The combination of formal power series and appropriate summability methods is considered for the inversion of the non-linear, distributed-parameter model of a boundary controlled tubular reactor. The inversion is perf...
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The combination of formal power series and appropriate summability methods is considered for the inversion of the non-linear, distributed-parameter model of a boundary controlled tubular reactor. The inversion is performed in order to realize the tracking of certain prescribed output trajectories in open-loop control. Simulation results illustrate the applicability of the design approach for the example of finite-time transitions between set-points for a tubular bioreactor.
Modern fire-rescue turntable ladders are constructed in a lightweight mode to increase their maximum operation velocities, maximum length, and outreach respectively. Hence, the ladder has a limited stiffness and will ...
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Modern fire-rescue turntable ladders are constructed in a lightweight mode to increase their maximum operation velocities, maximum length, and outreach respectively. Hence, the ladder has a limited stiffness and will be more and more subject to oscillations of deflection along with dominant overtones. This paper deals with the active oscillation damping of such ladders. A new feedforward and feedback control strategy is applied. The feedforward control is calculated through system inversion of a multi-body system utilizing its differentially flatness. The design of the feedback is based on partial differential equations (PDE) describing a Euler– Bernoulli model of a beam with a concentrated point mass at the end. The modal representation of the system is constructed based on the analytical form of the eigenfunctions. For active oscillation damping by feedback without a dynamical observer the ladder was equipped with a gyroscope additionally to strain gauges. Due to computational efforts and measurement noise a reduced state vector is disposed for stabilization. The proposed control approach allows damping the fundamental oscillation as well as the first dominant overtone and asymptotically stabilizing the system around the reference trajectory. Measurement results from the IVECO DLK 55 CS fire-rescue turntable ladder validate the good performance of the control.
It is well known that a Schur-class function S (contractive operator-valued function on the unit disk) can be realized as the transfer function S(z) = D + zC(I - zA)(-1) B of a conservative discrete-time linear system...
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It is well known that a Schur-class function S (contractive operator-valued function on the unit disk) can be realized as the transfer function S(z) = D + zC(I - zA)(-1) B of a conservative discrete-time linear system (x(n + 1) = Ax(n) + Bu(n), y(n) = Cx(n) + Du(n) with U = [(A)(B)(C)(D)] unitary). One method of proof of this result (the "lurking isometry" method) identifies a solution U of the problem as a unitary extension of a partially defined isometry V determined by the problem data. Reformulated in terms of the graphs of V and U, solutions are identified with embeddings of an isotropic subspace of a certain Krein space K constructed from the problem data into a Lagrangian subspace (maximal isotropic subspace of K). The contribution here is the observation that this reformulation applies to other types of realization problems as well, e.g., realization of positive-real or J-contractive operator-valued functions over the unit disk (respectively over the right half plane) as the transfer function of a discrete-time (respectively, continuous-time) conservative system, i.e., an input-state- output system for which there is a quadratic storage function on the state space for which all system trajectories satisfy an energy-balance equation with respect to the appropriate supply rate on input-output pairs. The approach allows for unbounded state dynamics, unbounded input/output operators and descriptor-type state-space representations where needed in a systematic way. These results complement recent results of Arov-Nudelman, Hassi-de Snoo-Tsekanovskii, Belyi-Tsekanovskii and Staffans and fit into the behavioral frameworks of Trentelman-Willems and Georgiou-Smith.
This paper proposes a method for the on-line determination of the concentration profiles in a Simulated Moving Bed (SMB) process in terms of discrete measurement values. A direct solution of this state observation pro...
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The paper deals with different pipeline models and their simulation. First, a nonlinear distributedparameters model is derived, which is then linearised and its transfer function is obtained by a Laplace transformati...
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The paper deals with different pipeline models and their simulation. First, a nonlinear distributedparameters model is derived, which is then linearised and its transfer function is obtained by a Laplace transformation and corresponding initial and boundary conditions. The pipeline is represented as a two-port system. Four representations are presented and two of them - the hybrid ones which are used in practice-are studied further. They involve three different transcendent transfer functions which are then approximated by rational transfer functions using a Pade approximation. The derived models describe the pipeline as a lumped parametersystem. Due to the approximation of the high frequency gain, the derived models are only valid for a class of models - namely well damped pipelines. The derived models were comparatively verified on the basis of the measurements on a real pipeline. (C) 2000 IMACS/Elsevier Science B.V. All rights reserved.
This paper presents a class of asymptotically stable end-point regulators for a flexible SCARA/Cartesian robot. Firstly, the closed-loop stability is proven for the original distributed-parameter system;then, through ...
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This paper presents a class of asymptotically stable end-point regulators for a flexible SCARA/Cartesian robot. Firstly, the closed-loop stability is proven for the original distributed-parameter system;then, through explicitly solving the partial differential equations (PDE's) of the system, asymptotic stability is obtained for the undamped truncated system, in which the distributed flexibility of the robot link is represented by an arbitrary finite number of flexible modes. The controllers possess some attractive advantages for practical applications. computer simulations are provided to illustrate the effectiveness of the approach.
An investigation has been undertaken in order to understand the evolution of particle size distributions during suspension polymerization. Experiments have shown that the interplay of breakage and coalescence phenomen...
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An investigation has been undertaken in order to understand the evolution of particle size distributions during suspension polymerization. Experiments have shown that the interplay of breakage and coalescence phenomena with the change in viscosity and interfacial tension due to reaction may cause the appearance of both bimodal and unimodal distributions during the course of the reaction. A detailed model based on a population balance coupled with the polymerization kinetics has been developed in order to describe the experimental data.
This paper deals with the concept of substrate absorption rate measurement. This parameter seems to be essentially important for monitoring and controlling of every biotechnological process. Considering the plug-flow ...
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This paper deals with the concept of substrate absorption rate measurement. This parameter seems to be essentially important for monitoring and controlling of every biotechnological process. Considering the plug-flow distributedparameter bioreactor (working as a part of waste water treatment plant) as a 'true' bacterial system, theoretical approach to the substrate consumption rate is given and the concept of obtaining this parameter value is proposed. Measuring of the substrate concentration at some point located along the bioreactor tube (without applying further identification methods) allows to approximate current value of desired parameter very successfully. Moreover, the total mass of the substrate consumed in bioreactor may be easily calculated basing on the substrate consumption rate value. It allows to perform the optimal control of considered process.
Based on a distributed-parameter model, a tentative attempt is presented to improve the algorithm in the software of continuous rolling process control. In this paper, the new algorithm of dynamic parameters is more s...
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Based on a distributed-parameter model, a tentative attempt is presented to improve the algorithm in the software of continuous rolling process control. In this paper, the new algorithm of dynamic parameters is more simple in constitution than before. Conserned with protection the coordinated control of driving system is discussed. For overcome the influence of roll eccentricity, the optimal tracking of gauge control is given, and the simulative calculation shows that it has a strong reproduced ability for linear combination of step, ramp and sine. Furthermore, the temperature evaluation and fine adjustment are expounded briefly.
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