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Intermittent Feedback-Control Strategy for Stabilizing Inverted Pendulum on Manually Controlled Cart as Analogy to Human Stick Balancing.

Yoshikawa N, Suzuki Y, Kiyono K, Nomura T - Front Comput Neurosci (2016)

Bottom Line: To this end, the motions of a CIP stabilized by human subjects were experimentally acquired, and computational models of the system were employed to characterize the experimental behaviors.We first confirmed fat-tailed non-Gaussian temporal fluctuation in the acceleration distribution of the pendulum, as well as the power-law distributions of corrective cart movements for skilled subjects, which was previously reported for stick balancing.We then showed that the experimental behaviors could be better described by the models with an intermittent delayed feedback controller than by those with the conventional continuous delayed feedback controller, suggesting that the human CNS stabilizes the upright posture of the pendulum by utilizing the intermittent delayed feedback-control strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University Toyonaka, Japan.

ABSTRACT
The stabilization of an inverted pendulum on a manually controlled cart (cart-inverted-pendulum; CIP) in an upright position, which is analogous to balancing a stick on a fingertip, is considered in order to investigate how the human central nervous system (CNS) stabilizes unstable dynamics due to mechanical instability and time delays in neural feedback control. We explore the possibility that a type of intermittent time-delayed feedback control, which has been proposed for human postural control during quiet standing, is also a promising strategy for the CIP task and stick balancing on a fingertip. Such a strategy hypothesizes that the CNS exploits transient contracting dynamics along a stable manifold of a saddle-type unstable upright equilibrium of the inverted pendulum in the absence of control by inactivating neural feedback control intermittently for compensating delay-induced instability. To this end, the motions of a CIP stabilized by human subjects were experimentally acquired, and computational models of the system were employed to characterize the experimental behaviors. We first confirmed fat-tailed non-Gaussian temporal fluctuation in the acceleration distribution of the pendulum, as well as the power-law distributions of corrective cart movements for skilled subjects, which was previously reported for stick balancing. We then showed that the experimental behaviors could be better described by the models with an intermittent delayed feedback controller than by those with the conventional continuous delayed feedback controller, suggesting that the human CNS stabilizes the upright posture of the pendulum by utilizing the intermittent delayed feedback-control strategy.

No MeSH data available.


Related in: MedlinePlus

Time-series data for two experimental subjects with the corresponding phase portraits, cart-acceleration distributions, PSD functions, and ICM distributions. (A,B) are for Subjects 1 and 6, respectively. The data for each subject are a segmented piece (60 s). Top left, tilt angle; top right, PSD; bottom left, phase portrait with a piece of trajectory for a selected period of 20 s; bottom middle, cart-acceleration distribution; bottom right, ICM distribution. The red curves in the acceleration distribution represent the Gaussian. The vertical red lines in the ICM and PSD represent the values of two indices: the ICM-median and PSD-PF. See the text for details.
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Figure 3: Time-series data for two experimental subjects with the corresponding phase portraits, cart-acceleration distributions, PSD functions, and ICM distributions. (A,B) are for Subjects 1 and 6, respectively. The data for each subject are a segmented piece (60 s). Top left, tilt angle; top right, PSD; bottom left, phase portrait with a piece of trajectory for a selected period of 20 s; bottom middle, cart-acceleration distribution; bottom right, ICM distribution. The red curves in the acceleration distribution represent the Gaussian. The vertical red lines in the ICM and PSD represent the values of two indices: the ICM-median and PSD-PF. See the text for details.

Mentions: Figure 3 shows the time-series data for two subjects (Subjects 1 and 6) with the corresponding phase portraits, cart-acceleration distributions, PSD functions, and ICM distributions. The non-gray-shaded rows in Table 2 indicate the values of the five indices, i.e., ( ICM-median, PSD-PF, SD-θ), for each of the six skilled subjects. Subject 1—one of the most skilled subjects as shown in Table 1—exhibited the second-largest non-Gaussianity index , which is consistent with the apparent fat tail in the acceleration distribution shown in Figure 3A. Regarding two other most skilled subjects (Subjects 3 and 5), the non-Gaussianity in terms of was also large for Subject 3 but not as large for Subject 5. Nevertheless, the values of deviated significantly from zero for all skilled subjects (see Figure 3B for Subject 6), meaning that movement variability for the skilled subjects in this task can be well characterized by the non-Gaussian acceleration distribution, as reported by previous studies (Cabrera and Milton, 2004a; Cluff and Balasubramaniam, 2009). The non-Gaussianity in terms of was also large for all the skilled subjects, indicating that the acceleration distribution for each subject always exhibited leptokurtosis at the origin. Frequent appearances of the acceleration imply that the subjects frequently did not control the motions of the cart.


Intermittent Feedback-Control Strategy for Stabilizing Inverted Pendulum on Manually Controlled Cart as Analogy to Human Stick Balancing.

Yoshikawa N, Suzuki Y, Kiyono K, Nomura T - Front Comput Neurosci (2016)

Time-series data for two experimental subjects with the corresponding phase portraits, cart-acceleration distributions, PSD functions, and ICM distributions. (A,B) are for Subjects 1 and 6, respectively. The data for each subject are a segmented piece (60 s). Top left, tilt angle; top right, PSD; bottom left, phase portrait with a piece of trajectory for a selected period of 20 s; bottom middle, cart-acceleration distribution; bottom right, ICM distribution. The red curves in the acceleration distribution represent the Gaussian. The vertical red lines in the ICM and PSD represent the values of two indices: the ICM-median and PSD-PF. See the text for details.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835456&req=5

Figure 3: Time-series data for two experimental subjects with the corresponding phase portraits, cart-acceleration distributions, PSD functions, and ICM distributions. (A,B) are for Subjects 1 and 6, respectively. The data for each subject are a segmented piece (60 s). Top left, tilt angle; top right, PSD; bottom left, phase portrait with a piece of trajectory for a selected period of 20 s; bottom middle, cart-acceleration distribution; bottom right, ICM distribution. The red curves in the acceleration distribution represent the Gaussian. The vertical red lines in the ICM and PSD represent the values of two indices: the ICM-median and PSD-PF. See the text for details.
Mentions: Figure 3 shows the time-series data for two subjects (Subjects 1 and 6) with the corresponding phase portraits, cart-acceleration distributions, PSD functions, and ICM distributions. The non-gray-shaded rows in Table 2 indicate the values of the five indices, i.e., ( ICM-median, PSD-PF, SD-θ), for each of the six skilled subjects. Subject 1—one of the most skilled subjects as shown in Table 1—exhibited the second-largest non-Gaussianity index , which is consistent with the apparent fat tail in the acceleration distribution shown in Figure 3A. Regarding two other most skilled subjects (Subjects 3 and 5), the non-Gaussianity in terms of was also large for Subject 3 but not as large for Subject 5. Nevertheless, the values of deviated significantly from zero for all skilled subjects (see Figure 3B for Subject 6), meaning that movement variability for the skilled subjects in this task can be well characterized by the non-Gaussian acceleration distribution, as reported by previous studies (Cabrera and Milton, 2004a; Cluff and Balasubramaniam, 2009). The non-Gaussianity in terms of was also large for all the skilled subjects, indicating that the acceleration distribution for each subject always exhibited leptokurtosis at the origin. Frequent appearances of the acceleration imply that the subjects frequently did not control the motions of the cart.

Bottom Line: To this end, the motions of a CIP stabilized by human subjects were experimentally acquired, and computational models of the system were employed to characterize the experimental behaviors.We first confirmed fat-tailed non-Gaussian temporal fluctuation in the acceleration distribution of the pendulum, as well as the power-law distributions of corrective cart movements for skilled subjects, which was previously reported for stick balancing.We then showed that the experimental behaviors could be better described by the models with an intermittent delayed feedback controller than by those with the conventional continuous delayed feedback controller, suggesting that the human CNS stabilizes the upright posture of the pendulum by utilizing the intermittent delayed feedback-control strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University Toyonaka, Japan.

ABSTRACT
The stabilization of an inverted pendulum on a manually controlled cart (cart-inverted-pendulum; CIP) in an upright position, which is analogous to balancing a stick on a fingertip, is considered in order to investigate how the human central nervous system (CNS) stabilizes unstable dynamics due to mechanical instability and time delays in neural feedback control. We explore the possibility that a type of intermittent time-delayed feedback control, which has been proposed for human postural control during quiet standing, is also a promising strategy for the CIP task and stick balancing on a fingertip. Such a strategy hypothesizes that the CNS exploits transient contracting dynamics along a stable manifold of a saddle-type unstable upright equilibrium of the inverted pendulum in the absence of control by inactivating neural feedback control intermittently for compensating delay-induced instability. To this end, the motions of a CIP stabilized by human subjects were experimentally acquired, and computational models of the system were employed to characterize the experimental behaviors. We first confirmed fat-tailed non-Gaussian temporal fluctuation in the acceleration distribution of the pendulum, as well as the power-law distributions of corrective cart movements for skilled subjects, which was previously reported for stick balancing. We then showed that the experimental behaviors could be better described by the models with an intermittent delayed feedback controller than by those with the conventional continuous delayed feedback controller, suggesting that the human CNS stabilizes the upright posture of the pendulum by utilizing the intermittent delayed feedback-control strategy.

No MeSH data available.


Related in: MedlinePlus