Global Navigation Through Local Reference Frames

2006 ◽  
pp. 274-285
Author(s):  
John Pisokas
Keyword(s):  
Reference Frames ◽  
Local Reference ◽  
Global Navigation

Flexible Multibody Dynamics Based on a Fully Cartesian System of Support Coordinates

1993 ◽  
Vol 115 (2) ◽  
pp. 294-299 ◽  
Author(s):  
N. Vukasovic ◽  
J. T. Celigu¨eta ◽  
J. Garci´a de Jalo´n ◽  
E. Bayo
Keyword(s):  
Multibody Dynamics ◽  
Reference Frames ◽  
Deformable Body ◽  
Equations Of Motion ◽  
Flexible Multibody Dynamics ◽  
Body Motion ◽  
Cartesian System ◽  
Flexible Multibody ◽  
Local Reference ◽  
Rigid Multibody

In this paper we present an extension to flexible multibody systems of a system of fully cartesian coordinates previously used in rigid multibody dynamics. This method is fully compatible with the previous one, keeping most of its advantages in kinematics and dynamics. The deformation in each deformable body is expressed as a linear combination of Ritz vectors with respect to a local frame whose motion is defined by a series of points and vectors that move according to the rigid body motion. Joint constraint equations are formulated through the points and vectors that define each link. These are chosen so that a minimum use of local reference frames is done. The resulting equations of motion are integrated using the trapezoidal rule combined with fixed point iteration. An illustrative example that corresponds to a satellite deployment is presented.

scholarly journals Connection Between Non-Rotating Local Reference Frames by Means of the World Function

1991 ◽  
Vol 127 ◽  
pp. 262-265
Author(s):  
J.M. Gambi ◽  
P. Romero ◽  
A.San Miguel ◽  
F. Vicente
Keyword(s):  
Reference Frames ◽  
Riemann Tensor ◽  
Space Time ◽  
General Character ◽  
Order Of Approximation ◽  
First Order ◽  
The World ◽  
Local Reference ◽  
General Relativistic ◽  
World Function

AbstractBy means of the world function an approximate transformation showing the Riemann tensor between the Fermi coordinates associated to two non-rotating local reference frames is derived in a General Relativistic space-time. One of the observer’s world lines is resticted to be a time-like geodesic of the space-time, and the other is a time-like curve of a general character. The space-time where the transformation is evaluated is supposed to be of small curvature, and the calculations are carried out in a first order of approximation with respect to the Riemann tensor.

scholarly journals Astrometry in Local Reference Frames for Deep Space Navigation

1988 ◽  
Vol 129 ◽  
pp. 333-334
Author(s):  
R. N. Treuhaft
Keyword(s):  
Reference Frames ◽  
Local Network ◽  
Single Source ◽  
Deep Space ◽  
Space Navigation ◽  
Source Method ◽  
Long Baseline ◽  
Sample Covariance ◽  
Local Reference ◽  
Navigation Accuracy

Future deep space missions will benefit from submilliarcsecond angular navigation accuracy (< 25 km projected distance at Neptune). Conventional Very Long Baseline Interferometry (VLBI) measurement strategies entail observations of a radio source (RS) and spacecraft pair. To increase the 3–5 milliarcsecond accuracies currently attainable, instrumental improvements could be coupled with either of two methods: 1) Use improved calibration measurements with the single RS as the spacecraft reference, or 2) use a reference frame established by a local network of RS's near the spacecraft to reduce the contribution of sky-dependent error sources. The demanding baseline vector (earth orientation) and tropospheric calibrations needed to realize submilliarcsecond accuracy with the single-source strategy would not be necessary with the multi-source strategy. The two strategies are compared via a sample covariance analysis. In this analysis, the single-source method yields 1.5 milliarcseconds for the navigation accuracy, while the multi-source method yields 0.5 milliarcseconds.

The problem of conflicting reference frames when investigating three-dimensional space in surface-dwelling animals

2013 ◽  
Vol 36 (5) ◽  
pp. 564-565 ◽  
Author(s):  
Francesco Savelli ◽  
James J. Knierim
Keyword(s):  
Empirical Analysis ◽  
Reference Frames ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Local Reference ◽  
Surface Dwelling ◽  
The Impact ◽  
Experimental Strategies ◽  
Three Dimensional Space

AbstractIn a surface-dwelling animal like the rat, experimental strategies for investigating the hippocampal correlates of three-dimensional space appear inevitably complicated by the interplay of global versus local reference frames. We discuss the impact of the resulting confounds on present and future empirical analysis of the “bicoded map” hypothesis by Jeffery and colleagues.

Kinematic Performance Analysis of the Double Wishbone Independent Front Suspension

2012 ◽  
Vol 490-495 ◽  
pp. 348-354
Author(s):  
Jia Qi Jin ◽  
Jiao Jiao Li
Keyword(s):  
Reference Frames ◽  
Transformation Method ◽  
Plane Motion ◽  
Local Motion ◽  
Vector Method ◽  
Front Suspension ◽  
Local Reference ◽  
Wheel Alignment ◽  
Kinematic Performance ◽  
The Right

The vector method is applied to study the kinematic performance of the double wishbone independent front suspension.The model of the right front suspension is established in this paper, on this basis, the local motion reference frames of the upper and lower arms are established by using the coordinate transformation method. Therefore, the space relations between of the arms can be transformed into the plane motion of their respectively local reference frame by this method. Furthermore, the variable law of the wheel alignment parameters with the swing angle φ of the lower arm, is obtained through establishing the constrain equations of the key points.

Screw Theory Based Metrology for Design and Error Compensation of Machine Tools

2001 ◽  
Author(s):  
Sang-Ku Moon ◽  
Yong-Mo Moon ◽  
Sridhar Kota ◽  
Robert G. Landers
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Reference Frames ◽  
Screw Theory ◽  
Mathematical Framework ◽  
Functional Representation ◽  
Local Reference ◽  
Filtering Technique ◽  
Five Axis

Abstract The paper presents a generalized mathematical framework for computation and compensation of tool tip errors in multi-axis machine tools using screw theory. In contrast to conventional Denavit–Hartenberg notation, Screw theory offers several advantages including: (i) modeling of complex machine tool configurations with rotational axes, (ii) tractability of error propagation which simplifies solution of inverse kinematics and subsequent error-compensation procedures, and (iii) functional representation of error screws in a global reference frame rather than cumbersome coordinate transformations of local reference frames. Kinestatic filtering technique [11,12] is adopted for evaluating the compensatability of errors and the Jacobian is used for error compensation. The methodology is illustrated using a five-axis machine tool with two rotational axes.

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