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Three important problems in the study of grasping and manipulation by m ultiingered robotic hands are: a Given a grasp characterized by a set of contact points and the associated contact models, determine if the grasp has force closure; b If the grasp does not have force closure, determine if the ngers are able to apply a speciied resultant wrench o n t h e(More)
This article study the dynamics of parallel manipula-tors. We first have a brief review and discussion on different dynamics formulations in literature(Newton-Euler, Direct Lagrangian, and Lagrange-D'Alembert formulation on the reduced system). Then we show the equivalence of these methods. Based on the concepts from differential manifold, we prove that(More)
Dextrous manipulation is a problem of paramount importance in the study of multiingered robotic hands. Given a grasped object, the main objectives are: a generate trajectories for the nger joints so that through the eeects of contact constraints, the object can be transferred to a goal grasp connguration; and b derive control algorithms to realize planned(More)
As we all know, singularity is commonly encountered in parallel mechanisms. It is shown that the behavior of singularity of parallel mechanisms could be more complicated than that of serial ones. However, it is not very clear whether singularity will bring problems to kinematics, dynamics or other characteristics and what result will be caused when parallel(More)
The purpose of this study was to evaluate the effectiveness of application of muscle relaxants and celecoxib in early recovery after total knee arthroplasty (TKA). One hundred and fifty patients were randomized 1:1:1 to receive either both of muscle relaxants and celecoxib or muscle relaxants alone or placebo for 2 weeks (50 patients in each group). VAS(More)