A support vector machine with guadratic polynomial kernel function based nonlinear model multi-step-ahead optimizing predictive controller was presented. A support vector machine based predictive model was established...A support vector machine with guadratic polynomial kernel function based nonlinear model multi-step-ahead optimizing predictive controller was presented. A support vector machine based predictive model was established by black-box identification. And a quadratic objective function with receding horizon was selected to obtain the controller output. By solving a nonlinear optimization problem with equality constraint of model output and boundary constraint of controller output using Nelder-Mead simplex direct search method, a sub-optimal control law was achieved in feature space. The effect of the controller was demonstrated on a recognized benchmark problem and a continuous-stirred tank reactor. The simulation results show that the multi-step-ahead predictive controller can be well applied to nonlinear system, with better performance in following reference trajectory and disturbance-rejection.展开更多
Dual-point composition control for a high-purity ideal heat integrated distillation column (HIDiC) is addressed in this work. Three measures are suggested and combined for overcoming process inherent nonlinearities:(1...Dual-point composition control for a high-purity ideal heat integrated distillation column (HIDiC) is addressed in this work. Three measures are suggested and combined for overcoming process inherent nonlinearities:(1) variable scaling; (2) multi-model representation of process dynamics and (3) feedforward compensation. These strategies can offer the developed control systems with several distinct advantages: (1) capability of dealing with severe disturbances; (2) tight tuning of controller parameters and (3) high robustness with respect to variation of operating conditions. Simulation results demonstrate the effectiveness of the proposed methodology.展开更多
Proportion integral differential generalized predictive control(PID-GPC), a new type of generalized predictive control(GPC) is introduced, and its quality is analyzed with internal model control (IMC). A very importan...Proportion integral differential generalized predictive control(PID-GPC), a new type of generalized predictive control(GPC) is introduced, and its quality is analyzed with internal model control (IMC). A very important characteristic, which distinguishes GPC from ordinary IMC, and the robust effect are found. At the same time, a robust region is obtained according to the control laws, so that the defect that the robust analysis could be carried out only with stable models is overcome. It is verified that the robustness of PID-GPC is stronger than general GPC.展开更多
An iterative learning model predictive control （ILMPC） technique is applied to a class of continuous/batch processes. Such processes are characterized by the operations of batch processes generating periodic strong ...An iterative learning model predictive control （ILMPC） technique is applied to a class of continuous/batch processes. Such processes are characterized by the operations of batch processes generating periodic strong disturbances to the continuous processes and traditional regulatory controllers are unable to eliminate these periodic disturbances. ILMPC integrates the feature of iterative learning control （ILC） handling repetitive signal and the flexibility of model predictive control （MPC）. By on-line monitoring the operation status of batch processes, an event-driven iterative learning algorithm for batch repetitive disturbances is initiated and the soft constraints are adjusted timely as the feasible region is away from the desired operating zone. The results of an industrial application show that the proposed ILMPC method is effective for a class of continuous/batch processes.展开更多
Wave breaking is an important process that controls turbulence properties and fluxes of heat and mass in the upper oceanic layer.A model is described for energy dissipation per unit area at the ocean surface attribute...Wave breaking is an important process that controls turbulence properties and fluxes of heat and mass in the upper oceanic layer.A model is described for energy dissipation per unit area at the ocean surface attributed to wind-generated breaking waves,in terms of ratio of energy dissipation to energy input,windgenerated wave spectrum,and wave growth rate.Also advanced is a vertical distribution model of turbulent kinetic energy,based on an exponential distribution method.The result shows that energy dissipation rate depends heavily on wind speed and sea state.Our results agree well with predictions of previous works.展开更多
Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinea...Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.展开更多
Operation optimization is an effective method to explore potential economic benefits for existing plants. The m.aximum potential benefit from operationoptimization is determined by the distances between current operat...Operation optimization is an effective method to explore potential economic benefits for existing plants. The m.aximum potential benefit from operationoptimization is determined by the distances between current operating point and process constraints, which is related to the margins of design variables. Because of various ciisturbances in chemical processes, some distances must be reserved for fluctuations of process variables and the optimum operating point is not on some process constraints. Thus the benefit of steady-state optimization can not be fully achied（ed while that of dynamic optimization can be really achieved. In this study, the steady-state optimizationand dynamic optimization are used, and the potential benefit-is divided into achievable benefit for profit and unachievable benefit for control. The fluid catalytic cracking unit （FCCU） is used for case study. With the analysis on how the margins of design variables influence the economic benefit and control performance, the bottlenecks of process design are found and appropriate control structure can be selected.展开更多
Electric product house of magnesium alloy sheet is usually obtained by warm stamping owing to its poor plasticity and formability at room temperature.The formability of AZ31B magnesium alloy sheet can be improved by r...Electric product house of magnesium alloy sheet is usually obtained by warm stamping owing to its poor plasticity and formability at room temperature.The formability of AZ31B magnesium alloy sheet can be improved by repeated unidirectional bending(RUB)process through control of(0002)basal texture.Compared with as-received sheet,the Erichsen value(IE)of the sheet underwent RUB process increases to 5.90 from 3.53 at room temperature.It is also confirmed that cell phone houses could be stamped successfully in crank press with AZ31B magnesium alloy sheets underwent RUB process.It provides an alternative to the electronics industry in the application of magnesium alloys.展开更多
Lung cancer is one of the most common malignant tumors in the world. Non-small cell lung cancer （NSCLC） accounts for approximately 80% of lung cancer cases, and approximately 75% of patients are diagnosed in the mid...Lung cancer is one of the most common malignant tumors in the world. Non-small cell lung cancer （NSCLC） accounts for approximately 80% of lung cancer cases, and approximately 75% of patients are diagnosed in the middle and late stages. The treatment methods mainly include surgery, chemotherapy, radiotherapy, molecular targeted therapy, traditional Chinese medicine therapy, and immune therapy. We summarize the current status of lung cancer-related treatment options and targets.展开更多
By taking advantage of the separation characteristics of nonlinear gain and dynamic sector inside a Hammerstein model, a novel pole placement self tuning control scheme for nonlinear Hammerstein system was put forward...By taking advantage of the separation characteristics of nonlinear gain and dynamic sector inside a Hammerstein model, a novel pole placement self tuning control scheme for nonlinear Hammerstein system was put forward based on the linear system pole placement self tuning control algorithm. And the nonlinear Hammerstein system pole placement self tuning control(NL-PP-STC) algorithm was presented in detail. The identi fication ability of its parameter estimation algorithm of NL-PP-STC was analyzed, which was always identi fiable in closed loop. Two particular problems including the selection of poles and the on-line estimation of model parameters, which may be met in applications of NL-PP-STC to real process control, were discussed. The control simulation of a strong nonlinear p H neutralization process was carried out and good control performance was achieved.展开更多
This paper proposes a decoupling control scheme with two-degrees-of-freedom (2DOF) control structure. In the proposed scheme, two multivariable controllers are designed based on Internal Model Control (IMC) theory for...This paper proposes a decoupling control scheme with two-degrees-of-freedom (2DOF) control structure. In the proposed scheme, two multivariable controllers are designed based on Internal Model Control (IMC) theory for setpoint tracking and disturbance rejection independently. An analytical approximation method is utilized to reduce the order of the controllers. By adjusting the corresponding controller parameter, the setpoint tracking and disturbance rejection of each control loop can be tuned independently. In the presence of multiplicative input uncertainty, a calculation method is also proposed to derive the low bounds of the control parameters in order to guarantee the robust stability of the system. Simulations are illustrated to demonstrate the validity of the proposed control scheme.展开更多
The course-keeping control of underactuated hovercraft with two aft propellers was considered. The control of the heading error and cross-track error was accomplished by the yaw torque merely in this case. The hovercr...The course-keeping control of underactuated hovercraft with two aft propellers was considered. The control of the heading error and cross-track error was accomplished by the yaw torque merely in this case. The hovercraft dynamic model is nonlinear and underactuated. At first the Controllability of course-keeping control for hovercraft was proved, then a course-keeping control law was derived that keeps hovercraft heading constant as well as minimizes the lateral movement of hovercraft. The proposed law guarantees heading error and sway error all converge to zero exponentially. Simulation tests were carried out to illustrate the effectiveness of the proposed control law. For further research, the disturbance influence would be considered in the dynamic equations.展开更多
文摘A support vector machine with guadratic polynomial kernel function based nonlinear model multi-step-ahead optimizing predictive controller was presented. A support vector machine based predictive model was established by black-box identification. And a quadratic objective function with receding horizon was selected to obtain the controller output. By solving a nonlinear optimization problem with equality constraint of model output and boundary constraint of controller output using Nelder-Mead simplex direct search method, a sub-optimal control law was achieved in feature space. The effect of the controller was demonstrated on a recognized benchmark problem and a continuous-stirred tank reactor. The simulation results show that the multi-step-ahead predictive controller can be well applied to nonlinear system, with better performance in following reference trajectory and disturbance-rejection.
基金Supported by the New-Energy and Industry Technology Development Organization (NEDO) through the Energy Conservation Center of Japan.
文摘Dual-point composition control for a high-purity ideal heat integrated distillation column (HIDiC) is addressed in this work. Three measures are suggested and combined for overcoming process inherent nonlinearities:(1) variable scaling; (2) multi-model representation of process dynamics and (3) feedforward compensation. These strategies can offer the developed control systems with several distinct advantages: (1) capability of dealing with severe disturbances; (2) tight tuning of controller parameters and (3) high robustness with respect to variation of operating conditions. Simulation results demonstrate the effectiveness of the proposed methodology.
基金Supported by the National Science & Technology Key Project(No. 2001BA204B01-02), the National Natural Science Foundation of China (No. 60174021) and the Key Project of Tianjin Natural Science Foundation(No. 013800711).
文摘Proportion integral differential generalized predictive control(PID-GPC), a new type of generalized predictive control(GPC) is introduced, and its quality is analyzed with internal model control (IMC). A very important characteristic, which distinguishes GPC from ordinary IMC, and the robust effect are found. At the same time, a robust region is obtained according to the control laws, so that the defect that the robust analysis could be carried out only with stable models is overcome. It is verified that the robustness of PID-GPC is stronger than general GPC.
基金Supported by the National Creative Research Groups Science Foundation of China （60721062） and the National High Technology Research and Development Program of China （2007AA04Z162）.
文摘An iterative learning model predictive control （ILMPC） technique is applied to a class of continuous/batch processes. Such processes are characterized by the operations of batch processes generating periodic strong disturbances to the continuous processes and traditional regulatory controllers are unable to eliminate these periodic disturbances. ILMPC integrates the feature of iterative learning control （ILC） handling repetitive signal and the flexibility of model predictive control （MPC）. By on-line monitoring the operation status of batch processes, an event-driven iterative learning algorithm for batch repetitive disturbances is initiated and the soft constraints are adjusted timely as the feasible region is away from the desired operating zone. The results of an industrial application show that the proposed ILMPC method is effective for a class of continuous/batch processes.
基金Supported by the National Natural Science Foundation of China(Nos. 40876013,40906008,41176011,41106012,and U0933001) and GDUPS(2010)
文摘Wave breaking is an important process that controls turbulence properties and fluxes of heat and mass in the upper oceanic layer.A model is described for energy dissipation per unit area at the ocean surface attributed to wind-generated breaking waves,in terms of ratio of energy dissipation to energy input,windgenerated wave spectrum,and wave growth rate.Also advanced is a vertical distribution model of turbulent kinetic energy,based on an exponential distribution method.The result shows that energy dissipation rate depends heavily on wind speed and sea state.Our results agree well with predictions of previous works.
文摘Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.
基金Supported by the National Natural Science Foundation of China(21006127)the National Basic Research Program of China(2012CB720500)the Science Foundation of China University of Petroleum(KYJJ2012-05-28)
文摘Operation optimization is an effective method to explore potential economic benefits for existing plants. The m.aximum potential benefit from operationoptimization is determined by the distances between current operating point and process constraints, which is related to the margins of design variables. Because of various ciisturbances in chemical processes, some distances must be reserved for fluctuations of process variables and the optimum operating point is not on some process constraints. Thus the benefit of steady-state optimization can not be fully achied（ed while that of dynamic optimization can be really achieved. In this study, the steady-state optimizationand dynamic optimization are used, and the potential benefit-is divided into achievable benefit for profit and unachievable benefit for control. The fluid catalytic cracking unit （FCCU） is used for case study. With the analysis on how the margins of design variables influence the economic benefit and control performance, the bottlenecks of process design are found and appropriate control structure can be selected.
基金Project(50504019)supported by the National Natural Science Foundation of ChinaProject(2008BB4040)supported by the Science Foundation of Chongqing,ChinaProject(2008AA4028)supported by Scientific and Technological Project of Chongqing Science and Technology Commission,China
文摘Electric product house of magnesium alloy sheet is usually obtained by warm stamping owing to its poor plasticity and formability at room temperature.The formability of AZ31B magnesium alloy sheet can be improved by repeated unidirectional bending(RUB)process through control of(0002)basal texture.Compared with as-received sheet,the Erichsen value(IE)of the sheet underwent RUB process increases to 5.90 from 3.53 at room temperature.It is also confirmed that cell phone houses could be stamped successfully in crank press with AZ31B magnesium alloy sheets underwent RUB process.It provides an alternative to the electronics industry in the application of magnesium alloys.
文摘Lung cancer is one of the most common malignant tumors in the world. Non-small cell lung cancer （NSCLC） accounts for approximately 80% of lung cancer cases, and approximately 75% of patients are diagnosed in the middle and late stages. The treatment methods mainly include surgery, chemotherapy, radiotherapy, molecular targeted therapy, traditional Chinese medicine therapy, and immune therapy. We summarize the current status of lung cancer-related treatment options and targets.
文摘By taking advantage of the separation characteristics of nonlinear gain and dynamic sector inside a Hammerstein model, a novel pole placement self tuning control scheme for nonlinear Hammerstein system was put forward based on the linear system pole placement self tuning control algorithm. And the nonlinear Hammerstein system pole placement self tuning control(NL-PP-STC) algorithm was presented in detail. The identi fication ability of its parameter estimation algorithm of NL-PP-STC was analyzed, which was always identi fiable in closed loop. Two particular problems including the selection of poles and the on-line estimation of model parameters, which may be met in applications of NL-PP-STC to real process control, were discussed. The control simulation of a strong nonlinear p H neutralization process was carried out and good control performance was achieved.
基金NSFC (No.60704021,60474031) , NCET (No.04-0383)Australia-China Special Fund for Scientific & Technological Cooperation
文摘This paper proposes a decoupling control scheme with two-degrees-of-freedom (2DOF) control structure. In the proposed scheme, two multivariable controllers are designed based on Internal Model Control (IMC) theory for setpoint tracking and disturbance rejection independently. An analytical approximation method is utilized to reduce the order of the controllers. By adjusting the corresponding controller parameter, the setpoint tracking and disturbance rejection of each control loop can be tuned independently. In the presence of multiplicative input uncertainty, a calculation method is also proposed to derive the low bounds of the control parameters in order to guarantee the robust stability of the system. Simulations are illustrated to demonstrate the validity of the proposed control scheme.
文摘The course-keeping control of underactuated hovercraft with two aft propellers was considered. The control of the heading error and cross-track error was accomplished by the yaw torque merely in this case. The hovercraft dynamic model is nonlinear and underactuated. At first the Controllability of course-keeping control for hovercraft was proved, then a course-keeping control law was derived that keeps hovercraft heading constant as well as minimizes the lateral movement of hovercraft. The proposed law guarantees heading error and sway error all converge to zero exponentially. Simulation tests were carried out to illustrate the effectiveness of the proposed control law. For further research, the disturbance influence would be considered in the dynamic equations.
