Dr. Mehdi Ahmadian, Virginia Tech
The primary objective of this research is to design and develop a practical energy harvester tie (EHT) that can be used for setting up remote electric power stations to satisfy the needs of the railroad industry. The need for power in remote places often arises from the implementation of sensors or other devices that require DC power. The lack of the availability of power has been limiting the implementation of smart technologies on railroad tracks that can bring much operational efficiency and cost savings. This project will design and develop an EHT that can be used for providing power to track mounted systems or through a wireless charging station for devices that are not track mounted. One such application is drones that are often railroads desire to operate, but their applications are limited with the limited flying range. The remote station that is possible to set up through the implementation of EHT promises to not only make it possible to install smart systems on the rail but also significantly increase the operational viability of critical technologies such as drones.
This study evaluates a compact electromagnetic energy harvester that can be installed at the railroad tracks. The design integrates a mechanical motion rectifier (MMR) with an embedded one-way clutch in the bevel gears, to convert the movement that commonly exists at the track due to passing train wheels into a unidirectional rotation of the generator. The ball screw mechanism is configured such that it has reduced backlash and thus can more efficiently harvest energy from low-amplitude vibrations.
A porotype energy harvester tie will be designed, fabricated, and tested expensively in the field. The design will include the integration of a proven energy harvester concept into a composite railroad tie that is suitable as a direct retrofit with a conventional railroad tie. The intergradation into a conventional railroad tie provides ease of field installation and improved the efficiency in harvesting the mechanical energy at the rail. The integrated design, referred to as the “smart tie,” not only protects the energy harvester, the wiring harness, and supporting electronics from the maintenance-of-the-way equipment but also positions the harvester in a mechanically advantageous position that can maximize the track-induced motion, and hence the harvested power. Although for testing purposes, the smart tie uses a modified composite tie, it can be integrated into other track tie arrangements that used for revenue service track, including concrete and wooden ties.