Response time and performance of a high-torque magneto-rheological fluid limited slip differential clutch

In this study, the response time and system characterization analyses of a high-torque magneto-rheological (MR) fluid limited slip differential (LSD) clutch are presented. The response time of the clutch is examined based on the objective of keeping the relative velocity difference of the shafts of the clutch less than a predetermined threshold value. The experimental setup allows the application of an external disturbance to the system, so that the relative velocity difference exceeds the threshold value. A velocity-based, closed-loop control system is designed and tested. Additionally, system identification experiments are performed to determine system parameters such as bearing friction coefficients, dry and viscous torque coefficients. These parameters are utilized in the theoretical response time analyses of the MR fluid LSD clutch. It is demonstrated that the overall response time of the system varies between 20 and 65 ms as a function of operating velocity and electromagnet current, including the response times of the controller, solenoid inductance and MR fluid and inertia effects. The response time reduces by increasing solenoid current and increasing the operating velocity.