Electromagnetic Damper Velocity-Adaptive Filter Control
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Solution Overview
Problem
Electromagnetic damper systems that rely solely on electric motors for vibration damping face challenges in reducing operating sounds at high frequencies and delayed vibration damping responses at high input velocities, which can compromise vehicle riding comfort.
Innovation Solution
An electromagnetic damper system that includes a relative velocity detection unit, a filter unit with adjustable gain characteristics, and a target vibration damping force determining unit, which uses a normal filter at low velocities and a delay inhibition filter at high velocities to enhance damping force response without delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a filtering process is applied to the target vibration damping force in the high frequency range to reduce motor operating sounds, then the operating sound is suppressed, but the vibration damping force is produced too late for high input velocity vibrations
Solution Approach 1:
The filter characteristics are made dynamically adjustable based on the vibration input velocity. When vibration input velocity exceeds a threshold, the filter switches to a second set of characteristics with lower attenuation in the high frequency range, enabling timely response to high-velocity vibrations while maintaining noise suppression during normal operation
Solution Approach 2:
The filtering parameters (gain characteristics) are changed based on the detected vibration input velocity. The system transitions between different filter configurations depending on whether the input velocity is below or above the threshold, optimizing the balance between noise reduction and response speed
2Volume of moving object
If only an electromagnetic damper is used to reduce system size, then the damper system size is reduced, but motor operating sounds occur in the high frequency range
Solution Approach 1:
A filtering process is introduced as an intermediary between the motor and the vibration damping force output. The filter attenuates high frequency components of the motor operating sound while preserving the essential vibration damping function, allowing the electromagnetic damper to operate without hydraulic components
Solution Approach 2:
The traditional hydraulic damper system is replaced with an electromagnetic damper system. The electromagnetic damper uses motor-driven mechanical advantage to produce vibration damping forces, eliminating the need for hydraulic fluid and components, though introducing motor operating sounds that are managed through filtering
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 suppresses motor operating sounds at low velocities and reduces time delays in high-frequency ranges, ensuring timely activation of vibration damping forces even at high input velocities, thereby improving vehicle riding comfort.
Implementation Method 1
an electromagnetic damper that produces a vibration damping force by a driving force of an electric motor
Implementation Method 2
a filter unit that performs a filtering process of increasing a gain characteristic of an unsprung resonance frequency range and of decreasing gain characteristics of other frequency ranges
Data Source
AI summary
A relative velocity between a sprung mass and an unsprung mass of a vehicle is calculated by differentiating a stroke amount of an electromagnetic damper with respect to time. The relative velocity is compared with a predetermined value that is set in advance, and a determination is made whether or not the relative velocity is the predetermined value or higher. In a case where the relative velocity is lower than the predetermined value (relative velocity<predetermined value), a normal filter is selected, and a gain G of only an unsprung resonance frequency range is increased. On the other hand, in a case where the relative velocity is the predetermined value or higher (relative velocity≥predetermined value), a delay inhibition filter is selected, and a gain of a high frequency range is increased compared to the normal filter.