• Title/Summary/Keyword: Slack Strain

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Constitutive Model of Tendon Responses to Multiple Cyclic Demands(I) -Experimental Analysis-

  • Chun, Keyoung-Jin;Robert P. Hubbard
    • Journal of Mechanical Science and Technology
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    • v.15 no.7
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    • pp.1002-1012
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    • 2001
  • The work reported here is an extensive study of tendon response to multiple cyclic tests including 3% constant peak strain level test (A-type test), 3% constant peak strain level test with two rest periods (B-type test), and 3∼4% different peak strain level test (C-type test). A sufficient number of specimens were tested at each type of the test to statistically evaluate many changes in response during testing and differences in response between each type of the test. In cyclic tests, there were decreses (relaxations) in the peak stresses and hysteresis, increases in the slack strains, and during lower peak strain level (3%) cyclic block after higher peak strain level (4%) cyclic block in the C-type tests. Considering the results of this study and those of the other study of multiple cyclic tests with rest periods by Hubbard and Chun, 1985, recovery phenomena during the rest periods occurred predominantly at the beginning of the rest periods. Consistently in both studies, the effects of rest periods were small and transient compared to the effects of the cyclic extensions. The recovery with cycles at lower peak strain level (3%) after higher peak strain level (4%) in the C-type test has not been previously documented. This recovery seems to be a natural phenomena in tissue behavior so that collagenous structures recover during periods of decreased demand.

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Control of tendon driven one-link manipulator

  • Choi, H.R.;Lee, Y.T.;Kim, J.H.;Chung, W.K.;Youm, Y.
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.290-295
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    • 1992
  • Tendon driven method to drive one joint using two actuators is developed and implemented. While the method has advantages over conventional transmissions, it also has several drawbacks like tendon slack, elongation and endurability. In this paper, a compensation method of the intrinsic non-linearities of tendon is proposed to improve the performance of antagonistic tendon driven method. In this method, tendon tension measurement is prerequisite which is measured with strain gauge type tension sensor. The developed method is implemented on one link test bed with colocated and non-colocated position sensor.

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