A Novel Bidirectional MRF Based Actuator: Configuration, Optimal Design and Experimental Validation

In this research, development of a new bidirectional MRF based actuator (BMRA) is presented. In this configuration, the housing and the input shaft of BMRA rotate in opposite direction at the same speed via bevel gear system. On the input shaft, a disc made of magnetic steel is fastened. Another disc, also made of magnetic steel, is fastened to the output shaft of the BMRA. The two discs are embedded inside housing. The gap between two discs and housing is filled by magnetorheological fluid (MRF). Two exciting coils are placed on second disc to generate the required magnetic field to transfer a required torque from the first disc and from the housing to the second disc. When exciting first coil, the output shaft rotates in clockwise direction (the input shaft rotation direction) whereas exciting second coil makes the output shaft rotates in counter-clockwise (the housing rotation direction). The optimal design of BMRA is conducted considering maximum braking torque and minimum the mass of the structure. The balancing composition motion optimization algorithm (BCMO) is employed to solve the optimization problem. A prototype of the optimized BMRA is manufactured to validate the optimal results. Besides, experimental work is performed to evaluate the performance of the prototype. Torque response in clockwise and counter-clockwise at different value of step applied current is measured and compared with the calculated ones. The results show that the novel proposed configuration of BMRA is more compact than other previous configurations in the same transmitting torque. Moreover, the bottle neck magnetic phenomenon of conventional configurations is eliminated.