Electromagnetic Dampers for Motorcycle Suspensions: Control Strategies and Performance Assessment

With increasing awareness of reducing emissions and conservation of energy, along with increasing comfort and road safety, more and more companies are developing and adopting regenerative suspensions, both in the motorcycle and automotive field. These systems can not only recover some part of the energy otherwise dissipated by the suspension in the form of heat, but also can help reduce CO2 emissions. ??This led to the advent of active and semi-active suspension systems, which are the most advanced suspension systems technology at present. The semi-active suspensions are more widely used in the motorcycles since more than a decade, because they are able to provide the best compromise between cost and performance (with low power request). Thanks to the hybridization and electrification of the vehicles in general, active suspensions would be the next step, as they are already implemented in the automotive industry. Active devices provide all the forces between the vehicle body and the unsprung mass, and work in all four quadrants of the force-velocity plot, thus require high power than semi-active systems. However, the performance is much better than the semi-active ones. ??To this end, this thesis project focuses on the study and implementation of possible active control strategies for motorcycle applications. For this purpose, an electrohydrostatic regenerative shock absorber is used which is able to convert hydraulic power into electric power, and vice-versa. To study the damper behaviour in dynamic conditions, a mono-corner (quarter car) model was used which represents the front suspension of a motorcycle. First, an ideal damper model was created in Matlab and Simulink. Then to simulate a real passive damper, a lookup table was used which comes from experimental characterization that represents a typical hydraulic actuator. Furthermore, skyhook and groundhook control strategies were implemented to the model and the efficiency map of the motor was also used to account for losses during power evaluation. After trying different combinations of the damping coefficients, finally their simulation results are compared with each other to ascertain the optimal configuration.