Active Suspension Gain Tuning Across Road Vibration Frequencies
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Solution Overview
Problem
Existing vehicle suspension control systems struggle to effectively adjust the balance of control gains between displacement, velocity, and acceleration terms, leading to inadequate vibration damping, especially when encountering varying frequency components from road surface inputs.
Innovation Solution
A vehicle suspension control device and method that utilize an actuator and electronic control unit to apply control forces based on a required control amount including displacement, velocity, and acceleration terms, with a calculation process to determine control gains for each frequency band, increasing gains for damping effects and decreasing gains for excitation effects, thereby optimizing vibration reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control gain is simply reduced when the magnitude of a frequency component increases, then the decrease in vibration damping effect is reduced, but it is not possible to appropriately adjust the balance of control gains between displacement, velocity, and acceleration terms
Solution Approach 1:
The control gain adjustment is segmented by frequency band and by control term type. The ECU calculates the magnitude of frequency components in multiple frequency bands, identifies the specific frequency band with the largest magnitude, and then selectively adjusts control gains for different control terms (displacement, velocity, acceleration) based on their vibration damping or excitation effects in that specific frequency band. This segmented approach allows independent optimization of each control term's gain rather than applying a uniform reduction to all terms.
Solution Approach 2:
The control gains are made dynamic and adaptive rather than fixed. The ECU continuously monitors road surface vibration information, calculates frequency component magnitudes in real-time, and dynamically adjusts the control gains of displacement, velocity, and acceleration terms according to the identified specific frequency band. This dynamic adjustment enables the system to optimize vibration damping performance adaptively under varying road conditions while maintaining appropriate balance between different control terms.
2Reliability
If a required control amount with multiple control terms is used to reduce sprung structure vibration, then the vibration damping capability is improved, but the balance between control gains of different terms cannot be appropriately adjusted
Solution Approach 1:
The system implements feedback control by continuously monitoring road surface vibration information, calculating the magnitude of frequency components in multiple frequency bands, identifying the specific frequency band with the largest magnitude, and using this feedback to determine appropriate control gains for displacement, velocity, and acceleration terms. This feedback mechanism enables automatic and appropriate balance adjustment among control terms based on actual vibration conditions, improving vibration damping capability while managing control complexity through systematic gain determination.
3Reliability
If control gains are increased for vibration damping effect in the specific frequency band, then the damping performance is improved, but vibration excitation in the same frequency band may increase
Solution Approach 1:
The control gain adjustment applies local quality by treating different control terms differently based on their specific effects in the identified frequency band. For each control term (displacement, velocity, acceleration), the system evaluates whether it has a vibration damping effect or a vibration excitation effect in the specific frequency band, and then selectively increases or decreases its control gain accordingly. This localized, term-specific gain adjustment optimizes damping performance while minimizing vibration excitation rather than applying uniform gain changes to all control terms.
Data Source
AI summary
A vehicle suspension control device includes: an actuator configured to apply a control force in a vertical direction between an unsprung structure and a sprung structure; and an electronic control unit configured to control the actuator so as to generate the control force according to a required control amount for reducing vibration of the sprung structure. The required control amount includes at least two control terms of a displacement term, a velocity term, and an acceleration term related to displacement, velocity, and acceleration of the sprung structure. The electronic control unit calculates a magnitude of a frequency component of each of a plurality of frequency bands included in road surface vibration information, and determines a control gain of each of the at least two control terms so as to change based on the magnitude of the frequency component of each of the plurality of frequency bands.