2021-04-162015-10-010094114X03741052WOS;000359433800017SCOPUS;2-s2.0-84931270181http://hdl.handle.net/10784/29299Monolithic and thus fully compliant surgical graspers are promising when they provide equal or better force feedback than conventional graspers. In this work for the first time a fully compliant grasper is designed to exhibit zero stiffness and zero operation force. The design problem is addressed by taking a building block approach, in which a pre-existing positive stiffness compliant grasper is compensated by a negative stiffness balancer. The design of the balancer is conceived from a 4-bar linkage and explores the rigid-body-replacement method as a design approach towards static balancing. Design variables and sensitivities are determined through the use of a pseudo-rigid-body model. Final dimensions are obtained using rough hand calculations. Justification of the pseudo rigid body model as well as the set of final dimensions is done by non-linear finite element analysis. Experimental validation is done through a titanium prototype of 40 mm size having an unbalanced positive stiffness of 61.2 N/mm showing that a force reduction of 91.75% is achievable over a range of 0.6 mm, with an approximate hysteresis of 1.32%. The behavior can be tuned from monostable to bistable. The rigid-body-replacement method proved successful in the design of a statically balanced fully compliant mechanism, thus, widening the design possibilities for this kind of mechanism. (C) 2015 Elsevier Ltd. All rights reserved.enghttps://v2.sherpa.ac.uk/id/publication/issn/0094-114XStatic balancingZero stiffnessPseudo-rigid-body modelCompliant mechanismsLaparoscopic grasperRigid-body-replacement-methodinfo:eu-repo/semantics/article2021-04-16Lamers, A.J.Gallego Sánchez, J.A.Herder, J.L.10.1016/j.mechmachtheory.2015.05.014