Hydraulically driven joint for a force feedback manipulator

Recently, surgical manipulators have been widely used to support human operations, such as surgical operations. These manipulator systems are suitable for careful work, but they have a few problems. One problem is that the manipulators are not equipped with haptic sensing functions. When a manipulator does not employ haptic sensing functions, an operator can only conduct an operation using visual feedback. Therefore, to substitute for visual detection, it is necessary for the operator to use advanced techniques to determine physical contact during an operation. We have developed a new mechanism to solve this problem. A hydraulically driven joint is constructed in a spherical bearing and bellows tubes that enables a haptic sense display for the operator. This system can measure the small forces acting on the tips of the manipulator using Pascal's principle. A model of the system is derived from the relationship between the internal pressure of the bellows tube and the refraction angles of the joint. In this study, we quantitatively investigated the relationship between the internal pressure of the bellows tubes and the refraction angles of the joint. To estimate the refraction angle, we measured the quantity of water that was provided from syringes. It was confirmed that the developed system allowed for an estimation of both the strength and direction of the external force applied to the manipulator by measuring the bellows tubes’ internal pressure. This report describes the prototype joint.