Conventional vascular intervention radiology (VIR) procedure presents a few challenges to overcome, which are radiation exposure issue during the procedure under X-ray, physical and mental burdens to the operator in handling catheter and guidewire. We propose a robotic approach to resolve such problems. Specifically, this paper deals with usability test of master devices to control four degrees of freedom (4-DOF) robotic vascular intervention system. The usability of two master devices was measured in terms of task completion time and NASA-TLX index. Both novice and expert group participated in master-slave vascular intervention procedure based on abdominal blood vessel phantom. We found that position to velocity based master device is much effective compared to position to position based master device.

This paper describes design and application of a novel counter-balancing stackable parallel mechanism. The stackable mechanism is designed by combining a five-bar and a couple of parallelograms. This design allows a compact design and wide workspace as compared to prior parallel type counter-balancing mechanisms. A linear geometry of this mechanism guarantees static balancing in the whole workspace. This mechanism was successfully applied to otologic.

Much attention has not been paid to analysis of the open-loop stability for gravity counter-balancing of parallel mechanisms or closed-chain mechanisms. The open-loop stability is crucial especially in passively counter-balanced mechanisms where no actuators are involved. Passive hands-on device is such an example. A general stiffness model is derived for general closed-chain mechanism including counter-weight model. As a measure of the open-loop stability, we employ the determinant of the stiffness matrix. A parallel mechanism having 3 translational DOF (degree of freedom) is employed as an exemplary device. An antagonistically counter-balancing is found the most stable method. We conduct dynamic simulation and experiment to confirm the open-loop stability of the system.