Image: A soft pop-up arm performing tissue counter-traction on a porcine stomach (Image courtesy of the Wyss Institute).
Multiple soft actuators can improve robotic arm distal dexterity by incorporating a rigid skeleton that pops up to assist in surgical procedures.
Under development at the Wyss Institute for Biologically Inspired Engineering (Boston, MA, USA), the hybrid manufacturing paradigm combines pop-up book microelectromechanical systems (MEMS) manufacturing with soft-lithographic techniques in order to produce millimeter-scale mechanisms with embedded sensing and user-defined distributed compliance. The hybrid soft pop-up actuators, which are powered by water pressure, are connected to the rigid components of the multi-articulated robotic arm with an irreversible chemical bond, without the need of any adhesive.
The multi-articulated robotic arm can then be integrated into current flexible endoscopes to improve distal dexterity and enable tissue retraction. Capacitive sensing is used to measure forces applied to the tissue, giving the surgeon a sense of where the arm is and how it's moving. The arm is also equipped with a suction cup--inspired by octopus tentacles--to safely interact with tissue. According to the researchers, the fabrication method allows for bulk manufacturing and also allows for increased levels of complexity for more sensing or actuation. The study was published on August 2, 2017, in Advanced Materials Technologies.
“The idea behind this technology is basically to obtain the best of both worlds, by combining soft robotic technologies with origami-inspired rigid structures,” said lead author Sheila Russo, PhD. “Using this fabrication method, we were able to design a device that can lie flat when the endoscope is navigating to the surgical area, and when the surgeon reaches the area they want to operate on, they can deploy a soft system that can safely and effectively interact with tissue.”
“The ability to seamlessly integrate gentle yet effective actuation into millimeter-scale deployable mechanisms fits naturally with a host of surgical procedures,” concluded senior author Professor Robert Wood, PhD, who developed pop-up fabrication. “We are focused on some of the more challenging endoscopic techniques, where tool dexterity and sensor feedback are at a premium, and can potentially make the difference between success and failure.”
Wyss Institute for Biologically Inspired Engineering