Emine ZAOUALI : "« Kinetic Energy Harvesters for TPMS Applications..."

PhD work : "Kinetic Energy Harvesters for TPMS Applications : Design, Modeling and Experimental Validation"

Abstract :

Energy Harvesters (EH) became one of the most attractive technologies in science and engineering thanks to its significant role in saving energy. One famous application of this system is its use to power Tire Pressure Monitoring Systems (TPMS). Depsite there is a huge quantity of kinetic energy in rotating car's wheels, the fact that rotations of the wheel induce a high level of centrifugal forces presents a major drawback that deprive the harvesting of this type of energy. In this thesis, a kinetic energy harvester is designed, modeled and fabricated. Different designs of multi-pendulum system which are known to be easily unstable are modeled and putted under experiment. The harvested energy is also compared between different designs for the steady-state and the transient responses. Mainly, two new researches challenges are present in this case of study comparing to exicting studies. First, the fact that the pendulum is implemented into the car's wheel induce a rotative excitation which is composition of a horizontal and a vertical excitations at the same time. Second, as we look for maximizing the harvested energy, our interest is presented not only to steady-state response but also to transient response. The proof of concept on the use of pendulum-based energy harvester rotating wheels is tackled, considering a simple concentrated mass designs to analyze the motion and the possibility to harvest energy from rotating wheels with variable speeds. The equations of motion of four designs considered in transient behvior, are presented and derived. The time response of the angular position and angular velocity were calculated for different damping coefficients and initial conditions. The RMS value of the angular velocity used to estimate the harvested energy depends on the initial conditions. A test bench is also setted up to reproduce the behavior of the pendulum mounted into a rotating disk. The solution for the steady-state behavior of three pendulum designs, generated at angular velocity for different rotation speeds, is experimentally tested. Three different regimes exists: oscillations around the vertical axis, aperiodic oscillations and oscillations around the radial axis. The aperiodic regime gives better output voltage for each pendulum. Then, a half-sine input function is used to record the transient output voltage generated for different initial positions of the disk for each pendulum. An analytical analysis is proposed to analyze the steady-state response under constant rotation speeds, because it represents a non negligible part of the regime of motion of the wheels. The method of multiple scales is applied for the equations of motion governing the motion of the Rott's pendulum when small oscillations are assumed around the radial positions. For the two proposed sets of geometrical dimensions, parametric resonance of the first and second modes while two to one internal resonance is satisfied can be achieved. In both cases, the analytically derived resonance conditions, shows that large amplitude of motions can be achieved if a critical value of the rotation speed is reached. However, if the speed is further increase the amplitude is again highly reduced. In fact, the treated case is specific to the TPMS case because the rotation speed in this case is at the same time the frequency excitation force and the amplitude of the stabilizing force represented here by the centrifugal force.

Jury members :

- Sergio BELLIZZI, CNRS Research Director, Laboratoire de Mécanique et d’Acoustique LMA - UMR 7031 AMU - CNRS - Centrale Marseille, Reporter
- Mohamed ICHCHOU, Professor, LTDS UMR 5513, Ecole Centrale de Lyon, Reporter
- Claude Henri LAMARQUE, CNRS Research Director, Ecole Nationale des Travaux Publics de l’État, ENTPE, LTDS, UMR 5513, Reviewer
- Fehmi NAJAR, Professor, Ecole Polytechnique de Tunisie, LASMAP, Reviewer
- Najib KACEM, Assistant Professor, UBFC, Institut Femto-ST, UMR CNRS 6174, PhD Co-director
- Emmanuel FOLTETE, Professor, Université Bourgogne – Franche-Comté, PhD Director

Location : Amphithéâtre Mesnage, ENSMM  (26 Rue de l'Épitaphe, 25000, BESANCON).