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Vink, W.J. (author), de Jonge, J.B. (author)
The present report is part of a "Manual" on aircraft loads, that is being prepared by NLR. It contains a computer program, to be used in combination with "MATLAB4 for Windows" (Student Edition) software, to study aircraft loading due to turbulence. It includes a simple aircraft response model with two rigid and three flexible symmetric degrees...
report 1997
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Moek, G. (author)
In this report, the application of estimation theory to three problems from aerospace research is described. The applications considered deal with spacecraft attitude estimation, software reliability modelling and estimation, and with a satellite-based navigation algorithm. Maximum likelihood estimation is used in the software reliability case...
report 1991
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Roos, N. (author)
In this thesis, which consists of two parts, two different subjects are discussed. In the first part of the thesis a logic for reasoning with inconsistent knowledge will be described. The second part of the thesis contains a proposal for to view a reasoning process as a process of constructing a partial model of the world we are reasoning about....
report 1991
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van Woerkom, P.T.L.M. (author)
Numerical simulation of the dynamics of multi-body systems constitutes a central part in the design and analysis of modern space-based systems. The report focuses on the development of a recursive formulation of the dynamics of flexible spacecraft-robotmanipulator systems, suitable for efficient numerical simulation. The rather well-established...
report 1990
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Groothuizen, R.J.P. (author)
An inverse robot kinematics method is being developed that is to be applicable to any sequential rigid robot. In this report, first requirements are identified and a survey of existing methods is given. An. evaluation of these methods with respect to the requirements then shows that a method based on optimization is the best candidate. It...
report 1990
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Blom, H.A.P. (author)
Stochastic processes with a decision-directed control are considered as controlled Markov processes, the state space of which is hybrid; i.e. a product of a discrete set and a Euclidean space. This approach yields a mathematical model for many problems of decision-directed stochastic control. In general, the observations made from the "past" and...
report 1990
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van der Vooren, J. (author), van der Wees, A.J. (author)
The mathematical background is described of a method that is currently being developed at NLR to calculated wave drag in transonic potential flow. The method is a generalization and extension of Garabedian's and McFadden's idea of determining wave drag by volume-integration of the artificial viscosity. The generalization of Garabedian's and...
report 1990
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Spekreijse, S.P. (author), Venis, A.C.J. (author)
An efficient Roe-type flux-difference scheme for chemically reacting inviscid compressible flow in thermal equilibrium is presented. The numerical scheme is validated. Three well known chemical models are compared. The set of testcases concerned quasi one-dimensional hypersonic nozzle flows, with and without strong normal Shockwaves.
report 1990
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ten Dam, A.A. (author)
Numerical simulation of constrained dynamical systems is known to exhibit stability problems even when the unconstrained system can be simulated in a stable manner. We show that not the constraints themselves, but the transformation of a continuous set of equations to a discrete set of equations is the true source of the stability problem....
report 1990
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ten Dam, A.A. (author), Dieleman, P. (author)
This report describes the results of an evaluation of numerical integration schemes to be used for the digital simulation of second order ordinary differential equations (ODE's) which are characteristic for multibody systems such as space manipulators. The study focuses on dedicated schemes for this type of systems. Main attention is paid to the...
report 1990
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van Woerkom, P.T.L.M. (author)
The report contains the development of the dynamics equations of a spacecraftmanipulator system with chain topology. The spacecraft may be flexible. The attached manipulator consists of an arbitrary number of links, connected by single degree-of-freedom rotational joints. None, any, or all of the links may be flexible. A rigid or flexible...
report 1990
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van Woerkom, P.T.L.M. (author)
The report focuses on the mathematical modelling of the dynamics of spacecraft based manipulators displaying structural flexibility in their links. The equations of motion must be cast in a form suitable for efficient numerical simulation. Equations of motion found in literature are usually written in the form of an augmented system of...
report 1989
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Labrujère, T.E. (author)
A method is described, which is the result of further work on a measured boundary condition method developed at NLR, aiming at on-line application. The method requires a minimum of measured tunnel-wall pressures and applies a fast algorithm for the calculation of the wall interference. Some numerical test results are discussed.
report 1989
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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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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
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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
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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
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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
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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
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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
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