Showing papers on "Rotation around a fixed axis published in 2004"

Surgical instrument incorporating an articulation mechanism having rotation about the longitudinal axis

Abstract: A surgical instrument particularly suited to endoscopic articulates an end effector by including an end effector having a geared articulation mechanism that converts rotational motion from a handle portion. A hollow articulation drive tube transfers the rotation motion in some versions to a spear gear, bevel gear or snaggle tooth gear articulation mechanism. Alternatively, one or more threaded drive rod offset from a longitudinal axis engages a worm gear or flex-neck articulation mechanism.

Electrical or photocontrol of the rotary motion of a metallacarborane

Abstract: Rotary motion around a molecular axis has been controlled by simple electron transfer processes and by photoexcitation. The basis of the motion is intramolecular rotation of a carborane cage ligand (7,8-dicarbollide) around a nickel axle. The Ni(III) metallacarborane structure is a transoid sandwich with two pairs of carbon vertices reflected through a center of symmetry, but that of the Ni(IV) species is cisoid. The interconversion of the two provides the basis for controlled, rotational, oscillatory motion. The energies of the Ni(III) and Ni(IV) species are calculated as a function of the rotation angle.

Substrate processing apparatus

Abstract: PROBLEM TO BE SOLVED: To provide a substrate processing apparatus capable of making uniform gas distribution and temperature distribution even for a large sized wafer, and forming a highly uniform thin film SOLUTION: A longitudinal substrate processing apparatus is configured in such a way that a boat 2 for holding a substrate in a reaction tube performs a central axis rotational motion where it rotates around a central axis, and an eccentric axis rotational motion where it rotates around a position shifted from the central axis simultaneously As shown in FIG (a), the boat 2 performs the eccentric axis rotational motion as an arrow A2 while performing the central axis rotational motion as an arrow A1 in the reaction tube 1 Consequently, a locus of a point q on the wafer 3 draws a hypocycloid curve as shown in FIG (b) without drawing a locus of a concentric circle It is therefore possible to make uniform the temperature distribution over the entire surface of the wafer 3 even if the wafer 3 is rotated In the same manner, it is also possible to make uniform the gas distribution over the entire surface of the wafer 3 COPYRIGHT: (C)2007,JPO&INPIT

Hydrodynamic coupling of two rotating spheres trapped in harmonic potentials.

Abstract: We theoretically study in detail the hydrodynamic coupling of two equal-sized colloidal spheres at low Reynolds numbers assuming the particles to be harmonically trapped with respect to both their positions and orientations. By taking into account the rotational motion, we obtain a rich spectrum of collective eigenmodes whose properties we determine on the basis of pure symmetry arguments. Extending recent investigations on translational correlations [J.-C. Meiners and S. R. Quake, Phys. Rev. Lett. 82, 2211 (1999)], we derive the complete set of autocorrelation and cross-correlation functions emphasizing the coupling of rotation to translation which we illustrate in a few examples. An important feature of our system is the self-coupling of translation and rotation of one particle mediated by the neighboring particle that is clearly visible in the appropriate autocorrelation function. This coupling is a higher-order effect and therefore not included in the widely used Rotne-Prager approximation for the hydrodynamic mobilities.

Figure Rotation of Cosmological Dark Matter Halos

Abstract: We have analyzed galaxy- and group-sized dark matter halos formed in a high-resolution ΛCDM numerical N-body simulation in order to study the rotation of the triaxial figure, a property in principle independent of the angular momentum of the particles themselves. Such figure rotation may have observational consequences, such as triggering spiral structure in extended gas disks. The orientation of the major and minor axes are compared at five late snapshots of the simulation. Halos with significant substructure or that appear otherwise disturbed are excluded from the sample. We detect smooth figure rotation in 288 of the 317 halos in the sample. The pattern speeds follow a lognormal distribution centered at Ωp = 0.148 h km s-1 kpc-1 with a width of 0.83. These speeds are an order of magnitude smaller than required to explain the spiral structure of galaxies such as NGC 2915. The axis about which the figure rotates aligns very well with the halo minor axis in 85% of the halos and with the major axis in the remaining 15% of the halos. The figure rotation axis is usually reasonably well aligned with the angular momentum vector. The pattern speed is correlated with the halo spin parameter λ but shows no correlation with the halo mass. The halos with the highest pattern speeds show particularly strong alignment between their angular momentum vectors and their figure rotation axes. The figure rotation is coherent outside 0.12rvir. The measured pattern speed and degree of internal alignment of the figure rotation axis drops in the innermost region of the halo, which may be an artifact of the numerical force softening. The axis ratios show a weak tendency to become more spherical with time.

Bouncing mode operated scanning micro-mirror

Abstract: A MEMS apparatus for scanning an optical beam comprises a mirror operative to perform a rotational motion to a maximum rotation angle around a mirror rotation axis formed in a double active layer silicon-on-insulator (SOI) substrate. The apparatus may include a bouncing mechanism operative to provide a bouncing event and to reverse the rotational motion. The bouncing event provides the mirror with a piecewise linear response to actuation by intrinsically nonlinear electrostatic forces. In a particular embodiment, the bouncing mechanism includes a vertical comb drive stator built in the same active layer of the double active layer SOI substrate, while actuator comb drive stators are built in a different active layer.

Intermittent nature of acceleration in near wall turbulence.

Abstract: Using direct numerical simulation of a fully developed turbulent channel flow, we investigate the behavior of acceleration near a solid wall. We find that acceleration near the wall is highly intermittent and the intermittency is in large part associated with the near wall organized coherent turbulence structures. We also find that acceleration of large magnitude is mostly directed towards the rotation axis of the coherent vortical structures, indicating that the source of the intermittent acceleration is the rotational motion associated with the vortices that causes centripetal acceleration.

Micro-Doppler Radar Signatures for Itelligent Target Recognition

Abstract: : Mechanical vibrations or rotations (micro-motion dynamics) of structures on a target may introduce frequency modulation on the radar return from the target's body. The modulation due to this vibration or rotation is referred to as the micro-Doppler (m-D) phenomenon. In this report, the m-D effect is introduced and the mathematics of micro-Doppler signatures, induced by simple sinusoidal vibrations or rotations, is developed. Simulated results confirm that the mathematical analysis is valid. The m-D features derived from a target's vibrational/rotational motion are extracted by utilizing discrete wavelet transforms. During this process, the time domain radar signal is decomposed into a set of components that are represented by different wavelet scales. The m-D features are extracted by sorting the components that are associated with the vibrational/rotational motions of a target and is achieved by applying the inverse wavelet transform. After the extraction of m-D features, time-frequency analysis is employed to analyze the oscillation and to estimate the motion parameters. The vibration/rotation rate is estimated by taking the autocorrelation of the time sequence data. The findings show that these results have higher precision after the m-D extraction since only vibrational/rotational components are employed. The proposed method of the m-D extraction has been successfully applied to both simulated data and experimental helicopter and human data. The preliminary results clearly demonstrate that the m-D signatures can be observed by radar and suggest that applications of m-D should be investigated and exploited for target detection, classification and recognition. It is recommended %hat the exploitation of micro-Doppler, as a new identification/recognition tool, be undertaken as it could impact all aspects of radar sensing and may enhance the effectiveness of Automatic Target Recognition (ATR) and Automatic Gait Recognition (AGR) techniques. We recommend that

Gyroscopic steering tool using only a two-axis rate gyroscope and deriving the missing third axis

Abstract: A two-axis gyroscope used on a bottom hole assembly can be used for determining a rate of rotation about the rotational axis of a BHA. The method takes advantage of possible misalignment of at least one axis of the two axis gyroscope from orthogonality with respect to the rotational axis of the BHA, resulting in the misaligned gyro being sensitive to BHA rotation.

Direct manipulation and observation of the rotational motion of single optically trapped microparticles and biological cells in microvortices.

Abstract: This paper describes a method for manipulating and monitoring the rotational motion of single, optically trapped microparticles and living cells in a microvortex. To induce rotation, we placed the microparticle at the center of rotation of the vortex and used the recirculating fluid flow to drive rotation. We have monitored the rotation of single beads (which ranged in diameter from a few micrometers to tens of micrometers) and living cells in a microvortex. To follow the rotation of a smooth and symmetrically shaped bead, we first ablated a small region (∼1 μm) on the bead. An Ar+ laser was then tightly focused (∼0.5-μm spot size) onto the bead, and rotation was tracked by recording changes in the level of backscattered laser light as the ablated region repeatedly transited the laser focus. Using this method, we have followed bead rotation that varied in frequency from 0.15 to 100 Hz and have studied the effect of bead diameter on the rate of rotation at a given fluid flow rate. To monitor the rotation o...

Center of percussion of hand-held implements

Abstract: The center of percussion is commonly regarded as a sweet spot when referring to a baseball bat or a tennis racquet because it is assumed that there will be no sudden motion of the handle with respect to the hand if the corresponding axis of rotation passes through the hand. A problem with this interpretation is that the hand extends over a finite length of the handle and exerts an opposing reaction force on the handle. The hand also changes the total mass and moment of inertia of the system, while the arm restricts free motion of the hand. Experimental results are presented showing that the axis of rotation passes through the hand or the wrist for all the usual impact points on a hand-held implement. As a result, the impact point that feels best is usually the node of the fundamental vibration mode, not the center of percussion.

Motion correction of magnetic resonance images using moments of spatial projections

Abstract: Magnetic resonance images reconstructed from a radial/projection acquisition are corrected for motion corruption caused by in-plane translational and in-plane rotational motion of an imaged subject using only the projection data itself. The method is based on the consistency properties of the 0 th , 1 st , and 2 nd order moments of the spatial domain projections. In-plane translational motion is corrected by shifting/aligning the spatial projections according to the center of mass of each projection, which is calculated using the 0 th and 1 st moments. In-plane rotational motion is accounted for by determining the rotational motion time record using the 2 nd moment information. The determination of the rotational motion time record using the 2 nd moments is made possible by acquiring the successive MR projections at a view angle spacing that is substantially 45° and thus achieves sufficient linear independence. The translation-corrected spatial projections are reconstructed using the actual projection view angles, which are sum of the intended projection view angles plus the detected in-plane rotational motion time record. The calculation may also be performed in real-time during data acquisition in order to reacquire projections found to be too inconsistent due to through plane motion or other changes that are not in-plane rigid body motions or to acquire projections determined to be missing from the data set due to rotational motion.

Drill bit, system, and method for drilling a borehole in an earth formation

Abstract: A drill bit for drilling a borehole in an earth formation, the drill bit having a central longitudinal axis and being operable by applying at least a rotary motion about the central longitudinal axis and optionally applying longitudinal reciprocal movement to the drill bit so as to exert a percussive force on the borehole bottom, the drill bit comprising a surface provided with a plurality of shear cutters (9) having a rake surface arranged to induce a scraping movement along the borehole bottom upon application of the rotary motion, the rake surface during operation facing the direction of rotation at a back-rake angle of less than 90° wherein the backrake angle is defined as the angle included between the projection of a line perpendicular to said rake surface on a plane defined by the central longitudinal axis and the direction of the tangential velocity component of the shear cutter and a plane perpendicular to said longitudinal axis, whereby one or more of the shear cutters is provided with a pre-cut flat impact surface (19) essentially parallel to the plane perpendicular to the longitudinal axis.

Hamel coefficients for the rotational motion of an N–dimensional rigid body

Abstract: Many of the kinematic and dynamic concepts relating to rotational motion have been generalized for Ndimensional rigid bodies. In this paper a new derivation of the generalized Euler equations is pr...

Industrial truck with a lateral frame opening and a door with a double hinge

Abstract: An industrial truck has a vehicle frame ( 1 ) with a frame portion ( 2 ) having a lateral frame opening ( 2 b ) for receiving a battery block. A door ( 3 ) covers the frame opening ( 2 b ) and may be pivoted outwardly about a substantially vertical axis of rotation (A 1 ). To allow the door ( 3 ) to be opened approximately 180°, the door ( 3 ) is connected to the vehicle frame ( 1 ) by a double hinge ( 5 ). A second axis of rotation (A 2 ) is set apart and parallel to the first axis of rotation (A 1 ) and is alterable in its position when the door ( 3 ) pivots about the first axis of rotation (A 1 ). A device for obstructing a rotational motion of the door ( 3 ) about the second axis of rotation (A 2 ) can be provided, which device can be active in the pivoting range between the closed position and an open position that is approximately at right angles.

Solid-State 2H NMR Studies of Cyclophosphazene Inclusion Compounds: Order and Dynamics of the Benzene Guests

Abstract: Variable-temperature 2 H NMR investigations were been carried out to study the molecular behavior of perdeuterated benzene in the inclusion compound with tris(1,2-dioxyphenyl)cyclotriphosphazene. A comprehensive variable-temperature 2 H NMR study is presented comprising line shape studies and spin-spin and spin-lattice relaxation experiments. The experimental data clearly indicate the presence of highly mobile guest species at room temperature. Sample cooling gives rise to characteristic line shape effects at around 140 K that can be attributed to a slowing of the rotational motion (nondegenerate three-fold jump processes) of the guest species about the cyclophosphazene channel long axis. The rotation of the benzene molecules about their molecular C 6 axes can be followed to even lower temperatures (∼40 K). A quantitative analysis of the experimental data is achieved by appropriate computer simulations taking into account various motions of the benzene guests. The derived activation energies for the overall rotations are rather small with values of 5.4 ′ 0.3 and 4.2 ′ 0.1 kJ/mol for motion about the channel long axis and 2.1 ′ 0.1 kJ/mol for rotation about the molecular C 6 axis. However, these values are larger than those reported earlier for aliphatic cyclic guests, which directly points to stronger nonbonded guest-host interactions in the present systems. The guest ordering is described by an almost perpendicular orientation of the benzene C 6 axis with respect to the cyclophosphazene channel long axis. The ordering of the benzene guests, which is reduced by fast overall fluctuations of small amplitude, is substantially higher than that observed in related systems, which again can be attributed to the aforementioned guest-host interactions.

Compensation method for rotation angle of rotation angle detector

Abstract: PROBLEM TO BE SOLVED: To provide a compensation method for angle of rotation of an angle of rotation detector with high precision in which mechanical error of gears and electric error of an absolute angle of rotation detector are compensated with fewer compensation angle data. SOLUTION: In the angle of rotation detector for steering of multiple rotation used for a car body control system of a car, a motor 15 for rotating a rotary shaft to be tested 7, a motor controller 14 for controlling the absolute angle of rotation of the motor 15 and an encoder 16 for detecting the absolute angle of rotation of the motor 15 are combined. The difference between the absolute angle of rotation of the rotary shaft to be tested 7 actually rotated by the motor 15 and a calculated absolute angle of rotation at every specific interval of the rotary shaft to be tested 7 obtained from absolute angle of rotation detectors 4 and 5 of a second and a third gears 2 and 3 is stored in a non-volatile memory 11 as a compensation angle. In the specific calculated absolute angles of rotation, the calculated absolute angle of rotation of the rotary shaft to be teste 7 is compensated with the difference between a straight line of the calculated absolute angle of rotation obtained using the compensation angle for the before and after the calculated absolute angle of rotation and a straight line of an ideal absolute angle of rotation not including a rotation detection error. COPYRIGHT: (C)2006,JPO&NCIPI

Torque transfer system and method of using the same

Abstract: A system for transferring rotational motion includes a first rotational shaft extending along a first axial direction, and a second rotational shaft disposed along a second axial direction and spaced apart from the first rotational shaft, wherein the first rotational shaft is magnetically coupled to the second rotational shaft.

Real time rotational motion compensation algorithm for focusing spot-SAR / ISAR images in case of variable rotation-rate

Abstract: The problem of compensating image blurring induced by target rotation in Spot-SAMSAR imaging is investigated. Oppositely to what is generally assumed, the case of a variable rotation-rate during coherent processing time is considered since this usually happens in forward looking SAR geometry as well as in aircraft or ship ISAR imaging. A novel algorithm is proposed to solve the addressed problem with particular emphasis given to a possible mechanisation for real-time applications. To this respect, the performance in terms of required computational load is analysed. The concept of the proposed algorithm is derived by a suitable simplification of the SARllSAR signal phase equation. The effectiveness oftbe proposed algorithm is verified also by processing real radar data acquired during extensive flights campaign: the dramatic improvement, with respect to traditional techniques, demonstrates the effectiveness of the proposed approach.

Systems and methods for rotation of objects

Abstract: Systems and methods for rotating objects that shift the center of gravity of an object from a position outside the rotation axis area of the object to a position within the rotation axis area of the object.

Method for detecting a bit jam condition using a freely rotatable inertial mass

Abstract: An improved method is provided for controlling a power tool having a rotary shaft. The method includes: disposing an inertial mass in a housing of the power tool, such that the inertial mass is freely rotatable about an axis of rotation which is axially aligned with the rotary shaft; monitoring rotational motion of the power tool in relation to the inertial mass during operation of the power tool; and activating a protective operation based on the rotational motion of the power tool in relation to the inertial mass.

Steering transmission device and steering apparatus

Abstract: In a vehicle steering transmission device, a first gear is rotatable on a rotational axis to rotate in accordance with a vehicle steering operation, a second gear is rotatable on the rotational axis and connectable to a vehicle wheel so that an orientation of the vehicle wheel is changed, an intermediate gear engages with the first and second gears, a support member is rotatable on the rotational axis while supporting the intermediate gear in such a manner that the intermediate gear is rotatable on another rotational axis which another rotational axis intersects the rotational axis and extends perpendicularly to the rotational axis, and a driving device drives the support member to rotate on the rotational axis so that a differential rotational motion is generated between the first and second gears.

Linear into rotatory or vice versa motion convertor

Abstract: An apparatus for converting linear motion into rotary motion or vice versa comprising a shaft (12) which is rotatable about a fixed axis (14) and carrying a circular cam (16) mounted eccentrically relative to that axis (14), the cam (16) being rotatably mounted within a disc (22) which is in turn rotatably mounted within a housing (24) mounted for linear reciprocating motion along a rectilinear axis (26) in a direction transverse to the axis (14) of the shaft (12) whereby reciprocating motion of the housing (24) along the rectilinear axis (26) is converted into rotation of the shaft (12), or rotation of the shaft (12) is converted into reciprocating motion of the housing (24) along the rectilinear axis (26).

The rotational centroid and its application in quantum molecular dynamics simulations

Abstract: The centroid molecular dynamics (CMD) method is extended to the rotational motion of rigid bodies. An algorithm is developed that homogeneously samples the orientational neighbourhood associated with the quantum degrees of freedom of a specified orientational centroid and by design ensures the constancy of the centroid. As part of this development a general definition for an orientational centroid (or average rotation), as well as a procedure to determine it, are presented. The application of this CMD methodology in quantum simulations of rigid body systems is discussed and demonstrated for a simple system.

Rotation angle detecting apparatus and method of detecting rotation angle

Abstract: A rotation angle detecting apparatus having a reference signal-generating device that generated a reference signal; a rotation angle detecting section that generated an output signal in response to the reference signal; a feedback control section that determines a rotational angular speed based on the output signal and performs feedback control to calculate a rotation angle; and a free-running range change device that narrows a free-running range of the rotational angular speed at a time of starting settling of the rotation angle. In the rotation angle detecting apparatus, the free-running range of the rotational angular speed at the time of starting the settling of the rotation angle is narrowed, whereby the settling time can be shortened. Accordingly, the time that elapses before it becomes possible to detect a rotation angle can be shortened correspondingly.

Shaft-coupling mechanism for electric power-steering

Abstract: PROBLEM TO BE SOLVED: To provide a durable shaft-coupling mechanism for electric power-steering in which backlash and play are hardly caused in the direction around the axis even in a long-term use between one rotation shaft, e.g. the rotation shaft coupled to an output rotation-shaft of an electric motor, and the other rotation shaft, e.g. a steering shaft coupled to a steering wheel, and transmission of impulse at the time of reverse rotation of the electric motor and vibration of brushes to the steering wheel can be reduced without causing an unpleasant steering-feel. SOLUTION: The shaft-coupling mechanism 1 for an electric power-steering 1 comprises a coupling base-body 3 coupled to the rotation shaft 2, a coupling base-body 5 coupled to the steering shaft 4 as a rotation shaft, and a rotation-transmitting member 6. The rotation-transmitting member 6 is provided between the coupling base-bodies 3 and 5, and transmits the rotation around the axis of the coupling main-body 3, i.e. rotation in the direction of R to the coupling base-body 5 as rotation in the direction of the R. COPYRIGHT: (C)2006,JPO&NCIPI

On the translational and rotational motion of nonlinear optical structures as a whole

Abstract: The possibility of determining the translational and rotational instantaneous velocities of the motion of a field structure as a whole from the field distribution at the same instant of time is demonstrated for nonlinear optical systems described by an evolution equation of a very general form