Current limitations of modern laparoscopic and robot-assisted surgical systems are due to restricted access through trocar ports, lack of haptic feedback, and difficulties with rigid robot tools operating inside a confined space. Yet biological “manipulators”, like the octopus arm and the elephant trunk, can manipulate objects while controlling the stiffness of selected body parts and being inherently compliant when interacting with objects. The Stiff-Flop project, with the Partnership of EAES, aims at creating a soft robotic arm that can squeeze through a standard trocar-ports, reconfigure itself and stiffen by hydrostatic actuation to perform compliant force control tasks while facing unexpected situations. The complete system consist of the soft manipulator with a gripper at the tip, distributed sensing, biologically inspired actuation and control architectures, learning and developing cognition through interaction with a human instructor, and manipulating soft objects in complex and uncertain environments.
The STIFF-FLOP Surgical System
The figure below shows the Vision for the STIFF-FLOP Surgical Project.
Multiple STIFF-FLOP arms are inserted through a 50mm incision into the patient (about 40mm diameter opening when Trocar port is inserted). Each arm (max diameter of 10mm) made of soft silicone is flexible, bendable and extensible in length. The operator can navigate the tip of any STIFF-FLOP arm while the body of the arms will autonomously follow in an intelligent way. The robotic arms can be equipped with tools used for laparoscopic surgery. The standard laparoscopic camera in the figure below can also be replaced by a flexible camera integrated into another STIFF-FLOP arm if required.
When manipulating soft tissue, the stiffness of the soft robot arm can be varied so that a range of force magnitudes can be exerted for certain procedural steps of a surgery.
The surgeon will navigate this system via a console which is similar to the da Vinci master. Sensation through haptic feedback allows operating more intuitively.
The following video shows one STIFF-FLOP arm (of a larger scale) with an integrated HF cutter at the tip: