Changes in limb dynamics during the practice of rapid arm movements

Schneider, Klaus; Zernicke, Ronald F.; Schmidt, Richard A.; Hart, Timothy J.

doi:10.1016/0021-9290(89)90064-x

Cited by 174 publications

(77 citation statements)

References 28 publications

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“…This improvement must involve effects of motor learning for the upper limbs and trunk movement 2,23) . In addition, changes in postural control may affect this improvement ensuring postural stability for the performance of a Values are mean ± standard deviation.…”

Section: Discussionmentioning

confidence: 99%

Effects of Repetitive Reaching Movements on Performance and Postural Control

et al. 2011

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Abstract.[Purpose] The purpose of this study was to examine whether muscle activity and joint movement in the lower limbs related to postural control are affected by repetitive reaching movements.[Methods] Fourteen healthy subjects attempted to reach a small target as fast as possible while standing. The target was placed at approximately the maximum reach distance. The reaching movement was repeated 50 times. Positions of each body segment were measured by three-dimensional motion analysis. Surface electromyograms (EMG) of tibialis anterior (TA) and gastrocnemius (GAS) were recorded. Parameters related to reaching performance and postural control were analyzed.[Results] With repetition of reaching movements, movement time and peak reaching velocity related to performance significantly increased. In addition, the onset of the EMG activity of TA appeared earlier, the integrated EMG activity of TA and GAS increased, and the maximum ankle dorsiflexion angle increased significantly. Changes in postural response were correlated with those of reaching performance. Moreover, postural response changed earlier than reaching performance.[Conclusion] Changes in postural control were induced by repeated reaching movements. These results suggest that changes in postural control associated with the central nervous system occur in advance in order to improve reaching performance.

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Section: Discussionmentioning

confidence: 99%

Effects of Repetitive Reaching Movements on Performance and Postural Control

et al. 2011

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“…We are interested in exploiting and controlling the passive dynamic behaviour and interlink dynamics [13,8], however optimizing even the two degree of freedom double pendulum system is computationally very intensive. In his seminal 1967 work, Bernstein [1] suggested that when learning complex high dimensional tasks, humans at first restrict or freeze redundant degrees of freedom to simplify the learning process and then gradually release them as they become more skilled at the task.…”

Section: Problem Simplificationmentioning

confidence: 99%

Exploiting passive dynamics for robot throwing task

Thandiackal

Brandle

Leach

et al. 2012

2012 IEEE/RSJ International Conference on Intelligent Robots and Systems

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This thesis considers the control of clutches on the Double Pendulum Robot which allows the introduction of passivity into actuated joints. Considering the task of throwing using minimum energy, the goal is to throw a ball to a minimum desired distance. As this problem involves active and passive actuation, as well as inherent discontinuities due to the clutches, the control problem becomes difficult. However, an optimization approach for the underactuated throw is proposed that is able to cope with the latter mentioned difficulties. In the process, discretization as well as dynamic programming incorporating Value Iteration is utilized to find the solution. The method is not restricted to throwing and can also be applied to other tasks. In order to discover the full extent of passivity in the double pendulum, unactuated and underactuated throwing are exploited. For the unactuated throw, advantageous initial conditions that lead to long distance throws are found. Moreover, throwing trajectories using underactuation to improve energy consumption are presented and evaluated in simulation and experiments.

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“…Human arms can be thought of as masses connected by springs, whose frequency response makes the energy and the control required to move the arm vary with frequency [26]. Humans certainly learn to exploit the dynamics of their limbs for rhythmic tasks [42], [43]. Robotic examples of this idea include open-loop stable systems where the dynamics are exploited giving systems which require little or no active control for stable operation (e.g.…”

Section: B Tuning Of the Cpg Parametersmentioning

confidence: 99%

“…In this case, the endogenous frequency of CPG is proportional to 1 τ . It was pointed out that the proper value of the ττ ′ for stable oscillation is within 0.1, 0.5 ⎡ ⎤ ⎣ ⎦ [42]. After tuning the time constants of the CPG, other parameters of CPG can be tuned by using the necessary conditions for free oscillation.…”

Section: B Tuning Of the Cpg Parametersmentioning

confidence: 99%