A study of vehicle electromagnetic regenerative shock absorber
Creators: name: Zhang, Ran
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 400803
subject: Electrical energy generation (incl. renewables, excl. photovoltaics)
classificationCode: 401702
subject: Dynamics, vibration and vibration control

description: The technology of energy harvesting from shock absorber has become more promising over the years with a potential for implementation. The aim of the research is to improve the energy harvesting ability of the regenerative shock absorber and evaluate its feasibility operating in the real road condition on the vehicle. <br><br>This thesis consists of 7 chapters to address the research questions raised from the existing research gaps based on the literature reviews: 1. How can the performance of the electromagnetic energy harvester in 2DOF system be improved? 2. For the direct drive and indirect drive regenerative shock absorbers, which one has better performance? 3. How can the half vehicle model with regenerative shock absorbers be modelled for the premium energy harvesting performance? <br><br>In order to answer the research questions, firstly a 2 degrees of freedom oscillating system resembling the quarter vehicle suspension system is constructed with the electromagnetic harvester and validated by the simulation model. It is found that the peak power output occurs at natural frequency. Base excitation amplitude and external resistance can also affect the system power output. As for the energy harvester, better energy harvesting performance can be achieved through two factors: coil speed with respect to the magnets and the electro-mechanical coupling constant. The double speed mechanism can increase the coil speed with respect to the magnets and is applied on a design of novel regenerative shock absorber. It is found that increasing the coil speed with respect to the magnets for 2 times can result in increasing the power output by 4 times. A novel indirect drive regenerative shock absorber with the arm-teeth system is also designed and fabricated to answer the second research question. The results show 2 that the power output can be substantially increased compared with the traditional direct drive regenerative shock absorber. It is also found that the arm-teeth system makes the regenerative shock absorber more sensible to parameter optimization and has the potentials to increase the energy harvesting bandwidth. <br><br>As the response to research question three, a half vehicle suspension system model is established with two indirect drive regenerative shock absorbers. The Taguchi method is unitized for the parameter optimization. With the application of the random road excitation displacement amplitude, the optimized model can harvest more energy than the non-optimized model when the vehicle is driving on the Class A, Class C and Class E road. Lastly a full vehicle suspension system model is developed as an extension to the half vehicle suspension system model. It is found that at high frequency range, the peak power output ratio of full vehicle suspension system is same as that of the half and quarter vehicle suspension system. The advantages of the full vehicle suspension system are more obvious at low frequency range or when the vehicle is driving on the off-road condition.