Dynamic Damper Control Using Magnetorheological Elastomers
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Solution Overview
Problem
Existing dynamic damper systems using magnetorheological elastomers struggle with long-term stability and effectiveness in controlling vibration frequencies due to temperature variations and manufacturing differences, making it difficult for inexpensive microcomputers to precisely adjust the spring constant and maintain accurate vibration reduction.
Innovation Solution
A dynamic damper control device utilizing a control unit with a fixed-point arithmetic unit, including a target frequency determining unit, acceleration sensors, and an elasticity properties controller, adjusts the magnetic force applied to magnetorheological elastomers based on calculated transfer function coefficients to swiftly follow target vibration frequencies, reducing the need for complex calculations and enhancing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dynamic damper uses magnetorheological elastomer to make spring constant variable, then the proper frequency can be adjusted, but the spring constant varies with temperature and time making long-term stability difficult to achieve
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors the actual vibration frequency and compares it with the target frequency, then adjusts the spring constant accordingly to maintain accurate frequency matching despite temperature variations and material property changes over time
Solution Approach 2:
The patent dynamically changes the spring constant parameter of the magnetorheological elastomer based on real-time vibration frequency measurements, allowing the system to adapt to varying operating conditions while maintaining optimal vibration reduction performance
2Reliability
If the frequency of dynamic damper is adjusted to follow detected frequency using vibration detector and displacement detector, then vibration reduction effectiveness is improved, but the calculation complexity exceeds the capability of inexpensive microcomputers
Solution Approach 1:
The patent extracts only the essential frequency information from vibration signals using a frequency detector, discarding unnecessary displacement calculation complexity, and focuses control effort solely on frequency matching which can be achieved with simpler computations suitable for inexpensive microcomputers
Solution Approach 2:
The patent replaces complex mechanical measurement systems (vibration detector and displacement detector) with a simplified frequency detection approach that uses engine speed signals and vibration frequency analysis, substituting mechanical complexity with electronic signal processing that is computationally lighter
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 enables rapid and precise adjustment of dynamic damper frequencies to match target vibrations, improving long-term stability and reducing vibration effectively without requiring expensive processors or complex calculations, thus overcoming the limitations of existing systems.
Implementation Method 1
a dynamic damper that can make the proper frequency f variable by using a magnetorheological elastomer (MRE) as a spring
Implementation Method 2
the strength of magnetic fields generated by a current flowing through a coil and applied to rubber mixed with a magnetic body is controlled, thereby making the stiffness of the rubber variable
Data Source
AI summary
A controller includes a target frequency determining unit, first and second acceleration sensors, and a predetermined variable calculator. The target frequency determining unit determines a target frequency from a vibration state of a vibration source. The first acceleration sensor obtains a first acceleration of a mass member. The second acceleration sensor obtains a second acceleration of a vibration controlled member. The predetermined variable calculator calculates a predetermined variable of a transfer function of the first acceleration with respect to the second acceleration at the target frequency. If the predetermined variable is a numeric value other than 0, the controller changes a magnetic force generated in an electromagnet.