Haptic interface with hybrid actuator for virtual needle insertion and tissue cutting

For medical training purposes, most operations can be considered as a combination of two main action types that require much practice: needle insertion and tissue cutting. A haptic interface is highly desirable for training medical personnel in a virtual environment on these two fundamental tasks. In this study, we developed a compact haptic device that can simulate both of these tasks. The device employs a hybrid actuator with a strong and stable response to reflect realistic tissue behavior. The hybrid actuator uses a custom designed MR-brake coupled in series with a DC-servomotor. Stiff tissues that exhibit high levels of resistance forces, such as bone and tendon, could be rendered as well as the fine force variations in heterogeneous soft tissue simulation. Furthermore, the new device provides additional improvements to previously developed haptic scissors by other researchers since the new hybrid actuator can provide a wider range of forces with less current consumption.