Mingjing Qi

Self-lifting artificial insect wings via electrostatic flapping actuators

We present self-lifting artificial insect wings by means of electrostatic actuation for the first time. Excited by a DC power source, biomimetic flapping motions have been generated to lift the artificial wings 5cm above ground (limited by the current experimental setup) under an operation frequency of 50-70Hz. Three achievements have been accomplished: (1) first successful demonstration of self-lifting electrostatic flying wings; (2) low power consumption as compared to other actuation schemes; and (3) self-adjustable rotating wing design to provide the lifting force. As such, this work can lead to a new class of electrostatic flapping actuators for artificial flying insects.

A low cycle fatigue test device for micro-cantilevers based on self-excited vibration principle

This paper reports a low-cycle fatigue test device for micro-cantilevers, which are widely used in micro scale structures. The working principle of the device is based on the phenomenon that a micro-cantilever can be set into self-excited vibration between two electrodes under DC voltage. Compared with previous devices, this simple device can produce large strain amplitude on non-notched specimens, and allows a batch of specimens to be tested simultaneously. Forty-two micro-cantilever specimens were tested and their fatigue fracture surfaces exhibit typical low cycle fatigue characteristics. As such, the device is very attractive for future fatigue investigation for micro scale structures.

Low voltage electromagnetically driven artificial flapping wings

We present low voltage electromagnetically driven artificial flapping wings for the first time under an estimated output power of 64.8μW at 22Hz using a driving voltage of only 5.5V. Three distinctive achievements have been accomplished in this work: (1) a small-size electromagnetic actuator using low driving voltage and a simplified model for its optimization; (2) direct actuation of flapping wings without any regulating mechanism by mechanical means; and (3) feasibility of unsynchronized flapping modes by individually controlled wing operations for flight controls. As such, this work advances the drive and control options for actuators used in the field of artificial Flapping-wing Micro Aerial Vehicles (FMAVs).

High-Voltage Flexible Microsupercapacitors Based on Laser-Induced Graphene

High-voltage energy-storage devices are quite commonly needed for robots and dielectric elastomers. This paper presents a flexible high-voltage microsupercapacitor (MSC) with a planar in-series architecture for the first time based on laser-induced graphene. The high-voltage devices are capable of supplying output voltages ranging from a few to thousands of volts. The measured capacitances for the 1, 3, and 6 V MSCs were 60.5, 20.7, and 10.0 μF, respectively, under an applied current of 1.0 μA. After the 5000-cycle charge-discharge test, the 6 V MSC retained about 97.8% of the initial capacitance. It also was recorded that the all-solid-state 209 V MSC could achieve a high capacitance of 0.43 μF at a low applied current of 0.2 μA and a capacitance of 0.18 μF even at a high applied current of 5.0 μA. We further demonstrate the robust function of our flexible high-voltage MSCs by using them to power a piezoresistive microsensor (6 V) and a walking robot (>2000 V). Considering the simple, direct, and cost-effective fabrication method of our laser-fabricated flexible high-voltage MSCs, this work paves the way and lays the foundation for high-voltage energy-storage devices.

Artificial insect wings with biomimetic wing morphology and mechanical properties

The pursuit of a high lift force for insect-scale flapping-wing micro aerial vehicles (FMAVs) requires that their artificial wings possess biomimetic wing features which are close to those of their natural counterpart. In this work, we present both fabrication and testing methods for artificial insect wings with biomimetic wing morphology and mechanical properties. The artificial cicada (Hyalessa maculaticollis) wing is fabricated through a high precision laser cutting technique and a bonding process of multilayer materials. Through controlling the shape of the wing venation, the fabrication method can achieve three-dimensional wing architecture, including cambers or corrugations. Besides the artificial cicada wing, the proposed fabrication method also shows a promising versatility for diverse wing types. Considering the artificial cicada wings characteristics of small size and light weight, special mechanical testing systems are designed to investigate its mechanical properties. Flexural stiffness, maximum deformation rate and natural frequency are measured and compared with those of its natural counterpart. Test results reveal that the mechanical properties of the artificial cicada wing depend strongly on its vein thickness, which can be used to optimize an artificial cicada wings mechanical properties in the future. As such, this work provides a new form of artificial insect wings which can be used in the field of insect-scale FMAVs.