Comparison of field-controlled characteristics between ER and MR clutches

This paper presents torque control characteristics of ER (electro-rheologic al) and MR (magneto-rheological) clutches. As a first step, Bingham propert ies of ER and MR fluids are experimentally distilled under the shear mode. A nondimensional model of the clutches is established for reasonable compar ison. Two clutches have the same principal design parameters such as outer radius of the disc and electrode gap size. Following the manufacturing of t wo clutches on the basis of the nondimensional model, field-dependent torqu e levels are experimentally evaluated. A PID (proportional-integral-derivat ive) controller is then designed and experimentally realized to achieve des ired torque. Both regulating and tracking torque control responses of the t wo clutches are evaluated and compared. In addition, control durability for torque tracking is undertaken to provide a practical feasibility of the pr oposed clutches.