Vehicle Steering Control via Side Slip Angle Estimation
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Solution Overview
Problem
Existing vehicle steering systems, particularly motor-driven power steering (MDPS) systems, face challenges in enhancing the sense of unity between driver input and vehicle motion and stability by effectively controlling the side slip angle during vehicle travel.
Innovation Solution
An apparatus and method that include an assist torque determination module, return control module, side slip angle estimation module, side slip control module, correction unit, and torque compensation unit, which work together to determine and adjust assist torque and steering return torque based on driver input and vehicle state information to manage side slip angles, thereby improving steering system control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional MDPS systems control steering assist force based on driver input and basic vehicle state, then steering assist function is provided, but the sense of unity between driver input and vehicle motion is insufficient and vehicle stability is not optimized
Solution Approach 1:
The patent implements feedback control by continuously monitoring the side slip angle and using it to adjust the steering return torque. The controller receives feedback from sensors measuring vehicle state parameters and dynamically adjusts the motor output torque to maintain optimal side slip angle, thereby improving vehicle stability through closed-loop control.
Solution Approach 2:
The patent introduces side slip angle as an intermediary parameter that mediates between driver steering input and vehicle motion response. By estimating and controlling the side slip angle, the system optimizes the relationship between driver intent and actual vehicle behavior, enhancing the sense of unity without requiring direct complex control of multiple vehicle parameters.
2Ease of operation
If side slip angle control is added to the steering system, then vehicle stability and sense of unity are improved, but the control system complexity increases
Solution Approach 1:
The patent replaces complex mechanical steering linkages with an electric motor-driven system that provides precise control through electronic actuation. The motor-driven power steering mechanism substitutes traditional hydraulic or mechanical force multiplication systems, allowing for more flexible and programmable control strategies to achieve desired steering feel and vehicle stability.
Solution Approach 2:
The patent dynamically changes control parameters including motor output torque, steering return torque, and side slip angle targets based on vehicle operating conditions. The controller adjusts these parameters in real-time according to speed, steering angle, and estimated side slip angle, optimizing steering characteristics across different driving scenarios without requiring physical system changes.
3Speed
If the steering return torque is increased to improve returnability, then the steering wheel returns to center faster, but the sense of unity between driver input and vehicle motion deteriorates
Solution Approach 1:
The patent implements dynamic control of steering return torque that adapts to vehicle speed and steering conditions. At lower speeds where quick return is beneficial, the system provides stronger return torque. At higher speeds where vehicle stability and coherence are paramount, the system reduces return torque and uses side slip angle control to maintain stable vehicle motion, thereby balancing returnability with motion coherence.
Data Source
AI summary
An apparatus and a method for controlling a vehicle steering system, which are capable of improving a sense of unity between driver's driving input and vehicle motion and the stability of the vehicle by estimating a side slip angle and performing return control, may include an assist torque determination module for determining assist torque for steering assist, a return control module for determining steering return torque for returning the steering wheel to a neutral position, a side slip angle estimation module for estimating a side slip angle, a side slip control module for determining a return control gain value in a response to the estimated side slip angle, a correction unit of correcting the determined steering return torque in a response to the return control gain value, and a torque compensation unit of determining final assist torque by compensating the determined assist torque with the corrected steering return torque.