M. Fernandez-Munoz

In this paper, the experimental validation of an innovative clutch based on magnetorheological fluids (MRFs) excited by permanent magnets is described. The device, used in automotive applications to engage and disengage the vacuum pump, is tested using a standardized Worldwide harmonized Light-duty Test Cycle (WLTC). A test bench is built, and the system is observed in its operation for one hour, considering two consecutive WLTCs. The temperature increase slightly impacts the clutch’s behavior; in particular, the on-state performance of the device, mainly determined by the magnetic field-induced torque, remains largely unaffected by the temperature increase. The results showed that the performance of the proposed MRF-based device is only marginally affected by the phenomena that take place during the actual operation (e.g., temperature increase, shaft slip), confirming the effectiveness of the design.

A novel concept of a rotary electromagnetic actuator for positioning with ultra-low power consumption is presented. The device is based on harnessing potential magnetic energy stored between permanent magnets facing each other with opposing magnetization polarities. When combined with an active electromagnetic control and passive stabilization system, the rotor of the device can switch between stable equilibrium positions in a fast way with a minimal fraction of the power and energy consumption of a traditional electromagnetic actuator. In this paper, a theoretical model, supported by finite element analysis results, is presented. The actuator has been designed in detail to operate as an optical filter wheel actuator. Calculations demonstrate that the device has the potential to provide a power-consumption saving of up to 86.6% and an energy consumption reduction of up to 58.6% with respect to a traditional filter wheel actuator.