A new haptic interface device capable of continuous-time impedance display within sampling-period: application to hard surface display

In this paper, we discuss displaying a virtual object with coupling impedance by a haptic interface device with long sampling period. For such system to be stable, coupling impedance has to be set low. But it means that the operator feels soft surface of the virtual object and it is not suitable for displaying a virtual object with hard surface. This is because the system is a discrete time system. So we propose a haptic interface device with analog springs and dampers that exert reaction force continuously. The method can decrease the influence of the sampling period and make haptic interface more stable. Finally we perform some experiments with two dimensional virtual environment to confirm the effect of the proposed method.