Grasping objects with environmentally induced position uncertainty.

Due to noisy motor commands and imprecise and ambiguous sensory information, there is often substantial uncertainty about the relative location between our body and objects in the environment. Little is known about how well people manage and compensate for this uncertainty in purposive movement task...

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Autores principales:	Vassilios N Christopoulos, Paul R Schrater
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2009
Materias:	Biology (General) QH301-705.5
Acceso en línea:	https://doaj.org/article/cb6e256ac63b48d6abd1dae48e0ad29f
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spelling	oai:doaj.org-article:cb6e256ac63b48d6abd1dae48e0ad29f2021-11-25T05:42:54ZGrasping objects with environmentally induced position uncertainty.1553-734X1553-735810.1371/journal.pcbi.1000538https://doaj.org/article/cb6e256ac63b48d6abd1dae48e0ad29f2009-10-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/19834543/pdf/?tool=EBIhttps://doaj.org/toc/1553-734Xhttps://doaj.org/toc/1553-7358Due to noisy motor commands and imprecise and ambiguous sensory information, there is often substantial uncertainty about the relative location between our body and objects in the environment. Little is known about how well people manage and compensate for this uncertainty in purposive movement tasks like grasping. Grasping objects requires reach trajectories to generate object-fingers contacts that permit stable lifting. For objects with position uncertainty, some trajectories are more efficient than others in terms of the probability of producing stable grasps. We hypothesize that people attempt to generate efficient grasp trajectories that produce stable grasps at first contact without requiring post-contact adjustments. We tested this hypothesis by comparing human uncertainty compensation in grasping objects against optimal predictions. Participants grasped and lifted a cylindrical object with position uncertainty, introduced by moving the cylinder with a robotic arm over a sequence of 5 positions sampled from a strongly oriented 2D Gaussian distribution. Preceding each reach, vision of the object was removed for the remainder of the trial and the cylinder was moved one additional time. In accord with optimal predictions, we found that people compensate by aligning the approach direction with covariance angle to maintain grasp efficiency. This compensation results in higher probability to achieve stable grasps at first contact than non-compensation strategies in grasping objects with directional position uncertainty, and the results provide the first demonstration that humans compensate for uncertainty in a complex purposive task.Vassilios N ChristopoulosPaul R SchraterPublic Library of Science (PLoS)articleBiology (General)QH301-705.5ENPLoS Computational Biology, Vol 5, Iss 10, p e1000538 (2009)
institution	DOAJ
collection	DOAJ
language	EN
topic	Biology (General) QH301-705.5
spellingShingle	Biology (General) QH301-705.5 Vassilios N Christopoulos Paul R Schrater Grasping objects with environmentally induced position uncertainty.
description	Due to noisy motor commands and imprecise and ambiguous sensory information, there is often substantial uncertainty about the relative location between our body and objects in the environment. Little is known about how well people manage and compensate for this uncertainty in purposive movement tasks like grasping. Grasping objects requires reach trajectories to generate object-fingers contacts that permit stable lifting. For objects with position uncertainty, some trajectories are more efficient than others in terms of the probability of producing stable grasps. We hypothesize that people attempt to generate efficient grasp trajectories that produce stable grasps at first contact without requiring post-contact adjustments. We tested this hypothesis by comparing human uncertainty compensation in grasping objects against optimal predictions. Participants grasped and lifted a cylindrical object with position uncertainty, introduced by moving the cylinder with a robotic arm over a sequence of 5 positions sampled from a strongly oriented 2D Gaussian distribution. Preceding each reach, vision of the object was removed for the remainder of the trial and the cylinder was moved one additional time. In accord with optimal predictions, we found that people compensate by aligning the approach direction with covariance angle to maintain grasp efficiency. This compensation results in higher probability to achieve stable grasps at first contact than non-compensation strategies in grasping objects with directional position uncertainty, and the results provide the first demonstration that humans compensate for uncertainty in a complex purposive task.
format	article
author	Vassilios N Christopoulos Paul R Schrater
author_facet	Vassilios N Christopoulos Paul R Schrater
author_sort	Vassilios N Christopoulos
title	Grasping objects with environmentally induced position uncertainty.
title_short	Grasping objects with environmentally induced position uncertainty.
title_full	Grasping objects with environmentally induced position uncertainty.
title_fullStr	Grasping objects with environmentally induced position uncertainty.
title_full_unstemmed	Grasping objects with environmentally induced position uncertainty.
title_sort	grasping objects with environmentally induced position uncertainty.
publisher	Public Library of Science (PLoS)
publishDate	2009
url	https://doaj.org/article/cb6e256ac63b48d6abd1dae48e0ad29f
work_keys_str_mv	AT vassiliosnchristopoulos graspingobjectswithenvironmentallyinducedpositionuncertainty AT paulrschrater graspingobjectswithenvironmentallyinducedpositionuncertainty
_version_	1718414485365981184

Grasping objects with environmentally induced position uncertainty.

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