Angular Velocity Sensor Electrostatic Displacement Control
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Solution Overview
Problem
Angular velocity sensors with vibrating members face challenges in maintaining detection precision due to unnecessary displacement of drive pieces in the normal direction, which affects the accuracy of angular velocity detection.
Innovation Solution
The sensor employs a configuration with a first substrate, a vibrating member, and auxiliary electrodes to maintain a constant distance between control and auxiliary electrodes, using electrostatic forces to prevent displacement of the drive pieces in the normal direction, thereby enhancing detection precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first and second drive pieces are vibrated with rectangular cross-sections, then the manufacturing process is simplified, but the side surfaces cannot be completely perpendicular to the front and rear surfaces, causing rounded connection portions that lead to unintended displacement in the normal direction and reduced detection precision
Solution Approach 1:
The patent applies preliminary anti-action by introducing auxiliary electrodes that generate electrostatic forces to counteract the unintended displacement of drive pieces in the normal direction before it affects detection precision. The control circuit detects displacement and applies corrective electrostatic forces to suppress the harmful motion, thereby maintaining detection accuracy despite the rounded connection portions inherent in rectangular cross-section manufacturing
Solution Approach 2:
The patent changes the physical state by utilizing electrostatic forces generated through voltage application to the auxiliary electrodes. By adjusting the voltage parameter, the system dynamically compensates for the geometric imperfections of the rectangular cross-section, converting an electrical parameter (voltage) into a mechanical counter-force that prevents harmful displacement
2Ease of manufacture
If the connection portions are rounded due to etching processes, then the manufacturing is easier, but the drive pieces experience unintended vibration in the normal direction which transmits moments to the detection piece and degrades detection precision
Solution Approach 1:
The patent implements feedback control by using the control circuit to detect the displacement of drive pieces in the normal direction and dynamically adjusting the voltage applied to the auxiliary electrodes. This closed-loop feedback system continuously counteracts the harmful vibrations caused by rounded connection portions, maintaining detection reliability despite manufacturing imperfections
Solution Approach 2:
The auxiliary electrodes act as an intermediary mechanism between the drive pieces and the detection system. Rather than trying to eliminate the rounded connection portions, the patent introduces this intermediate electrostatic control system that mediates the harmful effects of the rounded portions by applying corrective forces to suppress unintended vibrations
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 configuration effectively suppresses displacement of the drive pieces, thereby improving the detection precision of angular velocity by maintaining a consistent distance between electrodes, ensuring accurate angular velocity measurement.
Implementation Method 1
A capacitance is generated between the first drive piece auxiliary electrode and the first drive piece control electrode. The first drive piece control circuit adjusts, based on the capacitance generated between the first drive piece control electrode and the first drive piece auxiliary electrode, the voltage to be applied to the first drive piece auxiliary electrode so that a distance between the first drive piece control electrode and the first drive piece auxiliary electrode is maintained to be constant.
Implementation Method 2
the voltage to be applied to the first drive piece auxiliary electrode is adjusted to keep the constant distance between the first drive piece control electrode and the first drive piece auxiliary electrode. In other words, an electrostatic force between the first drive piece control electrode and the first drive piece auxiliary electrode is adjusted to keep the constant distance
Implementation Method 3
When an angular velocity is applied in this state, a pair of Coriolis forces whose directions are opposite to each other along a projecting direction are generated in the first and second drive pieces, and moments generated by the Coriolis forces are transmitted to the detection piece through the base portion.
Data Source
AI summary
An angular velocity sensor includes a first substrate having first and second surfaces, a vibrating member disposed on the first substrate and including a drive piece capable of vibrating along the first substrate, a second substrate disposed on the first surface side, a first drive piece control electrode, a first drive piece auxiliary electrode, and a first drive piece control circuit applying a voltage to the first drive piece auxiliary electrode. The first drive piece control circuit adjusts, based on the capacitance generated between the first drive piece control electrode and the first drive piece auxiliary electrode, the voltage to be applied to the first drive piece auxiliary electrode to maintain a constant distance between the first drive piece control electrode and the first drive piece auxiliary electrode.