Suspension Control Device Road Surface Adaptation
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Solution Overview
Problem
Existing suspension control devices fail to appropriately control damping force in accordance with varying road surface conditions, affecting vehicle stability and ride comfort.
Innovation Solution
A suspension control device that includes a road surface determining section and a control variable calculating section, which calculates a steering-based desired control variable using a threshold setting section, multiplying section, and selecting section, referencing steering torque signals to adjust damping force based on road surface conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the damping force is controlled based on steering torque only, then the suspension responds to driver input, but it fails to adapt to varying road surface conditions
Solution Approach 1:
The control system dynamically adjusts the damping force control strategy based on detected road surface conditions. When rough road surfaces are detected, the system switches to a control mode that prioritizes ride comfort over steering responsiveness, and vice versa for smooth surfaces. This dynamic adaptation allows the system to handle varying road conditions effectively without requiring completely separate control systems for different scenarios.
Solution Approach 2:
The system changes the control parameters (damping force characteristics) based on detected road surface conditions. By modifying the damping force calculation parameters according to the roughness level, the system achieves adaptability to different road surfaces while using the same fundamental control structure, thus balancing adaptability with acceptable system complexity.
2Reliability
If the damping force is increased to handle rough roads, then ride comfort improves, but steering responsiveness deteriorates
Solution Approach 1:
The system dynamically adjusts damping force characteristics based on real-time road surface detection. When rough roads are detected, the system increases damping force to improve ride comfort. When smooth roads are detected, it reduces damping force to maintain steering responsiveness. This dynamic adjustment allows the system to optimize for either ride comfort or steering responsiveness depending on current road conditions, rather than being fixed at one setting.
Solution Approach 2:
The control system continuously monitors road surface conditions and periodically adjusts damping force characteristics accordingly. This periodic reevaluation and adjustment allows the system to maintain optimal performance by switching between comfort-oriented and responsiveness-oriented damping characteristics as road conditions change during vehicle operation.
3Measurement precision
If multiple control variables are calculated and selected, then control precision improves, but calculation complexity increases
Solution Approach 1:
The control variable calculation is segmented into multiple candidate calculations, each optimized for different road surface conditions. The system calculates multiple potential control variables (first candidate, second candidate, etc.) and then selects the most appropriate one based on detected road conditions. This segmentation allows precise control for each condition type while keeping the selection logic relatively simple.
Solution Approach 2:
The system uses feedback from road surface detection to select the appropriate control variable from multiple candidates. The detection result feeds back into the control variable selection process, allowing the system to choose the most suitable control variable based on current conditions. This feedback mechanism enables precise control adaptation without requiring complex real-time calculations for all possible scenarios simultaneously.
Data Source
AI summary
A road surface condition is determined appropriately. A road surface determining section (84) configured to determine a road surface state includes a threshold setting section (845) configured to set a threshold for determining the road surface state, so that a value of a desired control variable is multiplied by a coefficient determined in accordance with a result of the determination by the road surface determining section (84).