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廖淳旭 (Chun-Hsu Liao)
廖淳旭 (Chun-Hsu Liao)
Investigations of two symmetric suspensions for micro accelerometers
Investigations of two symmetric suspensions for micro accelerometers
可應用於微加速計之兩種對稱型懸吊結構研究
可應用於微加速計之兩種對稱型懸吊結構研究
In this study, our research focuses on the suspension structure of the micro accelerometer. In order to achieve optimal results we explore various parameters in all aspects to understand its influences on spring coefficient, expecting the higher micro-accelerometer's sensitivity as well as the deviation of the structure be reduced accordingly. This paper presents a new “point symmetrical” suspension configuration, it remains the same spring coefficient of two plane axes even if disturbed by the size deviations from process, and thus keeps equal sensitivity of two axes, reducing the error of the electrical signals. This paper also proposes a new “coil suspension structure”, it compares with the most commonly used serpentine spring through the finite element analysis software ANSYS® and then analyzes the pros and cons of two springs with point symmetrical configuration.
In this study, our research focuses on the suspension structure of the micro accelerometer. In order to achieve optimal results we explore various parameters in all aspects to understand its influences on spring coefficient, expecting the higher micro-accelerometer's sensitivity as well as the deviation of the structure be reduced accordingly. This paper presents a new “point symmetrical” suspension configuration, it remains the same spring coefficient of two plane axes even if disturbed by the size deviations from process, and thus keeps equal sensitivity of two axes, reducing the error of the electrical signals. This paper also proposes a new “coil suspension structure”, it compares with the most commonly used serpentine spring through the finite element analysis software ANSYS® and then analyzes the pros and cons of two springs with point symmetrical configuration.
The spring coefficient K can be calculated from determination of the resonance with its resonant modes as well as resonant frequency by using the ANSYS ® simulation software. On the condition of the same K value at plane axes, the coefficient K of coil spring at Z-axis is smaller implicating its applicability of the three-axis accelerometer due to its higher sensitivity at Z-axis. Meanwhile in the same plane K value the smaller area is needed for coil spring. It means that overall sensitivity is relatively higher because of a larger effective mass of the block. By adjustment of the spring and its impact on the resonant frequency of rotation mode, we understand the need to position coil spring a little farther from the center in order to make spin resonant frequency greater than linear resonance frequency, so that element prevents from spinning. Finally it is concluded that the coupling error of coil spring is smaller than winding spring by observing the ratio of X-axis displacement over Y-axis displacement when simulating 3G on Y-axis acceleration.
The spring coefficient K can be calculated from determination of the resonance with its resonant modes as well as resonant frequency by using the ANSYS ® simulation software. On the condition of the same K value at plane axes, the coefficient K of coil spring at Z-axis is smaller implicating its applicability of the three-axis accelerometer due to its higher sensitivity at Z-axis. Meanwhile in the same plane K value the smaller area is needed for coil spring. It means that overall sensitivity is relatively higher because of a larger effective mass of the block. By adjustment of the spring and its impact on the resonant frequency of rotation mode, we understand the need to position coil spring a little farther from the center in order to make spin resonant frequency greater than linear resonance frequency, so that element prevents from spinning. Finally it is concluded that the coupling error of coil spring is smaller than winding spring by observing the ratio of X-axis displacement over Y-axis displacement when simulating 3G on Y-axis acceleration.
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