Liwei Lin (Advisor)

Research Advised by Professor Liwei Lin

Lin Group:  List of Projects | List of Researchers

An Improved Lumped Element Model for Circular-Shape pMUTs

Sedat Pala
Liwei Lin
2022

This paper presents an improved lumped element model for clamped, circular-shape, piezoelectric micromachined ultrasonic transducers (pMUTs). A small signal equivalent circuit is developed to include electrical, mechanical, and acoustic domains, which are analyzed separately and combined with the associated couplings. For the first time, a two-term mode shape approach is adapted to reveal intrinsic and extrinsic properties of a pMUT, such as equivalent circuit parameters, input impedance, velocity, displacement, bandwidth, quality factor, directivity, and the on-axis pressure in the...

A Moisture-Resistant Soft Actuator with Low Driving Voltages for Haptic Stimulations in Virtual Games

Wenying Qiu
Zhaoyang Li
Guocheng Wang
Yande Peng
Min Zhang
Xiaohao Wang
Junwen Zhong
Liwei Lin
2022

Strong and robust stimulations to human skins with low driving voltages under high moisture working conditions are desirable for wearable haptic feedback applications. Here, a soft actuator based on the “air bubble” electret structure is developed to work in high-moisture environments and produce haptic sensations to human skin with low driving voltages. Experimentally, the water soaking and drying process has been conducted repeatedly for the first time and the 20th time to test the antimoisture ability of the actuator as it recovers its output force up 90 and 65% of the initial...

Fanping Sui

Alumni
Mechanical Engineering
Professor Liwei Lin (Advisor)
Ph.D. 2022

Fanping Sui received his B.S. in Theoretical and Applied Mechanics from University of Science and Technology of China in 2018 (ranked 1st) and M.S. in Mechanical Engineering from University of California, Berkeley in 2019. He is currently pursuing Ph.D. in MEMS/Nano in Mechanical Engineering at UC Berkeley under the supervision of Professor Liwei Lin.

BPN855: Flexible Energy Harvester, Sensor, and Actuator

Yu Long
2022

Flexible, wearable, and implantable devices are expected to become more abundant due to developments in materials and microfabrication technologies. In our previous work, we have successfully achieved a kind of flexible actuators that can work at low voltage and give haptic feedback. Now we are moving forward to develop energy harvesters with various sets of flexible materials and structures that can 1) harvest energy from outside stable environment; 2) generate electricity in a relatively long time; and 3) give enough energy output to power up small devices.

...

BPN877: Pulse Acquisition and Diagnosis for Health Monitoring

Ruiqi Guo
2022

Traditional Chinese medicine(TCM) has existed for more than two thousand years and one of the important diagnostic methods is the pulse diagnosis. It generally takes decades of training for a practitioner to master this skill as pulse acquisition and diagnosis require long-term experiences and are very subjective. The project aims to use the combination of advanced sensor technology and artificial intelligence to emulate the TCM practice for health monitoring. A flexible piezoelectric film is designed to record the wrist pulse data. A group of representative pulse features has been...

Yu Long

Alumni
Mechanical Engineering
Professor Liwei Lin (Advisor)
Ph.D. 2022

Yu received her B.E. in Material Science & Engineering from Tsinghua University in 2018. She is currently pursuing a Ph.D. in Mechanical Engineering under the supervision of Prof. Liwei Lin and is expected to graduate in 2022. Her research interest lies in polymers and their applications in energy harvesters.

Dissertation title: Renewable Polymeric Energy Harvesters from Moisture and Heat

Ruiqi Guo

Alumni
Mechanical Engineering
Professor Liwei Lin (Advisor)
Ph.D. 2022

At present, Ruiqi is a Ph.D.student in Liwei Lin Lab. In 2019, Ruiqi earned his Masters degree in Advanced Energy Technology at UC Berkeley.

Dissertation Title: Machine Learning for MEMS Structure Design and Pulse Signal Analysis

Sedat Pala

Alumni
Mechanical Engineering
Professor Liwei Lin (Advisor)
Ph.D. 2022

Sedat Pala received the B.S (1st ranked, Fall 2015) and M.Sc. (Most Successful Student) in Mechanical Engineering from Middle East Technical University (METU), Ankara, Turkey in 2015 and 2017, respectively. He also completed a minor degree in Business Administration in METU, 2015. He is currently pursuing a Ph.D. in MEMS/Nano in Mechanical Engineering at UC Berkeley under the supervision of Prof. Liwei Lin and expected to graduate in 2022.

Accelerating the MEMS Design Process via Deep Learning

Ruiqi Guo
2022
Spring 2022 BSAC Research Review Presentation View Slides View Presentation

BSAC Researchers Advised by Professor Liwei Lin