Research On Swing Type Energy Harvester Using Mechanical Energy

In recent years, micro electronic technique and wireless communicationtechnique developed rapidly, contributing to the widespread of low-powerdissipation portable devices in our daily life. However, there are many defectsrelating to the traditional method using chemical batteries as power supply, such asshort life cycle, huge volume and pollution. It is quite difficult to charge orexchange batteries regularly for some devices such as oceanographic buoy andunder sea detecting instruments because of the limitation of their installation sites.How to provide a steady power for these devices remains to be solved. At present,energy harvesters collecting solar energy, wind energy, ocean wave energy, vibrationenergy and human motion energy have been proposed, but none of them can providea steady electric energy in a direct way.In this paper, a new type of energy harvester have been proposed, which cannot only harvest random and fluctuating energy in the environment, but can alsoprovide a relatively steady speed for micro electric generator to produce steadyelectric energy. The generator mainly consists of torsion spring tighteningmechanism, a speed governing mechanism and an acceleration gear train, and cangather kinetic energy and potential energy in ambient though the inertia of thependulum under external stimulation. The swing motion of the pendulum istransfered to tighten the torsion spring thougth the function of torsion springthighten mechanism. The torsion spring can provide a relative stable torque,therefore the random fluctuating energy is transformed to potential energy of torsionspring and can be used to drive following mechanism to produce electric energy.The potential energy of torsion spring can be released at a certain rate under thecontrol of speed governing mechanism, making it possible to drive micro electricgenerators at a certain speed though the usage of an acceleration gear train and theone-way cluth. The vibration frequency of the speed governing mechanism isdetermined by the balance wheel’s rotational inertia and stiffness of the hair spring.Different output speed and power can be captured by adjusting the hairspring’sstiffness..At the beginning of this paper, operating principle and design process aredetailed introduced, along with the structure, installation and fasten method,location distribution and transmission relationships. Mathematical model is built onthe torsion spring tightening process, numerical and dynamic simulation areconducted afterwards, the influences of structure parameters on torsion spring tightening process is analyzed. Afterwards, a3-body collision model andmathematical equations are built of the speed governing mechanism, numerical anddynamic simulations are conducted as well. In the end, revelant experimentalresearches are conducted to study the influences hairspring length and mainspringtorque exert on the frequency and magnitude of balance wheel motion throughacoustic and video processing methods. Because the pressure of time, researches onelectricity generation performance of the generator will be put off.