A compact 4-DoF MR damper with semi-independent damping adjustment

Magnetorheological (MR) fluid-based damper systems have been known for their novel property to adjust its damping forces in milliseconds by changing the applied magnetic field strength. This adaptability comes along with a rather simple design compared to classical fluidic damper systems. However, the known operating modes of the MRF, such as shear, flow, squeeze, and pinch mode, are only able to generate damping in one specific direction. On the contrary, vibrations could occur not only in one direction but also in several directions. Therefore, it is desirable to have damping generated not only in one direction but also in several directions. In the worst case, N dampers would need to be installed to dampen vibrations in N translational and rotational directions. In this work, a damper design for a single and compact 4-DoF magnetorheological-based damper is proposed. The compactness is achieved by integrating several control elements to control the MR fluid. It is done by installing five electromagnets in one MR damper without adding any extra fluid chamber so that only one fluid chamber is needed for the damper system. Depending on the direction of the acting vibration, the corresponding electromagnet is then activated accordingly, which changes the state of the MR fluid in the chamber locally. Experimental investigations are conducted and the results are presented in this work. It can be seen from the results, that the design allows the MR damper to possess four degree-of-freedom by using only a single fluid chamber. Moreover, the damping can be adjusted, depending on the damping requirement.