Utilizing flow rate and pressure data in and out of the mud circulation loop provides a driller with real-time trends for the early detection of well-control problems that impact the drilling efficiency. This paper pr...
详细信息
Utilizing flow rate and pressure data in and out of the mud circulation loop provides a driller with real-time trends for the early detection of well-control problems that impact the drilling efficiency. This paper presents state estimation for infinite-dimensional systems used in the process monitoring of oil well drilling. The objective is to monitor the key process variables associated with process safety by designing a model-based nonlinear observer that directly utilizes the available information coming from the continuous-time online process output measurements at the topside of the well. The observer consists of a copy of the plant plus output injection terms where the gain is computed analytically in terms of the Bessel function of the first kind. The design is tested using data from a real-field drilling commissioning test in the North Sea by Statoil Oil Company. The results show that the design estimates the flow and pressure accurately.
The problem of suppressing the slugging phenomenon is investigated. Industrial oil facilities such as gas-lifted wells and offshore production oil-risers are examples of systems where occurs such phenomenon. To study ...
详细信息
The problem of suppressing the slugging phenomenon is investigated. Industrial oil facilities such as gas-lifted wells and offshore production oil-risers are examples of systems where occurs such phenomenon. To study this problem, we consider that these systems are written as a set of 3 x 3 hyperbolic partial differential equations of balance laws, where the control variable appears at the boundary condition. By means of the characteristic coordinates approach, we deduce the stabilizing control law. The exponential stability of the equilibrium is proved by means of a Lyapunov stability analysis. Through simulation results, the method is shown effective in stabilizing the slugging phenomenon.
Reliable modeling and robust control of heat transfer processes are tasks with many applications in engineering. Such tasks are relevant, for example, in control of high-temperature fuel cells, in manufacturing of sem...
详细信息
Reliable modeling and robust control of heat transfer processes are tasks with many applications in engineering. Such tasks are relevant, for example, in control of high-temperature fuel cells, in manufacturing of semiconductor devices, control and modeling of welding processes, and for a reliable description of tube-like gas heater structures. For this reason, control-oriented modeling procedures for spatially distributed heating systems are described in this paper. The resulting models, derived from a spatial semi-discretization employing a finite volume modeling technique, are parameterized by means of experimental identification procedures. These models are then used for the design of robust controllers as well as for state and disturbance observers. An experimental validation on a test rig available at the Chair of Mechatronics at the University of Rostock concludes this paper.
Dynamics modelling and control design for elastic rods with distributedparameters are under study. The constitutive laws are specified by an integral equality according with the method of integro-differential relatio...
详细信息
Dynamics modelling and control design for elastic rods with distributedparameters are under study. The constitutive laws are specified by an integral equality according with the method of integro-differential relations. A numerical algorithm is developed to solve direct and inverse dynamic problems in linear elasticity based on the Ritz method and finite element technique. The control problem is to obtain the rod motion from some initial state to terminal one at a fixed time with the minimal mean energy. The exact solution is found with a specific triangular space-time mesh and a piecewise polynomial displacement input.
Consider a network with linear dynamics on the edges, and observation and control in the nodes. Assume that on the edges there is no damping, and so the dynamics can be described by an infinite-dimensional, port-Hamil...
详细信息
Consider a network with linear dynamics on the edges, and observation and control in the nodes. Assume that on the edges there is no damping, and so the dynamics can be described by an infinite-dimensional, port-Hamiltonian system. For general infinite-dimensional systems, the zero dynamics can be difficult to characterize and are sometimes ill-posed. However, for this class of systems the zero dynamics are shown to be well-defined. Using the underlying structure, simple characterizations and a constructive procedure can be obtained.
The state observation problem is tackled for a system of n coupled reaction-diffusion PDEs, possessing the same diffusivity parameter and equipped with boundary sensing devices. Particularly, a backstepping-based obse...
详细信息
The state observation problem is tackled for a system of n coupled reaction-diffusion PDEs, possessing the same diffusivity parameter and equipped with boundary sensing devices. Particularly, a backstepping-based observer is designed and the exponential stability of the error system is proven with an arbitrarily fast convergence rate. The transformation kernel matrix is derived in the explicit form by using the method of successive approximations, thereby yielding the observer gains in the explicit form, too. Simulation results support the effectiveness of the suggested design.
This paper presents the dynamic modeling and vibration control design of a floating wind turbine system. Two flexible mooring lines attached to a flexible wind turbine tower (taut-moored floating spar) are used to rep...
详细信息
ISBN:
(纸本)9781479999767
This paper presents the dynamic modeling and vibration control design of a floating wind turbine system. Two flexible mooring lines attached to a flexible wind turbine tower (taut-moored floating spar) are used to represent the dynamics of system. The wind turbine tower is modeled as an Euler-Bernoulli beam, and the mooring lines are modeled as two strings. The control laws are designed to suppress vibrations of both wind turbine tower and the mooring lines. Based on the construction of a physically motivated Lyapunov function, the bounded stability is proved with the proposed control. Numerical examples illustrate the performance of the control system.
A novel scheme for an optimal feedback-control of distributed parameter systems is proposed. Therefore, the optimal control problem for the two-dimensional incompressible Navier-Stokes-Equations with an actuation via ...
详细信息
ISBN:
(纸本)9781479978878
A novel scheme for an optimal feedback-control of distributed parameter systems is proposed. Therefore, the optimal control problem for the two-dimensional incompressible Navier-Stokes-Equations with an actuation via boundary-conditions is set up. Afterwards the Navier-Stokes-Equations and their adjoint equations are solved numerically. A model reduction is performed for both solutions using the POD-Galerkin procedure. The optimal feedback control is computed online from the reduced order models in each time step without need of further optimization. Results are shown for closed-loop simulations with the Navier-Stokes-Equations.
The present work proposes an extension of single-step feedback linearization with pole-placement formulation to the class of nonlinear hyperbolic systems. In particular, the mathematical formulation in the context of ...
详细信息
The present work proposes an extension of single-step feedback linearization with pole-placement formulation to the class of nonlinear hyperbolic systems. In particular, the mathematical formulation in the context of singular PDE theory is utilized via system of first order quasi-linear singular PDEs within the nonlinear hyperbolic PDE setting to obtain single step state nonlinear transformation and feedback control law with prescribed closed loop dynamics. The solution of quasi linear singular PDE is guaranteed by the Lyapunov's auxiliary theorem and locally invertible analytic transformation is applied by the full state feedback law to yield desired stable hyperbolic PDE system with assignable dynamics. The simultaneous state transformation and feedback linearization are realized in one step, avoiding the restrictions existing in other approaches.
A boundary control method for nonlinear partial differential equations (PDEs) is developed, with the use of differential flatness theory. First, following the procedure for numerical solution of nonlinear PDEs, it is ...
详细信息
A boundary control method for nonlinear partial differential equations (PDEs) is developed, with the use of differential flatness theory. First, following the procedure for numerical solution of nonlinear PDEs, it is shown that the PDE is equivalently represented by a set of nonlinear ordinary differential equations (ODEs) and an associated state equations model. For the local subsystems, into which a nonlinear PDE is decomposed, it becomes possible to apply boundary control. Next, the controller design proceeds by showing that the state-space model of the nonlinear PDE stands for a differentially flat system. Moreover, for each subsystem which is related to a nonlinear ODE, a virtual control input is computed, that can invert the subsystem's dynamics and can eliminate the subsystem's tracking error. From the last row of the state-space description, the control input (boundary condition) that is actually applied to the nonlinear PDE system is found. This control input contains recursively all virtual control inputs which were computed for the individual ODE subsystems associated with the previous rows of the state-space equation. Thus, by tracing the rows of the state-space model backwards, at each iteration of the control algorithm, one can finally find the control input that should be applied to the nonlinear PDE system so as to assure that all its state variables will converge to the desirable setpoints. By applying the proposed boundary control, it is shown that the nonlinear PDE dynamics can be made to track the designated variation profile.
暂无评论