# Multi-Unit Coupled Motion Hybrid Generator Based on a Simple Pendulum Structure
## 4 Conclusions  
In summary, based on traditional swinging generators, this study innovatively designed a multi-unit coupled motion hybrid generator. The device integrates eight power generation units, comprising triboelectric nanogenators (TENGs), electromagnetic generators (EMGs), and piezoelectric nanogenerators (PENGs), using simple pendulum motion as the excitation signal. Through the coupled motion design between different types of generators, the space utilization rate was significantly improved. At a frequency of 0.5 Hz and a swing angle of 15\({}^{\circ}\), the S-TENG and EMG in the MCM-HG exhibited coupled motion, achieving peak output voltages of 353 V and peak currents of 4.1 mA after rectification. This combined high voltage and large current output leveraged the complementary advantages of both generators to achieve satisfactory results. Meanwhile, the P-TENG and PENG also demonstrated coupled motion, enabling multiple outputs from a single excitation within one cycle. The total output power of the MCM-HG was 22.07 mW, with a corresponding power density of 7.36 W/m\({}^{3}\), which is 6.35 times higher than that of the rolling-based swinging structure triboelectric nanogenerator. Additionally, the MCM-HG performed well in practical applications: after charging a 47 \(\mu\)F capacitor to 5 V, it successfully powered a calculator; and after charging a 470 \(\mu\)F capacitor to 3 V, it successfully powered a thermo-hygrograph. These results indicate that the MCM-HG not only has significant advantages in low-frequency wave energy harvesting but also offers new ideas for marine energy collection and provides strong technical support for the sustainable development of future marine IoT.  
The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app15105454/s1](https://www.mdpi.com/article/10.3390/app15105454/s1)]([https://www.mdpi.com/article/10.3390/app15105454/s1](https://www.mdpi.com/article/10.3390/app15105454/s1)). Video S1: MCM-HG drives a calculator on a six-degree-of-freedom platform; Video S2: MCM-HG drives a thermo-hygrograph on a six-degree-of-freedom platform. Figure S1: The physical image of the PCB coil; Figure S2: The photo of the PCB coil embedded in the acrylic plate; Figure S3: The physical image of the S-TENG combined with the P-EMG; Figure S4: The physical image of the P-TENG combined with the PENG; Figure S5: The physical photograph of the MCM-HG; Figure S6: Durability testing of the TENG, with 43,200 cycles at a frequency of 0.5 Hz; Figure S7: Durability testing of the PENG, with 43,200 cycles at a frequency of 0.5 Hz; Figure S8: Durability testing of the EMG, with 43,200 cycles at a frequency of 0.5 Hz; Table S1: Individual Unit Output and Total Output of the Integrated System.  
Conceptualization, Y.L. and L.W.; methodology, Y.L. and L.W.; validation, Y.L.; writing--original draft preparation, Y.L.; writing--review and editing, all authors; supervision, L.W.; funding acquisition, L.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key R&D Project from the Minister of Science and Technology, grant number 2021 YFA1201603.  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the corresponding authors upon request.  
The research was supported by all authors.