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Mechanical Sciences An open-access journal for theoretical and applied mechanics

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Mech. Sci., 3, 85-93, 2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
05 Dec 2012
A statically balanced and bi-stable compliant end effector combined with a laparoscopic 2DoF robotic arm
J. Lassooij1, N. Tolou1, G. Tortora2, S. Caccavaro2, A. Menciassi2, and J. L. Herder1 1Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of Biomechanical Engineering, Mekelweg 2, 2628 CD Delft, The Netherlands
2The BioRobotics Institute, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, 56127 Pisa, Italy
Abstract. This article presents the design of a newly developed 2DoF robotic arm with a novel statically balanced and bi-stable compliant grasper as the end effector for laparoscopic surgery application. The arm is based on internal motors actuating 2 rotational DoFs: pitch and roll. The positive stiffness of the monolithic grasper has been compensated using pre-curved straight guided beams that are preloaded collinear with the direction of actuation of the grasper. The result is a fully compliant statically balanced laparoscopic grasper. The grasper has been successfully adapted to a robotic arm. The maximum force and stiffness compensations were measured to be 94% and 97% (i.e. near zero stiffness) respectively. Furthermore, the feasibility of adjusting for bi-stable behavior has been shown. This research can be a preliminary step towards the design of a statically balanced fully compliant robotic arm for laparoscopic surgery and similar areas.

Citation: Lassooij, J., Tolou, N., Tortora, G., Caccavaro, S., Menciassi, A., and Herder, J. L.: A statically balanced and bi-stable compliant end effector combined with a laparoscopic 2DoF robotic arm, Mech. Sci., 3, 85-93,, 2012.
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