Design And Experimental Research Of Energy Harvesting Device For Plantar Motion

With the rapid development of modern micro-electromechanical system(MEMS)technology,human wearable microelectronic devices have been widely used.However,at present,such devices are affected by their small battery capacity and battery life.The human body has a large amount of mechanical energy generated in the process of exercise,which can be used to provide power support for some special occasions or emergency situations by harvesting the mechanical energy in human movement.Therefore,a human motion plantar energy harvesting device is studied in this paper,and the action mechanism,dielectric materials,structural units and output efficiency of different forms of energy harvesting are studied.In addition,this paper also sets up a testing device for the excitation position,amplitude,frequency and efficiency of the piezoelectric chip,which can be used to study the influence of different factors on the energy harvesting effect of the piezoelectric chip through experimental testing.it provides an effective basis for the structural design of the follow-up device.The main research work of this paper is as follows:(1)The main contents are as follows: 1 the development status of existing human motion energy harvesting devices is studied.From the aspects of the structure,efficiency and position of the energy trap,the electromagnetic,friction,piezoelectric and compound energy harvesting technologies are explained and sorted out in detail,and the advantages and disadvantages of different energy harvesting modes are analyzed and compared.The key technologies and development trends of energy trappers are summarized.(2)The test platform for the energy harvesting characteristics of the piezoelectric chip is built,and the influence of different excitation conditions on the energy harvesting effect of the piezoelectric chip is explored.In order to study the influence of the amplitude and frequency of the piezoelectric chip on its energy harvesting characteristics,a testing platform is designed in this paper,which is based on the crank-slider mechanism and is composed of main frame,governor,tachometer,motor and fixed seat.by testing the output efficiency of a specific piezoelectric chip under different excitation frequencies and amplitudes,the best output efficiency parameters are obtained,which provides a parameter basis for the structural design of the follow-up device.(3)The existing energy storage circuit is introduced,and an energy storage circuit for piezoelectric energy harvesting is designed by Altium Designer software,and the energy harvesting efficiency of different input modes is tested by experiments.In this paper,the MAX666 low power regulator chip is used to realize the stable output of electric energy through rectifying filter and voltage stabilization,and finally charge the miniature lithium battery and realize the storage of electric energy.The energy harvesting efficiency of different input modes(single input,series input,parallel input and double input)is explored through charging experiments,and the best input mode is obtained.the results provide a basis for the connection mode of subsequent piezoelectric chips with multi-source input.(4)On the basis of theory,simulation and experimental tests,a principle prototype of plantar energy harvesting device for human motion is designed and made,including the structure part and the circuit part.Based on the optimal energy harvesting parameters,the frequency rising multiple and vibration amplitude of the device are determined,and the structure of the device is designed and dynamically simulated by Solid Works and Ansys Workbench.Based on the optimal connection mode,the input mode of the storage circuit is determined.Finally,the device is made by 3D printing and PCB board,and tested and verified by experiments.