Vibration-based energy harvesting has been investigated in this paper with the goal to utilize the ambient vibration energy to power small electronic components by converting vibration energy into electrical energy. A simply supported beam with a bonded high density piezoelectric patch to the surface is considered for the analysis. Analytical model for free vibration analysis is developed by starting with the linear constitutive relations for the beam and the patch. The equation of motion for transverse vibration of the beam is developed by considering the elastic as well as electrical properties in the generalized Hookes law and accordingly a transverse displacement function satisfying the simply supported boundary conditions is used for achieving the modal frequencies. Additionally, an analytical model is developed in order to estimate the energy generated under the action of a harmonic force applied on the surface of the patch. The results of the analytical model are validated using simulation software ANSYS and COMSOL.The developed analytical model is used to study the behavior of a simply supported harvester with various patch dimensions and locations. This paper throws light on parametric studies of eigen frequencies as well as extracted power corresponding to operating conditions.
Steer-by-wire (SBW) systems are considered as one of the most significant innovations among the technologies developed for advanced driver-assistance systems and autonomous vehicles. The main control challenge in a SBW system is to follow the steering commands in the face of parametric uncertainties and external disturbances; crucially, perturbations in inertial parameters and damping forces give rise to state-dependent uncertainties, which cannot be bounded a priori by a constant. However, the state-of-the-art control methods of SBW system rely on a priori bounded uncertainties, and thus, become inapplicable when state-dependent dynamics become unknown. This work, to the best of the authors' knowledge for the first time, proposes an adaptive control framework that can tackle the state-dependent uncertainties and external disturbances in a typical SBW system without any a priori knowledge of their structures and of their bounds. The stability of the closed-loop system is studied analytically via uniformly ultimately bounded notion and the effectiveness of the proposed solution is verified via simulations against the state-of-the-art solution.
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