Liwei Lin (Advisor)

This paper reports drastically improved accuracy of real-time gas detections by a scalable machine learning fusion system which utilizes encoder-decoder structures and a decision fusion model. Advancements as compared to the state-of-the-art works include: 1) increased gas sensing accuracy of a carbon dioxide sensor with a Mean Absolute Percentage Error (MAPE) of 2.97% in real-time tests; 2) drastically reduced sensor response/recovery time from ~9 mins to 2 mins; and 3) good proof-of-concept demonstrations for both generalization and robustness across different gas sensors. As such, this...

This work reports a platform based on ultrasound for mid-air particle manipulations using a 2×2 piezoelectric micromachined ultrasonic transducer (pMUT) array. Three achievements have been demonstrated as compared to the state-of-art: (1) high SPL (sound pressure level) of 120 dB at a distance 12 mm away by an individual lithium-niobate pMUT; (2) a numerically simulated and experimentally demonstrated 2D focal point control scheme by adjusting the phase-delay of individual pMUTs; and (3) the experimental demonstration of moving a 0.7 mg foam plastic particle of 12 mm away in the mid-air by...

The miniaturization of insect-scale flying robots with untethered flights is extremely challenging as the tradeoff between mass and power becomes problematic. Here, a subcentimeter rotating-wing robot of 21 mg in weight and 9.4 mm in wingspan driven by a single-axis alternating magnetic field has accomplished navigable flights. This artificial flying robot is the lightest and smallest to realize untethered and controllable aerial travels including hovering, collision recovery, and route adjustments. Experimentally, it has achieved a high aerodynamic efficacy with a measured lift-to-drag...