Piezoelectric energy harvesters have been extensively researched for use with wireless sensors or low power consumption electronic devices. Most of the piezoelectric energy harvesters cannot generate enough power for potential applications. In this study, we explore the parameters, including gap and proof mass, that can affect the damping of the cantilever to optimize the design of the energy harvester. A finite analysis is conducted using COMSOL Multiphysics software. Usually, this type of simulation is performed using the loss factor. However, it is known that results from the loss factor produce models that do not fit the experimental data well. In fact, the result of output voltage using the loss factor is 50% higher than the real value, which is due to ignoring the adverse effect of a superimposing mechanical damping of different constituent materials. In order to build a true model, Rayleigh damping coefficients are measured to use in a simulation. This resulted in a closer fit of modeling and experimental data, and a 5 times better output voltage from the optimized energy harvester compared with using the smallest gap and mass.

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The article proposes the use of a differential inertial sensors system for detection of the trench depth under operation. The inertial sensors are employed to detect a posture of the trencher and as a result to determine an angle difference through inertial sensors located on a vehicle (as a reference) and on the trencher arm. In this way, the undesirable, disturbing effects caused by unevenness of the field etc. are significantly reduced or even eliminated. The trench depth calculation procedure combines the angle difference and relative dimensions of the trencher structure. It is displayed on a monitor in real time. To perform a remote monitoring, the system is equipped with wireless transmission module using an upper-computer. To decrease data oscillation under operation, the calculated angles need to be filtered. Therefore, simulation based on Kalman filter in MATLAB was performed and found Q/R rate takes an important role in filtering and filtering test verified it. In field test, error rate between trench depth measured and detected is within 5 % what confirms the practical usefulness of the developed measuring system for the trench depth detection.

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