Piezoelectric Sensor Layout for Low-Frequency Vibration Control
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Solution Overview
Problem
Existing vibration control systems using piezoelectric element actuators and sensors amplify vibrations in frequencies less than 100 Hz, leading to noise generation when feedback gain is increased for effective vibration control.
Innovation Solution
A plate-like member vibration control device with piezoelectric element actuators and sensors arranged to induce anti-resonance in the output voltage at frequencies less than a predetermined value, preventing vibration amplification and noise generation, while allowing increased feedback gain for effective vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback gain is increased to improve vibration control effectiveness, then vibration suppression performance is improved, but vibration amplification occurs in frequency range of 100 Hz or less generating noise
Solution Approach 1:
The patent changes the physical parameters of the piezoelectric element sensor, specifically its width and position relative to the actuators, to modify its frequency response characteristics. By adjusting these parameters, the sensor's anti-resonance frequency is shifted to occur below 100 Hz, which prevents the amplification of low-frequency vibrations when feedback gain is increased, thereby resolving the contradiction between vibration control effectiveness and noise generation
Solution Approach 2:
The patent utilizes the anti-resonance phenomenon of the piezoelectric element sensor to prevent vibration amplification. By designing the sensor's mechanical and electrical characteristics such that its anti-resonance frequency occurs below 100 Hz, the system naturally attenuates low-frequency vibrations in the feedback loop, allowing high feedback gain to be applied without causing noise-generating vibration amplification in the 100 Hz or less frequency range
2Reliability
If feedback gain is set to large value to enhance vibration control amount, then vibration suppression is improved, but vibration amplification occurs in frequency range of 100 Hz or less
Solution Approach 1:
The patent modifies the physical parameters of the piezoelectric element sensor (width and position) to change its frequency response characteristics. This parameter adjustment shifts the anti-resonance frequency to below 100 Hz, creating a natural attenuation zone that prevents vibration amplification in the low-frequency range even when large feedback gain is applied, thus improving vibration suppression without compromising stability
3Object-generated harmful factors
If piezoelectric element sensor and actuators are arranged to cause anti-resonance at low frequencies, then noise generation is prevented, but device layout complexity increases
Solution Approach 1:
The patent achieves noise prevention by adjusting specific parameters of the piezoelectric element sensor (its width and position relative to actuators) rather than through complex layout designs. This parameter-based approach allows anti-resonance to occur below 100 Hz with a relatively simple and regular arrangement of sensors and actuators, minimizing layout complexity while still preventing noise generation
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 solution effectively suppresses vibrations and reduces noise by causing anti-resonance in the output voltage at low frequencies, enhancing vibration control performance and noise reduction in the frequency range of 100 Hz or less.
Implementation Method 1
a piezoelectric element sensor (piezoelectric element for detection) and a piezoelectric element actuator (piezoelectric element for vibration control) are fixed to a peripheral wall surface of a damper of a suspension device of an automobile, the piezoelectric element sensor detects its own deformation caused by vibration of the damper as a voltage signal
Implementation Method 2
the piezoelectric element actuator is driven to stretch and compress the damper to suppress the vibration
Data Source
AI summary
A vibration control device of a plate-like member 11 includes: a plurality of piezoelectric element actuators 14; at least one piezoelectric element sensor 15; and a control circuit 17 that performs feedback control of operation of the piezoelectric element actuators 14 based on an output voltage of the piezoelectric element sensor 15 so as to suppress vibration of the plate-like member 11. A layout of the piezoelectric element sensor 15 and the piezoelectric element actuators 14 is set such that anti-resonance occurs in an output voltage of the piezoelectric element sensor 15 in a range where the vibration frequency of the plate-like member 11 is equal to or less than a predetermined value. Therefore, generation of noise can be prevented at the frequency. As a result, a gain can be increased at a control target frequency. Therefore, vibration can be suppressed, and noise can be reduced.