Research On Piezoelectric Vibration Energy Harvester For Cutting Section Of Roadheader

At present,coal mine tunneling technology is developing in the direction of intelligence and unmanned.Building wireless sensor network to realize intelligent rapid tunneling is a prerequisite for the formation of intelligent mining,but at present,wireless sensor nodes are mainly powered by chemical batteries,and it is difficult to maintain and replace in the harsh environment of heading face.The existing piezoelectric energy harvester is difficult to make effective use of the wide-band vibration generated by the roadheader,and it is easy to be damaged when excited by the sudden change of vibration.In view of the above problems,this paper carries out the research on the vibration energy harvester for the cutting part of the roadheader,extracts the vibration characteristics of the cutting part of the roadheader in many ways,and puts forward a separate excitation piezoelectric vibration energy harvester.Through the mutual verification of theory and experiment,we explore the law between the structural parameters and its electrical output characteristics,improve the structure output voltage and output power,and realize the auxiliary power supply for wireless low-power sensor nodes.First of all,through the time-frequency domain analysis of the real vibration signal of the roadheader,the finite element simulation analysis of the simplified model of the cutting part of the roadheader,and the acquisition and analysis of the vibration signal of the cutting experiment on the similar theoretical test bench,the vibration characteristics of the cutting part of the roadheader in the time and frequency domain are analyzed,and it is concluded that the vibration generated under the working condition of the roadheader is mainly concentrated in the radial direction,and the suitable frequency range for piezoelectric vibration energy harvesting is 24-30 Hz.Secondly,according to the vibration characteristics of the cutting part of the roadheader under working conditions,a separated excitation piezoelectric vibration energy harvester is proposed.By separating the excitation mass from the beam itself,the upper limit of the mass that can be carried in the structure is greatly increased,thus the output voltage and output power of the structure are improved.By introducing nonlinear magnetic force,the resonant frequency domain of the structure is broadened and the robustness of the structure is improved.The electromechanical coupling model of the structure is established,and the position of the neutral layer of the piezoelectric beam structure is analyzed by using the piezoelectric theory and mechanical knowledge,the main parameters affecting the electrical output characteristics of the structure are found.The changing trend of the nonlinear magnetic force in the structure is deduced,thus the ability of wide-band energy harvest of the structure is deduced,and the relationship between the resonant frequency domain of the system and the structural parameters is analyzed,which provides a theoretical basis for the optimization of the structure in the following article.Finally,a piezoelectric vibration energy harvester test-bench is built to verify the characteristics of high output,wide band and high robustness of the separated excitation piezoelectric energy harvester.The relationship between the external environmental vibration excitation intensity,the size parameters of the structure and the electrical output characteristics is explored,and the optimization direction and parameter adjustment method of the structure are determined.According to the space limitation around the cutting part of the roadheader,the structural array is designed and manufactured,the external circuit of the energy harvester is designed through simulation analysis,and the array experiment is carried out.The experimental results show that when the external load of the six-circle array is 50kΩ,the amplitude is 2.0g and the excitation frequency is 27 Hz,the output voltage(Vrms)reaches the highest value of 19.2V,and the corresponding output power is 7.373 m W,and can maintain a continuous and effective output in the frequency band with the width of 8Hz.Under laboratory conditions and on the vibration test bench of the cutting part of the roadheader,the energy harvester is used as the power supply module to power the wireless switch and distance sensor successfully,and it is verified that the energy harvester can assist the power supply for low power wireless sensor nodes.Figure [83] Table [13] Reference [75]...