Modeling, analytical solutions and experiment of a mechanical-transmission type energy harvester

Abstract

In metro rail transit, wireless sensor networks play a vital role in monitoring. With the increasing application of the steel-spring floating slab track (SFST), harvesting track vibration energy to power underground wireless sensors has emerged as an innovative and eco-friendly solution. In this paper, a practical mechanical-transmission type energy harvester employing a helical multi-stage structure (MEHHM) is designed for the SFST. A comprehensive theoretical model with mechanical parameters considered is established under harmonic excitation as well as within the vehicle-SFST-MEHHM coupled system. A reconstructed harmonic balance (RHB) method assisted by the two-point tracking method is employed to solve the semi-analytical periodic responses of the transmission, enabling an efficient tracing of solution curves. Results show that the mechanical parameters have obvious influence on the dynamic responses, output performance and transmission stability of the MEHHM. Experimental results show a good agreement with the simulation. Under the harmonic displacement excitation of 4 mm and 2 Hz, the average output power can reach a high level of 33.73 W. Under the floating slab displacement excitation at 60 km/h train speed, application tests are conducted to verify the MEHHM’s output capacity. Overall, our work advances the theoretical modeling and analysis of energy harvesting for SFSTs, offering new insights into the research framework for rail transit energy harvesting.