In this technical note, we develop a full state feedback law for disturbance rejection in systems described by linear 2 x 2 partial differential equations of the hyperbolic type, with the disturbance modelled as an au...
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In this technical note, we develop a full state feedback law for disturbance rejection in systems described by linear 2 x 2 partial differential equations of the hyperbolic type, with the disturbance modelled as an autonomous, finite dimensional linear system affecting the PDE's left boundary, and actuation limited to the right boundary. The effect of the disturbance is rejected at an arbitrary point in the domain within a finite time. The performance is demonstrated through simulation.
In this paper, we derive new readily testable criteria for exponential stabilizability, approximate controllability, and exact controllability for multiplicative systems arising from linear partial differential equati...
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In this paper, we derive new readily testable criteria for exponential stabilizability, approximate controllability, and exact controllability for multiplicative systems arising from linear partial differential equations on an infinite domain. These multiplicative systems have an unbounded semigroup generator, but bounded input and output operators. The theoretical results are illustrated by several examples. In particular, explicit, easily verifiable conditions for exponential stabilizability, approximate and exact controllability are given for second-order P.D.E. systems. Dual results for exponential detectability, approximate and exact observability are also included.
We focus on shaping the long-term spatiotemporal dynamics of transport-reaction processes which can be described by semi-linear partial differential equations (PDEs). The dynamic shaping problem is addressed via error...
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We focus on shaping the long-term spatiotemporal dynamics of transport-reaction processes which can be described by semi-linear partial differential equations (PDEs). The dynamic shaping problem is addressed via error dynamics regulation between the governing PDE and a target PDE which describes the desired spatiotemporal behavior. A model order reduction methodology is utilized to construct the required reduced order models (ROMs) for governing and target dynamics via Galerkin's method. We subtract the governing from the target ROMs to obtain reduced offset dynamics error. Then an output feedback sliding mode control structure is synthesized to stabilize the reduced error dynamics and correspondingly synchronize the system and the target spatiotemporal behaviors. A Luenberger-type dynamic observer is applied to estimate the states of the governing ROM required by the sliding mode controller. The proposed approach is applied to address the thermal spatiotemporal dynamic shaping problem in a tubular chemical reactor. (C) 2015 Elsevier Ltd. All rights reserved.
Uniform exponential stability of the time varying singular distributedparameter system is discussed in the light of GE 0 - semigroup theory and GE mild evolution operators in Hilbert space. The necessary and suffici...
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Uniform exponential stability of the time varying singular distributedparameter system is discussed in the light of GE 0 - semigroup theory and GE mild evolution operators in Hilbert space. The necessary and sufficient conditions concerning the exponential stability are given.
This paper considers the adaptive estimation of parabolic partial differential equations with boundary control and observation. Structured perturbations enter at the boundary and are collocated either with the control...
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ISBN:
(纸本)9781467386838
This paper considers the adaptive estimation of parabolic partial differential equations with boundary control and observation. Structured perturbations enter at the boundary and are collocated either with the control or the measurement. Various combinations of boundary control, observation and structured perturbations are considered and viewed as evolution equations in a Hilbert space via the use of Dirichlet maps. When certain conditions are met, the systems can utilize results on the adaptive estimation of positive real infinite dimensional systems. Extensive simulation studies of 1D parabolic partial differential equation with the structured perturbation collocated either with the input or the output operator are presented to demonstrate the utilization of results on adaptive estimation of positive real infinite dimensional systems for diffusion PDEs.
Methods for the careful design of optimal experiments for the identification of the structure and parameters of transport models often strongly depend on a-priori knowledge about the unknown model. However, this kind ...
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Methods for the careful design of optimal experiments for the identification of the structure and parameters of transport models often strongly depend on a-priori knowledge about the unknown model. However, this kind of knowledge is usually poor for complex systems. We propose a novel procedure that is less sensitive with respect to poor a-priori knowledge;it relies on an optimization problem to maximize the information content of the measurement data for the purpose of model identification. Specifically, based on existing model-based methods, optimal design of experiments is addressed in the context of three-dimensional, time-dependent transport problems by introducing experiment design variables and the transport coefficient as degrees of freedom of the optimization. The problem is solved by means of an iterative strategy that - by sequentially designing a series of experiments - strives to adjust the settings of the experimental conditions by exploiting the results from previous experiments. The key methodical ingredient of the novel procedure is the use of incremental model identification introduced previously. The suggested procedure is illustrated by means of an extensive numerical case study for a convection-diffusion equation originating from the modeling and simulation of energy transport in laminar wavy film flow. (C) 2015 Elsevier Ltd. All rights reserved.
In this brief, we explore the use of conformal mapping theory to reduce the complexity in PDE backstepping boundary observer design. The technique is applied to a genetic analysis microchip that features a collocated ...
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In this brief, we explore the use of conformal mapping theory to reduce the complexity in PDE backstepping boundary observer design. The technique is applied to a genetic analysis microchip that features a collocated sensor-actuator architecture in which the temperature of the reaction chamber is the spatially distributed control variable. The size and structure of the microchip do not allow for sensor placement within the reaction chamber, making temperature estimation mandatory. The PDE backstepping boundary observer design is chosen to provide real-time data from the temperature inside the microchip. The standard PDE backstepping boundary observer design results in a partial differential equation for the kernel function with double the spatial dimension of the original problem, which makes the design intractable for the problems with dimensions higher than one. We show that the spatial domain of the original problem can be reduced with the use of the conformal mapping. The resulting observer is tested and experimentally validated, shown excellent performance with respect to the spacial L2 norm of the estimation error.
Flow control has the potential to mitigate concentration polarization and fouling in membrane systems by enhancing mixing near the membrane surface. Although Computational Fluid Dynamics (CM) modeling has been used to...
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Flow control has the potential to mitigate concentration polarization and fouling in membrane systems by enhancing mixing near the membrane surface. Although Computational Fluid Dynamics (CM) modeling has been used to study the effect of externally induced unsteady flow on mass transfer enhancement, the analysis based on CM results is computationally expensive and cannot be performed systematically. Existing systematic approaches to quantify mixing enhancement only consider hydrodynamics but not the direct effect on mass transfer improvement, due to the difficulties caused by the non spatially invariant nature of the mass transfer phenomenon. This paper presents a reduced order model that combines the discretized mass transfer and linearized Navier-Stokes partial differential equations. The proposed model can be used to simulate and systematically analyze mass transfer enhancement caused by the flow induced by a pair of electrodes. When the Reynolds number and temporal frequency of the external field are low (Re < 2000), the effect of a forced wall slip velocity on the overall flow profile in a 2D channel can be approximated by its instantaneous component. This allows mass transfer enhancement to be analyzed explicitly using a discretized mass transfer equation. The results predicted by the reduced order model are in good agreement with CFD simulations. The benefit of the proposed reduced order model is demonstrated by the frequency response analysis to identify the temporal frequency that has the maximum effect on mass transfer enhancement. (C) 2014 Elsevier Ltd. All rights reserved.
We consider the stabilization of nonlinear ODE systems with actuator dynamics modeled by a wave PDE whose boundary is moving and is a function of time and of the ODE's state. Such a problem is inspired by applicat...
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We consider the stabilization of nonlinear ODE systems with actuator dynamics modeled by a wave PDE whose boundary is moving and is a function of time and of the ODE's state. Such a problem is inspired by applications in oil drilling where the position of the drill bit is a state variable in the ODE modeling the friction-dominated drill bit dynamics while at the same time being the position of the moving boundary of the wave PDE that models the distributed torsional dynamics of the drillstring. For moving boundaries that depend only on time, we extend the global result recently developed by Bekiaris-Liberis and Krstic for constant boundaries. For moving boundaries that also depend on the ODE's state, we develop a local result where the initial condition is restricted in such a way that it is ensured that the rate of movement of the boundary (both leftward' and rightward') is bounded by unity in closed-loop. For strict-feedforward systems under wave actuator dynamics with moving boundaries, the predictor-based feedback laws are obtained explicitly. The feedback design is illustrated through an example. Copyright (c) 2013 John Wiley & Sons, Ltd.
In this paper, we design a boundary control law and an observer for a flexible string system with external disturbance and input backlash. A novel `disturbance-like' term is put forward to cancel the effect of inp...
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ISBN:
(纸本)9781467386838
In this paper, we design a boundary control law and an observer for a flexible string system with external disturbance and input backlash. A novel `disturbance-like' term is put forward to cancel the effect of input backlash nonlinearity. Under the proposed control, we show that the transverse deflection is regulated effectively despite of the existence of external disturbance. The control parameters are chosen to ensure the control performance of the system. Simulations are provided to verify the effectiveness of the proposed control scheme.
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