AI summary
A method and system for controlling motor driven power steering are provided. The system includes a magnetic field generation detection module that detects generation of a magnetic field upon operating an electric part of a vehicle and a torque offset determination unit that determines whether a temporary torque offset has occurred in a torque to be applied to a motor based on a detection signal of the magnetic field generation detection module. A torque offset correction unit then corrects the torque offset to a normal torque range based on a torque offset correction logic in response to determining that the torque offset has occurred.