Research On Multi-directional Piezoelectric Energy Harvesting Device Based On Rope Driv

With the development of wireless sensor networks,providing reliable and clean energy for wireless sensors has become a research hotspot.Chemical batteries have disadvantages such as environmental pollution,high maintenance cost,and frequent replacement.Therefore,they cannot meet the requirements of long-term stable operation of wireless sensor nodes.Because of the small size of wireless sensor nodes,and the power consumption is generally less than 10 m W.Vibration energy exists widely in the environment,which can meet the energy demand of wireless sensor nodes.Because of the advantages of high energy density and simple structure,the piezoelectric vibration energy harvesting device has become a research hotspot.The piezoelectric vibration energy harvester usually works in the field environment and other variable conditions,that is,the external excitation of the piezoelectric vibration energy harvester always changes indeterminate in a certain range.In this paper,the nonlinear dynamic characteristics of M-shaped piezoelectric energy harvester(MEH)are investigated.In view of the lack of multi-direction capability of traditional piezoelectric energy harvesters,proposed a novel rope-driven piezoelectric energy harvester for multidirectional vibrations.The main research contents are as follows.Based on lumped parameter method,the parameter model and electromechanical governing equation of M-beam piezoelectric energy harvester are analyzed.The influence of the depth of the potential well on the performance of the piezoelectric vibration energy harvester is analyzed by Matlab simulation software.The simulation results show that the initial frequencies of periodic and chaotic motion of the mechanical oscillator are lower in a deep well with the same excitation strength.In addition,the periodic motion of MEH in a deep well configuration has a wider band than that in a shallow well configuration,while the band width of the chaotic motion is narrower than that in a shallow well configuration.The output response of MEH under sinusoidal excitation of different intensities was analyzed.The simulation results show that the bandwidth of periodic motion and chaotic motion will be improved with the increase of excitation strength when the depth of potential well is constant.The bandwidth fraction of periodic motion and chaotic motion can reach 0.8Hz and 3.2Hz under the condition of shallow potential well and 3 m/s2.Finally,the attractive domains of MEH in different potential Wells were analyzed.The results show that the probability of MEH oscillating in the deep well increases with the increase of the gap between the depth and the depth of the potential well.The proposed Rope-driven Piezoelectric Energy Harvester For Multidirectional Vibrations(RPEH)is experimentally researched.The energy capture effect of the device under sweep excitation is analyzed.Experimental results show that RPEH can effectively transform vibration energy in any direction.In d=100 mm configuration(rope slack state),RPEH has better operation bandwidth.The proposed harvester can offer an operation bandwidth of 3.6Hz,2.1 Hz and 3.6 Hz under 5 m/s~2 excitation in three directions,which is increased by 140%,40%and 140%than that of the linear piezoelectric cantilever,respectively.When the excitation is in the x or z-direction,the voltage response of RPEH is obviously hardening response due to the large translation motion of the ball.