Aerial-aquatic unmanned vehicles are a combination of unmanned aerial vehicles and unmanned submersibles, capable of conducting patrols in both the air and underwater domains. This article introduces a novel aerial-aquatic unmanned vehicle that integrates fixed-wing configuration and flapping-wing configuration. In order to improve the low efficiency of the classic diagonal motion trajectory, this paper proposed an improved diagonal motion trajectory based on joint optimization of the stroke angle and angle of attack curve. The proposed method has been verified through simulations and experiments. A prototype was developed and experiments were completed, both indoors and outdoors, wherein the system’s transmedium transition capability and flapping propulsion performance were comprehensively validated. Additionally, utilizing flapping propulsion, an average underwater propulsion speed of 0.92 m/s was achieved.

A miniature high-sensitivity Fabry-Perot (F-P) resonant pressure sensor was developed by transferring multilayer graphene (MLG) onto a copper mesh with a bore diameter of 20 μm. The resonance of graphene membrane suspended and clamped on the copper mesh was opto-thermally excited and detected via optical fiber F-P interference. The measured resonant behaviors showed that the sensor achieved a maximum resonant frequency of 1.11 MHz with a good sensitivity of 10.4 kHz/kPa in the tested range of 0.01 to 50 kPa, which is much higher than that of common silicon resonant pressure sensor with a normal sensitivity of 0.1-0.4 kHz/kPa. Also, the output stability within 4200 seconds demonstrated an extremely low frequency deviation of 0.18% at 6 mW of optical power and 0.16% at 5 mW of optical power, thereby verifying a great potential in highly sensitive pressure measurement.