Showing papers on "Angular velocity published in 1999"

Where are the r modes of isentropic stars

Abstract: Almost none of the r-modes ordinarily found in rotating stars exist, if the star and its perturbations obey the same one-parameter equation of state; and rotating relativistic stars with one-parameter equations of state have no pure r-modes at all, no modes whose limit, for a star with zero angular velocity, is a perturbation with axial parity. Similarly (as we show here), rotating stars of this kind have no pure g-modes, no modes whose spherical limit is a perturbation with polar parity and vanishing perturbed pressure and density. Where have these modes gone? In spherical stars of this kind, r-modes and g-modes form a degenerate zero-frequency subspace. We find that rotation splits the degeneracy to zeroth order in the star's angular velocity Ω, and the resulting modes are generically hybrids, whose limit as Ω → 0 is a stationary current with axial and polar parts. Lindblom & Ipser have recently found these hybrid modes in an analytic study of the Maclaurin spheroids. Since the hybrid modes have a rotational restoring force, they call them "rotation modes" or "generalized r-modes." Because each mode has definite parity, its axial and polar parts have alternating values of l. We show that each mode belongs to one of two classes, axial-led or polar-led, depending on whether the spherical harmonic with lowest value of l that contributes to its velocity field is axial or polar. We numerically compute these modes for slowly rotating polytropes and for Maclaurin spheroids, using a straightforward method that appears to be novel and robust. Timescales for the gravitational-wave driven instability and for viscous damping are computed using assumptions appropriate to neutron stars. The instability to nonaxisymmetric modes is, as expected, dominated by the l = m r-modes with simplest radial dependence, the only modes which retain their axial character in isentropic models; for relativistic isentropic stars, these l = m modes must also be replaced by hybrids of the kind considered here.

Angular velocity sensor

Abstract: An angular velocity sensor includes four mass members which are connected by retaining beams, and the retaining beams are fixed to a substrate at node portions which correspond to nodes of the retaining beams when the mass members vibrate such that two adjacent mass members are in opposite phases. The mass members vibrate in an X-axis direction while the overall center of gravity is maintained at an approximately constant position. Two mass members disposed at the central region move in a Y-axis direction in accordance with an angular velocity about a Z axis, and the angular velocity is detected on the basis of the displacements thereof. The mass members vibrate in a stable vibrational state and dimensional errors or other problems, are compensated for by their shapes that are symmetric to each other in the Y-axis direction. Accordingly, the detection accuracy and reliability of the sensor are improved.

An existence theorem for the Navier-Stokes flow in the exterior of a rotating obstacle

Abstract: We consider the three-dimensional Navier-Stokes initial value problem in the exterior of a rotating obstacle. It is proved that a unique solution exists locally in time if the initial velocity possesses the regularity L 1/2. This regularity assumption is the same as that in the famous paper of Fujita & Kato. An essential step for the proof is the deduction of a certain smoothing property together with estimates near t≡0 of the semigroup, which is not an analytic one, generated by the operator in the space L 2, where ω stands for the angular velocity of the rotating obstacle and P denotes the projection associated with the Helmholtz decomposition.

Time-Optimal Control of Axisymmetric Rigid Spacecraft Using Two Controls

Abstract: In this paper, we consider the minimum-time reorientation problem of an axisymmetric rigid spacecraft with two independent control torques mounted perpendicular to the spacecraft symmetry axis. The objective is to reorient the spacecraft from an initial attitude, with some angular velocity, to a e nal attitude with a certain angular velocity in minimum time. All possible control structures, including both singular and nonsingular arcs, arestudied completely byderivingthecorrespondingformulasand thenecessary optimality conditions. Itisshown that a second-order singular control can be part of the optimal trajectory. It is also shown that for an inertially symmetric and a nonspinning axisymmetric rigid body, it is possible for ine nite-order singular controls to be part of or the whole optimal trajectory. In particular, for a nonspinning axisymmetric rigid body, the second-order singular trajectory is shown to be an eigenaxis rotation. An efe cient method for numerically solving the optimal controlproblem,basedonacascadedcomputationalschemethatusesbotha directmethodand anindirectmethod, is also presented. Numerical examples demonstrate optimal reorientation maneuvers with both nonsingular and singular subarcs, and comparisons are made between eigenaxis rotations and the true time-optimal rotations.

Effect of field size, head motion, and rotational velocity on roll vection and illusory self-tilt in a tumbling room.

Abstract: The effect of field size, velocity, and visual fixation upon the perception of self-body rotation and tilt was examined in a rotating furnished room. Subjects sat in a stationary chair in the furnished room which could be rotated about the body roll axis. For full-field conditions, complete 360 degrees body rotation (tumbling) was the most common sensation (felt by 80% of subjects). Constant tilt or partial tumbling (less than 360 degrees rotation) occurred more frequently with a small field of view (20 deg). The number of subjects who experienced complete tumbling increased with increases in field of view and room velocity (for velocities between 15 and 30 degrees s-1). The speed of perceived self-rotation relative to room rotation also increased with increasing field of view.

Observers for tire/road contact friction using only wheel angular velocity information

Abstract: The paper is devoted to the problem of tire-road friction estimation using only angular wheel velocity which can not always been computed from actual sensors. Tire forces information is relevant to problems like: optimization of anti-look brake systems, traction system, and diagnosis of the road friction conditions, etc.

Axisymmetric propagating vortices in the flow between a stationary and a rotating disk enclosed by a cylinder

Abstract: The destabilization of the stationary basic flow occurring between two disks enclosed by a cylinder is studied experimentally when the radius of the disks is large compared to the spacing. In the explored range of the cell aspect ratio, when one disk only is rotating, circular vortices propagating to the centre are observed above a critical angular velocity. These structures occur naturally but can also be forced by small modulations of the angular velocity of the disk. For each rotation rate the dispersion relation of the instability is experimentally reconstructed from visualizations and it is shown that this dispersion relation can be scaled by the boundary layer thickness measured over the disk at rest. The bifurcation is found to be of supercritical nature. The effect of the forcing amplitude is in favour of a linear convective nature of this instability of the non-parallel inward flow existing above the stationary disk. The most unstable temporal frequency is found to be about four times the frequency of the rotating disk. The evolution of the threshold of this primary instability is described for different aspect ratios of the cell. Finally, two sets of experiments made under transient conditions are presented: one in order to investigate further a possible convective/absolute transition for the instability, and the other to compare with the impulsive spin-down-to-rest experiments of Savas (1983).

Robot device and control method thereof

Abstract: Acceleration information, rotation angle information and rotation angular velocity information are detected by an acceleration sensor and a rotation angle sensor, and detected signals are stored into a storage section in time series. Specific information such as dispersion is calculated from the stored time series signals, and the state of the robot device is determined from the specific information. When it is detected as the state of the robot device that the robot device is lifted up, the movement of a predetermined movable part which acts to the outside is stopped.

What can be learned from the Couette-Taylor experiment

Abstract: The turbulent transport of angular momentum plays an important role in many astrophysical objects, but its mod- elization is still far from satisfactory. We discuss here what can be learned from laboratory experiments. We analyze the results obtained by Wendt (1933) and Taylor (1936) on the classical Couette-Taylor flow, in the case where angular momentum in- creases with distance from the rotation axis, which is the most interesting for astrophysical applications. We show that when the gap between the coaxial cylinders is wide enough, the cri- terion for the onset of the finite amplitude instability can be expressed in terms of a gradient Reynolds number. Based on Wendt's results, we argue that turbulence may be sustained by differential rotation when the angular velocity decreases out- ward, as in keplerian flows. From the rotation profiles and the torque measurements we deduce a prescription for the turbulent viscosity which is independent of gap width; with some caution it may be applied to stellar interiors and to accretion disks.

Angular velocity sensing device

Abstract: The angular velocity sensing device is structured in such a manner that a first vibration element 1 having piezoelectric elements or electrodes (two or more) for generating oscillation and a second vibration element 2 having piezoelectric elements or electrodes (two or more) for sensing angular velocity are connected through first connection portions (two or more) on nodes of vibration (two or more) of the first vibration element 1, and the second vibration element 2 and a supporting portion are connected with each other through second connection portions (two or more). These first, second vibration elements, the supporting portion, and the first, second connection portions have a plane structure with almost uniform thickness, and both of the first vibration element and the second vibration element are made to have symmetric shapes with respect to the common center point P.

Controller of electric power-steering system

Abstract: To provide a controller of an electric power-steering system, capable of improving the steering performance by presuming a motor angular speed ω in a range in which the angular speed of a motor is small and moreover very accurately presuming the motor angular speed and thereby, completely showing the functions for compensating the inertia of the motor and controlling the astringency of a vehicle. Because the presumed error of a back electromotive force between a model motor and a motor to be actually mounted is proportional to a motor current, a dead zone of a motor angular speed having a width proportional to a motor current is set to the presumed value of the motor angular speed. When the motor current is small, the width of the dead zone also decreases. Therefore, it is possible to presume an angular speed ω even in a region where the motor angular speed is small. Moreover, a motor angular speed is presumed by defining impedance models of motor driving systems in an intermittent mode and a continuous mode.

Rotation in molecular clouds

Abstract: We have investigated a broad range of evi- dence concerning rotation in molecular clouds. As a con- sequence, we show that trends in specic angular momen- tum J=M and angular velocity are inconsistent with certain models of isothermal, non-magnetic cloud rota- tion. Similarly, models of rotation which invoke turbulent vorticity may have only limited applicability to clumps and condensations. There is evidence to favour an im- portant r^ ole for rotation in maintaining the stability of disks, larger cloud structures, and perhaps a large frac- tion of intermediate sized clouds, whilst rotation may also be implicated in maintaining observed departures from cloud sphericity. Although it is conceivable that magnetic braking is responsible for the radial decrement in specic angular momentum, it appears that observed gradients dln(J=M)/dln(R) are signicantly shallower than is nor- mally anticipated through this mechanism. The variation of angular momentum with cloud mass M (viz. J / M 1:7 ) appears to be highly correlated, and is consistent with models of clump merging in isother- mal rotating clouds. Similarly, the orientations of the an- gular velocity vectors for clumps and condensations ap- pear broadly random, suggesting a turbulent origin for observed components of or, alternatively, a process of randomisation through magnetic and/or dynamic clump interactions. By contrast, isolated clouds (and perhaps also disks) are shown to have angular velocity vectors ori- ented predominantly towards the north and south galac- tic poles; a distribution which would be anticipated were components of J to arise from galactic shear. We show, nally, that most of the cloud subgroups ap- pear to follow similar functional trends in J, J=M ,a nd. Disks and rings, on the other hand, appear to depart from these variations to a signicant degree; a dierence which

Turbulence in differentially rotating flows. What can be learned from the Couette-Taylor experiment

Abstract: The turbulent transport of angular momentum plays an important role in many astrophysical objects, but its modelization is still far from satisfactory. We discuss here what can be learned from laboratory experiments. We analyze the results obtained by Wendt (1933) and Taylor (1936) on the classical Couette-Taylor flow, in the case where angular momentum increases with distance from the rotation axis, which is the most interesting for astrophysical applications. We show that when the gap between the coaxial cylinders is wide enough, the criterion for the onset of the finite amplitude instability can be expressed in terms of a gradient Reynolds number. Based on Wendt's results, we argue that turbulence may be sustained by differential rotation when the angular velocity decreases outward, as in keplerian flows. From the rotation profiles and the torque measurements we deduce a prescription for the turbulent viscosity which is independent of gap width; with some caution it may be applied to stellar interiors and to accretion disks.

Presupernova Evolution of Rotating Massive Stars I: Numerical Method and Evolution of the Internal Stellar Structure

Abstract: The evolution of rotating stars with zero-age main sequence (ZAMS) masses in the range 8 to 25 M_sun is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational velocity on the ZAMS ranges from zero to ~ 70 % of break-up. Redistribution of angular momentum and chemical species are then followed as a consequence of rotationally induced circulation and instablities. The effects of the centrifugal force on the stellar structure are included. Uncertain mixing efficiencies are gauged by observations. We find, as noted in previous work, that rotation increases the helium core masses and enriches the stellar envelopes with products of hydrogen burning. We determine, for the first time, the angular momentum distribution in typical presupernova stars along with their detailed chemical structure. Angular momentum loss due to (non-magnetic) stellar winds and the redistribution of angular momentum during core hydrogen burning are of crucial importance for the specific angular momentum of the core. Neglecting magnetic fields, we find angular momentum transport from the core to the envelope to be unimportant after core helium burning. We obtain specific angular momenta for the iron core and overlaying material of 1E16...1E17 erg s. These values are insensitive to the initial angular momentum. They are small enough to avoid triaxial deformations of the iron core before it collapses, but could lead to neutron stars which rotate close to break-up. They are also in the range required for the collapsar model of gamma-ray bursts. The apparent discrepancy with the measured rotation rates of young pulsars is discussed.

The Initial Conditions for Formation of Low-Mass Stars: Kinematics and Density Structure of the Protostellar Envelope in B335

Abstract: We have observed dense molecular gas toward a deeply embedded protostar in B335 using the Nobeyama 45 m telescope and the Nobeyama Millimeter Array. The H13CO+ and C18O maps taken by the 45 m telescope show elongated features perpendicular to the axis of molecular outflow, suggesting that these emission lines arise from a dense disklike envelope surrounding the protostar. The size and mass of the H13CO+ disklike envelope are 0.17 × 0.15 pc and 2.4 M☉, respectively. The C18O envelope gas has a linear velocity gradient along its major axis indicative of a rigid rotation with an angular velocity of 1.1 × 10-14 radians s-1. The density profile derived from the C18O and H13CO+ data shows a power law of ρ(r)~ρ0r-1.95~(a2/2πG)r-2 over the radius range between 0.03 and 0.2 pc. In addition, the coefficient of the density profile is consistent with Shu's solution rather than Larson's, though there is uncertainty particularly in the fractional abundance of the H13CO+ molecule. Our results suggest that the protostar in B335 was formed in an isothermal core with a rigid rotation. The interferometric observations of the H13CO+ line reveal a dense compact feature centered on the protostar. This compact feature has a size of 2000 AU, and its elongation is roughly perpendicular to the outflow axis. We thus consider that this compact feature is an inner part of the disklike envelope. There is a velocity gradient along the minor axis of the feature which might be interpreted as a disk infalling motion. The previous observations also suggested the existence of infalling motion toward the protostar B335 IRS. In addition, the inner envelope shows a rotating motion of Vθ=0.14 km s-1 at r=490 AU. This rotational velocity is smaller than the corresponding Keplerian velocity of ~0.42 km s-1, indicating that the inner envelope is not rotationally supported.

Intercepting Moving Objects During Self-Motion.

Abstract: It is generally assumed that in catching a fly ball, an efficient strategy for dealing with the horizontal component of the ball's trajectory is for the observer to keep the angular position of the ball constant with respect to his head. That strategy is called the constant bearing angle or CBA strategy. Maintenance of angular constancy results in the simultaneous arrival of both observer and ball at the landing spot. The authors analyzed the approach behavior of 26 subjects in a ball-interception task with straight paths for both the subjects and the ball. Subjects moved at a velocity that maintained a close-to-constant horizontal angular position of the ball with respect to the end effector throughout the approach phase rather than a constant bearing angle with respect to their head. Velocity adaptations occurred as a function of the changes in the angular velocity of the ball in such a way that a positive or negative angular velocity was canceled. Thus, an actor following the CBA strategy does not need to know where and when the ball will arrive (i.e., a predictive strategy), because reliance on the CBA strategy ensures that he will make the appropriate adaptations that enable him to arrive at the right place in the right time.

Perceiving surface slant from deformation of optic flow.

Abstract: Perceived surface orientation and angular velocity were investigated for orthographic projections of 3-D rotating random-dot planes. It was found that (a) tilt was accurately perceived and (b) slant and angular velocity were systematically misperceived. It was hypothesized that these misperceptions are the product of a heuristic analysis based on the deformation, one of the differential invariants of the first-order optic flow. According to this heuristic, surface attitude and angular velocity are recovered by determining the magnitudes of these parameters that most likely produce the deformation of the velocity field, under the assumption that all slant and angular velocity magnitudes have the same a priori probability. The results of the present investigation support this hypothesis. Residual orientation anisotropies not accounted for by the proposed heuristic were also found.

Instability of the nonvortex state toward a quantized vortex in a Bose-Einstein condensate under external rotation

Abstract: The instability condition of the non-vortex state toward vortex formation is exa mined within the Bogoliubov theory when a Bose-Einstein condensate is under exte rnally forced rotation. The obtained critical angular velocity combined with the previous stability cond itions for a votex yields a detailed phase diagram in the critical velocity vs t he system parameter. This facilitates vortex formation experiments for alkali atom gases confined in a harmonic potential.

Axisymmetric propagating vortices in the flow between a stationary and a rotating disk enclosed by a cylinder

Abstract: The destabilization of the stationary basic flow occurring between two disks enclosed by a cylinder is studied experimentally when the radius of the disks is large compared to the spacing. In the explored range of the cell aspect ratio, when one disk only is rotating, circular vortices propagating to the centre are observed above a critical angular velocity. These structures occur naturally but can also be forced by small modulations of the angular velocity of the disk. For each rotation rate the dispersion relation of the instability is experimentally reconstructed from visualizations and it is shown that this dispersion relation can be scaled by the boundary layer thickness measured over the disk at rest. The bifurcation is found to be of supercritical nature. The eect of the forcing amplitude is in favour of a linear convective nature of this instability of the non-parallel inward flow existing above the stationary disk. The most unstable temporal frequency is found to be about four times the frequency of the rotating disk. The evolution of the threshold of this primary instability is described for dierent aspect ratios of the cell. Finally, two sets of experiments made under transient conditions are presented: one in order to investigate further a possible convective/absolute transition for the instability, and the other to compare with the impulsive spin-down-to-rest experiments of Savas (1983).

A new speed observer for control system of induction motor

Abstract: A new speed observer for control system of induction motor is proposed in the paper. Disturbances are defined, estimated and used in the observer instead of products of rotor angular velocity and rotor flux vector components. The disturbances and rotor flux vector components are used to calculate the rotor angular velocity. Very low errors between the estimated and real rotor angular velocity in steady states and transients have been observed in the new observer for values very close or equal to zero. Properties of the control system with new speed observer have been investigated and results of simulations are presented.

Stability of vortices in inhomogeneous Bose condensates subject to rotation: A three-dimensional analysis

Abstract: We study the stability of vortex-lines in trapped dilute gases subject to rotation. We solve numerically both the Gross-Pitaevskii and the Bogoliubov equations for a 3d condensate in spherically and cilyndrically symmetric stationary traps, from small to very large nonlinearities. In the stationary case it is found that the vortex states with unit and $m=2$ charge are energetically unstable. In the rotating trap it is found that this energetic instability may only be suppressed for the $m=1$ vortex-line, and that the multicharged vortices are never a local minimum of the energy functional, which implies that the absolute minimum of the energy is not an eigenstate of the $L_z$ operator, when the angular speed is above a certain value, $\Omega > \Omega_2$.

The Structure of the Central Disk of NGC 1068: A Clumpy Disk Model

Abstract: NGC 1068 is one of the best-studied Seyfert II galaxies, for which the black hole mass has been determined from the Doppler velocities of water maser. We show that the standard α-disk model of NGC 1068 gives disk mass between the radii of 0.65 and 1.1 pc (the region from which water maser emission is detected) to be about 7 × 107 M☉ (for α = 0.1), more than 4 times the black hole mass, and a Toomre Q-parameter for the disk is ~0.001. This disk is therefore highly self-gravitating and is subject to large-amplitude density fluctuations. We conclude that the standard α-viscosity description for the structure of the accretion disk is invalid for NGC 1068. In this paper, we develop a new model for the accretion disk. The disk is considered to be composed of gravitationally bound clumps; accretion in this clumped disk model arises because of gravitational interaction of clumps with each other and the dynamical frictional drag exerted on clumps from the stars in the central region of the galaxy. The clumped disk model provides a self-consistent description of the observations of NGC 1068. The computed temperature and density are within the allowed parameter range for water maser emission, and the rotational velocity in the disk falls off as r-0.35.

Method and apparatus for steering the attitude of a satellite

Abstract: A method is disclosed for controlling the attitude of a satellite by controlling the speed of the gimbals of CMGs in a cluster of CMGs, the CMG having respective wheels mounted on gimbals that are mounted on a satellite platform to rotate about different orientation axes. From starting conditions and end conditions relating to attitude and angular speed and time, a cluster configuration is determined that is remote from any singular configuration such that exchanging angular momentum between the cluster of CMGs and the satellite during a given length of time will give rise to the desired attitude maneuver. The orientation of each gimbal is changed in simultaneous and independent manner into its reference orientation by using an angular position reference, applied in an open loop in the local servo-control of the angular positions of the gimbals.

Blur correction apparatus

Abstract: PROBLEM TO BE SOLVED: To provide a blur correction apparatus which can perform highly precise blur correction, by considering the control sampling delay of the angular velocity sensor. SOLUTION: This blur correction apparatus 100 has, for example, a blur correction lens 4, to optically correct the image blur responding to the output of the angular velocity sensor 3 which detects the instability of a camera 2, a PSD 7 which detects the position of the blur correction lens 4, a support state determining section 21 to discriminate the state of the camera 2, hand held or firmly secured from the output of the angular velocity sensor 3, a speed bias calculating section 28 to decide the change amount of the target speed according to the output of the PSD 7 or the position of the blur correcting lens 4 calculated from the target speed which is the output of the correction formula operating section 26, and a phase lead correction section 25 for correcting the phase lag of the angular velocity sensor 3. When the support state determining section 21 determines that camera is securely fixed, the speed bias calculating section 28 increases the change amount of the target speed, and the phase lead correction section 25 cancels the correction operation, or changes the parameters. COPYRIGHT: (C)2005,JPO&NCIPI

Developments in Human Centered Cueing Algorithms for Control of Flight Simulator Motion Systems

Abstract: The authors conducted further research with cueing algorithms for control of flight simulator motion systems. A variation of the so-called optimal algorithm was formulated using simulated aircraft angular velocity input as a basis. Models of the human vestibular sensation system, i.e. the semicircular canals and otoliths, are incorporated within the algorithm. Comparisons of angular velocity cueing responses showed a significant improvement over a formulation using angular acceleration input. Results also compared favorably with the coordinated adaptive washout algorithm, yielding similar results for angular velocity cues while eliminating false cues and reducing the tilt rate for longitudinal cues. These results were confirmed in piloted tests on the current motion system at NASA-Langley, the Visual Motion Simulator (VMS). Proposed future developments by the authors in cueing algorithms are revealed. The new motion system, the Cockpit Motion Facility (CMF), where the final evaluation of the cueing algorithms will be conducted, is also described.

Eye-position dependence of three-dimensional ocular rotation-axis orientation during head impulses in humans.

Abstract: If horizontal saccades or smooth-pursuit eye movements are made with the line-of-sight at different elevations, the three-dimensional (3D) angular rotation axis of the globe tilts by half the vertical eye eccentricity. This phenomenon is named ”half-angle rule” and is a consequence of Listing’s law. It was recently found that the ocular rotation axis during the horizontal vestibulo-ocular reflex (VOR) on a turntable also tilts in the direction of the line-of-sight by about a quarter of the eye’s vertical eccentricity. This is surprising, since, in a ”perfect” VOR, the angular rotation axis of the eye should be independent from the position of the eye to fully compensate for the 3D angular head rotation. We asked whether this quarter-angle strategy is a general property of the VOR or whether the 3D kinematics of ocular movements evoked by vestibular stimulation would be less eye-position dependent at higher stimulus frequencies. Nine healthy subjects were exposed to horizontal head impulses (peak velocity ∼250°/s). The line-of-sight was systematically changed along the vertical meridian of a tangent screen. Three-dimensional eye and head movements were monitored with dual search coils. The 3D orientation of the angular eye-in-head rotation axis was determined by calculating the average angular velocity vectors of the initial 10° displacements. Then, the difference between the tilt angles of the ocular rotation axis during upward and downward viewing was determined and divided by the difference of vertical eccentricity (”tilt angle coefficient”). Control experiments included horizontal saccades, smooth-pursuit eye movements, and eye movements evoked by slow, passive head rotations at the same vertical eye eccentricities. On average, the ocular rotation axis during horizontal head-impulse testing at different elevations of the line-of-sight was closely aligned with the rotation axis of the head (tilt angle coefficient of pooled abducting and adducting eye movements: 0.11±0.17 SD). Values for slow head impulses, however, exceeded somewhat the quarter angle (0.33±0.12), while smooth-pursuit movements (0.50±0.09) and saccades (0.44±0.11) were closest to the half angle. These results demonstrate that the 3D orientation of the ocular rotation axis during rapid head thrusts is relatively independent of the direction of the line-of-sight and that ocular rotations elicited by head impulses are kinematically different from saccades, despite similar movement dynamics.

Device for estimating rolling condition of vehicle body with limits of roll angle and angular speed

Abstract: A device for estimating a rolling condition of a body of a vehicle having: a unit for estimating a first quantity (, γV, Gy, Ff) corresponding to roll angle () of the vehicle body around a rolling axis; a unit for estimating a second quantity corresponding to a change rate ( ˙) of the roll angle of the vehicle body; a unit for estimating a third quantity indicating a relative magnitude (/ limit , γV/(γV) limit , Gy/Gy limit , Ff/Ff limit ) of the first quantity with reference to a first limit value predetermined therefor; a unit for estimating a fourth quantity indicating a relative magnitude ( ˙/ ˙ limit ) of the second quantity with reference to a second limit value predetermined therefor; and a unit for estimating the rolling condition as a combination of the third and fourth quantities such that the rolling condition is intensified along with increase of the third quantity as well as increase of the fourth quantity.