Design and Development of Passive and Active Force Feedback Systems Using Magnetorheological Fluids

Abstract

Recently, haptic devices have been in use to increase the effectiveness of human-machine interfaces. On the forefront of this technology are passive, force-feedback controllers that resist or even limit motion. This motion control can be the result of a manipulator coming into contact with an object in either the virtual or physical world. Thus, an end-user can get both visual and tactile feedback on system operations. Furthermore, an active force-feedback controller can not only resist motion, but also create a reactive force that the user can sense. This active force-feedback is essential for delicate operations, such as telerobotic surgery, where a doctor needs to feel the difference between a spongy muscle and a hard bone. However, such haptic devices need to be simple and fast, so that they will not interfere with the existing system dynamics. A promising solution employs magnetorheological (MR) fluids in an active force-feedback controller. MR fluids feature a rheological change that is brought about when micron-sized particles within the fluid are exposed to a magnetic field. This change happens within milliseconds and can be used to create resistance quickly and easily. MR fluids can also be combined in a motor driven clutch mechanism to provide active resistance to the user with a force proportional to what the manipulator is experiencing. This paper will show the model development, design, construction, and control implementation of passive and active force-feedback devices.