Change In Direction Of Rotation Research Articles

Joint torque estimation method of industrial robot by combining error compensation model based on LSTM and iterative weighted parameter identification

It is essential for human-robot interaction to accurate joint torque value estimation of industrial robots without force/torque (F/T) sensors. The most common method to estimate the value of robot joint torque is based on dynamic model parameter identification. However, no matter how elaborate the modeling methods are used, there are always uncertainty errors when robot’s joint rotation direction changes. In this paper, an identification framework is proposed to estimate optimal model parameters, and a deep learning network is proposed to compensate for the uncertainty errors caused by the unmodeled dynamics part. At first, the dynamic parameters are estimated during the Least Squares (LS) identification process considering the noise influence and data outliers, and the nonlinear friction model is unified into the identification framework. Secondly, based on Long-Short Term Memory (LSTM) network, an error compensation model (ECM) is proposed to establish the mapping relationship between the joint motion and the identification errors. Finally, a 6-DOF robot is used for parameter identification and ECM validation. Experimental results show that the proposed identification method is better than the LS method. Compared with the torque value estimated by the identification method, the proposed ECM can compensate for the uncertainty errors and improve the torque estimation accuracy.

Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch.

The cytoplasmic ring (C-ring) of the bacterial flagellar motor controls the motor rotation direction, thereby controlling bacterial run-and-tumble behavior. The C-ring has been shown to undergo adaptive remodeling in response to changes in motor directional bias. However, the stoichiometry and arrangement of the C-ring is still unclear due to contradiction between the results from fluorescence studies and cryo-electron microscopy (cryo-EM) structural analysis. Here, by using the copy number of FliG molecules (34) in the C-ring as a reference, we precisely measured the copy numbers of FliM molecules in motors rotating exclusively counterclockwise (CCW) and clockwise (CW). We surprisingly found that there are on average 45 and 58 FliM molecules in CW and CCW rotating motors, respectively, which are much higher than previous estimates. Our results suggested a new mechanism of C-ring adaptation, that is, extra FliM molecules could be bound to the primary C-ring with probability depending on the motor rotational direction. We further confirmed that all of the FliM molecules in the C-ring function in chemotaxis signaling transduction because all of them could be bound by the chemotactic response regulator CheY-P. Our measurements provided new insights into the structure and arrangement of the flagellar switch. IMPORTANCE The bacterial flagellar switch can undergo adaptive remodeling in response to changes in motor rotation direction, thereby shifting its operating point to match the output of the chemotaxis signaling pathway. However, it remains unclear how the flagellar switch accomplishes this adaptive remodeling. Here, via precise fluorescence studies, we measured the absolute copy numbers of the critical component in the switch for motors rotating counterclockwise and clockwise, obtaining much larger numbers than previous relative estimates. Our results suggested a new mechanism of adaptive remodeling of the flagellar switch and provided new insights for updating the conformation spread model of the switch.

High-Precision Target Detection of Remote Sensing Image Based on Feature Enhancement with 6G Technology

We provide remote sensing image enhancement technology based on 6G nursing urine technology to solve the main problems and current challenges of target detection in remote sensing imaging. High-resolution images: to get a good image, first look at the remote control image, and objective findings on the remote control image play an important role in this process. Military and civilian use: at present, many advanced object detection algorithms have achieved success in natural imaging, but their development is limited by two factors: large variation in object size and low detection accuracy, the scale, rotation direction, and distribution density of remote sensing images. On the other hand, the first remote sensing image is usually a high-resolution, large-scale image, which requires more time than blank image detection. The model is fine-tuned on the ICDAR2015 training package for 60,000 repetitions. The same model experimentally reduced the image to 1280 × 768 and displayed the results in one dimension. Therefore, in order to solve the problem of low detection due to changes in azimuth, rotation direction, and velocity distribution, it is necessary to further study methods for detecting large-capacity remote sensing objects using abundant high-precision remote sensing technologies, sensing imaging service on remote sensing maps.

A new stylus orientation planning strategy for sculpture surface inspection based on touch position graph

On-machine inspection (OMI) is an important technology for precise machining. Accuracy and efficiency improvement is a challenge for sculpture surface inspection. Before the inspection, if the practical touch position on the stylus tip is calibrated accurately, more accurate compensation of the pre-travel error could be applied in the inspection results. Meanwhile, time consumption on the calibration process could be reduced if the number of preset to-be-calibrated positions in the calibration is as small as possible. Thus, for precise compensation, the practical touch position on the stylus tip needs to be assigned during the inspection. In further, to reduce the calibration time, the quantity of practical touch position on the stylus tip requires to be least. A new stylus orientation planning strategy that controls the practical touch positions on the stylus tip is investigated in this paper. In terms of the strategy, a touch position graph (TPG) is proposed for the five-axis machine tool to discover the relationships between the practical touch positions, the angle combinations of rotary axis and the stylus orientations. The practical touch positions on the stylus tip and the rotation direction change of the machine tool’s rotary axes can be reduced as much as possible by optimizing the stylus orientations. In further, the pre-travel error on each to-be-inspected point can be compensated by accurate calibration results and the introduction of the rotation axes error can be decreased to prove the inspection accuracy improvement. At last, an experiment is applied on the impeller to verify the proposed OMI planning strategy.

Reply to the 'Comment on "Microflow in a rhythmically expanding alveolar chip with dynamic similarity"' by A. Tsuda and F. S. Henry, Lab Chip, 2021, 21, DOI.

This article provides our response to a comment on our article published in Lab on a Chip (H. Lv, J. Dong, Y. Qiu, Y. Yang and Y. Zhu, Lab Chip, 2020, 20, 2394-2402) by Tsuda and Henry, Lab Chip, 2020.

Genetic Algorithm Approach for Gains Selection of Induction Machine Extended Speed Observer

The subject of this paper is gains selection of an extended induction machine speed observer. A high number of gains makes manual gains selection difficult and due to nonlinear equations of the observer, well-known methods of gains selection for linear systems cannot be applied. A method based on genetic algorithms has been proposed instead. Such an approach requires multiple fitness function calls; therefore, using a quality index based on simulations makes gains selection a time-consuming process. To find a fitness function that evaluates, in a short time, quality indices based on poles placement have been proposed. As the observer is nonlinear, equations describing the observer dynamics have been linearized. The relationship between poles placement and real dynamic properties has been shown. A series of studies has been performed to investigate the influence of the operating point of the machine on the dynamics of the observer. It has been proven that rotor speed has a significant impact on the placement of the poles and the observer may lose stability after a rotation direction change. A method of gains modification to maintain symmetrical properties of the observer for both directions has been presented. Experimental studies of the observer during machine reverse in the open and closed-loop control system have been performed. The results show that the observer can be implemented in a sensorless drive, using the proposed gains selection method.

Computer modeling of the vapour vortex orientation changes in the short low- temperature heat pipes

The results of computer studies of the vortex formation and orientation changes inside short heat pipes (HP’s) with profiled vapour channel in the Laval–liked nozzle form are presented. For the first time it was found that the vapour vortex of moist compressible vapour flow in the cooled part of vapour channel changes its rotational motion direction. The rotation direction of the toroidal vapour vortex is dependent on the heat power value, entering to the HP’s evaporator. With low heat power loads (a small temperature head) the rotational direction of the circular toroidal vapour vortex due to the Coanda effect and sticking moving vapour jets to the channel’s walls occurs from the periphery to the longitudinal axis of the vapour channel. While the heat power loads increasing, the direction of the toroidal vapour vortex ring rotation changes to the opposite, from the longitudinal axis to the periphery of the vapour channel. The thickness of the formed working fluid condensate film located under the toroidal vapour vortex also related to the evaporator heat power load and vapour vortex rotation direction. With weak temperature head, the vapour vortex rotates from the walls to the channel center and slow down the movement condensate film on the HP’s top cover surface to the capillary-porous insert, thereby increasing the effective film thickness. As the heat head increases, the vapour vortex rotation direction changes to the opposite one and direction of vapour flow and the liquid condensate film becomes the same, which leads to decrease in the effective film thickness. Experimental results of the condensate film thickness measurements, obtained with capacitive sensors show a sharp decrease in thickness with a temperature head increasing, what could be an indirect confirmation of the vapour vortex rotation direction changes. Numerical method for vapour turbulent flows based on Navier-Stokes (Reynolds) full equation system was used to calculate the moist vapour vortex flow in low-temperature HP’s.

The Changing Position of the Center of Mass of the Thorax During Growth in Relation to Pre-existent Vertebral Rotation.

Cross-sectional. The aim of this study was to analyze the thoracic center of mass (COM) position of children at different ages and evaluate its relation with the previously reported pre-existent rotational pattern of the normal spine. The normal, nonscoliotic thoracic spine is known to have a rotational pattern that changes direction during growth, a transition from left-sided toward right-sided rotation with increasing age. This matches the changing curve convexity seen when idiopathic scoliosis develops at different ages. Furthermore, the direction of pre-existent rotation was shown to be related to organ orientation; in situs inversus the rotation is opposite to situs solitus. Computed tomography (CT) scans of the thorax of infantile (0-4 years, n = 40), juvenile (4-10 years, n = 53), and adolescent (10-18 years, n = 62) children without spinal pathology were included from an existing database. The location of the COM inside the thorax was calculated based on Hounsfield-units, representing tissue mass. The COM offset was defined as the shortest distance to the midsagittal plane. At the infantile age, the COM was 2.5 ± 2.1 mm on the right side, at juvenile age not significantly deviated, and at adolescent age 3.1 ± 2.3 mm on the left side of the midsagittal plane. The mean COM offset correlated linearly with age (r = 0.77, P < 0.001). The COM shifts from slightly on the right side of the thorax at the infantile age, to neutral at juvenile age, to the left at adolescent age. This corresponds to the earlier demonstrated change in direction of pre-existent rotation in the normal spine with age, as well as with the well-known changing direction, from left to right, of thoracic curve convexity in scoliosis at different ages. N/ A.

Oscillatory shear potentiates latent TGF-\u03b21 activation more than steady shear as demonstrated by a novel force generator

Cardiovascular mechanical stresses trigger physiological and pathological cellular reactions including secretion of Transforming Growth Factor β1 ubiquitously in a latent form (LTGF-β1). While complex shear stresses can activate LTGF-β1, the mechanisms underlying LTGF-β1 activation remain unclear. We hypothesized that different types of shear stress differentially activate LTGF-β1. We designed a custom-built cone-and-plate device to generate steady shear (SS) forces, which are physiologic, or oscillatory shear (OSS) forces characteristic of pathologic states, by abruptly changing rotation directions. We then measured LTGF-β1 activation in platelet releasates. We modeled and measured flow profile changes between SS and OSS by computational fluid dynamics (CFD) simulations. We found a spike in shear rate during abrupt changes in rotation direction. OSS activated TGF-β1 levels significantly more than SS at all shear rates. OSS altered oxidation of free thiols to form more high molecular weight protein complex(es) than SS, a potential mechanism of shear-dependent LTGF-β1 activation. Increasing viscosity in platelet releasates produced higher shear stress and higher LTGF-β1 activation. OSS-generated active TGF-β1 stimulated higher pSmad2 signaling and endothelial to mesenchymal transition (EndoMT)-related genes PAI-1, collagen, and periostin expression in endothelial cells. Overall, our data suggest variable TGF-β1 activation and signaling occurs with competing blood flow patterns in the vasculature to generate complex shear stress, which activates higher levels of TGF-β1 to drive vascular remodeling.

An essential role of the mouse synapse-associated protein Syap1 in circuits for spontaneous motor activity and rotarod balance.

ABSTRACTSynapse-associated protein 1 (Syap1) is the mammalian homologue of synapse-associated protein of 47 kDa (Sap47) in Drosophila. Genetic deletion of Sap47 leads to deficiencies in short-term plasticity and associative memory processing in flies. In mice, Syap1 is prominently expressed in the nervous system, but its function is still unclear. We have generated Syap1 knockout mice and tested motor behaviour and memory. These mice are viable and fertile but display distinct deficiencies in motor behaviour. Locomotor activity specifically appears to be reduced in early phases when voluntary movement is initiated. On the rotarod, a more demanding motor test involving control by sensory feedback, Syap1-deficient mice dramatically fail to adapt to accelerated speed or to a change in rotation direction. Syap1 is highly expressed in cerebellar Purkinje cells and cerebellar nuclei. Thus, this distinct motor phenotype could be due to a so-far unknown function of Syap1 in cerebellar sensorimotor control. The observed motor defects are highly specific since other tests in the modified SHIRPA exam, as well as cognitive tasks like novel object recognition, Pavlovian fear conditioning, anxiety-like behaviour in open field dark-light transition and elevated plus maze do not appear to be affected in Syap1 knockout mice.

Structural design of the working mechanism of the plastic cup stacking machine

The paper presents the structural design of the plastic cup stacking machine working mechanism. Based on the set requirements, a new working mechanism consisting of a cam/gear mechanism is proposed. The cam mechanism enables the change of the kinematic parameters of the working elements, and the gear mechanism provides the change of rotation direction of the output links. Based on the geometrical parameters of the cam mechanism, two principal solution of the working mechanism have been considered. Kinematic position analysis was performed and regulation characteristics have been formed. Increasing the motion range of the output shaft is approximately equal for both solutions, and the change is close to linear. However, one solution has smaller overall dimensions and more favourable values of pressure angle which makes it more efficient. The proposed solution is reliable, efficient and it has a high positioning accuracy that provides high accuracy and repeatability of movement of the output links without a time delay. The driving motor maintains a nominal number of revolution for different kinematic parameters of the machine working elements, which is a significant advantage.

INVESTIGATION OF SEICHES AND SEICHELIKE OSCILLATIONS IN THE MODEL BASIN, APPROXMATING THE LADOGA LAKE

Seiches (single-period) and seiche-like oscillations (superposition of different seiche modes) were studied in a constant-depth rectangular model tank with dimensions characteristic ofLakeLadoga using the results of analytical solution of a system of long wave equations. The periods of the first fourteen seiche modes were calculated. The following values were found: 5.22; 2.61; 2.09; 1.94; 1.74; 1.63; 1.34; 1.30; 1.11; 1.04; 1.02; 0.97; 0.93 hours. The possible flow velocities were estimated. It is found that where the level oscillations amplitude was within25 cm, wave flow velocity did not exceed 11 cm/s for all the considered seiche modes. The spatial structure of level oscillations and characteristics of wave currents was analyzed. A classification of seiches has been produced. It is found that the formation of a variety of seiche-like oscillation systems is possible inLakeLadoga. These systems represent a superposition of several seiche modes. Their properties are determined by a set of interacting modes. Level oscillations in this case are not periodic and differ substantially from oscillations in the case of a single seiche. Three types of seiche-like oscillations have been distinguished. The first one corresponds to an interaction of longitudinal and transverse seiches. Nodal lines of the level are rotated over time, and the rotation direction changes periodically. The second type corresponds to an interaction or either longitudinal or transverse seiches with different periods. In this case, the number of nodal lines may change over time. They move parallel to a coordinate axis. Angles between these lines and coordinate axes are constant. The third type corresponds to an interaction of a longitudinal and a transverse seiches with equal periods. The position of nodal lines did not change with time. Maximum level elevations of seiche-like oscillations are close to the sum of the amplitudes of the interacting waves. The greatest magnitudes of wave current velocity were in all cases lower than the sum of flow velocities of the interacting modes. The goodness of fit of the calculated results to field data was quite satisfactory.

Effects of toroidal rotation on electron heat transport via changes in inertial force and impurity density

Two types of JT-60U discharges are studied with an emphasis on toroidal rotation: in one discharge, which is characterized by the existence of an internal transport barrier (ITB), electron heat transport in the core region is affected by the toroidal rotation direction, while in the other discharge, which is a conventional H-mode plasma without an ITB, the clear correlation between the toroidal rotation direction and electron heat transport is not observed. In both discharges, the impurity density is also found to vary together with the rotation velocity profile. With a flux-tube gyrokinetic code, we have found that the effects of the changes in the rotation velocity profile and the impurity density on electron heat transport are different between these discharges. Including the effects explains the tendency observed in the experiments. First, regarding the rotation velocity profile, which influences heat transport through the inertial force, the dependence of heat transport on the rotation direction changes, according to the gradient of the rotation velocity. Next, an increase in the impurity density stabilizes the ion temperature gradient mode, but can destabilize the trapped electron mode. Therefore, it is found that the difference in the impact of the impurity density on electron heat transport in these discharges can be attributed to the difference in the dominant instability.

非自明な振る舞いを生む群れの数理モデル &lt;i&gt;“Push-Forward model”&lt;/i&gt; の実機実現に向けて

We focus our attentions on the investigation of adaptive flocking behaviors consisting of a large population of agents nevertheless individual agents decide their actions by simple rules and local interactions. Based on the idea, we proposed a “Push-Forward model” exhibiting three nontrivial group behaviors; rotation, procession and sudden direction change. This paper tries to the realization of Push-Forward model. We verify from the experiments that swarm robots can produce two of three collective behaviors, namely, rotation and sudden turning in direction. On the other hand, the procession motion cannot be observed in the experiments due to the disturbances in real world.

Anomalously rotary polarization discovered in homochiral organic ferroelectrics.

Molecular ferroelectrics are currently an active research topic in the field of ferroelectric materials. As complements or alternatives of conventional inorganic ferroelectrics, they have been designed to realize various novel properties, ranging from multiferroicity and semiconductive ferroelectricity to ferroelectric photovoltaics and ferroelectric luminescence. The stabilizing of ferroelectricity in various systems is owing to the flexible tailorability of the organic components. Here we describe the construction of optically active molecular ferroelectrics by introducing homochiral molecules as polar groups. We find that the ferroelectricity in (R)-(−)-3-hydroxlyquinuclidinium halides is due to the alignment of the homochiral molecules. We observe that both the specific optical rotation and rotatory direction change upon paraelectric-ferroelectric phase transitions, due to the existence of two origins from the molecular chirality and spatial arrangement, whose contributions vary upon the transitions. The optical rotation switching effect may find applications in electro-optical elements.

Secondary vortices over surfaces with spanwise varying drag

ABSTRACTA spanwise heterogeneity of streamwise drag is known to lead to the formation of large secondary motions of Prandtl's second kind. Based on the data sets extracted from direct numerical simulations (DNS) of fully developed turbulent channel flow where streamwise stripes of free-slip surface with varying spanwise extension are introduced, we investigate the topological structure of the secondary motions. We find a complex restructuring of the secondary motion with increasing extent of free-slip/no-slip region where the width of the free-slip region in viscous units appears to be one important governing parameter for the vortex formation. The most striking feature of this restructuring is a change in the rotational direction of the major vortex pair such that the related high- and low-momentum pathways are found at different locations. The present results reveal that the spanwise inhomogeneity of the Reynolds stress distribution is strongly related to the observed change of rotational direction. In addition, it is shown that the vorticity source remains largely unchanged and mainly restricted to a rather small region close to the discontinuity in the boundary condition, despite the fact that the topology of secondary motions substantially changes with variation of the spanwise length scale. This suggests a complex interplay between the vortices that are generated at the surface discontinuities and the surrounding flow.

Measurement and numerical simulation of two-dimensional vibration of a single piano string

A piano string begins to vibrate vertically as soon as a hammer strikes it. After the vertical vibration has begun, the string then starts to rotate owing to the generation of horizontal vibration. The rotation direction changes several seconds later, which suggests that the frequencies of the vertical and horizontal components of the vibration are slightly different. We previously reported an equivalent mechanical circuit model for physically elucidating such two-dimensional movements of the string. In this presentation, we show the verification and validation of the equivalent model by comparing with experiments. The movements of a string in low frequencies were observed using a high-speed camera and a mirror. In order to increase the measurement accuracy of displacement, interpolation technique was applied to the correlation of recorded images. It was noted that the frequency of a partial vibration of the string in the vertical direction is higher or lower than that in the horizontal direction to the s...

Rolling Resistance and Mechanical Properties of Grinded Copper Surfaces Using Molecular Dynamics Simulation.

Mechanical properties of copper (Cu) film under grinding process were accomplished by molecular dynamics simulation. A numerical calculation was carried out to understand the distributions of atomic and slip vector inside the Cu films. In this study, the roller rotation velocity, temperature, and roller rotation direction change are investigated to clarify their effect on the deformation mechanism. The simulation results showed that the destruction of materials was increased proportionally to the roller rotation velocity. The machining process at higher temperature results in larger kinetic energy of atoms than lower temperature during the grinding process of the Cu films. The result also shows that the roller rotation in the counterclockwise direction had the better stability than the roller rotation in the clockwise direction due to significantly increased backfill atoms in the groove of the Cu film surface. Additionally, the effects of the rolling resistances on the Cu film surfaces during the grinding process are studied by the molecular dynamics simulation method.

Thermally induced nonlinear vibration of single-walled carbon nanotubes

The thermally induced nonlinear vibration of single-walled carbon nanotubes (SWNTs) was investigated, focusing on the peak broadening and/or multiple peaks of the frequency spectra. From Poincar\'e maps of SWNT tip trajectories, we observed two distinguishable patterns of vibration: planar and nonplanar (whirling) motion which appeared repeatedly. The alternation of the pattern is sometimes accompanied by a change of rotational direction. Proposed approximate solutions of nonlinear beam equations can reproduce well the alternation of the patterns for both cantilevered and suspended SWNTs. By using this analytical approach, we have found that multiple peaks of experimentally observed frequency spectra are due to the repeated and sudden alternations of two modes, induced by nonlinear effects.

Mechanical rotation of nanomagnet through interaction with an electromagnetic wave

We report a theoretical study on the effect of mechanical rotation of nanomagnet about a fixed axis due to its interaction with an electromagnetic wave with a frequency approaching that of ferromagnetic resonance. A stationary mode of rotation is investigated. We show that the rotation speed magnitude is proportional to the squared amplitude of the wave’s magnetic field, being maximum for a circularly polarized wave when the rotation direction changes for the opposite following a likewise change in the direction of polarization. The role of the magnetic anisotropy of nanomagnet is discussed. The effect is numerically estimated for molecular nanomagnet Fe8.