Modeling and Control of Single and Two Degree of Freedom Magnetorheological Fluid-based Haptic Systems for Telerobotic Surgery

In this study, the authors develop haptic systems for telerobotic surgery exploiting MR fluids for semiactive force feedback. To investigate the full range of tactile force exhibited by a particular MR damper design, a microstructural 3D kinetic theory-based model of MR fluids has been developed. In this model, microscale constitutive equations relate flow, stress, and particle orientation. The higher accuracy of the model in this regard gives better force representations of highly compliant objects. In this article, the model is utilized in force-feedback control of both a SDOF system and a 2DOF system. A state-feedback control algorithm is employed to track both the SDOF system, and the 2DOF system using specially designed MR force-feedback joysticks. The results demonstrate that the MR fluid-based force-feedback joysticks can be used effectively as haptic devices. It is also observed that both SDOF and 2DOF systems are nearly transparent in replicating the stiffness of different external objects, due to the light weight of the semiactive system and controller implementation.