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Prins, J.J.M. (author)
The existing fine attitude system of the Astronomical Netherlands Satellite was designed on the basis of conventional digital control techniques. The possibility of a more advanced approach is presented in this report. As an example, an alternative control algorithm for the scan mode has been developed with the use of state estimation and state...
report 1976
document
Traas, C.R. (author)
The report reviews a number of digital filtering methods and gives examples of their application. The methods include batch processing methods and rec\irsive methods, not only in the classical formulations but also in square-root formulations. The latter formulations have the purpose to prevent certain numerical inconveniences. Much attention is...
report 1976
document
van der Vooren, J. (author), Sanderse, A. (author)
A fully-conservative- finite difference algorithm is described to calculate the incompressible flow through a straight channel of varying rectangular cross section. Both the width and the height of the channel may vary independently. The algorithm has been used successfully in the design of the German-Dutch low speed wind tionel (DNW).
report 1977
document
Zwartbol, T. (author), Terpstra, A.P. (author), van Woerkom, P.T.L.M. (author), van den Dam, R.F. (author)
This document presents an approach to sampled data, on-board estimation and control of the attitude motion of manoeuvring spacecraft. Algorithms which are developed include: a - model following control of attitude manoeuvres b - estimation of spacecraft state (attitude, angular velocity, disturbance torque) c - optical-inertial attitude...
report 1982
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Veldman, A.E.P. (author), Lindhout, J.P.F. (author)
An outline is presented of a new code, called VISIAN, for the analysis of aerodynamic flows with strong viscous-inviscid interaction. The code is based on the recently developed quasi-simultsuieous method for the calculation of strongly interacting boundary layers. The feasibility of this method has already been demonstrated liy means of a...
report 1983
document
Blom, H.A.P. (author)
A sophisticated starting point for a probabilistic approach to the radar tracking problem is a Markov jump-diffusion model for the aircraft dynamics, its control and the radar measurements. From nonlinear filtering theory, a closed form description of the evolution of the conditional distribution of this Markov process can be obtained. This jump...
report 1983
document
van Woerkom, P.T.L.M. (author)
Software design for digital computer simulation of the dynamics of flexible spacecraft equipped with actuators and sensors, should take into account two properties of the overall system: (i) s.ampled-data control of the spacecraft leads to discontinuous inputs (forcing functions) in the differential equations of motion, thereby requiring...
report 1983
document
Simons, H.J. (author), Roefs, H.F.A. (author)
The class of (255, 255-2T) Reed-Solomon codes over CF(256) is studied in detail. In particular the encoding and decoding algorithms are elaborated. Main computational elements are the discrete Fourier transform for syndrome and error locator computation, Euclid's algorithm for solving the key equation and Horner's scheme for determining the...
report 1983
document
Slooff, J.W. (author)
An overview is provided of computational methods that can be used in solving the design problem of aerodynamics; i.e. the problem of finding the detailed shape of (parts of) configurations of which the gross geometric characteristics have already been determined in a preliminary, overall design process, and that, subject to certain constraints,...
report 1984
document
Koppenol, P.J. (author)
A computational method for solving the 3D Euler equations is studied. The method is based upon an upwind flux-difference splitting scheme by Osher, exhibiting an implicit mechanism for numerical viscosity, in connection with an explicit time-marching finite-volume technique. The computer program is developed to run efficiently on both a scalar...
report 1985
document
van Woerkom, P.T.L.M. (author)
Increases in size and mechanical complexity of spacecraft result in increased complexity of the mathematical model which describes the spacecraft dynamics. This results in turn in increased computational effort, in increased difficulties in understanding the characteristics of the spacecraft dynamics, and in increased difficulties in the design...
report 1985
document
de Pagter, P.J. (author), Renes, J.J. (author)
This report describes the results of a feasibility study on image data compression using spline approximation and image segmentation, with emphasis on earth observation applications. The main subjects dealt with, are: the data compression method, implementation aspects, the test software and test results. It appears that a reduction factor of 5...
report 1985
document
van den Dam, R.F. (author)
The central issue discussed in this paper is how a designer may profit from the use of mathematical simulation and optimization techniques. These techniques can be useful tools to support the designer in solving his design problem. The place and the potential of these techniques in the design process, as well as their use by the designer, are...
report 1985
document
Hounjet, M.H.L. (author)
A new method ARNSPNS is described for the calculation of steady and time-linearized unsteady incompressible potential flow about arbitrary lifting and nonlifting bodies in an arbitrary mean steady flow field, including rotation. The method belongs to the category of the so-called panel methods. Applications have been made to wind turbines...
report 1985
document
ten Have, A.A. (author)
Typical characteristics of various types of service loading are presented as they were discussed during the establishment of standardised test load sequences. Counting methods are reviewed and a simple and powerful algorithm is given to perform rainflow counting and to store the counting results afterwards. Synthesis procedures are discussed...
report 1987
document
de Reus, N.M. (author), Moek, G. (author), Olsder, G.J. (author)
A worldwide navigation system called NAVSAT is discussed. This positioning system is based on satellites which broadcast information which can be used by receivers of this Information to estimate their position. The motion of the users is modelled by splines. The estimation procedure is based on the extended Kalman filter approach.
report 1987
document
van Woerkom, P.T.L.M. (author), Guelman, M. (author)
Four well-known formalisms for mathematical modelling of the dynamics of a spacecraft/manipulator system are derived from the unifying d'Alembert principle. The Newton-Euler formalism is discussed in more detail, as it allows efficient numerical simulation. An algorithm is defined for the control of the manipulator end-effector motion in...
report 1987
document
Schippers, H. (author)
A description is given of TULIPS - a method for Transonic Unsteady Lifting Inviscid Potential-flow Simulation. The Mathematical formulation and the numerical approach are presented for flow about oscillating airfoils. TULIPS is based on the numerical integration of the unsteady full-potential equation in generalized coordinates. The equation is...
report 1988
document
van Woerkom, P.T.L.M. (author), Steenman, G.J.J. (author)
The objective of the study is the synthesis of an algorithm for the automatic control of an electromechanical actuator in the rotational joint of a multi-link, robotic manipulator. Control performance is assessed in terms of ability of the controlled joint to follow a commanded joint angle, or a commanded joint angular rate. Part One of the...
report 1988
document
Riks, E. (author), Merazzi, S. (author), de Boer, A. (author)
In many practical problems of plate and shell buckling, the pre-buckling state is linear and can be obtained from the linearized equations of elasticity. The computation of the buckling load and mode in such cases correponds to a linear eigenvalue problem that can easily be formulated and implemented in a finite element code. This report...
report 1988
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