Skyhook Chassis Damping for Critical Bump Body Motion
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Solution Overview
Problem
Existing active chassis systems for motor vehicles face challenges in effectively damping body movements over bumps without compromising driving comfort, as high damping values required for skyhook control lead to noticeable deterioration in comfort, and forward-looking sensor systems are complex and prone to errors.
Innovation Solution
The method involves selectively increasing the skyhook damping value only when critical body movements are anticipated by classifying spring deflection speeds and using a critical skyhook damping value significantly higher than normal, eliminating the need for complex sensor data processing and ensuring robust damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high skyhook damping values are used to damp body movements over bumps, then damping effectiveness is improved, but driving comfort deteriorates
Solution Approach 1:
The skyhook damping value is made dynamically adjustable based on road conditions. The control unit increases the damping value to a critical level only when bumps are detected by the forward-looking sensor system, and maintains normal lower damping values during regular driving, allowing the system to adapt its characteristics to different operating conditions
Solution Approach 2:
The damping parameter is changed selectively based on detected road conditions. When the sensor system identifies upcoming bumps, the skyhook damping value parameter is increased from normal levels to critical levels to provide effective damping, then reduced back to normal levels afterward to restore comfort
2Loss of time
If forward-looking sensor systems are used to determine road height profile, then bump anticipation capability is improved, but system complexity increases
Solution Approach 1:
The forward-looking sensor system serves multiple functions: it provides early warning of upcoming bumps for anticipation control, and also provides input for the classification system that determines when to activate critical damping values, making the sensor system more versatile and justifying its complexity through multiple uses
3Loss of time
If forward-looking sensor systems are used to determine road height profile, then bump detection capability is improved, but measurement precision deteriorates
Solution Approach 1:
The classification system acts as an intermediary between the forward-looking sensor system and the chassis control system. It processes the sensor data to determine whether detected road features represent critical bumps requiring high damping or normal variations, filtering out false positives and improving the reliability of control activation
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 approach provides effective damping of body movements over bumps with minimal impact on driving comfort, reducing the need for complex sensor systems and preventing erroneous activations, offering a robust and comfortable driving experience comparable to forward-looking sensor systems.
Implementation Method 1
body movements of the motor vehicle body resulting from bumps in the road are damped using the skyhook damping value dsky
Data Source
AI summary
A method for operating a chassis of a motor vehicle according to the principle of a skyhook control, the chassis having at least one adjustable damper according to which body movements of the motor vehicle body resulting from road bumps are damped using the skyhook damping value (dsky). When driving over a road bump, a classification is made as to whether a critical body movement of the motor vehicle body is to be expected, and that in case of a classification as a critical body movement, the critical classified body movement is compensated for using a stored critical skyhook damping value (dsky-crit) which is greater than the skyhook damping value (dsky).