Piezoelectric energy harvesting for tyre pressure measurement applications

Piezoelectric energy harvesters have been proposed as a means of supplying electrical power to remote tyre pressure monitoring systems. This solution avoids problems of battery replacement and allows the tyre pressure monitoring system to be self-powered. In this paper, a previously developed theoretical model is used to predict the electric output and mechanical responses of a cantilever beam energy harvester embedded within a car tyre. The radial deformation of the tyre is considered to provide base excitation to the energy harvester, and a bump stop is incorporated into the harvester design to limit the vibration amplitude and maintain the structural integrity of the harvester. The simulation results show that the harvester achieves maximum power output, with or without the stop, when the harvester location coincides with the tyre contact patch. It is also found that the average power output is reduced when a bump stop is used, but the bending stress in the cantilever reduces significantly as the displacement of the beam is limited. A comparison with published experimental results indicates good levels of agreement. The model developed can be used as a design tool to optimize the performance of energy harvesters in tyre applications, where a compromise between power generation and structural integrity is required.