Design and validation of a Magneto-Rheological clutch for practical control applications in human-friendly manipulation

In this paper we present the design and experimental validation of a Magneto-Rheological (MR) clutch developed for servo control applications in human friendly robotic systems. The clutch is developed as a practical prototype for potential industrial applications in the low to mid torque range. Conventional servo motors have been shown to lack the necessary properties to deliver intrinsically safe actuation for physical interaction with humans. Several human safe actuation paradigms have been proposed, however, tend to increase mechanical complexity as well as require more sophisticated control strategies. Furthermore, many of the proposed solutions have failed to demonstrate a practical implementation that provides the necessary performance capabilities required for practical applications in automation, as well as more general servo control applications. MR clutch devices have been shown to provide favorable characteristics for such tasks, however have focused primarily on haptic systems or low torque applications. The developed prototype MR clutch is capable of transmitting up to 75 Nm, and has a control bandwidth of approximately 30 Hz.