Experimental tests for the quantum behavior of a macroscopic degree of freedom: The phase difference across a Josephson junction

1987 ◽  
Vol 35 (10) ◽  
pp. 4682-4698 ◽  
Author(s):  
John M. Martinis ◽  
Michel H. Devoret ◽  
John Clarke
Keyword(s):  
Josephson Junction ◽  
Phase Difference ◽  
Experimental Tests ◽  
Degree Of Freedom ◽  
Quantum Behavior

scholarly journals Stability and Manoeuvrability Simulation of a Semi-Autonomous Submarine Free-Running Model SUBOFF with an Autopilot System

2021 ◽  
Vol 11 (1) ◽  
pp. 410
Author(s):  
Yu-Hsien Lin ◽  
Yu-Ting Lin ◽  
Yen-Jun Chiu
Keyword(s):  
Optimal Control ◽  
Experimental Tests ◽  
Degree Of Freedom ◽  
Line Of Sight ◽  
Pd Controller ◽  
Free Running ◽  
Simulation Results ◽  
Guidance Algorithm ◽  
Logic Operations ◽  
Six Degree Of Freedom

On the basis of a full-appendage DARPA SUBOFF model (DTRC model 5470), a scale (λ = 0.535) semi-autonomous submarine free-running model (SFRM) was designed for testing its manoeuvrability and stability in the constrained water. Prior to the experimental tests of the SFRM, a six-degree-of-freedom (6-DOF) manoeuvre model with an autopilot system was developed by using logic operations in MATLAB. The SFRM’s attitude and its trim polygon were presented by coping with the changes in mass and trimming moment. By adopting a series of manoeuvring tests in empty tanks, the performances of the SFRM were introduced in cases of three sailing speeds. In addition, the PD controller was established by considering the simulation results of these manoeuvring tests. The optimal control gains with respect to each manoeuvring test can be calculated by using the PID tuner in MATLAB. Two sets of control gains derived from the optimal characteristics parameters were compared in order to decide on the most appropriate PD controller with the line-of-sight (LOS) guidance algorithm for the SFRM in the autopilot simulation. Eventually, the simulated trajectories and course angles of the SFRM would be illustrated in the post-processor based on the Cinema 4D modelling.

Vibratory Feeding

1967 ◽  
Vol 182 (1) ◽  
pp. 135-152 ◽  
Author(s):  
A. H. Redford ◽  
G. Boothroyd
Keyword(s):  
Phase Difference ◽  
Experimental Tests ◽  
Harmonic Motion ◽  
Fundamental Limitations ◽  
Wide Range ◽  
Theoretical Predictions ◽  
The Coefficient Of Friction ◽  
Bowl Feeder ◽  
Vibratory Bowl Feeder ◽  
Vibratory Feeding

A brief review of previous work on the mechanics of vibratory conveying is presented followed by a new theoretical analysis of vibratory feeding on a track which vibrates with simple harmonic motion and where a phase difference may exist between the parallel and normal components of the track motion. For a wide range of practical conditions, the theoretical predictions are found to agree closely with the results of experimental tests. These show that certain fundamental limitations exist in the performance of conventional feeder drives where the two components of track motion are in-phase. From further theoretical and experimental work, it is shown that under conditions where the appropriate phase difference exists between the two components of track motion, many practical advantages over conventional vibratory feeding are obtained. With a new design of vibratory bowl feeder drive based on the results of the work, significantly higher conveying velocities may be obtained under stable feeding conditions and, further, these high conveying velocities are virtually independent of the coefficient of friction between the component and the track. The results of the present work apply equally to the design of spiral elevators and in-line vibratory feeders.

Online force control of a shape-memory-alloy-based 2 degree-of-freedom human finger via inverse model and proportional–integral–derivative compensator

2019 ◽  
Vol 30 (10) ◽  
pp. 1538-1548 ◽  
Author(s):  
F Mirzakhani ◽  
SM Ayati ◽  
P Fahimi ◽  
M Baghani
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tracking Error ◽  
Reference Signal ◽  
Experimental Tests ◽  
Degree Of Freedom ◽  
Heat Transfer Analysis ◽  
Proportional Integral Derivative ◽  
Proportional Integral ◽  
Arbitrary Reference

In this work, a model-based controller is developed to track the force at fingertip of an artificial hand. To do so, shape-memory-alloy wires are implemented as an actuator in the finger. Besides, different aspects of modeling, including force relations, kinematics, and heat transfer analysis, are investigated. A modified version of Brinson’s model is used to capture thermomechanical behavior of shape-memory-alloy wires. A controller is designed to control the applied potential difference between shape-memory-alloy wires and consequently control the electrical current in these wires based on the shape-memory-alloy wires model. The main goal of the proposed controller is force controlling of a 2-degree-of-freedom hand finger. This controller contains shape-memory-alloy constitutive model used for compensating system uncertainties. Furthermore, a proportional–integral–derivative controller/compensator is included in the closed-loop system. The compensator acts only on the derivative-type states, and this is one of the differences of this work compared to that of similar literature. The results of three arbitrary reference input signals are reported confirming the model prediction and simulation results are in good agreement with experimental tests. The analysis of the relative tracking error for an arbitrary reference signal is 11% in experimental test and 4% in the simulation.

Quantum Mechanics of a Macroscopic Variable: The Phase Difference of a Josephson Junction

Science ◽  
1988 ◽  
Vol 239 (4843) ◽  
pp. 992-997 ◽  
Author(s):  
J. CLARKE ◽  
A. N. CLELAND ◽  
M. H. DEVORET ◽  
D. ESTEVE ◽  
J. M. MARTINIS
Keyword(s):  
Quantum Mechanics ◽  
Josephson Junction ◽  
Phase Difference ◽  
Macroscopic Variable

An On-Line Measurement Technique for Machine Volumetric Error Compensation

1993 ◽  
Vol 115 (1) ◽  
pp. 85-92 ◽  
Author(s):  
J. Ni ◽  
S. M. Wu
Keyword(s):  
Measurement Technique ◽  
Error Compensation ◽  
Experimental Tests ◽  
Geometric Error ◽  
Degree Of Freedom ◽  
Volumetric Error ◽  
Measurement Systems ◽  
Line Measurement ◽  
Maximum Range ◽  
On Line

A hybrid on-line and off-line measurement technique is developed for machine volumetric error compensation based on a multiple-degree-of-freedom laser optical system. When implemented on a 3-axis machine up to 15 geometric error components can be measured simultaneously on-line and the remaining 6 components need to be calibrated off-line. Since the on-line measurement systems use different metrology bases, a modified volumetric error model is derived for a milling machine by considering the measurement features of the multiple-degree-of-freedom system. Through experimental tests, it was found that the discrepancy between the identified errors and the actual errors was less than 4 μm out of a maximum range of 20 μm.

TAMING CHAOS IN A DRIVEN JOSEPHSON JUNCTION

2001 ◽  
Vol 11 (07) ◽  
pp. 1897-1909 ◽  
Author(s):  
R. CHACÓN ◽  
F. PALMERO ◽  
F. BALIBREA
Keyword(s):  
Josephson Junction ◽  
Phase Difference ◽  
Initial Phase ◽  
Chaotic Dynamics ◽  
Numerical Results ◽  
Initial Phase Difference ◽  
Theoretical Predictions ◽  
Melnikov Analysis ◽  
Analytical Expressions ◽  
Good Agreement

We present analytical and numerical results concerning the inhibition of chaos in a single driven Josephson junction by means of an additional weak resonant perturbation. From Melnikov analysis, we theoretically find parameter-space regions, associated with the chaos-suppressing perturbation, where chaotic states can be suppressed. In particular, we test analytical expressions for the intervals of initial phase difference between the two excitations for which chaotic dynamics can be eliminated. All the theoretical predictions are in overall good agreement with numerical results obtained by simulation.

Design and operation of a 2-DOF leg–wheel hybrid robot

Robotica ◽  
2013 ◽  
Vol 31 (8) ◽  
pp. 1319-1325 ◽  
Author(s):  
Erika Ottaviano ◽  
Pierluigi Rea
Keyword(s):  
Mobile Robot ◽  
Low Cost ◽  
Experimental Tests ◽  
Degree Of Freedom

SUMMARYIn this paper the design and operation for a 2-Degree-of-Freedom, leg–wheel hybrid mobile robot are presented. A prototype of a low-cost and easy-to-use system, which is capable of straight walking and steering with two actuators only, has been designed and built. Simulation and experimental tests have been carried out to verify the engineering feasibility and operation of the proposed solution. The designed robot can be used for applications such as surveillance and inspection of disaster sites.

scholarly journals H-cluster stars

2012 ◽  
Vol 8 (S291) ◽  
pp. 435-437
Author(s):  
X. Y. Lai ◽  
R. X. Xu
Keyword(s):  
Low Temperature ◽  
Experimental Evidence ◽  
Lattice Qcd ◽  
Dense Matter ◽  
Experimental Tests ◽  
Degree Of Freedom ◽  
Compact Stars ◽  
Maximum Mass ◽  
Cold Dense Matter ◽  
Stiffening Effect

AbstractThe study of dense matter at ultra-high density has a very long history, which is meaningful for us to understand not only cosmic events in extreme circumstances but also fundamental laws of physics. In compact stars at only a few nuclear densities but low temperature, quarks could be interacting strongly with each other. That might produce quarks grouped in clusters, although the hypothetical quark-clusters in cold dense matter have not been confirmed due to the lack of both theoretical and experimental evidence. A so-called H-cluster matter is proposed in this paper as the nature of dense matter in reality.Motivated by recent lattice QCD simulations of the H-dibaryons (with structure uuddss), we are therefore considering here a possible kind of quark-clusters, H-clusters, that could emerge inside compact stars during their initial cooling, as the dominant components inside (the degree of freedom could then be H-clusters there). We study the stars composed of H-clusters, i.e., H-cluster stars, and derive the dependence of their maximum mass on the in-medium stiffening effect, showing that the maximum mass could be well above 2 M⊙ as observed and that the resultant mass-radius relation fits the measurement of the rapid burster under reasonable parameters. Besides a general understanding of different manifestations of compact stars, we expect further observational and experimental tests for the H-cluster stars in the future.

A Numerical Model to Reproduce Vortex Induced Vibrations of a Circular Cylinder

2006 ◽  
Author(s):  
Marco Belloli ◽  
Giorgio Diana ◽  
Ferruccio Resta ◽  
Sara Muggiasca
Keyword(s):  
Numerical Model ◽  
Circular Cylinder ◽  
Mechanical System ◽  
Wind Velocity ◽  
Experimental Tests ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Vortex Induced Vibrations ◽  
Linear Mechanical System

This article describes a numerical model to reproduce vortex induced vibrations of a circular cylinder. It consists in a single degree of freedom non linear mechanical system, with characterizing parameters identified on the basis of experimental tests in order to reproduce the main features of VIV, in particular vibration amplitudes as function of wind velocity and the energy introduction by the blowing fluid into the mechanical system.

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