Digitala Vetenskapliga Arkivet

Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Posture strategies generated by constrained optimization
KTH, Skolan för teknikvetenskap (SCI), Mekanik.
KTH, Skolan för teknikvetenskap (SCI), Mekanik.ORCID-id: 0000-0001-5417-5939
2012 (engelsk)Inngår i: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 45, nr 3, s. 461-468Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

For people with motion disorders, posture can impact fatigue, discomfort or deformities in the long term. Orthopedic treatments such as orthoses or orthopedic surgeries which change geometric properties can improve posture in these individuals. In this study, a model has been created to study posture strategies in such situations. A 3D mechanical model consisting of eight rigid segments and 30 muscle groups is used in which varying moment arms along the ranges of motion and biarticular muscles are considered. The method is based on static optimization, both to solve the load sharing in the muscle system and to choose posture strategy. The optimization computes the specific posture with minimal required effort (level of muscle activations), while fulfilling constraints containing subject specific ranges of motion, muscle strength/weakness and external support if present. Anthropometry and strength were scaled to each individual, based on reported pediatric anthropometry and strength values, combined with each individual's physical assessment. A control group of 10 able-bodied subjects as well as three subjects with motion disorders were studied, and simulated posture was compared with experimental data. The simulation showed reasonable to good agreement and ability to predict the effect of motion disorders and of external support. An example of application in parameter studies was also presented wherein ankle orthosis angles were varied. The model allows the user to study muscle activity at the muscle group level, position of center of mass and moments at joints in various situations.

sted, utgiver, år, opplag, sider
2012. Vol. 45, nr 3, s. 461-468
Emneord [en]
Posture, Multibody system, Static optimization
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-25703DOI: 10.1016/j.jbiomech.2011.11.053ISI: 000300863600008PubMedID: 22218283Scopus ID: 2-s2.0-84856035585OAI: oai:DiVA.org:kth-25703DiVA, id: diva2:359535
Forskningsfinansiär
Swedish Research Council
Merknad
QC 20120326Tilgjengelig fra: 2010-10-28 Laget: 2010-10-28 Sist oppdatert: 2022-06-25bibliografisk kontrollert
Inngår i avhandling
1. Human Postures and Movements analysed through Constrained Optimization
Åpne denne publikasjonen i ny fane eller vindu >>Human Postures and Movements analysed through Constrained Optimization
2009 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Constrained optimization is used to derive human postures and movements. In the first study a static 3D model with 30 muscle groups is used to analyse postures. The activation levels of these muscles are minimized in order to represent the individual's choice of posture. Subject specific data in terms of anthropometry, strength and orthopedic aids serve as input. The aim is to study effects from orthopedic treatment and altered abilities of the subject. Initial validation shows qualitative agreement of posture strategies but further details about passive stiffness and anthropometry are needed, especially to predict pelvis orientation. In the second application, the athletic long jump, a problem formulation is developed to find optimal movements of a multibody system when subjected to contact. The model was based on rigid links, joint actuators and a wobbling mass. The contact to the ground was modelled as a spring-damper system with tuned properties. The movement in the degrees of freedom representing physical joints was described over contact time through two fifth-order polynomials, with a variable transition time, while the motion in the degrees of freedom of contact and wobbling mass was integrated forwards in time, as a consequence. Muscle activation variables were then optimized in order to maximize ballistic flight distance. The optimization determined contact time, end configuration, activation and interaction with the ground from an initial configuration. The results from optimization show a reasonable agreement with experimentally recorded jumps, but individual recordings and measurements are needed for more precise conclusions.

 

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2009. s. viii, 26
Serie
Trita-MEK, ISSN 0348-467X ; 2009:06
Emneord
multibody system, optimal control, trajectory optimization, long jump, posture
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-10682 (URN)
Presentation
2009-06-11, Sal E51, Osquars Backe 18, KTH, Stockholm, 10:30 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2009-06-24 Laget: 2009-06-23 Sist oppdatert: 2022-06-25bibliografisk kontrollert
2. Simulation of Human Movements through Optimization
Åpne denne publikasjonen i ny fane eller vindu >>Simulation of Human Movements through Optimization
2012 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Optimization has been used to simulate human neural control and resulting movement patterns. The short term aim was to develop the methodology required for solving the movement optimization problem often arising when modelling human movements. A long term aim is the contribution to increased knowledge about various human movements, wherein postures is one specific case. Simulation tools can give valuable information to improve orthopeadic treatments and technique for training and performance in sports. In one study a static 3D model with 30 muscle groups was used to analyse postures. The activation levels of these muscles are minimized in order to represent the individual’s choice of posture. Subject specific data in terms of anthropometry, strength and orthopedic aids serve as input. The specific aim of this part was to study effects from orthopedic treatment and altered abilities of the subject. Initial validation shows qualitative agreement of posture strategies but further details about passive stiffness and anthropometry are needed, especially to predict pelvis orientation. Four studies dealt with movement optimization. The main methodological advance was to introduce contact constraints to the movement optimization. A freetime multiple phase formulation was derived to be able to analyse movements where different constraints and degrees of freedom are present in subsequent phases of the movements. The athletic long jump, a two foot high jump, a backward somersault and rowing were used as applications with their different need of formulation. Maximum performance as well as least effort cost functions have been explored. Even though it has been a secondary aim in this work the results show reasonable agreement to expected movements in reality. Case specific subject properties and inclusion of muscle dynamics are required to draw conclusions about improvements in the sport activity, respectively.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2012. s. x, 48
Serie
Trita-MEK, ISSN 0348-467X ; 2012:15
Emneord
multibody system, human movements, optimal control, trajectory optimization, long jump, posture, rowing, somersault
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-102158 (URN)978-91-7501-472-2 (ISBN)
Disputas
2012-09-28, V2, Teknikringen 76, KTH, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

QC 20120910

Tilgjengelig fra: 2012-09-10 Laget: 2012-09-10 Sist oppdatert: 2022-10-24bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Andre lenker

Forlagets fulltekstPubMedScopus

Søk i DiVA

Av forfatter/redaktør
Pettersson, RobertGutierrez-Farewik, Elena
Av organisasjonen
I samme tidsskrift
Journal of Biomechanics

Søk utenfor DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric

doi
pubmed
urn-nbn
Totalt: 131 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf