In this paper model reduction methods are used to obtain a nonlinear process model for designing a model predictive controller (MPC). The corresponding controller and its closed-loop response is then compared with con...
详细信息
In this paper model reduction methods are used to obtain a nonlinear process model for designing a model predictive controller (MPC). The corresponding controller and its closed-loop response is then compared with controllers that are determined from the original model and a linearized version of this model. The reduced dimensional nonlinear MPC controller performs almost as well as the nonlinear MPC controller that is based on the original model and considerably better than the linear MPC controller.
The prefilter based control relevant identification scheme proposed by Rivera et al.[14], for single input single output(SISO) system gives a model of the system which matches the true system in a range of frequencies...
详细信息
An iterative refinement approach is presented for designing a high performance control system for an imprecisely known plant. The design procedure involves the integration of identification and model predictive contro...
详细信息
An iterative refinement approach is presented for designing a high performance control system for an imprecisely known plant. The design procedure involves the integration of identification and model predictive control (MPC) using repeated closed-loop identification tests and successively improving the model (and ultimately, closed-loop performance) with each successive iteration. The method is appealing to industrial practice because real-time closed-loop data can be used directly to enhance the performance of a predictive controller without the need to deactivate the control loop during identification testing. The iterative refinement strategy is "plant-friendly" in that it tries to keep the identification test as short as possible while keeping the plant within operating limits and constraint. Constraint enforcement (on controlled, associated and manipulated variables) is naturally implemented through the use of MPC. The application of the method is demonstrated on a highly nonlinear diabatic (i.e., non-adiabatic) continuous stirred tank reactor problem.
An iterative refinement approach is presented for designing a high performance control system for an imprecisely known plant. The design procedure involves the integration of identification and model predictive contro...
详细信息
An iterative refinement approach is presented for designing a high performance control system for an imprecisely known plant. The design procedure involves the integration of identification and model predictive control (MPC) using repeated closed-loop identification tests and successively improving the model (and ultimately, closed-loop performance) with each successive iteration. The method is appealing to industrial practice because real-time closed-loop data can be used directly to enhance the performance of a predictive controller without the need to deactivate the control loop during identification testing. The iterative refinement strategy is "plant-friendly" in that it tries to keep the identification test as short as possible while keeping the plant within operating limits and contraints. Constraint enforcement (on controlled, associated and manipulated variables) is naturally implemented through the use of MPC. The application of the method is demonstrated on a highly nonlinear diabatic (i.e., nonadiabatic) continuous stirred tank reactor problem.
This paper describes the control design of a 1.5 MW free turbine with complex load. A nonlinear model of the engine with load has been developed within Simulink from details previously presented by Hill (1987). New pr...
详细信息
This paper describes the control design of a 1.5 MW free turbine with complex load. A nonlinear model of the engine with load has been developed within Simulink from details previously presented by Hill (1987). New predictive control technique, the so-called time varying weighting generalized predictive control (TGPC) is performed using a linearised model to represent the key components in the control design. The performance criteria are specified in terms of the stability margins, bandwidth and desired response of the engine to a severe load disturbance. The substantial change in system dynamics and the constraints on its manipulated variable (i.e. the throttle valve angle) offer a challenge to control engineers. Therefore, nonlinear simulations with parameter changes and full robustness/stability analysis are presented to support the conclusion that the design is robust/stable.
This paper is concerned with the design of predictive control without using the traditional dynamic model such as the state-space, input-output transfer function or step response model. The predictor or Kalman filter ...
详细信息
This paper is concerned with the design of predictive control without using the traditional dynamic model such as the state-space, input-output transfer function or step response model. The predictor or Kalman filter is obtained directly from the input/output experiment data. Certain matrices required by the predictor are calculated by decomposing data into past and future sections as used in the subspace identification method. Subspace approach eliminates the intermediate step of model structure selection such as model order and time-delay determination or truncation of the step response model in the identification stage, which simplifies the design procedure of the predictive controllers. However, subspace approach in its original form does not possess all important traditional predictive control features such as inclusion of an integrator for offset-free control, constraint handling, feedforward option and tuning of controllers through the disturbance model. These are several problems, among others, to be addressed in this paper. The proposed predictive controller is demonstrated on a pilot scale system.
The prefilter based open loop control-relevant identification scheme proposed for single input single output (SISO) systems by D.E. Rivera et al. (1992) is extended for multi input multi output (MIMO) systems using a ...
详细信息
The prefilter based open loop control-relevant identification scheme proposed for single input single output (SISO) systems by D.E. Rivera et al. (1992) is extended for multi input multi output (MIMO) systems using a multi input single output (MISO) structural framework. By selecting input output pair for control, the MIMO system is partitioned into individual SISO systems with the interacting branches acting on each SISO loop being treated as structured measured disturbances (in addition to the regular disturbance at each output). With this consideration, a methodology is proposed for design of separate prefilters for the individual channels, taking into account the performance specifications for each loop. The use of an uncorrelated set of inputs is proposed for obtaining accurate estimation of individual channel elements. The prefiltering for each individual loop has been shown to give good estimates of the control-relevant model for the direct as well as the interacting branches. Closed loop simulations, using decoupled internal model controllers, involving representative processes taken from the literature demonstrate the validity of the approach.
In this paper, a novel identification method, termed as latent variable least squares (LVLS) is introduced. LVLS describes linear steady-state process behavior by a reduced dimensional model. This is particularly usef...
详细信息
In this paper, a novel identification method, termed as latent variable least squares (LVLS) is introduced. LVLS describes linear steady-state process behavior by a reduced dimensional model. This is particularly useful for large-scale processes, which often present a considerable number of highly correlated process variables. Additionally, it is shown that LVLS can be utilized for process monitoring. In an application study on a real industrial process, it is shown that LVLS performs better than partial least squares, which is a competitive method that is similar in approach.
Guidelines for specifying design parameters for minimum crest factor multisine signals per the approach of Guillaume et al. are presented. These guidelines are evaluated for the identification of nonlinear process sys...
详细信息
Guidelines for specifying design parameters for minimum crest factor multisine signals per the approach of Guillaume et al. are presented. These guidelines are evaluated for the identification of nonlinear process systems. The minimum crest factor multisine signals offer some distinct advantages over both Schroeder phased multisine signals and m-level Pseudo-Random Sequence (m-level PRS) signals with respect to "plant-friendliness" considerations. These signals can be used to reduce the effects of nonlinearity in obtaining an empirical transfer function estimate (ETFE). As an example, the ETFE of a Rapid Thermal Processing (RTP) reactor simulation is constructed. "Plant-friendly" issues are also discussed and illustrated in the identification and control of a CSTR simulation via "Model-on-Demand" estimation. This provides a compelling example, since the "Model-on-Demand" estimator is a data-driven nonlinear identification approach.
作者:
D.E. RiveraM.E. FloresDepartment of Chemical
Bio and Materials Engineering and Control Systems Engineering Laboratory Manufacturing Institute Arizona State University Tempe Arizona 85287-6006 phone:(480)-965-9476
This paper describes efforts at Arizona State University to introduce substantive topics in system identification to undergraduate chemicalengineering students. Specifically, the paper focuses on how system identific...
详细信息
This paper describes efforts at Arizona State University to introduce substantive topics in system identification to undergraduate chemicalengineering students. Specifically, the paper focuses on how system identification issues relevant to industrial practice have been incorporated into a simulated gas-oil furnace experiment that is part of a senior-level process dynamics and control course (ChE 461).
暂无评论