A Soft Modular Manipulator for Minimally Invasive Surgery: Design and Characterization of a Single Module

This paper presents the concept design of a modular soft manipulator for minimally invasive surgery. Unlike traditional surgical manipulators based on metallic steerable needles, tendon-driven mechanisms, or articulated motorized links, we combine flexible fluidic actuators to obtain multidirectional bending and elongation with a variable stiffness mechanism based on granular jamming. The idea is to develop a manipulator based on a series of modules, each consisting of a silicone matrix with pneumatic chambers for 3-D motion, and one central channel for the integration of granular-jamming-based stiffening mechanism. A bellows-shaped braided structure is used to contain the lateral expansion of the flexible fluidic actuator and to increase its motion range. In this paper, the design and experimental characterization of a single module composed of such a manipulator is presented. Possible applications of the manipulator in the surgical field are discussed.