Design and analysis of energy-harvesting shock absorber with electromagnetic and fluid damping

Abstract

The design and numerical simulation of a linear generator for use in an automobile shock absorber are presented in this paper. The conceived linear generator employs high-performance rare earth permanent magnets with compact size to ensure efficient energy recovery. Finite element analysis and Matlab simulation are utilized to derive the generator configurations for the satisfactory utilization of magnets and optimized functioning. Experimentation was performed on a linear generator prototype and electromagnetic shock absorber to validate the numerical analysis. The numerical model is then utilized in the design of a full-scale energy-harvesting shock absorber with fluid damping and a linear generator. A novel feature of the presented work is the use of fluid amplification to simultaneously achieve energy dissipation and velocity amplification. Fluid amplification does not affect the dynamics of the system and increases the coil velocity by approximately eight times. Smooth variation in damping force, improved fail-safe characteristics, and absence of transmission elements, such as mechanical gears, are additional advantages of the system. Matlab Simscape evaluation is employed to analyze comfort, safety, and energy-harvesting characteristics, which are then compared with that of the conventional fluid shock absorber. Simulation with actual road excitation data indicates that the presented system harvests 15 W of the average power from each wheel. Lastly, the layout for integrating the presented shock absorber in McPherson suspension is discussed.