Although energy harvesting systems are extensively used in different fields, studies on the application of energy harvesters embedded in tires for vehicle control are rare and mostly focus on solving power supply problems of tire pressure sensors. Sensors are traditionally powered by an embedded battery, which must be replaced periodically because of its limited energy storage. Heightened interest in vehicle safety is expected to drive increased design and manufacture of in-tire sensors, which in turn, translates to rising demand for power generation in tires. These challenges emphasize the need to investigate the substitution of batteries and in-tire energy harvesting systems. Current in-tire energy harvesting methods involve piezoelectric, electromagnetic, and electrostatic power generation, whose energy sources include tire vibrations, deformations, and rotations. Piezoelectric harvesters are generally compact but operate for short durations. Electromagnetic generators exhibit higher power density but are less efficient than generators made from piezoelectric materials. The challenge presented by electrostatic generators is their requirement for certain launch conditions. The performance of different mechanisms depends on design, which is the key issue examined in research. The amount of harvested energy ranges from the microwatt to dozens of watts level, depending on individual structure and chosen principle. This article analyzes studies on in-tire energy harvesting systems to comprehensively compare existing principles and structures, as well as evaluate prospects for application. The modeling, simulation, and experimental validation in previous works are also summarized and categorized to provide guidance for future studies.
