A haptic knob based on the combination of shear mode and flow mode magnetorheological behaviors

Abstract

This study proposes a small haptic knob that provides kinesthetic torque feedback and vibrotactile feelings using magnetorheological fluids (MRF). A novel rotation shaft structure, including blades, is introduced into the haptic knob to simultaneously contribute two operation modes (shear and flow) of the MRF to its actuation. A simulation analysis is conducted to investigate the creation of the combinational mode in the haptic knob and to maximize the resistive torque by optimizing the blade angle. An experimental study is conducted to determine the optimal angle. Through experiments, the kinesthetic torque increased from 0.002 to 0.2 N·m as the current input was increased from 0 to 1.28 A. Furthermore, the haptic knob illustrated strong and stable vibrotactile feedback in the frequency range of 1–50 Hz.