Study on Design Optimization of a Capacitive Tilt Angle Sensor

Abstract

This paper presents a design optimization and validation of a two-axis cylindrical capacitive tilt angle sensor. The proposed sensor includes of five electrodes symmetrically arranged surrounding an air–liquid two phases cylindrical tube, forming two pairs of electrodes for roll and pith angle measurement. Cylindrical plastic tube filled partly with dielectric fluid with dielectric constant of 2. The proposed sensor can detect tilt angles in x-axis and y-axis, i.e. roll and pith angles. When the cylindrical plastic tube is rotated, the dielectric fluid covers a portion of the induction electrodes, thereby changing the differential capacitance value of the capacitor corresponding to the tilt angle. By measuring the capacitance change, the tilt angle can be estimated. Performance of the sensor was investigated by Finite element method using Comsol Multiphysics simulation software. Simulation results show the variation in capacitance with respect to the variation of tilt angle. Based on this simulation model, the structure of the electrodes was manipulated for maximizing the sensitivity for roll and pith sensing in an appropriate working range. Experiments were also conducted for validation. The experiment results are well matched with simulated results. The optimized sensor has working range from −70° to +70° with sensitivity of 3 mV/° in the roll angle and from −30° to +30° with sensitivity of 17 mV/° in the pitch angle.

KEYWORDS:

• Capacitive sensor
• Fluidic sensor
• Tilt angle measurement

Additional information

Notes on contributors

Ha Tran Thi Thuy

Ha Tran Thi Thuy received the BS degree in physics from Hanoi University of Science, Hanoi, Vietnam, in 1998, the MSc degree in electrical engineering from Vietnam National University, Hanoi, in 2002. She currently holds a position as a PhD student in the Post and Telecommunications Institute of Technology. Her main research interests include the development of microfluidic technologies for living cell manipulation and detection. Email: [email protected]

Hai Nguyen Dac

Hai Nguyen Dac received the BS degree in physics from Hanoi University of Science, Hanoi, Vietnam, in 1997, the M.Sc. degree in electronic engineering from Vietnam National University, Hanoi, in 2010, and the PhD degree from Posts and Telecommunications Institute of Technology, Hanoi, Vietnam, in 2017. His doctoral research concerned capacitive and sensing micro sensor for microparticle handling, micro-liquid channel sensor and microsystems technology. He is currently a lecturer at the Faculty of Electronics Engineering Technology, Hanoi University of Industry, Hanoi, Vietnam. His current research interests include capacitive and sensing micro sensor for microparticle handling, micro-liquid channel sensor, and biomedical sensor. Corresponding author. Email: [email protected]

Tuan Vu Quoc

Tuan Vu Quoc received the BS degree in physics and the MSc degree in electronic engineering from Vietnam National University, Hanoi, in 2002 and 2004, respectively. He currently is a researcher of the Vietnam Academy of Sciences and Technology, Hanoi, Vietnam works for and holds a position as a PhD student in the VNU – University of Engineering and Technology, Hanoi, Vietnam. Email: [email protected]

Thinh Pham Quoc

Thinh Pham Quoc received the BS degree in physics and the MSc degree in electrical engineering from Vietnam National University, Hanoi, in 2010 and 2012, respectively. He currently is a lecturer at the Thai Nguyen University, Thai Nguyen, Vietnam. Email: [email protected]

An Nguyen Ngoc

An Nguyen Ngoc (S’11) was born in Hanoi on 31 December 1988. He received the BE in telecommunication engineering from Hanoi University of Science and Technology in 2011. He received the ME and the PhD degrees in electrical, electronic and communication engineering from Chuo University, Japan, in 2014 and 2017, respectively. Since April 2017, he has been with University of Engineering and Technology–VNU, Hanoi, Vietnam, where he is currently a lecturer. His current research interests include micropump, sensors and material characterization using free space techniques. Email: [email protected]

Trinh Chu Duc

Trinh Chu Duc received his BS in physics from Hanoi University of Science, Hanoi, Vietnam, in 1998, MSc in electrical engineering from Vietnam National University, Hanoi, in 2002, and PhD degree from Delft University of Technology, Delft, The Netherlands, in 2007. His doctoral research concerned piezoresistive sensors, polymeric actuators, sensing microgrippers for microparticle handling, and microsystems technology. He is currently an associate professor with the Faculty of Electronics and Telecommunications, VNU University of Engineering and Technology, Vietnam. His current interests include bio sensors, microfluidic, MEMS sensors and actuators. He was the dean of the Faculty of Electronics and Telecommunications, UET from 2015 before becoming the vice rector of the VNU University of Engineering and Technology, Vietnam. He has been head of the Microelectromechanical Systems and Microsystems Department, since 2011. Email: [email protected]

Tung Thanh Bui

Tung Thanh Bui received his BS in electrical engineering from Vietnam National University, Hanoi (VNUH) in 2004, and ME and DEng degrees in science and engineering from Ritsumeikan University, Shiga, Japan, in 2008 and 2011, respectively. From 2011 to 2015, he was a post-doctoral researcher with the 3D Integration System Group, Nanoelectronics Research Institute (NeRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan. Currently, he is an assistant professor at the Faculty of Electronics and Telecommunication (FET), VNU University of Engineering and Technology, Hanoi, Vietnam. His current interests include microfluidic, bio sensors, MEMS sensors and actuators. Email: [email protected]