{"id":3919,"date":"2016-10-21T09:46:07","date_gmt":"2016-10-21T09:46:07","guid":{"rendered":"http:\/\/www.ehu.eus\/compmech\/?page_id=3919"},"modified":"2022-12-09T20:53:20","modified_gmt":"2022-12-09T20:53:20","slug":"parallel-robots-with-mixed-freedoms","status":"publish","type":"page","link":"https:\/\/www.ehu.eus\/compmech\/research-2\/projects\/parallel-robots-with-mixed-freedoms\/","title":{"rendered":"Parallel Robots with Mixed Freedoms"},"content":{"rendered":"

Name of the project: Parallel Robots with Mixed Freedoms<\/strong>
Reference: DPI2008-00159
<\/strong>Funding: Ministerio de Ciencia e Innovaci\u00f3n
<\/strong>Period: 2008 – 2010
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This project DPI 2008-00159\u00a0is a continuation of our late MEC’s project DPI 2005-02207, titled “Design, synthesis and verification of parallel manipulators for industrial production. The case of lower mobility platforms”. There, lower mobility (less than six degrees of freedom) manipulators with uncoupled freedoms, i.e. simple and invariant motions (translational, spherical, and SCARA), were analysed. Now, in this project, lower mobility manipulators with mixed freedoms have been treated. This latter characteristic means that translation and rotation are coupled so that complex screw motions are generated. The last feature is very relevant and influences the project’s objectives.<\/p>\n

\"parallel-robots\"Analysis, synthesis and design of these manipulators are complex matters. They require the development of a new theoretical approach, the use of specific mathematical tools such as Screw Theory and Group Theory, and the implementation of software for computational kinematics. Nonetheless, manipulators with mixed freedoms offer important returns. In particular, they reach higher velocities, have a wider workspace, and cover a variety of motions that are not obtainable in manipulators with uncoupled freedoms. Hence, they have an elevated potential for tasks where a continuous orientation of a tool is required, with an extensive range and dexterity.<\/p>\n

Regardless of the primarily theoretical nature of some of the project’s objectives, their application in Robotics has been sought. Therefore, first, a procedure for the analysis of the forty six types of spatial motions has been stated, covering a complete characterization that goes from mobility to screw systems. Second, this procedure is used to determine the motion requirements needed for the type synthesis. Third, a method for type synthesis, which solves the intersection of types of motion and some issues about finite displacements, has been proposed. Fourth, existing multi-objective optimization methods have been reviewed and the most appropriate has been adapted to the dimensional synthesis of this kind of manipulators. Finally, Lagragian Dynamics has been used to carry out the dynamic analysis using Lagrange multipliers.<\/p>\n

All these results have been applied to manipulators with capability to perform two rotations and translations. An example has been developed on the basis of a Solar Tracker. A four DoFs parallel manipulator has been designed that has two rotational and two translational freedoms.<\/p>\n

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