Showing papers on "Kinematics published in 1968"
Book•
24 Oct 1968
TL;DR: A set of heuristics is developed for moving a six degree-of-freedom manipulator from an initial position to a final position through a space containing obstacles, which results in a computer program shown to be able to direct a manipulator around obstacles.
Abstract: : The kinematics of manipulators is studied. A model is presented which allows for the systematic description of new and existing manipulators. Six degree-of-freedom manipulators are studied. Several solutions to the problem of finding the manipulator configuration leading to a specified position and orientation are presented. Numerical as well as explicit solutions are given. The problem of positioning a multilink digital arm is also discussed. Given the solution to the position problem, a set of heuristics is developed for moving a six degree-of-freedom manipulator from an initial position to a final position through a space containing obstacles. This results in a computer program shown to be able to direct a manipulator around obstacles. (Author)
672 citations
TL;DR: Results of the analysis are the geometric position of the leg and the equivalent forces in the hip and knee joints as functions of time and the amount of work done as a function of cadence.
115 citations
TL;DR: The directions toward which the Sun and our galaxy are moving in space change rapidly, with increasing distance of the galaxies used as a reference frame as mentioned in this paper, which is a manifestation of the kinematics of the local supercluster and has an important bearing on the derivation of the Hubble constant.
Abstract: The directions toward which the Sun and our galaxy are moving in space change rapidly, with increasing distance of the galaxies used as a reference frame. This effect, which is a manifestation of the kinematics of the local supercluster, has an important bearing on the derivation of the Hubble constant.
36 citations
TL;DR: In this paper, a Bendix time of flight mass spectrometer has been modified to enable the determination of some ion-molecule reaction cross sections in the energy range 1 -100 eV.
Abstract: A Bendix time of flight mass spectrometer has been modified to enable the determination of some ion-molecule reaction cross sections in the energy range 1 — 100 eV. In the reactions studied X+ + D2 → XD++D where X may be Ar, N2 or CO, the results obtained agree with the predictions of the polarization theory in the range below 10 eV despite the fact that no intermediate complex is formed at these energies. Between about 10—50 eV where spectator stripping occurs the cross section follows an approximate E-l dependence. Above these energies the results are consistent with a transition to a region in which knock-on processes predominate and where an impulse approximation treatment would be valid.
23 citations
19 citations
Journal Article•
18 citations
TL;DR: In this article, the kinematic singularities and constraints of helicity amplitudes are studied in a unified way, and simple and compact formulas are obtained which enable one to read off the singularity and constraints for any particular two-body process.
Abstract: The kinematic singularities and constraints of helicity amplitudes are studied in a unified way. Relatively simple and compact formulas are obtained which enable one to read off the singularities and constraints for any particular two-body process. The points studied are the thresholds and pseudothresholds, $s=0$, and the boundary of the physical region. The fundamental assumption which underlies the method used here is that all kinematic singularities result from singular definitions of the helecity states.
12 citations
TL;DR: In this paper, a modification of Freudenstein's method for respacing the precision points in a kinematic synthesis is presented, and the number of points which have to be shifted to obtain minimum structural error is reduced to approximately half the total number of mechanism parameters used in the synthesis.
12 citations
9 citations
TL;DR: In this paper, the displacement analysis of a 6-bar linkage with auxiliary gearing is presented, and a method of kinematic analysis generally applicable to planar mechanisms is described.
Abstract: This note describes a method of kinematic analysis generally applicable to planar mechanisms. It is illustrated by the displacement analysis of a 6-bar linkage with auxiliary gearing.
TL;DR: In this paper, the relativistic kinematics of the motion of a continuum is studied by establishing certain invariant derivatives of measures of deformation, and Rigid body motion of the continuum in the Born sense is discussed.
Abstract: In this paper the relativistic kinematics of the motion of a continuum is studied by establishing certain invariant derivatives of measures of deformation. Rigid body motion of the continuum in theBorn sense is discussed.
TL;DR: In this article, an analysis of a pin-jointed frame subjected to dynamic or impulsive overload, of sufficient magnitude to cause permanent deformation, is presented, in terms of the kinematic conditions, dynamic conditions and the load-deformation characteristics assumed for the members.
TL;DR: Optimum approximation of velocity and displacement transformation curves in kinematic mechanism synthesis using damped least squares approach was achieved in this paper, where the transformation curves were obtained by a linear combination of the velocity and displacements.
Abstract: Optimum approximation of velocity and displacement transformation curves in kinematic mechanism synthesis using damped least squares approach
TL;DR: In this article, an algorithm for the computation of kinematic quantities in a general planar mechanism with lower Kinematic pairs is derived in the form of Fourier series having the angular displacement of the main crank as argument.
TL;DR: In this paper, the Lagrangian functions of a track chain and its links have been used to model the stresses on the links and their relative motions during a period of time for four forward speeds of a given tractor and for turning in first gear.
TL;DR: In this paper, a simplified method of presenting kinematic relationships in nuclear reactions is presented, which allows to obtain in a convenient way the energy of the reaction products as a function of the angle of emission in the laboratory frame for non-relativistic reactions.
15 Nov 1968
TL;DR: In this article, a program for simulating the motion of a rigid body containing a reaction wheel, damping media and torquing (magnetic or otherwise) is described.
Abstract: : This report describes a program for simulating the motion of a rigid body containing a reaction wheel, damping media and torquing (magnetic or otherwise). The dynamical equations are simulated in terms of the angular velocities in body-fixed coordinates and the kinematic equations are simulated in terms of direction cosines. The entire system of equations has been programmed using a fourth order predictor-corrector method with automatic step- size adjustment and a fourth order Runge-Kutta starting routine. The ratio of computer time to real time is between 1 to 10 and 2 to 1 for LES-5-type satellites.
01 Jun 1968
TL;DR: In this article, the geometric and kinematic description of the motion of an elastic-plastic body undergoing finite deformation is considered, and a configuration distinct from the initial and current configurations of the body is introduced.
Abstract: : The geometric and kinematic description of the motion of an elastic- plastic body undergoing finite deformation is considered. A configuration distinct from the initial and current configurations of the body is introduced, which is supposed to be the state of the body due to its plastic deformation alone, and also to be the reference configuration for elastic deformation. It is shown that the rate of deformation tensor may then be written as the sum of the rates of elastic and plastic deformation. Restrictions imposed by some physical assumptions are considered, and the form of some of the derived relations is given for two-dimensional deformations in Cartesian and cylindrical coordinates.
TL;DR: In many problems of galactic kinematics the authors need to know the proper motions of faint stars, as well as bright stars, within some well-defined reference frame, generally speaking, the accuracy required is greater for faint stars on account of their larger distances.
Abstract: In many problems of galactic kinematics we need to know the proper motions of faint stars, as well as bright stars, within some well-defined reference frame. Generally speaking, the accuracy required is greater for faint stars on account of their larger distances. Techniques at present used for determining proper motions vary according to apparent magnitude, and it is clearly desirable that all methods should give results which are capable of reduction to a common frame.