Analysis, Prototyping, and Experimental Characterization of an Adaptive Hybrid Electromagnetic Damper for Automotive Suspension Systems

In this paper, the concept of hybrid electromagnetic damping is explored and experimentally evaluated. The aim of the hybrid electromagnetic damping concept is to address the adaptive damping problem in vehicle suspension systems. In order to reach optimal performance, the damping characteristics of the vehicle suspension system must be capable of adaptively increasing or decreasing the amount of energy being absorbed by the system. For the sake of having the requisite functionality of variable damping, a multitude of solutions have been implemented, proposed, and evaluated at both the commercial and academic research levels. These solutions have met the variable damping requirements, but still, there are several crucial drawbacks associated with them. To overcome the shortcomings associated with the aforementioned variable damping solutions, a hybrid design consisting of a conventional hydraulic damper and a linear motor topology is fused together to build a hybrid variable damper. In the proposed hybrid electromagnetic design, the oil in the system acts as bias to provide fail-safe operation for the system, and the linear motor topology allows the requisite variable damping requirement to be achieved with the additional capacity for recovering energy from the system. We present an extended analysis of the electromagnetic damping component of the hybrid damper that can serve as a potent tool for the designers who seek to maximize the adaptability (and regeneration capacity) of the hybrid damper. Afterwards, based on the proposed hybrid electromagnetic concept, the design and fabrication of the first prototype are illustrated. An experimental setup and a test protocol are prepared, and different experiments are conducted to characterize the damping properties of hydraulic and electromagnetic components. Furthermore, friction forces, as well as power capacities, are scrutinized. The results indicate that the hybrid electromagnetic damper prototype is capable of providing a variable damping coefficient in a range of 1302-1540 N.s/m.