On the Feasibility and Suitability of MR Fluid Based Actuators in Human Friendly Manipulators

In this paper, we will discuss the potential benefits Magneto-Rheological fluids can bring to the field of human friendly manipulators. For several decades now, the robotics industry has postulated the emergence of a new breed of manipulators capable of safely interacting with humans. The integration of robots into human environments has always possessed a unique set of challenges. The primary concern has always been for the safety of the human coworkers. Insuring their safety has led to the desire to design manipulators with intrinsic safety characteristics. Specifically, it is noted that modern ‘human-safe’ manipulators are successful if they have minimized both their weight and reflected actuator inertia. The leading research accomplishing this relies on complex actuation systems. Such systems commonly suffer from degraded performance and high cost of development. Magneto-Rheological (MR) fluids are a class of smart-materials that can instantaneously, and reversibly alter their rheological properties under the influence of an applied magnetic field. Devices developed with such fluids are known to possess superior torque-to-inertia characteristics over conventional servo systems. Moreover, their simple mechanical construction suggests that manipulators using such devices could be developed at a lower cost. We have developed such a device to demonstrate some of these characteristics, and report on it in this paper.