Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportio...Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.展开更多
The main advantage of one-cycle control is its ability to reject input disturbance in one-cycle. Despite this great ability, it can not provide good responses in following commands and rejecting load disturbance. This...The main advantage of one-cycle control is its ability to reject input disturbance in one-cycle. Despite this great ability, it can not provide good responses in following commands and rejecting load disturbance. This study explores the way to overcome these problems by using another controller. Although the idea of using output feedback has been used in previous works, by considering a simple model for one-cycle controller, the design of the controller has become simpler in this work. In the proposed method, difficult mathematical modeling is avoided. Based on decupling of effects of feedback and input voltage disturbance, a simple model for one-cycle controller has been given. Therefore, by employing a conventional averaging method and the model of one-cycle controller, design of proportional integral differential controller has become straightforward.展开更多
The aim of the present study was to implant an efficient strategy for controlling the level of the effluent-oily foam interface in a DAF （dissolved air flotation） chamber of a pilot-scale prototype. DAF has been suc...The aim of the present study was to implant an efficient strategy for controlling the level of the effluent-oily foam interface in a DAF （dissolved air flotation） chamber of a pilot-scale prototype. DAF has been successfully used in the treatment of oily water, which is one of the main environmental problems in different industrial facilities. Along with important operational parameters, such as microbubble size and flow rate, the control strategy for the automation of a DAF chamber may be an important tool for increasing efficiency. Controlling the level was the strategy chosen to enhance the separation efficiency in a pilot-scale DAF prototype, with monitoring performed using a computational program in LabVIEW （laboratory virtual instrument engineering workbench）. The findings demonstrate that it is possible to maintain the level of the fluid at a reference value established by the operator using the software program through the application of classic proportional integral derivative controllers. Using this control tool, the efficiency of water-oil separation in the pilot flotation chamber prototype was increased to nearly 98%.展开更多
This paper deals with a scalar conservation law in 1-D space dimension, and in particular, the focus is on the stability analysis for such an equation. The problem of feedback stabilization under proportional-integral...This paper deals with a scalar conservation law in 1-D space dimension, and in particular, the focus is on the stability analysis for such an equation. The problem of feedback stabilization under proportional-integral-derivative(PID for short) boundary control is addressed. In the proportional-integral(PI for short) controller case, by spectral analysis, the authors provide a complete characterization of the set of stabilizing feedback parameters, and determine the corresponding time delay stability interval. Moreover, the stability of the equilibrium is discussed by Lyapunov function techniques, and by this approach the exponential stability when a damping term is added to the classical PI controller scheme is proved. Also, based on Pontryagin results on stability for quasipolynomials, it is shown that the closed-loop system sub ject to PID control is always unstable.展开更多
In this paper, a new algorithm which integrates the powerful firefly Mgorithm （FA） and the ant colony optimization （ACO） has been used in tracking control of ship steering for optimization of fractional-order prop...In this paper, a new algorithm which integrates the powerful firefly Mgorithm （FA） and the ant colony optimization （ACO） has been used in tracking control of ship steering for optimization of fractional-order proportional-integral-derivative （FOPID） controller gains. Particle swarm optimization （PSO） algorithm is also used to optimize FOPID controllers, and their performances are compared. It is found that FA optimized FOPID controller gives better performance than others. Sensitivity analysis has been carried out to see the robustness of optimum FOPID gains obtained at nominal conditions to wide changes in system parameters, and the optimum FOPID gains need not be reset for wide changes in system parameters.展开更多
基金Supported by the National Natural Science Foundation of China (61174059, 60934007, 61233004)the National Basic Research Program of China (2013CB035406)Shanghai Rising-Star Tracking Program (11QH1401300)
文摘Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.
文摘The main advantage of one-cycle control is its ability to reject input disturbance in one-cycle. Despite this great ability, it can not provide good responses in following commands and rejecting load disturbance. This study explores the way to overcome these problems by using another controller. Although the idea of using output feedback has been used in previous works, by considering a simple model for one-cycle controller, the design of the controller has become simpler in this work. In the proposed method, difficult mathematical modeling is avoided. Based on decupling of effects of feedback and input voltage disturbance, a simple model for one-cycle controller has been given. Therefore, by employing a conventional averaging method and the model of one-cycle controller, design of proportional integral differential controller has become straightforward.
文摘The aim of the present study was to implant an efficient strategy for controlling the level of the effluent-oily foam interface in a DAF （dissolved air flotation） chamber of a pilot-scale prototype. DAF has been successfully used in the treatment of oily water, which is one of the main environmental problems in different industrial facilities. Along with important operational parameters, such as microbubble size and flow rate, the control strategy for the automation of a DAF chamber may be an important tool for increasing efficiency. Controlling the level was the strategy chosen to enhance the separation efficiency in a pilot-scale DAF prototype, with monitoring performed using a computational program in LabVIEW （laboratory virtual instrument engineering workbench）. The findings demonstrate that it is possible to maintain the level of the fluid at a reference value established by the operator using the software program through the application of classic proportional integral derivative controllers. Using this control tool, the efficiency of water-oil separation in the pilot flotation chamber prototype was increased to nearly 98%.
基金supported by the ERC Advanced Grant 266907(CPDENL)of the 7th Research Framework Programme(FP7)FIRST,Initial Training Network of the European Commission(No.238702)PITNGA-2009-238702
文摘This paper deals with a scalar conservation law in 1-D space dimension, and in particular, the focus is on the stability analysis for such an equation. The problem of feedback stabilization under proportional-integral-derivative(PID for short) boundary control is addressed. In the proportional-integral(PI for short) controller case, by spectral analysis, the authors provide a complete characterization of the set of stabilizing feedback parameters, and determine the corresponding time delay stability interval. Moreover, the stability of the equilibrium is discussed by Lyapunov function techniques, and by this approach the exponential stability when a damping term is added to the classical PI controller scheme is proved. Also, based on Pontryagin results on stability for quasipolynomials, it is shown that the closed-loop system sub ject to PID control is always unstable.
基金the National Natural Science Foundation of China(No.51109090)the Natural Fund of Fujian Province(No.2015J01214)+2 种基金the Key Project of Fujian Provincial Department of Science & Technology(No.2012H0030)the University’s Innovative Project of Xiamen Science & Technology Bureau(No.3502Z20123019)the Project of New Century Excellent Talents of Colleges and Universities of Fujian Province(No.JA12181)
文摘In this paper, a new algorithm which integrates the powerful firefly Mgorithm （FA） and the ant colony optimization （ACO） has been used in tracking control of ship steering for optimization of fractional-order proportional-integral-derivative （FOPID） controller gains. Particle swarm optimization （PSO） algorithm is also used to optimize FOPID controllers, and their performances are compared. It is found that FA optimized FOPID controller gives better performance than others. Sensitivity analysis has been carried out to see the robustness of optimum FOPID gains obtained at nominal conditions to wide changes in system parameters, and the optimum FOPID gains need not be reset for wide changes in system parameters.
