To track the rapidly changing temperature profiles of thermal cycling of polymerase chain reaction （PCR） accurately, an innovative feedforward variable structural proportional-integral-derivative （FVSPID） controll...To track the rapidly changing temperature profiles of thermal cycling of polymerase chain reaction （PCR） accurately, an innovative feedforward variable structural proportional-integral-derivative （FVSPID） controller was developed. Based on the step response test data of the heat block, a reduced first order model was estabfished at different operating points. Based on the reduced model, the FVSPID controller combined a feedforward path with the variable structural proportional-integral-derivative （PID） control. The modified feedforward action provided directly the optimal predictive power for the desired setpoint to speed up the dynamic response. To cooperate with the feedforward action, a variable structural PID was applied, where the P mode was used in the case of the largest errors to speed up response, whereas the PD mode was used in the case of larger errors to suppress overshoot, and finally the PID mode was applied for small error conditions to eliminate the steady state offset. Experimental results illustrated that compared to the conventional PID controller, the FVSPID controller can not only reduce the time taken to complete a standard PCR protocol, but also improve the accuracy of gene amplification.展开更多
Precise temperature control to decrease movements in positions due to thermal expansion of work pieces is required in the manufacturing processes to achieve nanometer-order accuracy. We analytically examined the effec...Precise temperature control to decrease movements in positions due to thermal expansion of work pieces is required in the manufacturing processes to achieve nanometer-order accuracy. We analytically examined the effect of a method of minimizing movements in positions on a plate with varying generation of noise-heat. Control by monitoring temperature changes caused larger movements in positions than that without control because maximum change in temperature occurred at non-monitoring positions. The best method of minimizing movements in positions due to thermal expansion of a plate with varying generation of noise-heat was model predictive control by the monitoring movements and distributed temperature changes in the control heater according to the effects of the generation of noise-heat. The maximum movement in positions was 6 nm, which was 1/4 times of that without control.展开更多
The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our prev...The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our previous work,a novel industrial p-xylene oxidation reactor model using the free radical mechanism based kinetics has been developed.However,the disturbances such as production rate change,feed composition variability and reactor temperature changes widely exist in the industry process.In this paper,dynamic simulation of the PX oxidation reactor was designed by Aspen Dynamics and used to develop an effective plantwide control structure,which was capable of effectively handling the disturbances in the load and the temperature of the reactor.Step responses of the control structure to the disturbances were shown and served as the foundation of the smooth operation and advanced control strategy of this process in our future work.展开更多
The increasing pollution in the atmospheric layer has meant world-wide temperature variations, causing the melting of icecaps and floods, among other environmental factors. This change in temperature has been mainly c...The increasing pollution in the atmospheric layer has meant world-wide temperature variations, causing the melting of icecaps and floods, among other environmental factors. This change in temperature has been mainly caused by the indiscriminate emission of CO2, especially due to the rising number of vehicles in circulation. Researchers have identified that, among other types of fuel, diesel has the highest level of CO2 emission. Hence the need for the development of biodiesel, produced from oleaginous plants, aimed at reducing the emission of this harmful gas into the atmosphere, besides using renewable resources. However, as in any automation process, it is necessary to have sensors, actuators, and controllers, which together perform the automation and control of the production process. Besides that, there are other process variables to be accounted for, such as temperature, flow, and level. Considering such concept, and within the academic context, the creation process of a mini biodiesel plant will be described.展开更多
It is still very difficult for researchers and engineers to implement the simulation analysis including a complete process and a full model with the complicated arch dam and the foundation, and to evaluate the crackin...It is still very difficult for researchers and engineers to implement the simulation analysis including a complete process and a full model with the complicated arch dam and the foundation, and to evaluate the cracking potential in the construction and service periods. To take Xiaowan project of China for an example, a practical system of simulation feedback analysis, a specific cracking criterion, and a resolution for the conflicting requirements of temperature and stress/strain simulation are presented, which are put into a successful practice. The simulation results of temperature, stress, and cracking are identical well with the monitor data. A modified temperature control measure is propounded, and the significant effect is gained by adopting the new scheme.展开更多
基金Supported by the National Natural Science Foundation of China (No.60574038) and the Open Project Program of the State KeyLaboratory of Bioreactor Engineering/ECUST.
文摘To track the rapidly changing temperature profiles of thermal cycling of polymerase chain reaction （PCR） accurately, an innovative feedforward variable structural proportional-integral-derivative （FVSPID） controller was developed. Based on the step response test data of the heat block, a reduced first order model was estabfished at different operating points. Based on the reduced model, the FVSPID controller combined a feedforward path with the variable structural proportional-integral-derivative （PID） control. The modified feedforward action provided directly the optimal predictive power for the desired setpoint to speed up the dynamic response. To cooperate with the feedforward action, a variable structural PID was applied, where the P mode was used in the case of the largest errors to speed up response, whereas the PD mode was used in the case of larger errors to suppress overshoot, and finally the PID mode was applied for small error conditions to eliminate the steady state offset. Experimental results illustrated that compared to the conventional PID controller, the FVSPID controller can not only reduce the time taken to complete a standard PCR protocol, but also improve the accuracy of gene amplification.
文摘Precise temperature control to decrease movements in positions due to thermal expansion of work pieces is required in the manufacturing processes to achieve nanometer-order accuracy. We analytically examined the effect of a method of minimizing movements in positions on a plate with varying generation of noise-heat. Control by monitoring temperature changes caused larger movements in positions than that without control because maximum change in temperature occurred at non-monitoring positions. The best method of minimizing movements in positions due to thermal expansion of a plate with varying generation of noise-heat was model predictive control by the monitoring movements and distributed temperature changes in the control heater according to the effects of the generation of noise-heat. The maximum movement in positions was 6 nm, which was 1/4 times of that without control.
基金Supported by the Major State Basic Research Development Program of China(2012CB720500)the National Natural Science Foundation of China(U1162202)+2 种基金the Shanghai Second Polytechnic University Key Discipline Construction(4th term)-Control Theory&Control Engineering(XXKPY1308)the Cultivation Program of Young Teachers in Colleges and Universities of Shanghai(ZZegdl4013)the School Foundation of Shanghai Second Polytechnic University(EGD14XQD02)
文摘The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our previous work,a novel industrial p-xylene oxidation reactor model using the free radical mechanism based kinetics has been developed.However,the disturbances such as production rate change,feed composition variability and reactor temperature changes widely exist in the industry process.In this paper,dynamic simulation of the PX oxidation reactor was designed by Aspen Dynamics and used to develop an effective plantwide control structure,which was capable of effectively handling the disturbances in the load and the temperature of the reactor.Step responses of the control structure to the disturbances were shown and served as the foundation of the smooth operation and advanced control strategy of this process in our future work.
文摘The increasing pollution in the atmospheric layer has meant world-wide temperature variations, causing the melting of icecaps and floods, among other environmental factors. This change in temperature has been mainly caused by the indiscriminate emission of CO2, especially due to the rising number of vehicles in circulation. Researchers have identified that, among other types of fuel, diesel has the highest level of CO2 emission. Hence the need for the development of biodiesel, produced from oleaginous plants, aimed at reducing the emission of this harmful gas into the atmosphere, besides using renewable resources. However, as in any automation process, it is necessary to have sensors, actuators, and controllers, which together perform the automation and control of the production process. Besides that, there are other process variables to be accounted for, such as temperature, flow, and level. Considering such concept, and within the academic context, the creation process of a mini biodiesel plant will be described.
基金supported by the National Natural Sciences Foundation of China (Grant Nos. 51079109)
文摘It is still very difficult for researchers and engineers to implement the simulation analysis including a complete process and a full model with the complicated arch dam and the foundation, and to evaluate the cracking potential in the construction and service periods. To take Xiaowan project of China for an example, a practical system of simulation feedback analysis, a specific cracking criterion, and a resolution for the conflicting requirements of temperature and stress/strain simulation are presented, which are put into a successful practice. The simulation results of temperature, stress, and cracking are identical well with the monitor data. A modified temperature control measure is propounded, and the significant effect is gained by adopting the new scheme.
