Showing papers on "Angular velocity published in 1990"

Swing analyzing device

Abstract: A swing analyzing device comprising swing practice equipment such as a golf club, wherein acceleration sensors are arranged on the shaft or on an axis of the swing practice equipment, or near the axis, and a dynamic quantity representing a movement of the shaft, such as an angular velocity, angular acceleration, and angle of the shaft, is calculated from an output of the acceleration sensors. The acceleration sensors are preferably arranged on the shaft in a spaced apart relationship so that directions of detecting acceleration substantially coincide with an axis of the shaft. A further acceleration sensor can be arranged on the shaft so that a direction of detecting acceleration forms a certain angle with an axis of said shaft.

Multidimensional signal input device

Abstract: A device is provided which allows multidimensional information signals concerning coordinates, directions and the like of an object to be input to a CPU exactly as intended by an operator on a non-contact basis, and without restrictions on the place where it is used. Angular velocity detectors (4), (5), and (6) are provided on the X-axis, Y-axis, and Z-axis, orthogonal to each other of an operation unit which is shaped to be easily gripped by an operator or to be mounted on an articulation, shoulder, or head. The operation unit (1) is rotated and moved and, when the operator wishes to input information, push-buttons (2) and (3) provided on the operation unit (1) are turned on/off to command the start or stop of the counting of the output of the angular velocity detectors (4), (5), and (6). In response to the command, the angular velocity signals of the axes are converted into information to be input to the CPU through V/F converters, pulse conversion circuits, gate circuits, and counter circuits. The motion of an operator can be commanded as the operator intends in arbitrary space, thereby facilitating the movement of a robot arm and the rotation and movement on a display screen of a three-dimensional CAD system or graphic system. In addition, a person who has a handicap in his or her hand or leg can operate and issue commands.

Method and system for detecting the misfire of an internal combustion engine utilizing angular velocity fluctuations

Abstract: A hybrid method and system are disclosed for the detection of internal combustion engine misfires. The method and system are capable of detecting misfires even at very low occurrence rates in real time with inexpensive analog and digital (i.e. hybrid) electronics suitable for use on-board a vehicle, thus satisfying current and proposed exhaust emission control regulations. The method and system exploit a measurement of engine crankshaft angular velocity in conjunction with hybrid electronic signal processing. Once the angular velocity signal is conditioned to minimize the effects of random error and external disturbances, four alternate computationally efficient methods may be used to extract information pertaining to individual cylinder torque productions. Two of the methods employ extremal samples of the estimated torque or velocity waveform to obtain a random torque nonuniformity index or metric. The other two methods utilize a transformation into the frequency domain after the input data is first sampled and windowed to substantially lower probability of error. All of the methods provide an M-dimensional torque non-uniformity vector of individual cylinder performance for each individual engine cycle. The non-uniformity vector represents a compact and efficient measurement to which statistical decision theory is applied.

Method of and apparatus for copy controlling coordinate measuring probe with rotary table

Abstract: For copy measuring the coordinates of an object to be measured using a coordinate measuring probe by disposing a rotary table on a platen of a coordinate measuring machine and placing the object on said rotary table and further rotating the object through said rotary table, there are calculated a speed vector V of the probe when the rotary table is stationary at the rotational angle θ and an angular velocity ω of the rotary table by said probe speed vector V viewed from the axis center of the object, and lead and retardation of said rotational angle θ is adjusted so as to keep unchanged an angular relationship between the object and the probe to determine the angular velocity ω anew. Further, there is calculated a speed vector V R that follows up the movement of said angular velocity ω, and the vector sum V T =V+V R is issued as a speed command to the probe and said angular velocity ω is issued as a speed command to the rotary table. Therefore, one axis copy control owing to the rotary table is incorporated in addition to three-axis copy control of the probe when the rotary table is not used, to perform simultaneous four-axis copy control keeping unchanged the angular relationship between the object and the probe.

Gyroless platform stabilization techniques

Abstract: A method and apparatus for platform stabilization. The apparatus uses linear and/or angular accelerometers to derive the roll, pitch, and yaw components of the angular velocity of the vehicle the apparatus is mounted on. Based on the calculation of angular velocity or acceleration of the vehicle and the current rate and angle of rotation of the device to be stabilized, the apparatus generates setpoint and movement commands for servo motors that rotate the sensing device such that the line of sight of the sensing device is stabilized. A control system implements a velocity control system, or, alternatively, an acceleration control system. In one embodiment of the invention, the accelerometers are positioned on a mounting base along axes corresponding to the roll, pitch and yaw axes of the vehicle in a location adjacent to the sensing device. In an alternative embodiment, the accelerometers are positioned on the stabilized element itself, with the command strategy being to force gimbal rotations so that the output of the accelerometers is urged towards a null value.

The simulation of aerial movement—III. The determination of the angular momentum of the human body

Abstract: A method is presented for determining the angular momentum of the human body about its mass centre for general three–dimensional movements. The body is modelled as an 11 segment link system with 17 rotational degrees of freedom and the angular momentum of the body is derived as a sum of 12 terms, each of which is a vector function of just one angular velocity. This partitioning of the angular momentum vector gives the contribution due to the relative segmental movement at each joint rather than the usual contribution of each segment. A method of normalizing the angular momentum is introduced to enable the comparison of rotational movements which have different flight times and are performed by athletes with differing inertia parameters. Angular momentum estimates were calculated during the flight phases of nine twisting somersaults performed on trampoline. Errors in film digitization made large contributions to the angular momentum error estimates. For individual angular momentum estimates the relative error is estimated to be about 10% whereas for mean angular momentum estimates the relative error is estimated to be about 1%.

Bounds on time-to-collision and rotational component from first-order derivatives of image flow

Abstract: A moving rigid object produces a moving image on the retina of an observer. It is shown that only the first-order spatial derivatives of image motion are sufficient to determine (i) the maximum and minimum time-to-collision of the observer and the object and (ii) the maximum and minimum angular velocity of the object along the direction of view. The second or higher order derivatives whose estimation is expensive and unreliable are not necessary. (The second-order derivatives are necessary to determine the actual motion of the object.) These results are interpreted in the image domain in terms of three differential invariants of the image flow field: divergence, curl , and shear magnitude . In the world domain, the above results are interpreted in terms of the motion and local surface orientation of the object. In particular, the result that the minimum time-to-collision could be determined from only the first order derivatives has a fundamental significance to both biological and machine vision systems. It implies that an organism (or a robot) can quickly respond to avoid collision with a moving object from only coarse information. This capability exists irrespective of the shape or motion of the object. The only restriction is that motion should be rigid.

Operation of the permanent magnet synchronous machine without a mechanical sensor

Abstract: Permanent synchronous machines (PSM) score against asynchronous machines because of their simple control structure and a higher efficiency due to the small rotor losses. The necessity of sensors for angular speed and position represents a considerable restriction of robustness. Because of this, it is the aim of much research to substitute the mechanical sensors with more sophisticated models using only electrical quantities. If a certain angular velocity is exceeded, it is possible to determine the electrical rotor position from the EMF, which can simply be calculated from electrical terminal quantities (Schroedl and Stefan (1988)). At standstill and at low angular velocity, the EMF decreases and thus cannot be utilized to detect the rotor position. The author presents a new method for estimating angular position, velocity and load torque of PSMs. The method works properly at any speed and load condition. It combines the INFORM-principle ('indirect flux detection by online reactance measurement') by Schroedl and Stefan and the Kalman filter technique. >

Mobile robot navigating method

Abstract: A mobile robot navigating method for navigating an autonomous mobile robot utilizes a path planning unit, a posture control unit, a command signal converting unit, a current posture computing unit and a running mechanism, such as an autonomous carrier vehicle, capable of quickly and accurately controlling the mobile robot for steady running to a desired posture along a specified path. The mobile robot is controlled for running by a speed command including a desired speed for feed-forward control a speed correction for feed back control, and an angular velocity command including a desired angular velocity for feed-forward control and an angular velocity correction for feedback control. The mobile robot is controlled in a feed back and feed-forward control mode using the speed command and the angular velocity command so as to run steadily along an optimum path to a desired posture without meandering.

An identified model for human wrist movements.

Abstract: We have performed tests to find the mechanical properties of the hand and muscles driving wrist flexion and extension, and have identified parameters of a model. The hand acts as a nearly pure inertial load over most of its range of motion. It can be approximated as a rigid body rotating about a single axis. Viscosity of the wrist joint is negligible. Passive elastic torques are also small, except at extreme wrist angles. We measured torque as a function of wrist angle for maximum voluntary contractions, and angular velocity as a function of load. The torque/velocity curves for shortening muscles are well approximated by a Hill equation. To measure the "series elasticity" of the muscle equivalents, we imposed step changes in torque. The series stiffness is a monotonically increasing function of the preload, or "active state", in the Hill sense. We discuss the relationship of the measured parameters to properties of isolated muscles. To see the implications of the model structure for the "inverse problem" of identifying motor control signals, we simulated four models of different complexities, and found best fits to movement data, assuming simple pulse-shaped inputs. Inferred inputs depend strongly on model complexity. Finally, we compared the best fit control signals to recorded electromyograms.

Simple method for computing 3D motion and depth

Abstract: The nonlinear equation that relates the optical-flow field to 3-D motion and depth can be split by an exact algebraic manipulation to form three sets of equations. The first set relates the image velocities to the translational component of the 3-D motion alone. Thus, the depth and the rotational velocity need not be known or estimated prior to solving for the translational velocity. Once the translation has been recovered, the second set of equations can be used to solve for the rotational velocity. Finally, depth can be estimated with the third set of equations, given the recovered transaction and rotation. The algorithm applies to the general case of arbitrary motion with respect to an arbitrary scene. The authors show that the performance of the algorithm compares quite favorably with other proposed approaches. >

The mass of spinning rotors: no dependence on speed or sense of rotation

Abstract: ANOMALOUS mass reductions in spinning gyroscopes have been reported by Hayasaka and Takeuchi1. For one sense of rotation about a vertical axis the mass of the gyroscope appeared to be a linear function of the speed of rotation (albeit with non-zero intercept); in the other direction it did not. In the absence of any theoretical explanation of such behaviour these results are very puzzling. Here we present the results of weighing a 330-g spinning rotor as it freely spins down from speeds of 8,000 r.p.m. We observe some changes in its apparent mass, which are a function of both speed and sense of rotation, but they amount to only ∼5% of what would be required for consistency with ref. 1. If corrections are made for the effects of the friction couple slowing the rotor, and for changes in temperature, the observed effect is reduced by more than a factor of ten, and is no longer significant.

Depth and latitude dependence of the solar internal angular velocity

Abstract: One of the design goals for the dedicated helioseismology observing state located at Mount Wilson Observatory was the measurement of the internal solar rotation using solar p-mode oscillations. In this paper, the first p-mode splittings obtained from Mount Wilson are reported and compared with those from several previously published studies. It is demonstrated that the present splittings agree quite well with composite frequency splittings obtained from the comparisons. The splittings suggest that the angular velocity in the solar equatorial plane is a function of depth below the photosphere. The latitudinal differential rotation pattern visible at the surface appears to persist at least throughout the solar convection zone.

Maximal acceleration, maximal angular velocity, and causal influence

Abstract: The upper bounds to acceleration and angular velocity which are suggested by quantum gravitational effects are described, together with the relativistic bound to velocity, by means of a cone ℐ+ in the Lie algebra of the Poincare group. The connection between these bounds and the existence of a minimal measurable length (of the order of Planck's length) is illustrated by means of a simple model. The geometric properties of the cone ℐ+ and of other related structures are examined in some detail. The new geometric background requires some modifications of the concepts of causal influence and of spacetime coincidence, which are analyzed and shown to lead to some nonlocal features of the theory. Due to the smallness of Planck's length, these modifications to the causal relations cannot be observed by means of available experimental methods, but they could have some influence on the structure of elementary particles and on the very early cosmology.

Explicit-implicit staggered procedure for multibody dynamics analysis

Abstract: An explicit-implicit staggered time-integration procedure is presented for the solution of multibody dynamical equations involving large rotations and constraints. The algorithms adopts a two-stage modification of the central difference algorithm for integrating the translational coordinates and the angular velocity vector, and the midpoint implicit algorithm to solve the kinematical relation in terms of the Euler parameters for updating the angular orientations. The Lagrange multipliers to enforce the system constraints are obtained by implicitly integrating a parabolically regularized differential equation for the multipliers. The performance of the present procedure has been evaluated to applying the procedure to solve several sample problems. The results indicate that the procedure is robust in dealing with a variety of constraints and spatial kinematic motions, hence it is recommended for applications to general multibody dynamics analyses.

Galactic dynamo models without sharp boundaries

Abstract: A new numerical approach is introduced which allows investigation into the conditions for dynamogeneration of axisymmetric and non-axisymmetric large-scale magnetic field modes in galaxy models which are defined by axisymmetric distributions of the α-parameter, the angular velocity and the electrical conductivity The velocity field is assumed to be localized, however, the common assumption of a sharp boundary of the conducting region is dropped The possible anisotropy of the α-tensor is taken into account The critical dynamo numbers (excitation conditions) for different modes are obtained by a direct method The required steady states are attained by the use of an artificial non-linearity Initial test calculations demonstrate the efficacy of this new concept

Granular materials applicator

Abstract: A granular materials applicator is disclosed in which controlled metering rolls rotating at a preselected angular velocity provides volumetric displacement of the granular material irrespective of varying operating conditions.

Suspension control apparatus

Abstract: A vehicle behavior during cornering and turning is correctly grasped by computing and map-retrieving from output signal (V) of a vehicle speed sensor (1) and output signal (ωy) of a yaw angular velocity sensor (2) for detecting angular velocity about a yaw axis (B) of the vehicle (11), and rolling motion of the vehicle (11) during ordinary-turning or quick-turning is restrained by increasing damping force of shockabsorbers (3) of the suspension control apparatus.

Resonant flow of a rotating fluid past an obstacle : the general case

Abstract: We consider the flow of a rotating fluid past an antisymmetric obstacle placed on the axis of a cylindrical tube, for the case when the upstream flow is nearly resonant, or critical, so that the speed of a free linear long wave is nearly zero in the frame of reference of the obstacle. The perturbed flow is dominated by the resonant mode, whose amplitude satisfies a forced Korteweg-de Vries equation in this general case when the upstream flow contains radial shear and/or radially dependent angular velocity

Free vibration behavior of spinning shear-deformable plates composedof composite materials

Abstract: The theory accounts for geometric nonlinearity in the form of the Von Karman strains and the effects of rotatory inertia. The plate is permitted to have an arbitrary orientation offset from the axis of rotation. A finite element model is developed. The mode shapes as functions of angular velocity, pitch angle, and sweep angle are presented.

Design of a solid-state gyroscopic sensor made of quartz

Abstract: An angular rate sensor made out of a single piece of quartz has been studied. The piezoelectric effect in quartz is used both to excite a reference vibration in the plane of a tuning fork and to sense the vibration normal to this plane due to an externally applied rotation. The amplitude of the second vibration is directly proportional to the angular velocity of the applied rotation. In con- trast to ordinary types of tuning-fork gyroscopes, this sensor uses its stem only as a support. It also utilizes a fairly large resonance frequency. This enables the sensor to survive in a vibration-rich enviromnent. The well-established means of manufacturing used by watch crystal manufacturers can be used.

Brownian motion in a rotating flow

Abstract: The Langevin equations for a particle of an arbitrary shape and the correlation functions for the fluctuating forces, torques, or force-torque acting on the particle in a rotating flow are derived from the semimicroscopic level of coarse graining by using fluctuating hydrodynamics. In order to obtain the solution of the Navier-Stokes Langevin equation valid over the entire flow region, use is made of the method of matched asymptotic expansions in (Ω f a2/v)1/2≪ 1. The cases of slow and rapid rotation are analyzed. It is shown that the fluctuation-dissipation theorems hold up to the order of (Ω f a2/v)1/2 in both slow and rapid rotation, and that the diffusivity tensor depends on the angular velocity of the fluid and becomes anisotropic.

Engine control system

Abstract: In an engine control system of the type in which engine control data is calculated for each of a plurality of cylinders, rotation angular speeds of the crank shaft are sequentially detected as individual pistons of the plurality of cylinders take an identical, predetermined stroke position, for example, top speed position and rotation speed data and control data are calculated on the basis of the detected rotation angular speed.

Apparatus for preventing image from being blurred in camera

Abstract: An apparatus is provided for preventing an image from being blurred as it is being recorded on the film of a camera Angular velocity sensors are provided for detecting the angular velocity applied to the camera, and an actuator is provided for actuating a shutter of the camera to correct for the movement of the camera when the absolute value of the angular velocity detected by the angular velocity sensors is below a predetermined value

A method for computing the three-dimensional angular velocity and acceleration of a body segment from three-dimensional position data.

Abstract: A theoretical technique, based on the Method of Least Squares, was employed to solve for the three-dimensional components of the angular velocity and acceleration of a limb segment directly from experimentally recorded three-dimensional position data. Results showed that a minimum of four targets placed on the body segment, forming six relative position vector equations, were required to produce the most accurate results. It was also found that this method eliminates the errors due to soft tissue motion and system noise.

Magnetoconvection in rapidly rotating boussinesq and compressible fluids

Abstract: Finite amplitude convection is considered in a plane fluid layer rotating with angular velocity Ω about a horizontal axis in the y-direction. The fluid is electrically conducting, and a uniform horizontal magnetic field of strength B 0 is applied horizontally, in the x-direction, perpendicular to the rotation axis. The gravitational acceleration, g is parallel to Oz. The layer is infinite in y-extent but is bounded laterallyin the y-direction by vertical walls, which may be either stress-free or rigid, i.e. prevent fluid motion. The model is intended to simulate crudely conditions near the equator of the solar convection zone.