Showing papers on "Kinematics published in 1976"

The Effect of Duration, Rate of Onset, and Peak Sled Acceleration on the Dynamic Response of the Human Head and Neck

Abstract: A series of human experiments has been conducted to measure the response of the head and the first thoracic vertebrae to these parameters. Each subject was run at three conditions defined as high rate of onset-long duration, high rate of onset-short duration and low rate of onset-long duration at peak accelerations of 6, 10 and 15 G. Comparison time profiles of angular acceleration, angular velocity and linear resultant acceleration at the head anatomical origin and horizontal linear acceleration at the T//1 origin are presented for 5 to 8 subjects at each of the three peak sled acceleration levels. Regression coefficients of peak values of the kinematic parameters of onset and duration as defined by the sled profile are developed, as well as coefficients based on similar parameters defined from the profile of linear acceleration at T//1. Language: en

Interplanetary stream magnetism - Kinematic effects

Abstract: The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the solar wind, assuming that the solar wind velocity is constant and radial and that its azimuthal variations are not two rapid. The effects of the radial velocity profile in corotating streams on the magnetic fields were examined using kinematic approximation and a variety of field configurations on the inner boundary. Kinematic and dynamic effects are discussed.

Perturbation formulations for satellite attitude dynamics

Abstract: Two analytical developments for the arbitrarily torqued motion of an asymmetric rigid body, both of which utilize a new torque-free solution as the reference motion, are presented. The first is an Encke-type perturbation formulation in which differential equations for the angular velocity and orientation departures from Poinsot motion are derived. The second technique is a variation of parameters scheme in which an analogue of Herrick's two-body perturbative differentiation technique is employed. The torque-free motion constants selected for variation are initial orientation and initial angular velocity; differential equations which specify the time variation of these parameters are developed, so that the torque-free solution is then instantaneously valid in the presence of arbitrary torques. Both developments are motivated by classical perturbation theories in orbital mechanics. Extensive use is made of the Euler parameter description of body orientation and kinematics rather than the more conventional Euler angles in order to avoid the geometrical singularities implicit in the latter.

Comparison of Kinematic Parameters Between Hybrid II Head and Neck System with Human Volunteers for -Gx Acceleration Profiles

Abstract: Significant kinematic parameters of the head are compared between a Hybrid II head and neck and human volunteers subjected to the same -Gx sled acceleration profiles. Comparison time profiles between the dummy and human subjects for components of linear acceleration, velocity, and displacement of the head center of gravity and the first thoracic vertebral body (T1) anatomical origin, as well as components of angular acceleration, velocity, and displacement of the anatomical coordinate systems are prsesented for 6, 10, and 15G peak sled acceleration in the -Gx environment. Significant differences between the dummy and human volunteers are discussed in regard to peak values of parameters, time latencies, and overall shape agreement in a time window where motion is significant.

A Computation for Robots to Orient and Position Hand-Held Workpieces

Abstract: A computation is presented which enables robots with six degrees of freedom to orient and position workpieces against fixtures. It is assumed that the robot can grasp a single workpiece and that a vision system can determine the three-dimensional locations of three feature points on that workpiece. A feature point is a unique point on a workpiece, such as the apex of a cone, which may be located visually by examining neighboring edges or surfaces. The spatial relation between workpiece and fixture which is to be the goal of arm motion is specified by measurements taken as the workpiece is held with the correct posture by a programmer. These measurements are the spatial locations of three noncollinear feature points on the workpiece and three noncollinear feature points on the fixture. The computation presented adjusts for relative motion between fixture and robot if the vision system keeps track of the three feature points on the fixture. The solution to the equations presented is a set of arm link parameters which satisfy the goal of relative workpiece placement. The general form of the equations permits application of the computation to robots with different kinematic configurations.

Spacebar: kinematic design by computer graphics

Abstract: The development of kinematic mechanisms on the design board is often an extremely complex and time-consuming task. The SPACEBAR pre-gram allows the direct design and analysis of mechanisms on the terminal screen. All variables including linkage geometry, stiffness, and applied loading conditions can be input and/or changed from the terminal. The data can be described and displayed in three dimensions. All mechanism configurations can be cycled through their range of travel and viewed in their various geometric positions, again in three dimensions. Output data includes geometric positioning in orthogonal co-ordinates of each node point in the mechanism, velocity and acceleration of the mechanism node points throughout its range of travel, and internal loads and displacements of the individual node points and linkages. All analysis calculations are performed at the v.d.u. and take, at most, a few seconds to complete. Output data can be viewed at the scope and also printed at the discretion of the user.

Gear linkage for tipping lorry cab - has fixed pivot coaxial to tipping axis for constant setting

Abstract: The tipping cab (1) is fitted with a gear selector lever (2) on the floor and linked to the gear box (8). In this a first selector shaft (4) transmits the axial and rotational movements to a kinematic joint (6) whose main axis coincides with the tipping axis. A second shaft (7) links the kinematic joint to the gear box. The gear lever position remains in its setting during the tipping procedure, while the selected gear, or neutral, remains set in the gear box. The system allows relative vibrational movement of the cab on the chassis without affecting the gear setting.

Mach's principle, relative motion, and fundamental numbers of physics

Abstract: Mach's principle is discussed as a fundamental statement on kinematics, and an apparent contradiction is identified in the Lorentz-Minkowski form of the inertial metric. To resolve the incompatibility, length is redefined so that the speed of light is a field-dependent variable, although still constant for all inertial observers at a point in space-time. Gravitational theories with variableG are considered, and it is shown that a redefinition of length and time results in constantG and variablec.

Knitting machine needle bed drive - has two separate and identical parallel gram driving linkages with different stroke lengths

Abstract: A process and appts. are claimed for the drive of the needle beds in a knitting machine, where the needle bars tilt on the upper edge of the comb plate against the counter movement of the guide bars, with two identical kinematic drives with different stroke lengths for the needle beds in their upwards and downwards movements, to tilt round a fixed point of the upper edge of the comb plate. During the under laying there is an additional tilting away from the upper edge of the comb plate during the upwards movement, with a forward tilting movement during over laying followed by tipping back into the extended position to be returned to the casting-off position. The system allows the guide needle bars and the needle bars to be manipulated against each other so that trouble-free stitches are executed under all operating conditions, the mechanism also being suitable for double-row knitting machines.

A test of the proton-induced 2h break-up study for special kinematic conditions.

Abstract: Publisher Summary This chapter discusses a test of the proton-induced 2H break-up study for special kinematic conditions. The break-up of the deuteron by nucleons has been measured in various kinematic conditions. This chapter discusses an experiment on the proton-induced 2H break-up at 156 MeV with the detector angles θ1 and θ2 proposed by Lambert et al. to satisfy the kinematic conditions in which the spectator nucleon is at rest in the total center of mass system. These conditions that correspond to destructive interference minima have been found very sensitive to the N–N potential through 3-body Faddeev analysis. The cross-section of the deuteron break-up at 156 MeV might be explained by the FSA type three-body scattering theory even for the data in the regions far from QFS and FSI regions, by using the off-shell t-matrix element of the realistic potential for the first (and second) order scatterings, and the separable potentials for higher order scatterings. The second order scattering calculation results obtained by using the realistic potentials and off-shell t-matrix elements determine the unknown coefficients introduced for the used separable potentials.

A Note on the Application of the Basic Kinematical Law

Abstract: A set of guidelines is presented for correctly deriving the motion equations for a space vehicle by using the basic law of kinematics.