Servo-Type Vibration Detector Electrode Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional servo-type acceleration sensors face challenges in achieving high resonance frequency, low resonance peak, improved responsiveness, and high sensor sensitivity simultaneously, due to conflicting relationships between these performance metrics.
Innovation Solution
The proposed servo-type vibration detector reduces mechanical damping effects by dividing electrodes into multiple pieces and setting boundary portions to atmospheric pressure, and compensates for this reduction with electrical damping units in the servo amplifier, allowing independent setting of sensor sensitivity and dynamic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the void portion between electrodes is used for displacement detection, then sensor sensitivity is improved, but mechanical damping effect increases causing resonance peak and phase delay
Solution Approach 1:
The electrode surface is divided into multiple independent electrode pieces with gaps between them. This segmentation allows the void portion to communicate with atmospheric pressure through the gaps, reducing the mechanical damping effect of the squeeze film while maintaining sufficient capacitance for displacement detection. The electrode pieces are arranged such that their combined capacitance provides adequate sensitivity without generating excessive damping force.
Solution Approach 2:
Different regions of the electrode structure are given different properties: the electrode pieces have conductive surfaces for capacitance detection, while the gaps between them provide pressure equalization to atmospheric conditions. This local differentiation allows simultaneous achievement of sensitivity (through conductive electrode areas) and reduced damping (through gaps allowing pressure release).
2Speed
If resonance frequency is increased and resonance peak is reduced, then responsiveness is improved, but sensor sensitivity decreases
Solution Approach 1:
The system changes the damping parameter by introducing atmospheric pressure communication through gaps, which reduces the mechanical damping coefficient. This parameter change allows the resonance peak to be reduced and responsiveness improved without sacrificing sensitivity, as the electrode configuration maintains adequate capacitance while the damping effect is reduced through pressure equalization.
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 enables the achievement of ideal sensor dynamic characteristics, including reduced resonance peak and phase delay, while maintaining high sensor sensitivity, thus addressing the conflicting relationships in conventional sensors.
Implementation Method 1
a displacement detection unit configured to detect displacement of the movable member in the predetermined direction
Implementation Method 2
either a groove or a hole communicating with the atmosphere is formed at a relative movement surface between the movable-side electrode and the fixed-side electrode, and thereby reduce a damping effect of a dynamic fluid pressure being generated at the void portion
Implementation Method 3
a drive unit configured to be driven by a servo amplifier, the drive unit being configured to generate a generative force with which the movable member is returned to an origin position when a relative displacement of the movable member from the origin position is detected at the displacement detection unit
Data Source
AI summary
In the case of the conventional servo-type acceleration sensor, the sensor needs to be configured within a narrow range that simultaneously satisfies the following three conflicting challenges: (1) reduction in resonance peak, (2) improvement of responsiveness, and (3) improvement of sensor sensitivity. Therefore, there is a limit to performance improvement. A mechanical damping effect of a dynamic fluid pressure in the inter-electrode void portion is reduced by forming a flow hole, a flow groove, and the like at the relative movement surface of the electrode, and this damping effect is replaced with an equivalent damping unit by using an electrical circuit in the servo amplifier. As a result, although the sensor sensitivity, determined by the gap between the electrodes and the outer diameter of the electrode, and the sensor dynamic characteristics have conventionally been in a trade-off relationship, the sensor sensitivity and the sensor dynamic characteristics can be independently set.