Application Kinetic Energy Shaping to Controlling and Anticontrolling Chaotic Gait of Underactuated Compass-Gait Bipedal Robot

2017 ◽  
Author(s):  
Jin Xie ◽  
Bowen Sun ◽  
Wei Wei ◽  
Zhaohui Liu
Keyword(s):  
Kinetic Energy ◽  
Initial Phase ◽  
Bipedal Robot ◽  
Energy Shaping ◽  
Control Scheme ◽  
The One

Being different from uncontrolled and unpowered biped, an underactuated compass-gait bipedal robot is the one actuated at the ankle. Energy is inputted to control the gait of biped. Based on kinetic energy shaping, controlling and anti-controlling of chaotic gait are investigated in this paper. In order to provide energy at proper instant, the energy shaping function is modified as ksinθ1+θ0θ.12. This modification permits of taking the characteristic of gait of the biped into consideration by taking the best initial phase as initial phase, i.e. θ0=θ0*. The results of simulation show that the control scheme ksinθ1+θ0θ.12 is efficient in controlling and anti-controlling chaotic gait.

scholarly journals John Calvin on the gifts of the Holy Spirit in his commentary on Acts

2017 ◽  
Vol 82 (2) ◽  
Author(s):  
Erik van Alten
Keyword(s):  
Holy Spirit ◽  
Initial Phase ◽  
Human Error ◽  
John Calvin ◽  
Complete Picture ◽  
General Sense ◽  
The Holy Spirit ◽  
Book Of Acts ◽  
The One ◽  
The Church

John Calvin is often considered to have taught the cessation of the extraordinary gifts of the Holy Spirit. This certainly does not give the complete picture of how Calvin wrestled with those passages from Scripture which deal with the extraordinary gifts. In his commentary on the book of Acts Calvin makes a conscious effort to show that in most of the cases where the gifts of the Spirit are mentioned, the focus is not on the gifts in a general sense, but in an extraordinary sense. These extraordinary gifts had been limited to the initial phase of the church. The reasons that Calvin provides for this cessation is somewhat ambiguous. On the one hand Calvin indicates a very specific, divine purpose for the gifts, which limits its usefulness and existence until the point when the purpose had been achieved. However, there are also passages where one gets the impression that the cessation of the gifts was not necessarily divinely intended, but was due to human error. Of great importance is the way Calvin subsequently applies these texts to the readers of his own day. Johannes Calvyn oor die gawes van die Heilige Gees in sy kommentaar op Handelinge Dikwels word aangeneem dat Johannes Calvyn die beëindiging van die buitengewone gawes van die Heilige Gees voorgestaan het. Dit gee egter nie die volle prentjie van hoe Calvyn met daardie Skrifgedeeltes, waarin die buitengewone gawes behandel word, geworstel het nie. In sy kommentaar op die boek Handelinge wys Calvyn bewustelik daarop dat in die meeste gevalle waar die gawes van die Gees genoem word, die fokus nie op die gawes in ’n algemene sin is nie, maar eerder op die gawes in ’n buitengewone sin. Hierdie buitengewone gawes is beperk tot die beginfase van die kerk. Die redes wat Calvyn vir hierdie beëindiging aanvoer, is egter dubbelsinnig. Aan die eenkant wys Calvyn op ’n baie spesifieke, Goddelike doel met die gawes, waardeur hulle bruikbaarheid en voortbestaan beperk word tot die tyd toe die doel bereik is. Aan die anderkant, egter, is daar ook gedeeltes wat die indruk skep dat die beëindiging van die gawes nie noodwendig Goddelik bepaal is nie, maar ’n gevolg was van menslike sonde. Van groot belang is hoe Calvyn hierdie tekste vervolgens toepas op die lesers van sy eie tyd.

scholarly journals Quantum conductance staircase of holes in silicon nanosandwiches

2019 ◽  
Vol 20 (2) ◽  
pp. 81-98
Author(s):  
N. T. Bagraev ◽  
L. E. Klyachkin ◽  
A. M. Malyarenko ◽  
V. S. Khromov
Keyword(s):  
Kinetic Energy ◽  
Quantum Wells ◽  
Quantum Wires ◽  
Energy Gap ◽  
Point Contact ◽  
Quantum Conductance ◽  
One Dimensional ◽  
Drastic Increase ◽  
Quantum Point ◽  
The One

The results of studying the quantum conductance staircase of holes in one−dimensional channels obtained by the split−gate method inside silicon nanosandwiches that are the ultra−narrow quantum well confined by the delta barriers heavily doped with boron on the n−type Si (100) surface are reported. Since the silicon quantum wells studied are ultra−narrow (~2 nm) and confined by the delta barriers that consist of the negative−U dipole boron centers, the quantized conductance of one−dimensional channels is observed at relatively high temperatures (T > 77 K). Further, the current−voltage characteristic of the quantum conductance staircase is studied in relation to the kinetic energy of holes and their sheet density in the quantum wells. The results show that the quantum conductance staircase of holes in p−Si quantum wires is caused by independent contributions of the one−dimensional (1D) subbands of the heavy and light holes; these contributions manifest themselves in the study of square−section quantum wires in the doubling of the quantum−step height (G0 = 4e2/h), except for the first step (G0 = 2e2/h) due to the absence of degeneracy of the lower 1D subband. An analysis of the heights of the first and second quantum steps indicates that there is a spontaneous spin polarization of the heavy and light holes, which emphasizes the very important role of exchange interaction in the processes of 1D transport of individual charge carriers. In addition, the field−related inhibition of the quantum conductance staircase is demonstrated in the situation when the energy of the field−induced heating of the carriers become comparable to the energy gap between the 1D subbands. The use of the split−gate method made it possible to detect the effect of a drastic increase in the height of the quantum conductance steps when the kinetic energy of holes is increased; this effect is most profound for quantum wires of finite length, which are not described under conditions of a quantum point contact. In the concluding section of this paper we present the findings for the quantum conductance staircase of holes that is caused by the edge channels in the silicon nanosandwiches prepared within frameworks of the Hall. This longitudinal quantum conductance staircase, Gxx, is revealed by the voltage applied to the Hall contacts, Vxy, to a maximum of 4e2/h. In addition to the standard plateau, 2e2/h, the variations of the Vxy voltage appear to exhibit the fractional forms of the quantum conductance staircase with the plateaus and steps that bring into correlation respectively with the odd and even fractional values.

scholarly journals Synergies in coordination: a comprehensive overview of neural, computational, and behavioral approaches

2018 ◽  
Vol 120 (6) ◽  
pp. 2761-2774 ◽  
Author(s):  
Michaela Bruton ◽  
Nicholas O’Dwyer
Keyword(s):  
Motor Control ◽  
Hierarchical Control ◽  
Research Approach ◽  
Comprehensive Overview ◽  
Control Scheme ◽  
The One ◽  
Explanatory Concept ◽  
Different Levels ◽  
And Task

At face value, the term “synergy” provides a unifying concept within a fractured field that encompasses complementary neural, computational, and behavioral approaches. However, the term is not used synonymously by different researchers but has substantially different meanings depending on the research approach. With so many operational definitions for the one term, it becomes difficult to use as either a descriptive or explanatory concept, yet it remains pervasive and apparently indispensable. Here we provide a summary of different approaches that invoke synergies in a descriptive or explanatory context, summarizing progress, not within the one approach, but across the theoretical landscape. Bernstein’s framework of flexible hierarchical control may provide a unifying framework here, since it can incorporate divergent ideas about synergies. In the current motor control literature, synergy may refer to conceptually different processes that could potentially operate in parallel, across different levels within the same hierarchical control scheme. There is evidence for the concurrent existence of synergies with different features, both “hard-wired” and “soft-wired,” and task independent and task dependent. By providing a comprehensive overview of the multifaceted ideas about synergies, our goal is to move away from the compartmentalization and narrow the focus on one level and promote a broader perspective on the control and coordination of movement.

Control of a mobile robotic manipulator: a combined design approach

2018 ◽  
Author(s):  
Martín Crespo ◽  
Matías Nacusse ◽  
Sergio Junco ◽  
Vitalram Rayankula ◽  
Pushparaj Mani Pathak
Keyword(s):  
Arm Movement ◽  
Backstepping Technique ◽  
Energy Shaping ◽  
End Effector ◽  
Dc Motors ◽  
Operational Space ◽  
Control Actions ◽  
Moving Base ◽  
The One ◽  
Mobile Base

"This paper focuses on the problem of reducing via control actions the interaction between the mobile platform and the arm in a mobile robot equipped with a redundant planar manipulator. It is solved maintaining the mobile base as immobile as possible once it has been moved to a desired position, which serves to a double purpose. On the one hand, it helps keeping fixed the workspace of the manipulator, as predefined in the world coordinates, in order for the end-effector being able to reach the points where it has to perform its tasks. On the other hand, as this reduces the disturbances that the otherwise moving base would introduce on the arm movement, this serves to improve the precision in the execution of whatever task the end-effector has to perform. The problem is solved via a combination of operational space control to solve the arm tip trajectory tracking problem and energy-shaping and damping assignment to restrict the movement of the mobile base. The latter is achieved using a backstepping technique in the Bond Graph domain which emulates dissipation and stiffness at the base wheels coordinates through the control of the DC motors actuating them. Simulation results show the good performance of the control system."

scholarly journals Fully stabilized multi-TW optical waveform synthesizer: Toward gigawatt isolated attosecond pulses

2020 ◽  
Vol 6 (16) ◽  
pp. eaay2802 ◽  
Author(s):  
Bing Xue ◽  
Yuuki Tamaru ◽  
Yuxi Fu ◽  
Hua Yuan ◽  
Pengfei Lan ◽  
...  
Keyword(s):  
Harmonic Spectrum ◽  
Pump Laser ◽  
X Ray ◽  
High Order Harmonic ◽  
Delay Dependence ◽  
Control Scheme ◽  
Active Stabilization ◽  
Waveform Synthesis ◽  
Spectrum Intensity ◽  
The One

A stable 50-mJ three-channel optical waveform synthesizer is demonstrated and used to reproducibly generate a high-order harmonic supercontinuum in the soft x-ray region. This synthesizer is composed of pump pulses from a 10-Hz repetition-rate Ti:sapphire pump laser and signal and idler pulses from an infrared two-stage optical parametric amplifier driven by this pump laser. With full active stabilization of all relative time delays, relative phases, and the carrier-envelope phase, a shot-to-shot stable intense continuum harmonic spectrum is obtained around 60 eV with pulse energy above 0.24 μJ. The peak power of the soft x-ray continuum is evaluated to be beyond 1 GW with a 170-as transform limit duration. We found a characteristic delay dependence of the multicycle waveform synthesizer and established its control scheme. Compared with the one-color case, we experimentally observe an enhancement of the cutoff spectrum intensity by one to two orders of magnitude using three-color waveform synthesis.

Analysis of Turbulent Thermal Convection Between Horizontal Plates

1983 ◽  
Vol 105 (4) ◽  
pp. 789-794 ◽  
Author(s):  
M. Kaviany ◽  
R. Seban
Keyword(s):  
Temperature Distribution ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Thermal Convection ◽  
Equation Model ◽  
Experimental Results ◽  
Mixing Length ◽  
Mean Temperature ◽  
The Mean ◽  
The One

The one-equation model of turbulence is applied to the turbulent thermal convection between horizontal plates maintained at constant temperatures. A pseudo-three-layer model is used consisting of a conduction sublayer adjacent to the plates, a turbulent region within which the mixing length increases linearly, and a turbulent core within which the mixing length is a constant. It is assumed that the Nusselt number varies with the Rayleigh number to the one-third power. As a result, the steady-state distributions of the turbulent kinetic energy and the mean temperature are obtrained and presented in closed forms. These results include the effects of Prandtl number. The predictions are compared with the available experimental results for different Prandtl and Rayleigh numbers. Also included are the predictions of Kraichnan, which are based on a less exact analysis. The results of the one-equation model are in fair agreement with the experimental results for the distribution of the turbulent kinetic energy and the mean temperature distribution. The predictions of Kraichnan are in better agreement with the experimental results for the mean temperature distribution.

Development of drawing abilities in a distinct population: Depiction of perceptual principles by three children with congenital total blindness

2003 ◽  
Vol 27 (3) ◽  
pp. 193-200 ◽  
Author(s):  
Amedeo D’Angiulli ◽  
Stefania Maggi
Keyword(s):  
Initial Phase ◽  
Spatial Information ◽  
Vantage Point ◽  
The Other ◽  
Distinct Population ◽  
Congenital Blindness ◽  
Other Hand ◽  
Blind Children ◽  
Total Blindness ◽  
The One

We studied the development of spontaneous tactile drawing in three 12-year-old children with congenital total blindness and with no previous drawing tuition. In a period of 9 months, from an initial phase in which they were taught to draw tangible straight and curve raised lines, the three blind children went on making spontaneous raised outlines representing edges, surfaces of objects, vantage point, and motion. The corpus of drawings produced by these children shows that several aspects of outline pictures can be implemented through touch. The perceptual principles represented in these drawings are comparable to those commonly found in sighted children. On the one hand, this convergence indicates similarities in the way vision and touch mediate the acquisition and the conceptualisation of spatial information from objects and the environment. On the other hand, it reflects the influence of cross-modal plasticity typically associated with early or congenital blindness. This study suggests that drawing development in general does not depend on learning pictorial conventions. Rather it seems driven by natural generativity based on children’s knowledge of space and perceptual principles.

scholarly journals Dissipative Processes and Their Role in the Evolution of Radio Galaxies

Galaxies ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 70 ◽  
Author(s):  
Manel Perucho
Keyword(s):  
Particle Acceleration ◽  
Kinetic Energy ◽  
Radio Galaxies ◽  
Active Galaxies ◽  
Energy Budgets ◽  
Natural Question ◽  
Relativistic Jets ◽  
The One ◽  
Very High

Particle acceleration in relativistic jets, to very high levels of energy, occurs at the expense of the dissipation of magnetic or kinetic energy. Therefore, understanding the processes that can trigger this dissipation is key to the characterization of the energy budgets and particle acceleration mechanisms in action in active galaxies. Instabilities and entrainment are two obvious candidates to trigger dissipation. On the one hand, supersonic, relativistic flows threaded by helical fields, as expected from the standard formation models of jets in supermassive black-holes, are unstable to a series of magnetohydrodynamical instabilities, such as the Kelvin–Helmholtz, current-driven, or possibly the pressure-driven instabilities. Furthermore, in the case of expanding jets, the Rayleigh–Taylor and centrifugal instabilities may also develop. With all these destabilizing processes in action, a natural question is to ask how can some jets keep their collimated structure along hundreds of kiloparsecs. On the other hand, the interaction of the jet with stars and clouds of gas that cross the flow in their orbits around the galactic centers provides another scenario in which kinetic energy can be efficiently converted into internal energy and particles can be accelerated to non-thermal energies. In this contribution, I review the conditions under which these processes occur and their role both in jet evolution and propagation and energy dissipation.

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