Based on inverse transient analysis method, the identification calculation was performed by minimizing the inverse least square problem representing the difference between the measured and predicted transient response...
详细信息
Based on inverse transient analysis method, the identification calculation was performed by minimizing the inverse least square problem representing the difference between the measured and predicted transient response in the waxy oil pipeline. And Levenberg-Marquardt method was adopted to optimize the friction factors. The hydraulic transient was modeled using MOC. The Jacobian matrix of the friction factor's sensitivity was obtained by direct differentiation of the method of characteristic equations. By means of an example, the errors between the measured values and the calculated values of the middle point on the waxy oil pipeline were compared. The calculated values were solved by means of average, formular and identification friction factors. The results show that the identification method has good evaluation for the internal state variables. Identification basing on inverse transient method can be used to improve the accuracy of simulation and control with pipelines.
A flow reversal reactor for VOC combustion is controlled by the linear quadratic regulator (LQR), which uses dilution and internal electric heating as controls to confine the hot spot temperature within the two temper...
详细信息
A flow reversal reactor for VOC combustion is controlled by the linear quadratic regulator (LQR), which uses dilution and internal electric heating as controls to confine the hot spot temperature within the two temperature limits, in order to ensure complete conversion of the VOC and to prevent overheating of the catalyst. Three phases of operation, i.e., dilution phase, heating phase and inactive phase, are identified. In dilution and heating phases, the cost functions of the LQR control are defined in quadratic forms. In the inactive phase, the controllers are inactivated. A linear model is derived by linearization of a countercurrent pseudo-homogeneous model at two nominal operating conditions in the dilution phase and the heating phase, respectively. The feed concentration and the temperature profile are estimated on-line by using a high-gain observer with three temperatures measurements and are used in the LQR feedback control. Experiments are carried out on a medium-scale reversed flow reactor to demonstrate the proposed LQR control strategy. Results show that the LQR controller is highly efficient in maintaining normal operation of the reactor. (C) 2004 Elsevier Ltd. All rights reserved.
This paper is devoted to the multiple input multiple output (MIMO) model predictive control (MPC) of a catalytic reverse flow reactor (RFR). The RFR aims to reduce, by catalytic reaction, the amount of volatile organi...
详细信息
This paper is devoted to the multiple input multiple output (MIMO) model predictive control (MPC) of a catalytic reverse flow reactor (RFR). The RFR aims to reduce, by catalytic reaction, the amount of volatile organic compounds (VOCs) released in the atmosphere. The peculiarity of this process is that the gas flow inside the reactor is periodically reversed in order to trap the heat released during the reaction. The objective of this paper is to propose a solution to avoid the limitation seen in a previous study for the single input single output (SISO) control case. It was dealing with the impossibility to avoid degradation of the catalytic elements due to the excessive heating induced by the exothermic reaction. In order to overcome this issue, a ratio of the inlet (cold) gas flow is now bypassed into the central zone. This allows introducing a second manipulated variable: the dilution rate. The phenomenological model considered here for the MIMO MPC of the RFR is obtained from a rigorous first principles modeling. The resulting accurate nonlinear partial differential equation (PDE) model can be a drawback for the model based controller implementation. To overcome this issue, we use a MPC strategy previously developed: it combines a two phase approximation of the PDE model in an internal model control (IMC) structure. This strategy allows using a less accurate model and a less time-consuming control algorithm. Finally, efficiency of the control approach is shown in simulation. (C) 2004 Elsevier Ltd. All rights reserved.
The rest-to-rest maneuver of a single-link flexible manipulator using the geometrically exact nonlinear beam model is considered. It is shown that, with the joint torque only, a simple linear feedback law derived base...
详细信息
The rest-to-rest maneuver of a single-link flexible manipulator using the geometrically exact nonlinear beam model is considered. It is shown that, with the joint torque only, a simple linear feedback law derived based on a Lyapunov-type method stabilizes the highly nonlinear coupled system described by a set of integro-partial differential equations with coupled nonlinear boundary conditions.
暂无评论