A self-sensing omnidirectional pendulum harvester for smart oceans†

The construction of floating cities on the sea is an innovative solution for combating climate change and sea level rise. Ensuring the safe, long-term independent operation of floating cities is essential. In this paper, a self-sensing omnidirectional pendulum harvester is designed and tested, which consists of a wave energy harvester based on spherical gear (WEH-SG) and (long short-term memory) LSTM modules. The WEH-SG can provide power for floating cities by harvesting multi-directional waves. As a novel spatial meshing mechanism, the spherical gear (SG) can integrate the complex wave motion in any direction into a single direction, improving the efficiency of wave energy harvesting. Through the six degrees of freedom shaking table experiment with the prototype, it has been determined that the output performance of the WEH-SG is impacted by variables such as the wave frequency, amplitude, and internal size configuration of the prototype. The experimental findings indicate that WEH-SG can produce an output power of 32.23 mW at a wave frequency of 1 Hz and an amplitude of 30 mm. The WEH-SG's power generation efficiency is 253% of that of harvesting only unidirectional waves. The LSTM module collects and trains the system's generator signals and achieves 99.26% monitoring accuracy for environmental condition identification. Application scenario demonstrations were carried out to showcase the capability of WEH-SG to supply power to a digital temperature sensor. Combined with artificial intelligence and the Internet of Things, this system can provide sustainable, clean energy for floating cities and function as a sensor to monitor and warn about the state of the environment.