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The Lightweight Robot ElRob: Interesting Aspects in Modeling and Control
Author(s) -
Höbarth Wolfgang,
Gattringer Hubert,
Staufer Peter,
Bremer Hartmut
Publication year - 2011
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201110015
Subject(s) - flexibility (engineering) , kinematics , inverse kinematics , computer science , robot , focus (optics) , projection (relational algebra) , control theory (sociology) , control engineering , robot kinematics , frame (networking) , reference frame , frame of reference , task (project management) , control (management) , engineering , artificial intelligence , mathematics , algorithm , mobile robot , systems engineering , telecommunications , statistics , physics , classical mechanics , quantum mechanics , optics
The articulated robot ElRob, consisting of flexible links and joints, is considered in several publications. Recent developments are presented in this work. The overall goal of the research is to decrease the effects of structural elasticities in lightweight robots. For this purpose model‐based control concepts are investigated and very accurate and efficient kinematic and dynamic models are necessary. The robot is split into groups of bodies, the so called subsystems, with separated describing velocities and coordinate systems. To obtain structured equations of motion the Projection Equation is used. The beams are modelled using the floating frame of reference formulation and a Ritz‐approach. Because of its flexibility, the examined robot is an underactuated system leading to special difficulties. As an example is it not possible to compute the desired joint angles with respect to a reference path in task space for the flexible system (inverse kinematic problem). Different methods to solve this drawback and other problems resulting from flexibility are discussed with special focus on feed forward control and different feedback control concepts. The resulting end point error, the necessary control input and other interesting results for the laboratory experiment are presented and compared. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)