Stability and predictability in human control of complex objects
Previous research on movement control suggested that humans exploit stability to reduce vulnerability to internal noise and external perturbations. For interactions with complex objects, predictive control based on an internal model of body and environment is needed to preempt perturbations and inst...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing
2020
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| Online Access: | https://hdl.handle.net/1721.1/127235 |
| _version_ | 1826195471161360384 |
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| author | Bazzi, Salah Ebert, Julia Hogan, Neville Sternad, Dagmar |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Bazzi, Salah Ebert, Julia Hogan, Neville Sternad, Dagmar |
| author_sort | Bazzi, Salah |
| collection | MIT |
| description | Previous research on movement control suggested that humans exploit stability to reduce vulnerability to internal noise and external perturbations. For interactions with complex objects, predictive control based on an internal model of body and environment is needed to preempt perturbations and instabilities due to delays. We hypothesize that stability can serve as means to render the complex dynamics of the body and the task more predictable and thereby simplify control. However, the assessment of stability in complex interactions with nonlinear and underactuated objects is challenging, as for existent stability analyses the system needs to be close to a (known) attractor. After reviewing existing methods for stability analysis of human movement, we argue that contraction theory provides a suitable approach to quantify stability or convergence in complex transient behaviors. To test its usefulness, we examined the task of carrying a cup of coffee, an object with internal degrees of freedom. A simplified model of the task, a cart with a suspended pendulum, was implemented in a virtual environment to study human control strategies. The experimental task was to transport this cart-and-pendulum on a horizontal line from rest to a target position as fast as possible. Each block of trials presented a visible perturbation, which either could be in the direction of motion or opposite to it. To test the hypothesis that humans exploit stability to overcome perturbations, the dynamic model of the free, unforced system was analyzed using contraction theory. A contraction metric was obtained by numerically solving a partial differential equation, and the contraction regions with respect to that metric were computed. Experimental results showed that subjects indeed moved through the contraction regions of the free, unforced system. This strategy attenuated the perturbations, obviated error corrections, and made the dynamics more predictable. The advantages and shortcomings of contraction analysis are discussed in the context of other stability analyses. ©2018 Author(s). |
| first_indexed | 2024-09-23T10:13:11Z |
| format | Article |
| id | mit-1721.1/127235 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T10:13:11Z |
| publishDate | 2020 |
| publisher | AIP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1272352022-09-26T16:34:57Z Stability and predictability in human control of complex objects Bazzi, Salah Ebert, Julia Hogan, Neville Sternad, Dagmar Massachusetts Institute of Technology. Department of Mechanical Engineering Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences Previous research on movement control suggested that humans exploit stability to reduce vulnerability to internal noise and external perturbations. For interactions with complex objects, predictive control based on an internal model of body and environment is needed to preempt perturbations and instabilities due to delays. We hypothesize that stability can serve as means to render the complex dynamics of the body and the task more predictable and thereby simplify control. However, the assessment of stability in complex interactions with nonlinear and underactuated objects is challenging, as for existent stability analyses the system needs to be close to a (known) attractor. After reviewing existing methods for stability analysis of human movement, we argue that contraction theory provides a suitable approach to quantify stability or convergence in complex transient behaviors. To test its usefulness, we examined the task of carrying a cup of coffee, an object with internal degrees of freedom. A simplified model of the task, a cart with a suspended pendulum, was implemented in a virtual environment to study human control strategies. The experimental task was to transport this cart-and-pendulum on a horizontal line from rest to a target position as fast as possible. Each block of trials presented a visible perturbation, which either could be in the direction of motion or opposite to it. To test the hypothesis that humans exploit stability to overcome perturbations, the dynamic model of the free, unforced system was analyzed using contraction theory. A contraction metric was obtained by numerically solving a partial differential equation, and the contraction regions with respect to that metric were computed. Experimental results showed that subjects indeed moved through the contraction regions of the free, unforced system. This strategy attenuated the perturbations, obviated error corrections, and made the dynamics more predictable. The advantages and shortcomings of contraction analysis are discussed in the context of other stability analyses. ©2018 Author(s). NIH Grant (R01-HD-087089) NIH Grant (R01-HD-081346) NIH Grant (R21-DC-013095) NSF-NRI 1637854 NSF-EAGER-1548514 NSF-NRI 1637814 NSF-EAGER-1548501 Department of Energy Computational Science Graduate Fellowship (DOE CSGF) 2020-09-10T20:09:09Z 2020-09-10T20:09:09Z 2018-10 2018-05 2020-07-21T15:13:08Z Article http://purl.org/eprint/type/JournalArticle 1089-7682 https://hdl.handle.net/1721.1/127235 Bazzi, Salah et al., "Stability and predictability in human control of complex objects." Chaos: An Interdisciplinary Journal of Nonlinear Science 28, 10 (October 2018): 103103 doi. 10.1063/1.5042090 ©2018 Author(s) en https://dx.doi.org/10.1063/1.5042090 Chaos: An Interdisciplinary Journal of Nonlinear Science Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf AIP Publishing PMC |
| spellingShingle | Bazzi, Salah Ebert, Julia Hogan, Neville Sternad, Dagmar Stability and predictability in human control of complex objects |
| title | Stability and predictability in human control of complex objects |
| title_full | Stability and predictability in human control of complex objects |
| title_fullStr | Stability and predictability in human control of complex objects |
| title_full_unstemmed | Stability and predictability in human control of complex objects |
| title_short | Stability and predictability in human control of complex objects |
| title_sort | stability and predictability in human control of complex objects |
| url | https://hdl.handle.net/1721.1/127235 |
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