No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot Walker

In a multilegged walking robot several legs usually have ground contact and thereby form a closed kinematic chain. The control of such a system is generally assumed to require the explicit calculation of the body kinematics. Such a computation requires knowledge concerning all relevant joint angles...

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Main Authors: Josef Schmitz, Axel Schneider, Malte Schilling, Holk Cruse
Format: Article
Language:English
Published: Wiley 2008-01-01
Series:Applied Bionics and Biomechanics
Online Access:http://dx.doi.org/10.1080/11762320802221074
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author Josef Schmitz
Axel Schneider
Malte Schilling
Holk Cruse
author_facet Josef Schmitz
Axel Schneider
Malte Schilling
Holk Cruse
author_sort Josef Schmitz
collection DOAJ
description In a multilegged walking robot several legs usually have ground contact and thereby form a closed kinematic chain. The control of such a system is generally assumed to require the explicit calculation of the body kinematics. Such a computation requires knowledge concerning all relevant joint angles as well as the segment lengths. Here, we propose a biologically inspired solution that does not need such a body model. This is done by using implicit communication through the body mechanics (embodiment) and a local positive velocity feedback strategy (LPVF) on the single joint level. In this control scheme the locally measured joint velocity of an elastic joint is fed into the same joint during the next time step to maintain the movement. At the same time, an additional part of this joint controller observes the mechanical joint power to confine the positive feedback. This solution does not depend on changes of the geometry, e.g. length of individual segments, and allows for a simple solution of negotiation of curves. The principle is tested in a dynamics simulation on a six-legged walker and, for the first time, also on a real robot.
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spelling doaj-art-ca9a210768f845efb178dbb15011c7b52025-08-20T02:19:34ZengWileyApplied Bionics and Biomechanics1176-23221754-21032008-01-015313514710.1080/11762320802221074No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot WalkerJosef Schmitz0Axel Schneider1Malte Schilling2Holk Cruse3Department for Biological Cybernetics, Faculty of Biology, University of Bielefeld, P.O. Box 10 01 31, D-33501 Bielefeld, GermanyDepartment for Biological Cybernetics, Faculty of Biology, University of Bielefeld, P.O. Box 10 01 31, D-33501 Bielefeld, GermanyDepartment for Biological Cybernetics, Faculty of Biology, University of Bielefeld, P.O. Box 10 01 31, D-33501 Bielefeld, GermanyDepartment for Biological Cybernetics, Faculty of Biology, University of Bielefeld, P.O. Box 10 01 31, D-33501 Bielefeld, GermanyIn a multilegged walking robot several legs usually have ground contact and thereby form a closed kinematic chain. The control of such a system is generally assumed to require the explicit calculation of the body kinematics. Such a computation requires knowledge concerning all relevant joint angles as well as the segment lengths. Here, we propose a biologically inspired solution that does not need such a body model. This is done by using implicit communication through the body mechanics (embodiment) and a local positive velocity feedback strategy (LPVF) on the single joint level. In this control scheme the locally measured joint velocity of an elastic joint is fed into the same joint during the next time step to maintain the movement. At the same time, an additional part of this joint controller observes the mechanical joint power to confine the positive feedback. This solution does not depend on changes of the geometry, e.g. length of individual segments, and allows for a simple solution of negotiation of curves. The principle is tested in a dynamics simulation on a six-legged walker and, for the first time, also on a real robot.http://dx.doi.org/10.1080/11762320802221074
spellingShingle Josef Schmitz
Axel Schneider
Malte Schilling
Holk Cruse
No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot Walker
Applied Bionics and Biomechanics
title No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot Walker
title_full No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot Walker
title_fullStr No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot Walker
title_full_unstemmed No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot Walker
title_short No Need for a Body Model: Positive Velocity Feedback for the Control of an 18-DOF Robot Walker
title_sort no need for a body model positive velocity feedback for the control of an 18 dof robot walker
url http://dx.doi.org/10.1080/11762320802221074
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AT holkcruse noneedforabodymodelpositivevelocityfeedbackforthecontrolofan18dofrobotwalker