Inverse and forward kinematics and workspace analysis of a novel 5-DOF (3T2R) parallel–serial (hybrid) manipulator:

The proposed study provides a solution of the inverse and forward kinematic problems and workspace analysis for a five-degree-of-freedom parallel–serial manipulator, in which the parallel kinematic chain is made in the form of a tripod and the serial kinematic chain is made in the form of two carriages displaced in perpendicular directions. The proposed manipulator allows to realize five independent movements—three translations and two rotations motion pattern (3T2R). Analytical relationships between the coordinates of the end-effector and five controlled movements provided by manipulator's drives (generalized coordinates) were determined. The approach of reachable workspace calculation was defined with respect to available design constraints of the manipulator based on the obtained algorithms of the inverse and forward kinematics. Case studies are considered based on the obtained algorithms of inverse and forward kinematics. For the inverse kinematic problem, the solution is obtained in accordance with the given laws of position and orientation change of the end-effector, corresponding to the motion along a spiral-helical trajectory. For the forward kinematic problem, various assemblies of the manipulator are obtained at the same given values of the generalized coordinates. An example of reachable workspace designing finalizes the proposed study. Dimensions and extreme values of the end-effector orientation angles are calculated

Festival Internacional de Ballet

Programa del Festival Internacional de Ballet que va tenir lloc al Gran Teatre del Liceu entre el 17 de setembre i el 27 d'octubre de 1974. Hi van participar cinc companyies. La primera, el London Festival Ballet, dirigit per B. Grey, va interpretar "Les Sylphides", amb música de F. Chopin, "Tres Preludis" amb música d'A. Scriabin, "Webern opus 5" amb música d'A. Webern, "Le Corsaire" amb música de L. Minkus i "El petó de la fada" amb música d'Stravinski. La segona va ser la Nicolais Dance Theatre, que va interpretar "Divertissement - A", "Scenario" i "Foreplay,", i "Divertissement - B", "Cross-Fade" i "Suite de Sanctum. La tercera companyia va ser el Cos de Dansa del Gran Teatre del Liceu, dirigida per J. Magrinyà. Van interpretar la "Dansa de les hores" de "La Gioconda" amb música d'A. Ponchielli, "Festival de las flores en Genzano" d'E. Helsted, "4 bailes espanyoles del siglo XVIII" amb música d'A. Vives, J. Alfonso i M. de Falla entre altres, fragments de "Bohemios" d'A. Vives i "El sombrero de tres picos" de M. de Falla. També van ballar "A tiempo romantico", amb música d'E. Granados i Ferrer, "Clar de lluna" amb música de Debussy, "Ensayo" i "Rossio" amb música de Monjo Jr. I "La moza y el estudiante" amb música de T. BretónLa quarta companyia, el Ballet del Gran Teatre de Ginebra, va interpretar "Simfonia en do" amb música de G. Bizet, "Les quatre temperaments" amb música de P. Hindemith, "Raymonda" amb música d'A. Glazunov i "Le fils prodigue" amb música d'I. STravinski. El segon programa va estar format per "Agon", amb música d'I. Stravinski i G. Balanchine, "Daphnis et Chloe" amb música de M. Ravel adaptada per G. Skibine, "Concierto de Brandenburg nº3" amb música de J. S. Bach i Czarn, "Don Quijote" amb música de L. Mintkus i Obourmov i "La Valse amb música de M. Ravel i adaptació de G. Balanchine. Totes aquestes peces van ser coreografiades per G. Balanchine. Finalment, el Ballet de Wallonie, dirigit per H. Voos, va interpretar "El llac dels cignes" amb música de P. I. Txaikovski i "Ecce omo", amb música de G. Berghmans i coreografia de J. Lazzini, "Nomos alpha" amb música de I. Xenakis i coreografia de M. Béjart i "Petrouschka" amb música d'I. Stravinski i coreografia de M. Fokine. En tots els casos els va acompanyar l'Orquestra del Gran Teatre del Liceu, dirigida per A. Presser, T. Kern, G. Bond i G. Pérez BusquierOrquestra del Gran Teatre del Liceu, dirigida per A. Presser, T. Kern, G. Bond i G. Pérez BusquierDe cada obra s'ha digitalitzat un programa sencer. De la resta s'han digitalitzat les parts que són diferents

Dimensional (Parametric) Synthesis of the Hexapod-Type Parallel Mechanism with Reconfigurable Design

The study provides a solution to a dimensional synthesis problem for a hexapod-type reconfigurable parallel mechanism, which can change its configuration to realize different trajectories of its output link while having a single drive. The work presents an original procedure to find the dimensions of some mechanism’s links and their initial configuration to reproduce these trajectories. After describing the mechanism, the paper examines kinematic relations representing the basis for the subsequent synthesis algorithm. Next, the obtained expressions are extended and provide a system of equations to be solved. The structure of this equation system allows it to be solved effectively by numerical methods, which is demonstrated with an example. The proposed algorithm of dimensional synthesis does not require solving the optimization problems, in contrast to the familiar methods of dimensional synthesis of parallel mechanisms. Further, the suggested approach to the synthesis problem allows finding solution in a fast and computationally efficient manner

Novel Reconfigurable Spherical Parallel Mechanisms with a Circular Rail

The COVID-19 pandemic has placed unprecedented stress on the world healthcare system and demonstrated the need for modern automated robotic solutions for numerous medical applications. Often, robots that provide spherical motion of the end-effector are used in this area. In this paper, we discuss a spherical mechanism with a circular rail and provide several possible variations of the design: spherical robots with three or four legs and 4-DOF robots with an additional translational DOF, including a decoupled mechanism. The screw theory is used to analyze the mobility of the discussed mechanisms, and their advantages and drawbacks are discussed

Inverse and Forward Kinematic Analysis of a 6-DOF Parallel Manipulator Utilizing a Circular Guide

The proposed study focuses on the inverse and forward kinematic analysis of a novel 6-DOF parallel manipulator with a circular guide. In comparison with the known schemes of such manipulators, the structure of the proposed one excludes the collision of carriages when they move along the circular guide. This is achieved by using cranks (links that provide an unlimited rotational angle) in the manipulator kinematic chains. In this case, all drives stay fixed on the base. The kinematic analysis provides analytical relationships between the end-effector coordinates and six controlled movements in drives (driven coordinates). Examples demonstrate the implementation of the suggested algorithms. For the inverse kinematics, the solution is found given the position and orientation of the end-effector. For the forward kinematics, various assembly modes of the manipulator are obtained for the same given values of the driven coordinates. The study also discusses how to choose the links lengths to maximize the rotational capabilities of the end-effector and provides a calculation of such capabilities for the chosen manipulator design

Inverse and Forward Kinematic Analysis of a 6-DOF Parallel Manipulator Utilizing a Circular Guide

The proposed study focuses on the inverse and forward kinematic analysis of a novel 6-DOF parallel manipulator with a circular guide. In comparison with the known schemes of such manipulators, the structure of the proposed one excludes the collision of carriages when they move along the circular guide. This is achieved by using cranks (links that provide an unlimited rotational angle) in the manipulator kinematic chains. In this case, all drives stay fixed on the base. The kinematic analysis provides analytical relationships between the end-effector coordinates and six controlled movements in drives (driven coordinates). Examples demonstrate the implementation of the suggested algorithms. For the inverse kinematics, the solution is found given the position and orientation of the end-effector. For the forward kinematics, various assembly modes of the manipulator are obtained for the same given values of the driven coordinates. The study also discusses how to choose the links lengths to maximize the rotational capabilities of the end-effector and provides a calculation of such capabilities for the chosen manipulator design

Novel Reconfigurable Spherical Parallel Mechanisms with a Circular Rail

The COVID-19 pandemic has placed unprecedented stress on the world healthcare system and demonstrated the need for modern automated robotic solutions for numerous medical applications. Often, robots that provide spherical motion of the end-effector are used in this area. In this paper, we discuss a spherical mechanism with a circular rail and provide several possible variations of the design: spherical robots with three or four legs and 4-DOF robots with an additional translational DOF, including a decoupled mechanism. The screw theory is used to analyze the mobility of the discussed mechanisms, and their advantages and drawbacks are discussed

Virtual and Physical Prototyping of Reconfigurable Parallel Mechanisms with Single Actuation

The paper presents novel models of reconfigurable parallel mechanisms (RPMs) with a single active degree-of-freedom (1-DOF). The mechanisms contain three to six identical kinematic chains, which provide three (for the tripod) to zero (for the hexapod) uncontrollable DOFs. Screw theory is applied to carry out mobility analysis and proves the existence of controllable and uncontrollable DOFs of these mechanisms. Each kinematic chain in the synthesized mechanisms consists of planar and spatial parts. Such a design provides them with reconfiguration capabilities even when the driving link is fixed. This allows reproduction of diverse output trajectories without using additional actuators. In this paper, the model of a mechanism with six kinematic chains (hexapod) has been virtually and physically prototyped. The designing and assembling algorithms are developed using the detailed computer-aided design (CAD) model, which was further used to carry out kinetostatic analysis considering complex geometry of mechanism elements and friction among all contacting surfaces of joints. The developed virtual prototype and its calculation data have been further applied to fabricate mechanism elements and assemble an actuated full-scale physical prototype for future testing

Oxirapentyns F–K from the Marine-Sediment-Derived Fungus <i>Isaria felina</i> KMM 4639

Six new highly oxygenated chromene derivatives, oxirapentyns F–K (<b>2</b>–<b>7</b>), one new polyketide (<b>8</b>), one new benzofurane (<b>9</b>), and two known cyclodepsipeptides, isoisariin B and isaridin E, were isolated from the lipophilic extract of the marine-derived fungus <i>Isaria felina</i> KMM 4639. The structures of compounds <b>2</b>–<b>9</b> were determined using spectroscopic methods. The relative configurations of compounds <b>2</b>–<b>7</b> were established through a combination of NOE data and spin coupling constants, and these results were confirmed by X-ray crystallographic analysis of <b>4</b>. The absolute structures of all oxirapentyns were assumed based on their biogenetic relationship and confirmed using the modified Mosher’s method on <b>2</b> and <b>7</b>. Isariketide (<b>8</b>) showed moderate cytotoxicity toward HL-60 cells