Modeling and experimental research of contact surface for piezoelectric impact-excite power harvesting

Impact-excited piezoelectric cantilever power harvester has been found as an effective approach for solving the mismatch between the resonant frequency and input frequency. The structure design of the proof mass is discussed and the discussion focused on the impulsive contact surface design in this paper. Modeling and dynamic analysis of different contact surface are performed. Two-centimeter scale prototype harvesters which consist of different tip form are fabricated and tested. The measured powers with variable external resistance under different walking speed of each prototype are compared. For the piezoelectric cantilever with asymmetric contact surface, the output maximum average power is 23% more than the power generated by the piezoelectric bimorph cantilever with symmetric contact surface under the same condition.