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This paper deals with analysis and design of controllers for automatic control loops. The design of robust control systems and the examination of uncertain plant parameters will be carried out by graphical representation of controller and plant parameters.
Relay-type nonlinearities are studied and applied since the beginning of the automatic control era. They can be used to control a plant or to identify points of the frequency charateristic of the plant. In this paper, the idea of applying a relay for the estimation of a hard nonlinearity in the plant is introduced. Precisely, if the plant contains a relay-type nonlinearity. its value can be measured...
In this paper a microcontroller based digital control of an industrial application is presented. The positioning control of a ventilator piston in an artificial respiration device will be described. This new device will replace the old ventilator system which uses an analogous controller by a more modern one controlled by a microcontroller. In addition to hardware savings it is possible to get more...
In this paper a robust control design based on μ-Analysis and -Synthesis for a Thixoforming Process is presented. This process is a new manufacturing technology where metals are processed in their semi-solid state. To automate the process strict performance requirements have to be taken into consideration. The process model is characterized by strong nonlinearities and uncertain model parameters,...
This work deals with the design of a feedback control law for a mobile robot to follow a prescribed path. We present an original method based on a discrete linearization technique which allows to use some results from linear control analysis. By introducing piecewise constant variables we construct a new system close to the original one. We show that this new system can be put under normal form and...
A new generic optimal controller structure and regulator design method for linear systems are combined to form an iterative regulator refinement scheme, where the identification and control errors are identical. It is shown how a real nonlinear actuator limiting the amplitude of the control signal influences the control performances. Then the special modification of the original iterative scheme is...
We advance a method of pursuit for quasilinear control processes under conflict condition. This method is based on the use of Minkowski functions and their inverses which are constructed from multi-valued mappings connected with the original game problem. It is shown that this method justifies the rule of "parallel pursuit". well known in practice.
This paper develops a motion/force learning control scheme for constrained robot manipulators. The proposed algorithm is able to improve the performance of constrained end-effectors based on the previous operation as the action is repeated, it is very simple and computationally efficient. A sufficient condition is given to ensure the convergence of both motion control and force control. The simulation...
The paper discusses the problem of maximizing the torque of permanent magnet synchronous motors in the presence of voltage and current constraints. Formulas are given that are suitable to operation with voltage and current source inverters and to real-time computation. Generally, the available torque is limited by current constraints at low speeds and by voltage constraints at high speeds, but there...
It is shown how dry friction models can be incorporated into the design of a output trajectory tracking controller. The control is obtained by a numerical procedure which allows to computed the control based on the complete model. The approach is illustrated through the example of a flexible joint robot with joint friction.
We consider constructive methods of extension for a typical class of nonlinear optimal control problems, linear in control. A first order necessary optimality conditions for impulsive processes (Variational maximum principle) formulated. These conditions are used to research extremals and obtain the algorithms for solving optimal impulsive control problem iteratively.
In this paper, an innovative System Identification approach is applied in the frequency domain, where phasor measurements, as provided by frequency analyzers, are used. This algorithm is obtained through a careful analysis of the physics of the measurement situation, following which the machinery of minimum variance estimation is applied in a linear regression framework. This process renders an efficient...
Railned, a division of the national railway company in The Netherlands, is considering to improve and to partly automate planning procedures and control of the railway-network. It has asked CWI for advice on control. A hierarchical model is proposed with the levels of national railway network, traffic control district, and individual trains. At the level of traffic control district the optimal control...
This paper is concerned with predictive adaptive feedforward control from accessible disturbances, incorporating constraints in the manipulated variable variance. An algorithm, resulting from the modification of the MUSMAR controller, is presented. Its possible convergence points are characterized, using the ODE method for analysing stochastic recursive algorithms, as the local minima of the steady-state...
In this note we study new iterative projection methods for large linear dynamical systems. We show how simple preconditioning can produce accurate partial realizations for a system. For this purpose projector constructions based on the Eirola-Nevanlinna updating schemes for solving a linear equation are proposed. Different preconditioning techniques for effective calculation of projectors for dominant...
Problem of accurate control of steady-state of the linear time-invariant multivariable systems subject to bounded polyharmonic external disturbance and measurement noise of unknown frequencies and amplitudes is formulated. The way of its solution on the base of H∞ sub-optimal control with appropriate choice of weighting matrices of Riccati equations is proposed.
The main purpose of this work is to present four new packages in the computer algebra system MAPLE for analysis and synthesis of linear, time invariant, multi-variable systems. More specifically we examine a) the structure of rational matrices, b) the solution of ARMA-Representations, c) generalized state space representations of Polynomial Matrix Descriptions (PMDs) and d) solutions of diophantine...
A controller for solving the tracking problem of flexible robot arms with revolute joints is presented. In order to achieve this goal, the desired trajectory for the link (the flexible) coordinates is computed from the model of the robot arm. while the desired one for the joint (the rigid) coordinates can be assigned arbitrarily. The case of no structural damping is also considered.
In this paper we investigate the behavior of the discrete time AR (Auto Regressive) representations over a finite time interval, in terms of the finite and infinite spectral structure of the polynomial matrix involved in the AR-equation. A boundary mapping equation and a closed formula for the determination of the solution, in terms of the boundary conditions, are also given.
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