Predictive Shock Absorber Stiffness Control for Vehicle Body Movements
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Solution Overview
Problem
Existing chassis control methods for motor vehicles fail to optimally adjust shock absorber stiffness in response to varying vehicle body movements, such as those caused by braking and cornering, leading to inadequate damping and reduced driving comfort.
Innovation Solution
A shock absorber system with independently adjustable compression and rebound stages, utilizing valves to increase stiffness in anticipation of compressive or tensile loads, and leveraging microcontrollers and existing vehicle control units to analyze local and global movements for predictive damping adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shock absorber uses a single stiffness setting, then the device complexity is reduced, but the damping performance during specific vehicle body movements (braking, cornering) is inadequate
Solution Approach 1:
The shock absorber is divided into two independent adjustable stages: compression stage and rebound stage. Each stage has its own valve (first valve for compression, second valve for rebound) that can be controlled independently, allowing separate optimization of damping characteristics for compression and rebound movements during vehicle body motions like braking and cornering.
Solution Approach 2:
The shock absorber transitions from a static single-stiffness design to a dynamic two-stage adjustable system. The stiffness of each stage can be changed in real-time based on detected vehicle body movements, enabling the shock absorber to adapt its damping characteristics to different driving conditions such as braking, cornering, and road irregularities.
2Reliability
If the shock absorber stiffness is adjusted during vehicle body movement, then the damping performance is optimized, but the response time is insufficient due to signal transmission and processing delays
Solution Approach 1:
The control unit predicts vehicle body movements (such as pitch during braking or roll during cornering) in advance and activates the appropriate shock absorber stages before the movements occur. This predictive approach allows the shock absorber to be pre-positioned in the optimal damping state, eliminating the delay that would occur if adjustment happened after movement detection.
3Measurement precision
If additional sensors are added to detect vehicle body movements, then the measurement precision is improved, but the device complexity and cost increase
Solution Approach 1:
The control unit leverages existing vehicle control systems and sensors that serve multiple functions. For example, sensors originally designed for other vehicle functions (such as stability control or suspension management) are repurposed to detect vehicle body movements for shock absorber control, eliminating the need for dedicated additional sensors while maintaining measurement precision.
4Adaptability or versatility
If the shock absorber uses independent compression and rebound stage adjustment, then the adaptability to different driving conditions is improved, but the manufacturing complexity increases
Solution Approach 1:
The shock absorber is divided into two independent adjustable stages: compression stage and rebound stage. Each stage has its own valve (first valve for compression, second valve for rebound) that can be controlled independently, allowing separate optimization of damping characteristics for compression and rebound movements during vehicle body motions like braking and cornering.
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
The system effectively dampens vehicle body movements during braking and cornering, enhancing driving comfort by minimizing pitch and roll oscillations without the need for additional sensors, and optimizing shock absorber performance across different load phases.
Implementation Method 1
the first valve being switched to change, in particular increase, the stiffness of the compression stage before a compressive load of the shock absorber
Implementation Method 2
the second valve being switched to change, in particular increase, the stiffness of the rebound stage during the subsequently occurring compressive load
Implementation Method 3
the stiffness of the compression stage being changed, in particular increased, for a compressive load generated by a specific vehicle body movement
Data Source
AI summary
In a method for chassis control of a motor vehicle which has at least one wheel suspension, a vehicle body, and a shock absorber having a rebound stage, whose stiffness is adjustable, and a compression stage, whose stiffness is adjustable, the stiffness of the compression stage is changed for a compressive load of the shock absorber generated by a specific vehicle body movement, and the stiffness of the rebound stage is additionally changed for a subsequently following tensile load of the shock absorber generated by the specific vehicle body movement, or the stiffness of the rebound stage is changed for a tensile load of the shock absorber generated by a specific vehicle body movement, and the stiffness of the compression stage is additionally changed for a subsequently following compressive load of the shock absorber generated by the specific vehicle body movement.