Design of multi-degree motion haptic mechanisms using smart fluid-based devices

This article presents two different types of haptic masters capable of 4-degree- of-freedom (DOF) force feedback utilizing magnetorheological fluid (MR) and electrorheological (ER) fluid. The proposed ER master consists of a spherical joint for 3-DOF rotational motion and a linear device for 1-DOF translational motion, the MR haptic master consists bi-directional clutches associated with a planetary gear system and one-directional clutch with a bevel gear system. After showing the configuration of each haptic mechanism, the torque and force models of the actuators are derived based on the field-dependent Bingham model. After undertaking optimal design with spatial limitation and desired torque level, two different types of haptic master systems are manufactured. The torque and force responses are experimentally evaluated to validate practical feasibility of the proposed haptic masters for medical application.