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A generic, or more properly 1-generic, serial manipulator is one whose forward kine-matic mapping exhibits singularities of given rank in a regular way. In this paper, the product-of-exponentials formulation of a kinematic mapping together with the Baker–Campbell–Hausdorff formula for Lie groups is used to derive an algebraic condition for the regularity.
Checking the regularity of the inverse jacobian matrix of a parallel robot is an essential element for the safe use of this type of mechanism. Ideally such check should be made for all poses of the useful workspace of the robot or for any pose along a given trajectory and should take into account the uncertainties in the robot modeling and control. We… (More)
Engineers have for some time known that singularities play a significant role in the design and control of robot manipulators. Singularities of the kinematic mapping, which determines the position of the end–effector in terms of the manipu-lator's joint variables, may impede control algorithms, lead to large joint velocities, forces and torques and reduce… (More)
The analysis of singularities is a central aspect in the design of robotic manipulators. Such analyses are usually based on the use of geometric parameters like DH parameters. However, the manipulator kinematics is naturally described using the concept of screws and twists, associated to Lie groups and algebras. These give rise to general and… (More)
Erythrokeratodermia variabilis (EKV) is a well-described entity consisting of transient erythematous areas and fixed hyperkeratotic plaques. Here, a white infant girl with EKV consistent with the classic form of the disease and several previously described variants is presented. This patient was first seen at 6 weeks of age and subsequently followed until… (More)
Becker's nevus (BN) has been reported in association with smooth-muscle hamartoma, and an acneiform eruption and underlying structural anomalies of bone and soft tissues. We report a case of BN coexistent with a large connective-tissue nevus (CTN) on the right shoulder of a 74-year-old man. Whether this phenomenon represents the mere chance occurrence of… (More)
This thesis explores and evaluates MAXCCLUS, a bioinformatics clustering algorithm, which was designed to be used to cluster genes from microarray experimental data. MAXCCLUS does the clustering of genes depending on the textual data that describe the genes. MAXCCLUS attempts to create clusters of which it selects only the statistically significant clusters… (More)