Mat Nawi, Mohd Norzaidi (2015) One-Side-Electrode-Type Fluidic Sensing Mechanism Inspired from Fish Cupula. PhD thesis, Universiti Sains Malaysia.
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Abstract
Penambahbaikan reka bentuk penderia berasaskan silikon direalisasikan dengan teknik fabrikasi kompleks yang mungkin mengurangkan keteguhan dan kebolehpercayaan penderia. Selain itu, kebanyakan penderia aliran semasa hanya mampu mengukur aliran dalam satu arah dan memerlukan lebih daripada satu penderia untuk meningkatkan keupayaan terutamanya untuk penderiaan pelbagai arah. Masalah-masalah ini boleh ditambah baik dengan menggunakan sistem bendalir untuk pengukuran aliran bawah air yang diinspirasikan daripada mekanisma kupula pada badan ikan. Kupula menjadi pengantara daya-daya seretan dalam suasana sekeliling dan memindahkan pergerakan kepada sel-sel rambut untuk mendorong isyarat sel saraf. Reka bentuk penderia aliran yang dicadangkan dalam kajian ini terdiri daripada elektrod-satu-sisi dan membran berbentuk kubah yang diintegrasi dengan saluran mikro. Apabila aliran mengenai membran, ia memberikan pesongan dan menganjak elektrolit di dalam saluran mikro. Elektrod, melalui lapisan penebat mengesan pergerakan elektrolit dan memberi perubahan dalam kemuatan. Dalam peringkat reka bentuk, simulasi telah dimulakan dengan memilih tiga jenis struktur termasuk bentuk segi empat tepat dan silinder sel rambut dan juga bentuk kubah. Struktur kubah didapati lebih sesuai untuk penderiaan pelbagai arah kerana struktur simetri yang membenarkan daya seretan yang tetap dari arah yang berbeza. Parameter membran berbentuk kubah seperti dimensi dan bahan-bahan telah diubah dan disimulasi. Disebabkan oleh mekanisma penderiaan baru, penderia tekanan yang mempunyai membran rata telah difabrikasi sebagai ujian awal. Kedua-dua membran berbentuk kubah dan membran rata telah difabrikasi menggunakan proses litografi lembut. Kemudian, penderia tekanan berasaskan bendalir telah dicirikan berdasarkan kesan getaran dan suhu. Ujian kebolehpercayaan penderia tekanan untuk getaran dan suhu telah menunjukkan ralat pengukuran penderia ialah 3% oleh getaran lebih 25 Hz pada pecutan ± 2G dan 4%, untuk julat suhu daripada 10 hingga 50oC. Untuk pencirian penderia aliran berasaskan bendalir, frekuensi operasi dan masa tindak balas masing-masing adalah 1.2 kHz dan 0.35 s. Penderia ini dapat mengukur kadar aliran serendah 10 cm/s di dalam air, dengan resolusi 5 cm/s. Ujian berarahan menunjukkan bahawa penderia itu mampu untuk mengesan aliran dalam pelbagai arah dan sudut yang berbeza, di samping dapat mengesan objek bergerak pada jarak dekat. ________________________________________________________________________________________________________________________ Enhancement of silicon-based sensor designs is often realized using complex fabrication techniques which may reduce the robustness and reliability of the sensor. Also, most current flow sensors are only capable of measuring in one direction, requiring more than one sensor to improve capability, especially for multidirectional sensing. These problems may be enhanced using a fluidic system for underwater flow measurement, as inspired from the cupula mechanism on fish bodies. A cupula mediates the drags forces in the surrounding environment and transfers the movements into hair cells to induce the neuron signals. The proposed flow sensor design in this research consists of a one-side-electrode and dome-shaped membrane integrated with a microchannel. When the flow hits the membrane, it provides deflection and displaces the electrolyte inside the microchannel. The electrode, via its insulator layer senses the movement of the electrolyte and gives a change in capacitance value. During the design stage, the simulation was started by selecting three types of structure, including rectangular and cylinder shape of hair cell and also the dome-shaped. The dome structure has been found to be more suitable for multidirectional sensing due to its symmetry structure, which allows the constant drag force from different directions. Dome-shaped membrane parameters such as dimension and materials were varied and simulated. Due to the new sensing mechanism, the pressure sensor that has flat membrane was fabricated as a preliminary test. Both a dome-shaped membrane and flat membrane were fabricated using the soft lithography process. Then, a fluidic based pressure sensor was characterized based on vibration and temperature effect. A reliability test for the pressure sensor for vibration and temperature has demonstrated that the sensor measurement error was 3% by vibration over 25 Hz at acceleration ±2G and 4%, for a temperature range from 10 to 50oC. For the fluidic based flow sensor characterization, operating frequency and time response were 1.2 kHz and 0.35 s, respectively. This sensor was able to measure the flow rate at rates as low as 10 cm/s in water, with a resolution of 5 cm/s. The directionality test has shown that the sensor is capable of detecting flow in different direction and angle, while also being able to detect a moving object at close range.
| Item Type: | Thesis (PhD) |
|---|---|
| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=2205 |
| Subjects: | T Technology T Technology > TK Electrical Engineering. Electronics. Nuclear Engineering > TK7800-8360 Electronics |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraaan Elektrik & Elektronik (School of Electrical & Electronic Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 26 Jun 2018 04:40 |
| Last Modified: | 26 Jun 2018 04:40 |
| URI: | http://eprints.usm.my/id/eprint/40812 |
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