Steer-by-Wire Rack Stroke Limiting via Dynamic Motor Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing steer-by-wire systems fail to effectively limit rack stroke during external forces, leading to potential collisions, noise, and mechanical damage, while also altering the steering feel for the driver, and existing solutions either increase production costs or disrupt the steering feel.
Innovation Solution
A steering control apparatus and method that includes a sensing information collector, a motor operation determiner, and a control signal generator to manage the reaction force motor's limiting mode based on steering and rack information, allowing for dynamic adjustment of rack stroke to prevent collisions and maintain driver convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rack end stop function is used to limit rack stroke by increasing reaction torque or applying reverse current, then the rack stroke can be limited to prevent collision, but the steering feeling for the driver changes and may increase the sense of difference when strong reverse current is applied
Solution Approach 1:
The patent applies dynamics by making the rack stroke limit dynamic rather than fixed. The control unit adjusts the rack stroke limit based on detected steering information and vehicle speed, allowing the system to adapt to different operating conditions. This resolves the contradiction by enabling rack stroke limitation while maintaining natural steering feeling through conditional adjustment rather than constant restriction.
Solution Approach 2:
The patent changes the parameter of rack stroke limit based on operating conditions (steering angle, vehicle speed). By varying the rack stroke limit parameter dynamically according to detected conditions, the system achieves both reliable rack stroke limitation and maintains appropriate steering feeling for different driving scenarios.
2Device complexity
If the same rack stroke control value is provided for a predetermined target steering angle without considering external force, then the control system is simple, but the actual steering angle may increase or decrease more than the target steering angle when external force acts on the vehicle
Solution Approach 1:
The patent implements feedback by having the control unit detect steering information and vehicle speed, then adjust the rack stroke limit accordingly. This feedback mechanism ensures that the rack stroke limitation adapts to actual operating conditions, maintaining steering angle control accuracy while accounting for external forces without requiring complex additional hardware.
3Reliability
If a strong reverse current is applied to the reaction force motor to limit rack stroke, then the rack stroke can be effectively limited, but the sense of difference of the driver's steering feeling increases
Solution Approach 1:
The patent makes the rack stroke limitation dynamic by adjusting it based on detected steering information and vehicle speed. Instead of applying strong reverse current continuously, the system dynamically adjusts the rack stroke limit, achieving effective rack stroke limitation while maintaining smooth steering feeling by avoiding excessive reverse current application.
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
This solution effectively restricts rack stroke, reducing vehicle damage and stabilizing vehicle behavior while minimizing changes in steering feel, thus enhancing driver convenience and reducing the risk of mechanical damage.
Implementation Method 1
a reaction force motor provided on one side of the steering wheel for providing a reaction torque according to the rotation for steering
Implementation Method 2
a gear box for performing a steering action by linearly moving the steering shaft
Data Source
AI summary
The present disclosure relates to a steering control apparatus and method of the steer-by-wire system including a sensing information collector for collecting at least one of sensing information on a steering or sensing information on a rack, a motor operation determiner for determining a start of a motor limiting mode for a reaction force motor and an end of the motor limiting mode for the reaction force motor which provides a reaction torque to a steering wheel based on the collected sensing information, a control signal generator for generating a control signal corresponding to the start of the motor limiting mode or the end of the motor limiting mode based on the determined result, and a control signal output for outputting the generated control signal to the reaction force motor.