scholarly journals A single muscle's multifunctional control potential of body dynamics for postural control and running

2011 ◽  
Vol 366 (1570) ◽  
pp. 1592-1605 ◽  
Author(s):  
Simon Sponberg ◽  
Andrew J. Spence ◽  
Chris H. Mullens ◽  
Robert J. Full
Keyword(s):  
Postural Control ◽  
High Speed ◽  
Vertical Plane ◽  
Motor Units ◽  
The Body ◽  
Feedback Signal ◽  
Control Potential ◽  
Body Dynamics ◽  
Neural Feedback ◽  
Mechanical Feedback

A neuromechanical approach to control requires understanding how mechanics alters the potential of neural feedback to control body dynamics. Here, we rewrite activation of individual motor units of a behaving animal to mimic the effects of neural feedback without concomitant changes in other muscles. We target a putative control muscle in the cockroach, Blaberus discoidalis (L.), and simultaneously capture limb and body dynamics through high-speed videography and a micro-accelerometer backpack. We test four neuromechanical control hypotheses. We supported the hypothesis that mechanics linearly translates neural feedback into accelerations and rotations during static postural control. However, during running, the same neural feedback produced a nonlinear acceleration control potential restricted to the vertical plane. Using this, we reject the hypothesis from previous work that this muscle acts primarily to absorb energy from the body. The conversion of the control potential is paralleled by nonlinear changes in limb kinematics, supporting the hypothesis that significant mechanical feedback filters the graded neural feedback for running control. Finally, we insert the same neural feedback signal but at different phases in the dynamics. In this context, mechanical feedback enables turning by changing the timing and direction of the accelerations produced by the graded neural feedback.

Emphasizing Mechanical Feedback in Bio-Inspired Design and Education

2011 ◽  
Author(s):  
Justin Seipel
Keyword(s):  
Feedback Control ◽  
The Body ◽  
The Self ◽  
Biological Research ◽  
Biologically Inspired ◽  
System Architectures ◽  
Mechanical Control ◽  
Conventional View ◽  
Neural Feedback ◽  
Mechanical Feedback

Mechanical feedback in nature is a useful concept proposed by many researchers in different areas of biological research. The concept, at its core, is simply the idea that many mechanical processes in biology effectively act to assist in the self-stabilization of tasks, and therefore, serve functionally as a first level of feedback control. However, due to a conventional view of the nervous system as the ‘controller’ of the body, it has historically been assumed that the control of tasks does not critically depend on the self-stability properties of the mechanical (musculo-skeletal) system. More recent biological research has provided many examples that show neural feedback alone is not sufficient to control many tasks. This forces us to reframe our conventional view of feedback control in neuro-mechanical systems, and by extension, provide a more appropriate perspective when designing biologically-inspired system architectures. Here two ways of diagraming neuro-mechanical control are compared to understand whether one may be more helpful in framing neuro-mechanical control problems and biologically-inspired system design for engineering practitioners and students. This work, when developed further, is expected to provide new pedagogical frameworks for teaching neuromechanics, motor-control, and biologically-inspired methods of control.

ANALYSIS OF THE CREW PART OF THE LOCOMOTIVE TEM23 AND PROPOSALS FOR ELIMINATION OF DISADVANTAGES

2020 ◽  
Author(s):  
Dmitriy Antipin ◽  
Vladimir Vorobev ◽  
Denis Bondarenko ◽  
Gennadiy Petrov
Keyword(s):  
Vertical Plane ◽  
The Body ◽  
Diesel Locomotive ◽  
Design Features ◽  
Bogie Frame ◽  
Spring Suspension ◽  
In Series

The analysis of the design features of the bogie of the TEM23 shunting diesel locomotive is carried out. In the process of analysis, the directions of its improvement are determined. It is proposed to rotate the bogie frame in the vertical plane by reducing the body supports to two and using a pivot with low lowering, equip the bogies with pneumatic spring suspension in the form of two corrugations installed in series with shortened suspension springs. The proposed options for improving the undercarriage of a diesel locomotive will increase the competitiveness of products and reduce costs

Correction of Posture Deviations in the Sagittal Plane Using the Pilates Method

2019 ◽  
pp. 3-13
Author(s):  
Alexandru Cîtea ◽  
George-Sebastian Iacob
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Postural Control ◽  
Human Body ◽  
Sagittal Plane ◽  
The Body ◽  
Lower Limbs ◽  
Low Back ◽  
Pilates Method ◽  
The Relationship

Posture is commonly perceived as the relationship between the segments of the human body upright. Certain parts of the body such as the cephalic extremity, neck, torso, upper and lower limbs are involved in the final posture of the body. Musculoskeletal instabilities and reduced postural control lead to the installation of nonstructural posture deviations in all 3 anatomical planes. When we talk about the sagittal plane, it was concluded that there are 4 main types of posture deviation: hyperlordotic posture, kyphotic posture, rectitude and "sway-back" posture.Pilates method has become in the last decade a much more popular formof exercise used in rehabilitation. The Pilates method is frequently prescribed to people with low back pain due to their orientation on the stabilizing muscles of the pelvis. Pilates exercise is thus theorized to help reactivate the muscles and, by doingso, increases lumbar support, reduces pain, and improves body alignment.

Some Special Aspects of Hypersonic Flow Fields

1959 ◽  
Vol 63 (585) ◽  
pp. 508-512 ◽  
Author(s):  
K. W. Mangler
Keyword(s):  
Hypersonic Flow ◽  
High Speed ◽  
Flow Fields ◽  
The Body ◽  
Lower Velocity ◽  
Bow Wave ◽  
Total Head ◽  
Bow Shocks ◽  
Lower Entropy ◽  
Subsonic Region

When a body moves through air at very high speed at such a height that the air can be considered as a continuum, the distinction between sharp and blunt noses with their attached or detached bow shocks loses its significance, since, in practical cases, the bow wave is always detached and fairly strong. In practice, all bodies behave as blunt shapes with a smaller or larger subsonic region near the nose where the entropy and the corresponding loss of total head change from streamline to streamline due to the curvature of the bow shock. These entropy gradients determine the behaviour of the hypersonic flow fields to a large extent. Even in regions where viscosity effects are small they give rise to gradients of the velocity and shear layers with a lower velocity and a higher entropy near the surface than would occur in their absence. Thus one can expect to gain some relief in the heating problems arising on the surface of the body. On the other hand, one would lose farther downstream on long slender shapes as more and more air of lower entropy is entrained into the boundary layer so that the heat transfer to the surface goes up again. Both these flow regions will be discussed here for the simple case of a body of axial symmetry at zero incidence. Finally, some remarks on the flow field past a lifting body will be made. Recently, a great deal of information on these subjects has appeared in a number of reviewing papers so that little can be added. The numerical results on the subsonic flow regions in Section 2 have not been published before.

scholarly journals Wearable Vibration Sensor for Measuring the Wing Flapping of Insects

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 593
Author(s):  
Ryota Yanagisawa ◽  
Shunsuke Shigaki ◽  
Kotaro Yasui ◽  
Dai Owaki ◽  
Yasuhiro Sugimoto ◽  
...  
Keyword(s):  
High Speed ◽  
Environmental Changes ◽  
Underlying Mechanism ◽  
Indirect Measurement ◽  
Feedback Mechanism ◽  
The Body ◽  
Vibration Sensor ◽  
Wingbeat Frequency ◽  
Film Sensor ◽  
Insect Wing

In this study, we fabricated a novel wearable vibration sensor for insects and measured their wing flapping. An analysis of insect wing deformation in relation to changes in the environment plays an important role in understanding the underlying mechanism enabling insects to dynamically interact with their surrounding environment. It is common to use a high-speed camera to measure the wing flapping; however, it is difficult to analyze the feedback mechanism caused by the environmental changes caused by the flapping because this method applies an indirect measurement. Therefore, we propose the fabrication of a novel film sensor that is capable of measuring the changes in the wingbeat frequency of an insect. This novel sensor is composed of flat silver particles admixed with a silicone polymer, which changes the value of the resistor when a bending deformation occurs. As a result of attaching this sensor to the wings of a moth and a dragonfly and measuring the flapping of the wings, we were able to measure the frequency of the flapping with high accuracy. In addition, as a result of simultaneously measuring the relationship between the behavior of a moth during its search for an odor source and its wing flapping, it became clear that the frequency of the flapping changed depending on the frequency of the odor reception. From this result, a wearable film sensor for an insect that can measure the displacement of the body during a particular behavior was fabricated.

Influence of Attached Masses on Impact Forces and Running Style in Heel-Toe Running

1987 ◽  
Vol 3 (3) ◽  
pp. 264-275 ◽  
Author(s):  
Alexander Bahlsen ◽  
Benno M. Nigg
Keyword(s):  
Body Mass ◽  
High Speed ◽  
Impact Force ◽  
Force Plate ◽  
The Body ◽  
Additional Mass ◽  
Impact Forces ◽  
Running Shoes ◽  
High Speed Film ◽  
Vertical Impact

Impact forces analysis in heel-toe running is often used to examine the reduction of impact forces for different running shoes and/or running techniques. Body mass is reported to be a dominant predictor of vertical impact force peaks. However, it is not evident whether this finding is only true for the real body mass or whether it is also true for additional masses attached to the body (e.g., running with additional weight or heavy shoes). The purpose of this study was to determine the effect of additional mass on vertical impact force peaks and running style. Nineteen subjects (9 males, 10 females) with a mean mass of 74.2 kg/56.2 kg (SD = 10.0 kg and 6.0 kg) volunteered to participate in this study. Additional masses were attached to the shoe (.05 and .1 kg), the tibia (.2, .4, .6 kg), and the hip (5.9 and 10.7 kg). Force plate measurements and high-speed film data were analyzed. In this study the vertical impact force peaks, Fzi, were not affected by additional masses, the vertical active force peaks, Fza, were only affected by additional masses greater than 6 kg, and the movement was only different in the knee angle at touchdown, ϵ0, for additional masses greater than .6 kg. The results of this study did not support findings reported earlier in the literature that body mass is a dominant predictor of external vertical impact force peaks.

scholarly journals Optimal nonlinear eddy viscosity in Galerkin models of turbulent flows

2015 ◽  
Vol 766 ◽  
pp. 337-367 ◽  
Author(s):  
Bartosz Protas ◽  
Bernd R. Noack ◽  
Jan Östh
Keyword(s):  
Turbulent Flows ◽  
High Speed ◽  
Eddy Viscosity ◽  
Broad Class ◽  
Constitutive Relations ◽  
Body Height ◽  
Mixing Layer ◽  
The Body ◽  
Stream Velocity ◽  
Initial Vorticity

AbstractWe propose a variational approach to the identification of an optimal nonlinear eddy viscosity as a subscale turbulence representation for proper orthogonal decomposition (POD) models. The ansatz for the eddy viscosity is given in terms of an arbitrary function of the resolved fluctuation energy. This function is found as a minimizer of a cost functional measuring the difference between the target data coming from a resolved direct or large-eddy simulation of the flow and its reconstruction based on the POD model. The optimization is performed with a data-assimilation approach generalizing the 4D-VAR method. POD models with optimal eddy viscosities are presented for a 2D incompressible mixing layer at $\mathit{Re}=500$ (based on the initial vorticity thickness and the velocity of the high-speed stream) and a 3D Ahmed body wake at $\mathit{Re}=300\,000$ (based on the body height and the free-stream velocity). The variational optimization formulation elucidates a number of interesting physical insights concerning the eddy-viscosity ansatz used. The 20-dimensional model of the mixing-layer reveals a negative eddy-viscosity regime at low fluctuation levels which improves the transient times towards the attractor. The 100-dimensional wake model yields more accurate energy distributions as compared to the nonlinear modal eddy-viscosity benchmark proposed recently by Östh et al. (J. Fluid Mech., vol. 747, 2014, pp. 518–544). Our methodology can be applied to construct quite arbitrary closure relations and, more generally, constitutive relations optimizing statistical properties of a broad class of reduced-order models.

scholarly journals Turnover of the Active Fraction of IRS1 Involves Raptor-mTOR- and S6K1-Dependent Serine Phosphorylation in Cell Culture Models of Tuberous Sclerosis

2006 ◽  
Vol 26 (17) ◽  
pp. 6425-6434 ◽  
Author(s):  
O. Jameel Shah ◽  
Tony Hunter
Keyword(s):  
Cell Culture ◽  
Tuberous Sclerosis ◽  
High Speed ◽  
Serine Phosphorylation ◽  
Feedback Signal ◽  
Insulin Receptor Substrates ◽  
Igf I ◽  
Culture Models ◽  
Cell Culture Models

ABSTRACT The TSC1-TSC2/Rheb/Raptor-mTOR/S6K1 cell growth cassette has recently been shown to regulate cell autonomous insulin and insulin-like growth factor I (IGF-I) sensitivity by transducing a negative feedback signal that targets insulin receptor substrates 1 and 2 (IRS1 and -2). Using two cell culture models of the familial hamartoma syndrome, tuberous sclerosis, we show here that Raptor-mTOR and S6K1 are required for phosphorylation of IRS1 at a subset of serine residues frequently associated with insulin resistance, including S307, S312, S527, S616, and S636 (of human IRS1). Using loss- and gain-of-function S6K1 constructs, we demonstrate a requirement for the catalytic activity of S6K1 in both direct and indirect regulation of IRS1 serine phosphorylation. S6K1 phosphorylates IRS1 in vitro on multiple residues showing strong preference for RXRXXS/T over S/T,P sites. IRS1 is preferentially depleted from the high-speed pellet fraction in TSC1/2-deficient mouse embryo fibroblasts or in HEK293/293T cells overexpressing Rheb. These studies suggest that, through serine phosphorylation, Raptor-mTOR and S6K1 cell autonomously promote the depletion of IRS1 from specific intracellular pools in pathological states of insulin and IGF-I resistance and thus potentially in lesions associated with tuberous sclerosis.

A Benchmark Control Problem for Supercavitating Vehicles and an Initial Investigation of Solutions

2003 ◽  
Vol 9 (7) ◽  
pp. 791-804 ◽  
Author(s):  
John Dzielski ◽  
Andrew Kurdila
Keyword(s):  
High Speed ◽  
Linear Models ◽  
The Body ◽  
Control Surface ◽  
Force Model ◽  
Entire Body ◽  
Benchmark Problem ◽  
Supercavitating Vehicles ◽  
Forcing Function ◽  
Natural Cavitation

At very high speeds, underwater bodies develop cavitation bubbles at the trailing edges of sharp corners or from contours where adverse pressure gradients are sufficient to induce flow separation. Coupled with a properly designed cavitator at the nose of a vehicle, this natural cavitation can be augmented with gas to induce a cavity to cover nearly the entire body of the vehicle. The formation of the cavity results in a significant reduction in drag on the vehicle and these so-called high-speed supercavitating vehicles (HSSVs) naturally operate at speeds in excess of 75 m s-1. The first part of this paper presents a derivation of a benchmark problem for control of HSSVs. The benchmark problem focuses exclusively on the pitch-plane dynamics of the body which currently appear to present the most severe challenges. A vehicle model is parametrized in terms of generic parameters of body radius, body length, and body density relative to the surrounding fluid. The forebody shape is assumed to be a right cylindrical cone and the aft two-thirds is assumed to be cylindrical. This effectively parametrizes the inertia characteristics of the body. Assuming the cavitator is a flat plate, control surface lift curves are specified relative to the cavitator effectiveness. A force model for a planing afterbody is also presented. The resulting model is generally unstable whenever in contact with the cavity and stable otherwise, provided the fin effectiveness is large enough. If it is assumed that a cavity separation sensor is not available or that the entire weight of the body is not to be carried on control surfaces, limit cycle oscillations generally result. The weight of the body inevitably forces the vehicle into contact with the cavity and the unstable mode; the body effectively skips on the cavity wall. The general motion can be characterized by switching between two nominally linear models and an external constant forcing function. Because of the extremely short duration of the cavity contact, direct suppression of the oscillations and stable planing appear to present severe challenges to the actuator designer. These challenges are investigated in the second half of the paper, along with several approaches to the design of active control systems.

scholarly journals A faster escape does not enhance survival in zebrafish larvae

2017 ◽  
Vol 284 (1852) ◽  
pp. 20170359 ◽  
Author(s):  
Arjun Nair ◽  
Christy Nguyen ◽  
Matthew J. McHenry
Keyword(s):  
High Speed ◽  
Larval Fish ◽  
Body Position ◽  
Three Dimensional ◽  
Limited Range ◽  
The Body ◽  
Model Parameters ◽  
Fish Prey ◽  
Zebrafish Larvae ◽  
Fish Predators

An escape response is a rapid manoeuvre used by prey to evade predators. Performing this manoeuvre at greater speed, in a favourable direction, or from a longer distance have been hypothesized to enhance the survival of prey, but these ideas are difficult to test experimentally. We examined how prey survival depends on escape kinematics through a novel combination of experimentation and mathematical modelling. This approach focused on zebrafish ( Danio rerio ) larvae under predation by adults and juveniles of the same species. High-speed three-dimensional kinematics were used to track the body position of prey and predator and to determine the probability of behavioural actions by both fish. These measurements provided the basis for an agent-based probabilistic model that simulated the trajectories of the animals. Predictions of survivorship by this model were found by Monte Carlo simulations to agree with our observations and we examined how these predictions varied by changing individual model parameters. Contrary to expectation, we found that survival may not be improved by increasing the speed or altering the direction of the escape. Rather, zebrafish larvae operate with sufficiently high locomotor performance due to the relatively slow approach and limited range of suction feeding by fish predators. We did find that survival was enhanced when prey responded from a greater distance. This is an ability that depends on the capacity of the visual and lateral line systems to detect a looming threat. Therefore, performance in sensing, and not locomotion, is decisive for improving the survival of larval fish prey. These results offer a framework for understanding the evolution of predator–prey strategy that may inform prey survival in a broad diversity of animals.

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