Abstract-This paper presents the design and fabrication of Single-Port lapaRoscopy bImaNual roboT (SPRINT), a novel teleoperated robotic system for minimally invasive surgery. SPRINT, specifically designed for single-port laparoscopy, is a high-dexterity miniature robot, able to reproduce the movement of the hands of the surgeon, who controls the system through a master interface. It comprises two arms with six degrees of freedom (DOFs) that can be individually inserted and removed in a 30-mm-diameter umbilical access port. The system is designed to leave a central lumen free during operations, thus allowing the insertion of other laparoscopic tools. The four distal DOFs of each arm are actuated by on-board brushless dc motors, while the two proximal DOFs of the shoulder are actuated by external motors. The constraints generated by maximum size and power requirements led to the design of compact mechanisms for the actuation of the joints. The wrist is actuated by three motors hosted in the forearm, with a peculiar differential mechanism that allows us to have intersecting rollpitch-roll axes. Preliminary tests and validations were performed ex vivo by surgeons on a first prototype of the system. Index Terms-Bimanual robot, miniature robotic arm, minimally invasive surgery, robotic surgery, single-port laparoscopy (SPL).
SUMMARY
Jumping insects develop accelerations that can greatly exceed gravitational acceleration. Although several species have been analysed using different tools, ranging from a purely physical to a morpho-physiological approach, instantaneous dynamic and kinematic data concerning the jumping motion are lacking. This is mainly due to the difficulty in observing in detail events that occur in a few milliseconds. In this study, the behaviour of the green leafhopper, Cicadella viridis, was investigated during the take-off phase of the jump, through high-speed video recordings (8000 frames s−1). We demonstrate that C. viridis is able to maintain fairly constant acceleration during overall leg elongation. The force exerted at the foot–ground interface is nearly constant and differs from the force expected from other typical motion models. A biomechanical model was used to highlight that this ability relies on the morphology of C. viridis hind legs, which act as a motion converter with a variable transmission ratio and use the time-dependent musculo-elastic force to generate a nearly constant thrust at the body–ground interface. This modulation mechanism minimizes the risk of breaking the substrate thanks to the absence of force peaks. The results of this study are of broad relevance in different research fields ranging from biomechanics to robotics.
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