Memory-based passivation approach for 6-DOF haptic rendering of high stiffness virtual environment

In this paper, in order to have stable haptic interaction, we present an extension of memory-based passivation approach for 6 degree-of-freedom (DOF) haptic rendering while interacting with high stiffness virtual environment. We introduce a 6-DOF massless virtual proxy which is connected to the moving object on every DOF by a massless spring. Then, unlike the conventional memory based passivation approach, inspired from the graphical interpretation of passivity in force vs. position error together with torque vs. angular error graphs, we apply the revised memory-based passivation approach in six DOFs. After the extension, position/angular resolution became a problem, since it depends on configuration of the haptic device. In this paper, by revising the saving data procedure in pressing phase, and using a new algorithm in releasing phase, unlike the conventional memory based passivation approach, the extended idea is robust to both variation of resolution pulses and even skipped pulses. The proposed framework makes the haptic interface passive and stable in every DOF.