Parameter estimation of transfer function of viscous clutch with electrorheological fluid and torque control

This article concerns the identification of a transfer function which contains principal design and dynamic parameters of a hydraulic viscous disc clutch operated and controlled by an electrorheological (ER) fluid as a working fluid. A mathematical model of clutch dynamics is created as part of the clutch identification. It is considered that the changes in torque over time are described by transfer function represented by the first-order system with time delay. A prototypic clutch and a test bench are constructed, and tests are performed. A high voltage step input is used to trigger the torque changes. Constant parameters of the first-order system with time delay are identified on the basis of bench tests. According to the values of these parameters, a proportional-integral (PI) controller is selected for the closed-loop control system. It is found that operation of such a control system utilizing the identified design parameters is acceptable with high accuracy under external disturbances.