MDPS Friction Adjustment for Road Surface Adaptation
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Solution Overview
Problem
Existing motor driven power steering (MDPS) systems fail to adjust friction based on road surface conditions, leading to inadequate steering feeling, particularly on low friction surfaces like wet or snowy roads, where the steering wheel becomes too light, making it difficult to transmit optimal feedback to the driver.
Innovation Solution
A method and apparatus for detecting road surface conditions to classify them as normal, low friction, first uneven, or second uneven, and adjusting the friction of the MDPS unit by varying the supporting force of the active roll stabilizer based on these classifications, along with vehicle speed and stability management signals, to enhance steering feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If friction of the MDPS unit is kept constant with a same tuning map, then the steering system structure is simple and easy to control, but the steering feeling becomes inadequate on low friction surfaces like wet or snowy roads where the steering wheel becomes too light
Solution Approach 1:
The patent applies dynamics by making the friction of the MDPS unit adjustable rather than fixed. The control unit dynamically changes the friction level based on detected road surface conditions, allowing the steering system to adapt its characteristics to match varying external environments and maintain optimal steering feeling across different driving scenarios.
Solution Approach 2:
The patent implements parameter changes by modifying the friction parameter of the MDPS unit according to road surface conditions. The control unit adjusts friction levels based on detected conditions such as low friction surfaces (wet/snowy roads) versus high friction surfaces, thereby changing the physical parameter of friction to maintain appropriate steering feedback to the driver.
2Stability of the object's composition
If friction is increased on uneven road surfaces, then steering stability is improved, but the steering effort required from the driver increases
Solution Approach 1:
The patent applies parameter changes by adjusting the friction parameter of the MDPS unit based on detected road surface conditions. When uneven road surfaces are detected, the control unit increases friction to improve steering stability and prevent excessive steering wheel movement, while the system automatically manages the force requirement through active friction adjustment.
Solution Approach 2:
The patent implements feedback by using the control unit to detect road surface conditions and automatically adjust the friction level of the MDPS unit accordingly. This closed-loop feedback mechanism allows the system to respond to changing road conditions in real-time, maintaining optimal steering characteristics without requiring manual driver adjustment.
3Adaptability or versatility
If the MDPS unit uses a fixed friction setting, then the system is simpler and more reliable, but it cannot adapt to different road surface conditions such as wet, snowy, or unpaved roads
Solution Approach 1:
The patent applies dynamics by transforming the static friction setting into a dynamic, adjustable parameter. The control unit enables the MDPS unit to change its friction characteristics in real-time based on detected road surface conditions, allowing the system to adapt to various environments including wet roads, snowy roads, and unpaved surfaces while maintaining a relatively simple overall structure.
Data Source
AI summary
A method of adjusting friction of an MDPS unit may include detecting road surface conditions of a road on which a vehicle travels; classifying the road on which the vehicle travels into a normal road, a low frictional road, a road having a first uneven road surface, and a road having a second uneven road surface; and reducing friction of the MDPS unit of the vehicle when the road on which the vehicle travels is determined as the road having the first uneven road surface.