The risk of failure of the control loop can occur when a high-speed maglev train runs on viaduct.Meanwhile,the failure of the levitation magnets which balances the gravity of the maglev train could cause the train col...The risk of failure of the control loop can occur when a high-speed maglev train runs on viaduct.Meanwhile,the failure of the levitation magnets which balances the gravity of the maglev train could cause the train collision with track.To study the dynamic response of the train and the viaduct when the levitation magnet control loop failure occurs,a high-speed maglev train-viaduct coupling model,which includes a maglev controller fitted by measured force-gap data and considers the actual structure of train and viaduct,is established.Then the accuracy and effectiveness of the established approach are validated by comparing the computed dynamic responses and frequencies with the measurement results.After that,the dynamic responses of maglev train and viaduct are discussed under normal operation and control loop failures,and the most disadvantageous combination of control loop failures is obtained.The results show that when a single control loop fails,it only has a great influence on the failed electromagnet,and the maglev response of adjacent electromagnets has no obvious change and no collision occurs.But there is a risk of rail collisions when the dual control loop fails.展开更多
In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to...In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to)the typical size of oil and water droplets,the residence time and temperature of fluid and the dosage of demulsifier.Using the“Specification for Oil and Gas Separators”as a basis,the control loops and operating parameters of each separator are optimized Considering the Halfaya Oilfield as a testbed,it is shown that the proposed approach can lead to good results in the production stage.展开更多
3AQ1EE primary cut-out is produced by Hangzhou Siemens High Voltage Electrical Co., Ltd. The hydraulic operating mechanism of this type of breaker is new in technology and complex in structure, especially in the secon...3AQ1EE primary cut-out is produced by Hangzhou Siemens High Voltage Electrical Co., Ltd. The hydraulic operating mechanism of this type of breaker is new in technology and complex in structure, especially in the secondary control loop. In order to make the relevant staff understand and master the working principle of the hydraulic mechanism of this type of breaker as soon as possible, this paper analyzes, summarizes and concludes the secondary control loop diagram of the hydraulic mechanism of 3AQ1EE primary cut-out in simple terms combined with all kinds of faults of the hydraulic mechanism.展开更多
Owing to wide applications of automatic control systems in the process industries, the impacts of controller performance on industrial processes are becoming increasingly significant. Consequently, controller maintena...Owing to wide applications of automatic control systems in the process industries, the impacts of controller performance on industrial processes are becoming increasingly significant. Consequently, controller maintenance is critical to guarantee routine operations of industrial processes. The workflow of controller maintenance generally involves the following steps: monitor operating controller performance and detect performance degradation, diagnose probable root causes of control system malfunctions, and take specific actions to resolve associated problems. In this article, a comprehensive overview of the mainstream of control loop monitoring and diagnosis is provided, and some existing problems are also analyzed and discussed. From the viewpoint of synthesizing abundant information in the context of big data, some prospective ideas and promising methods are outlined to potentially solve problems in industrial applications.展开更多
The maximum power transfer capability(MPTC)of phase-locked loop(PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control l...The maximum power transfer capability(MPTC)of phase-locked loop(PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control loops.This paper reveals and compares the mechanisms of these violations across different control strategies.Using admittance decomposition and full-order state-space models for eigenvalue analysis,MPTC limitations from control loops and their interactions are identified.The small-signal stabilities of different control loops are compared under varying grid strength,and both static and dynamic MPTCs for each control mode are examined.This paper also explores how control loop interactions impact the MPTC,offering insights for tuning control loops to enhance stability in weak grids.For example,fast power control improves the MPTC when paired with a slow PLL,while power control has minimal effect when the PLL is sufficiently fast.The findings are validated through frequency scanning,eigenvalue analysis,simulations,and experiments.展开更多
When the power grid suffers from grid faults that cause phase disturbances,the grid-connected converter becomes destabilized by the interaction between the phase-locked loop(PLL)and the control loop.In this paper,the ...When the power grid suffers from grid faults that cause phase disturbances,the grid-connected converter becomes destabilized by the interaction between the phase-locked loop(PLL)and the control loop.In this paper,the stability of the PLL affected by the control loop under transient grid faults is studied.First,the equivalent model of the PLL under the influence of the control loop is established.Then,different response processes of PLLs under the ground fault with various control parameters are qualitatively analyzed.Furthermore,a small-signal model is proposed to assess the stability of the PLL under different control loop parameters.The system poles can be calculated to show the physical origin of the instability.Finally,simulations of a three-phase 21-level modular multilevel converter(MMC)built in PSCAD and a down-scale experiment is performed to verify the parameter influence of the control loop on the PLL.展开更多
A new type of brushless DC motor has been developed by using a square wave rare earth permanent magnet synchronous motor with its double loop control circuit. The double loop control scheme of the drive system yie...A new type of brushless DC motor has been developed by using a square wave rare earth permanent magnet synchronous motor with its double loop control circuit. The double loop control scheme of the drive system yields a combination of desired characteristics including simplified control structure, small ripple torque, high speed accuracy, wide operating speed range, and fast dynamic response. Experimental results confirm excellent characteristics of the motor.展开更多
This paper proposes a new structure to lower the power consumption of a variable gain amplifier（VGA） and keep the linearity of the VGA unchanged.The structure is used in a high rate amplitude-shift keying（ASK） bas...This paper proposes a new structure to lower the power consumption of a variable gain amplifier（VGA） and keep the linearity of the VGA unchanged.The structure is used in a high rate amplitude-shift keying（ASK） based IF-stage.It includes an automatic gain control（AGC） loop and ASK demodulator.The AGC mainly consists of sixstage VGAs.The IF-stage is realized in 0.18μm CMOS technology.The measurement results show that the power consumption of the whole system is very low.The system consumes 730μA while operating at 1.8 V.The minimum ASK signal the system could detect is 0.7 mV（peak to peak amplitude）.展开更多
When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control （OLPC） technology has to be adopted to enrich the target signal interference ratio （S...When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control （OLPC） technology has to be adopted to enrich the target signal interference ratio （Silt） and improve the system performance. The existing problems about DS-CDMA outer loop power control for multi-service are introduced and the power control theoretical model is analyzed. System simulation is adopted on how to obtain the theoretical performance and parameter optimization of the power control algorithm. The OLPC algorithm is improved and the performance comparisons between the old algorithm and the improved algorithm are given. The results show good performance of the improved OLPC algorithm and prove the validity of the improved method for multi-service.展开更多
A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of contro...A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of controlling the po- sition and attitude of both the satellite base and the payload grasped by the manipulator end effectors. The equations of motion in reduced-order form for the constrained system are derived by incorporating the constraint equations in terms of accelerations into Kane＇s equations of the unconstrained system. Model analysis shows that the resulting equations perfectly meet the requirement of adaptive controller design. Consequently, by using an indirect approach, an adaptive control scheme is proposed to accomplish position/attitude trajectory tracking control with the uncertain parameters be- ing estimated on-line. The actuator redundancy due to the closed-loop constraints is utilized to minimize a weighted norm of the joint torques. Global asymptotic stability is proven by using Lyapunov＇s method, and simulation results are also presented to demonstrate the effectiveness of the proposed approach.展开更多
With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case,...With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case, at first, each subsystem is distinctively represented by its model, since the outcomes point out that the chosen models have the same behavior as corresponding ones. Then, the industrial multivariable system and its presentation are achieved in line with the integration of these subsystems, since the interaction between them can not actually be ignored. To analyze the interaction presented, the Gershgorin bands need to be acquired, where the results are used to modify the system parameters to appropriate values. Subsequently, in the view of modeling results, the control concept in two different techniques including sequential loop closing control(SLCC) scheme and diagonal dominance control(DDC) schemes is proposed to implement on the system through the Profibus network, as long as the OPC(OLE for process control) server is utilized to communicate between the control schemes presented and the multivariable system. The real test scenarios are carried out and the corresponding outcomes in their present forms are acquired. In the same way, the proposed control schemes results are compared with each other, where the real consequences verify the validity of them in the field of the presented industrial multivariable system control.展开更多
A kind of transfigured loop shaping controller is presented in this paper. A transfigured loop shaping system puts a controller K in a feedback loop, while putting the dc gain of the controller K on the reference sign...A kind of transfigured loop shaping controller is presented in this paper. A transfigured loop shaping system puts a controller K in a feedback loop, while putting the dc gain of the controller K on the reference signal line. It is shown through frequency domain analysis and simulation that a transfigured controller can improve the dynamic behavior of a system. The transfigured loop shaping controller method is simple and effective and corresponds to the mixed sensitivity method of robust control theory, which improves the behavior of a system by iterative tuning of weighting functions. Satisfactory control results are obtained when it is applied to the design of an underwater vehicle. Keywords Loop shaping controller - underwater vehicle - transfiguration Zhang Xianku graduated from Beijing Institute of Clothing Technology, China, in 1990. He received the M. S. degree from Dalian Maritime University (DMU), China, in 1993 and the Ph.D. degree from DMU, in 1998. He is currently a professor at the Laboratory of Simulation and Control of Navigation Systems, Dalian Maritime University. His research interests include ship motion control and robust control.Jin Yicheng graduated from Zhejiang University, China, in 1967. He is currently a professor at the Laboratory of Simulation and Control of Navigation Systems, Dalian Maritime University. His research interests include simulating system of ship steering and visual control.展开更多
In order to improve the steady state performance,dynamic response and power factor of traditional power factor correction(PFC)digital control method and reduce the harmonic distortion of input current,a double closed ...In order to improve the steady state performance,dynamic response and power factor of traditional power factor correction(PFC)digital control method and reduce the harmonic distortion of input current,a double closed loop active power factorcorrection(APFC)control method with feed-forward is proposed.Firstly,the small signal model of Boost PFC control systemis built and the system transfer function is deduced,and then the parameters of the main device with Boost topology is estimated.By means of the feed-forward,the system can quickly respond to the change in input voltage.Furthermore,the use ofvoltage loop and current loop can achieve input current and output voltage regulation Simulink modeling shows that this methodcan effectively control the output voltage in case of input voltage largely fluctuating,improve the system dynamic response abilityand input power factor,and reduce the input current harmonic distortion展开更多
In this paper both numerical and experimental investigations have been carried out to suppress the vortex-induced vibration （VIV） of a circular cylinder in an electrically low-conducting fluid. The electromagnetic f...In this paper both numerical and experimental investigations have been carried out to suppress the vortex-induced vibration （VIV） of a circular cylinder in an electrically low-conducting fluid. The electromagnetic forces （Lorentz forces） in the azimuthal direction were generated through the mounted electrodes and magnets locally on the surface of the cylinder, which have been proved having an accelerating effect to the fluid on the surface of the cylinder. Results of computations are presented for synchronous vibration phenomenon of a cylinder at Re = 200, which are in good agreement with previous computational results. With the Lorentz forces loaded, the VIV of the cylinder has been suppressed successfully. Experimental results have also shown the same tendency and are in reasonable agreement with the numerical results.展开更多
The classical washout algorithm had fixed gains and manually constructed filters, so that it led to poor adaptability. Furthermore, it lost the sustained acceleration cues of high-and mid-frequency in cross-over(tilt-...The classical washout algorithm had fixed gains and manually constructed filters, so that it led to poor adaptability. Furthermore, it lost the sustained acceleration cues of high-and mid-frequency in cross-over(tilt-coordination) channel, and the acceleration of cross-over frequency was also limited by angular velocity limiter, so the false cues in flight simulation process were clearly perceived by pilots. The paper studied the characteristics of the classical washout algorithm and flight simulator motion platform, tried to redesign the source of cross-over acceleration channel and translation acceleration channel, and transferred the part of cross-over acceleration that was unsimulated sustained acceleration to translation acceleration channel. Comparisons were mainly made between classical washout algorithm and revised algorithm in a longitudinal/pitch direction. The evaluation was based on the implementation of human vestibular perception system. The results demonstrated that the revised algorithm could significantly reduce the phase lag, and improved the spikes tracking performance. Furthermore, sensory angular velocity and the error of sensory acceleration were strictly controlled within the threshold of human perception system, and the displacement was a little broader than the classical washout algorithm. Therefore, it was proved that the new algorithm could diminish the filters parameters and heighten the self-adaptability for the washout algorithm. In addition, the magnitude of false cues was remarkably reduced during flight simulator, and the workspace utilization of the motion platform was developed by "closed-loop" control system.展开更多
This paper investigates motion coupling disturbance（the so called surplus torque）in the hardware-in-the-loop（HIL）experiments.The＇＇velocity synchronization scheme＇＇was proposed by Jiao for an electro-hydraulic ...This paper investigates motion coupling disturbance（the so called surplus torque）in the hardware-in-the-loop（HIL）experiments.The＇＇velocity synchronization scheme＇＇was proposed by Jiao for an electro-hydraulic load simulator（EHLS）in 2004.In some situations,however,the scheme is limited in the implementation for certain reasons,as is the case when the actuator＇s valve signal is not available or it is seriously polluted by noise.To solve these problems,a＇＇dual-loop scheme＇＇is developed for EHLS.The dual-loop scheme is a combination of a torque loop and a position synchronization loop.The role of the position synchronization loop is to decouple the motion disturbance caused by the actuator system.To verify the feasibility and effectiveness of the proposed scheme,extensive simulations are performed using AMESim.Then,the performance of the developed method is validated by experiments.展开更多
A closed-loop control allocation method is proposed for a class of aircraft with multiple actuators. Nonlinear dynamic inversion is used to design the baseline attitude controller and derive the desired moment increme...A closed-loop control allocation method is proposed for a class of aircraft with multiple actuators. Nonlinear dynamic inversion is used to design the baseline attitude controller and derive the desired moment increment. And a feedback loop for the moment increment produced by the deflections of actuators is added to the angular rate loop, then the error between the desired and actual moment increment is the input of the dynamic control allocation. Subsequently, the stability of the closed-loop dynamic control allocation system is analyzed in detail. Especially, the closedloop system stability is also analyzed in the presence of two types of actuator failures： loss of effectiveness and lock-in-place actuator failures, where a fault detection subsystem to identify the actuator failures is absent. Finally, the proposed method is applied to a canard rotor/wing （CRW） aircraft model in fixed-wing mode, which has multiple actuators for flight control. The nonlinear simulation demonstrates that this method can guarantee the stability and tracking performance whether the actuators are healthy or fail.展开更多
To improve the penetrating ability and the welding quality of keyhole plasma arc welding, a novel penetration closed loop control system was established. In the system, welding current and plasma gas flow rate were se...To improve the penetrating ability and the welding quality of keyhole plasma arc welding, a novel penetration closed loop control system was established. In the system, welding current and plasma gas flow rate were selected as adjusting variables. The wavelet method was used to detect penetration status from welding arc voltage in real time. The control strategy of one keyhole per pulse was adapted to fulfill stable and high quality welding process. Experimental results show that the developed system can apparently increase the penetrating force of plasma arc and keyhole plasma arc welding is realized successfully in stainless steel with 10 mm in thickness. Moreover, the disturbances of gradual change and break change from 3 mm to 6 mm in thickness are come over due to the good response property of the developed system.展开更多
A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of ind...A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of induStrial parameter closed-loop process controlsystems is improved, and the work quality of the systems bettered.展开更多
In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model...In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model of closed loop control system including the engine, air fuel mixing and transportation, oxygen sensor and controller, etc., is developed. Various factors that influence the A/F control are studied by simulation. The simulation results show that the reference voltage of oxygen sensor will influence the mean value of A/F ratio, the controller parameters will influence the amplitude of A/F fluctuation, and the operating conditions of the engine determine the frequency of A/F fluctuations, the amplitude of A/F fluctuation can be reduced to within demanded values by logical selection of the signal acquisition method and controller parameters. Higher A/F fluctuation frequency under high speed and load can be reduced through software delay in the controller. The A/F closed loop control system based on the simulation results, accompanied with a rare earth element TWC, gives a better efficiency of conversion against harmful emissions.展开更多
基金Project(2021zzts0775) supported by the Independent Exploration and Innovation Project for Graduate Students of Central South University,ChinaProject(2021JJ30053) supported by the Hunan Natural Science Foundation,China。
文摘The risk of failure of the control loop can occur when a high-speed maglev train runs on viaduct.Meanwhile,the failure of the levitation magnets which balances the gravity of the maglev train could cause the train collision with track.To study the dynamic response of the train and the viaduct when the levitation magnet control loop failure occurs,a high-speed maglev train-viaduct coupling model,which includes a maglev controller fitted by measured force-gap data and considers the actual structure of train and viaduct,is established.Then the accuracy and effectiveness of the established approach are validated by comparing the computed dynamic responses and frequencies with the measurement results.After that,the dynamic responses of maglev train and viaduct are discussed under normal operation and control loop failures,and the most disadvantageous combination of control loop failures is obtained.The results show that when a single control loop fails,it only has a great influence on the failed electromagnet,and the maglev response of adjacent electromagnets has no obvious change and no collision occurs.But there is a risk of rail collisions when the dual control loop fails.
基金This study was supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2021QE030).
文摘In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to)the typical size of oil and water droplets,the residence time and temperature of fluid and the dosage of demulsifier.Using the“Specification for Oil and Gas Separators”as a basis,the control loops and operating parameters of each separator are optimized Considering the Halfaya Oilfield as a testbed,it is shown that the proposed approach can lead to good results in the production stage.
文摘3AQ1EE primary cut-out is produced by Hangzhou Siemens High Voltage Electrical Co., Ltd. The hydraulic operating mechanism of this type of breaker is new in technology and complex in structure, especially in the secondary control loop. In order to make the relevant staff understand and master the working principle of the hydraulic mechanism of this type of breaker as soon as possible, this paper analyzes, summarizes and concludes the secondary control loop diagram of the hydraulic mechanism of 3AQ1EE primary cut-out in simple terms combined with all kinds of faults of the hydraulic mechanism.
基金Supported by the National Basic Research Program of China(2012CB720505)the National Natural Science Foundation of China(21276137,61433001)+1 种基金Tsinghua University Initiative Scientific Research Programthe seventh framework programme(FP7-PEOPLE-2013-IRSES-612230)of European Union
文摘Owing to wide applications of automatic control systems in the process industries, the impacts of controller performance on industrial processes are becoming increasingly significant. Consequently, controller maintenance is critical to guarantee routine operations of industrial processes. The workflow of controller maintenance generally involves the following steps: monitor operating controller performance and detect performance degradation, diagnose probable root causes of control system malfunctions, and take specific actions to resolve associated problems. In this article, a comprehensive overview of the mainstream of control loop monitoring and diagnosis is provided, and some existing problems are also analyzed and discussed. From the viewpoint of synthesizing abundant information in the context of big data, some prospective ideas and promising methods are outlined to potentially solve problems in industrial applications.
基金funded by the Australian Renewable Energy Agency(No.2023/ARP010).
文摘The maximum power transfer capability(MPTC)of phase-locked loop(PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control loops.This paper reveals and compares the mechanisms of these violations across different control strategies.Using admittance decomposition and full-order state-space models for eigenvalue analysis,MPTC limitations from control loops and their interactions are identified.The small-signal stabilities of different control loops are compared under varying grid strength,and both static and dynamic MPTCs for each control mode are examined.This paper also explores how control loop interactions impact the MPTC,offering insights for tuning control loops to enhance stability in weak grids.For example,fast power control improves the MPTC when paired with a slow PLL,while power control has minimal effect when the PLL is sufficiently fast.The findings are validated through frequency scanning,eigenvalue analysis,simulations,and experiments.
基金This work was supported by the National Natural Science Foundation of China(51877159,51637007,U1866601).
文摘When the power grid suffers from grid faults that cause phase disturbances,the grid-connected converter becomes destabilized by the interaction between the phase-locked loop(PLL)and the control loop.In this paper,the stability of the PLL affected by the control loop under transient grid faults is studied.First,the equivalent model of the PLL under the influence of the control loop is established.Then,different response processes of PLLs under the ground fault with various control parameters are qualitatively analyzed.Furthermore,a small-signal model is proposed to assess the stability of the PLL under different control loop parameters.The system poles can be calculated to show the physical origin of the instability.Finally,simulations of a three-phase 21-level modular multilevel converter(MMC)built in PSCAD and a down-scale experiment is performed to verify the parameter influence of the control loop on the PLL.
文摘A new type of brushless DC motor has been developed by using a square wave rare earth permanent magnet synchronous motor with its double loop control circuit. The double loop control scheme of the drive system yields a combination of desired characteristics including simplified control structure, small ripple torque, high speed accuracy, wide operating speed range, and fast dynamic response. Experimental results confirm excellent characteristics of the motor.
基金supported by the National High-Tech Research and Development Program of China(Nos.2008AA010703,2009AA011606)the National Natural Science Foundation of China(No.60976023)
文摘This paper proposes a new structure to lower the power consumption of a variable gain amplifier（VGA） and keep the linearity of the VGA unchanged.The structure is used in a high rate amplitude-shift keying（ASK） based IF-stage.It includes an automatic gain control（AGC） loop and ASK demodulator.The AGC mainly consists of sixstage VGAs.The IF-stage is realized in 0.18μm CMOS technology.The measurement results show that the power consumption of the whole system is very low.The system consumes 730μA while operating at 1.8 V.The minimum ASK signal the system could detect is 0.7 mV（peak to peak amplitude）.
基金the National Natural Science Foundation of China (60532030).
文摘When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control （OLPC） technology has to be adopted to enrich the target signal interference ratio （Silt） and improve the system performance. The existing problems about DS-CDMA outer loop power control for multi-service are introduced and the power control theoretical model is analyzed. System simulation is adopted on how to obtain the theoretical performance and parameter optimization of the power control algorithm. The OLPC algorithm is improved and the performance comparisons between the old algorithm and the improved algorithm are given. The results show good performance of the improved OLPC algorithm and prove the validity of the improved method for multi-service.
基金supported by the National Natural Science Foundation of China(11272027)
文摘A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of controlling the po- sition and attitude of both the satellite base and the payload grasped by the manipulator end effectors. The equations of motion in reduced-order form for the constrained system are derived by incorporating the constraint equations in terms of accelerations into Kane＇s equations of the unconstrained system. Model analysis shows that the resulting equations perfectly meet the requirement of adaptive controller design. Consequently, by using an indirect approach, an adaptive control scheme is proposed to accomplish position/attitude trajectory tracking control with the uncertain parameters be- ing estimated on-line. The actuator redundancy due to the closed-loop constraints is utilized to minimize a weighted norm of the joint torques. Global asymptotic stability is proven by using Lyapunov＇s method, and simulation results are also presented to demonstrate the effectiveness of the proposed approach.
文摘With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case, at first, each subsystem is distinctively represented by its model, since the outcomes point out that the chosen models have the same behavior as corresponding ones. Then, the industrial multivariable system and its presentation are achieved in line with the integration of these subsystems, since the interaction between them can not actually be ignored. To analyze the interaction presented, the Gershgorin bands need to be acquired, where the results are used to modify the system parameters to appropriate values. Subsequently, in the view of modeling results, the control concept in two different techniques including sequential loop closing control(SLCC) scheme and diagonal dominance control(DDC) schemes is proposed to implement on the system through the Profibus network, as long as the OPC(OLE for process control) server is utilized to communicate between the control schemes presented and the multivariable system. The real test scenarios are carried out and the corresponding outcomes in their present forms are acquired. In the same way, the proposed control schemes results are compared with each other, where the real consequences verify the validity of them in the field of the presented industrial multivariable system control.
文摘A kind of transfigured loop shaping controller is presented in this paper. A transfigured loop shaping system puts a controller K in a feedback loop, while putting the dc gain of the controller K on the reference signal line. It is shown through frequency domain analysis and simulation that a transfigured controller can improve the dynamic behavior of a system. The transfigured loop shaping controller method is simple and effective and corresponds to the mixed sensitivity method of robust control theory, which improves the behavior of a system by iterative tuning of weighting functions. Satisfactory control results are obtained when it is applied to the design of an underwater vehicle. Keywords Loop shaping controller - underwater vehicle - transfiguration Zhang Xianku graduated from Beijing Institute of Clothing Technology, China, in 1990. He received the M. S. degree from Dalian Maritime University (DMU), China, in 1993 and the Ph.D. degree from DMU, in 1998. He is currently a professor at the Laboratory of Simulation and Control of Navigation Systems, Dalian Maritime University. His research interests include ship motion control and robust control.Jin Yicheng graduated from Zhejiang University, China, in 1967. He is currently a professor at the Laboratory of Simulation and Control of Navigation Systems, Dalian Maritime University. His research interests include simulating system of ship steering and visual control.
基金National Natural Science Foundation of China(No.61261029)
文摘In order to improve the steady state performance,dynamic response and power factor of traditional power factor correction(PFC)digital control method and reduce the harmonic distortion of input current,a double closed loop active power factorcorrection(APFC)control method with feed-forward is proposed.Firstly,the small signal model of Boost PFC control systemis built and the system transfer function is deduced,and then the parameters of the main device with Boost topology is estimated.By means of the feed-forward,the system can quickly respond to the change in input voltage.Furthermore,the use ofvoltage loop and current loop can achieve input current and output voltage regulation Simulink modeling shows that this methodcan effectively control the output voltage in case of input voltage largely fluctuating,improve the system dynamic response abilityand input power factor,and reduce the input current harmonic distortion
文摘In this paper both numerical and experimental investigations have been carried out to suppress the vortex-induced vibration （VIV） of a circular cylinder in an electrically low-conducting fluid. The electromagnetic forces （Lorentz forces） in the azimuthal direction were generated through the mounted electrodes and magnets locally on the surface of the cylinder, which have been proved having an accelerating effect to the fluid on the surface of the cylinder. Results of computations are presented for synchronous vibration phenomenon of a cylinder at Re = 200, which are in good agreement with previous computational results. With the Lorentz forces loaded, the VIV of the cylinder has been suppressed successfully. Experimental results have also shown the same tendency and are in reasonable agreement with the numerical results.
基金Supported by Wuhan Technical College of Communications Fund(Q2018001)China Institute of Communications Education Fund(1602-248)Wuhan Technical College of Communications Innovation Team(CX2018A07)
文摘The classical washout algorithm had fixed gains and manually constructed filters, so that it led to poor adaptability. Furthermore, it lost the sustained acceleration cues of high-and mid-frequency in cross-over(tilt-coordination) channel, and the acceleration of cross-over frequency was also limited by angular velocity limiter, so the false cues in flight simulation process were clearly perceived by pilots. The paper studied the characteristics of the classical washout algorithm and flight simulator motion platform, tried to redesign the source of cross-over acceleration channel and translation acceleration channel, and transferred the part of cross-over acceleration that was unsimulated sustained acceleration to translation acceleration channel. Comparisons were mainly made between classical washout algorithm and revised algorithm in a longitudinal/pitch direction. The evaluation was based on the implementation of human vestibular perception system. The results demonstrated that the revised algorithm could significantly reduce the phase lag, and improved the spikes tracking performance. Furthermore, sensory angular velocity and the error of sensory acceleration were strictly controlled within the threshold of human perception system, and the displacement was a little broader than the classical washout algorithm. Therefore, it was proved that the new algorithm could diminish the filters parameters and heighten the self-adaptability for the washout algorithm. In addition, the magnitude of false cues was remarkably reduced during flight simulator, and the workspace utilization of the motion platform was developed by "closed-loop" control system.
基金sponsored by the National Basic Research Program of China (No.2014CB046406)the Key Projects of the National Natural Science Foundation (No.51235002)
文摘This paper investigates motion coupling disturbance（the so called surplus torque）in the hardware-in-the-loop（HIL）experiments.The＇＇velocity synchronization scheme＇＇was proposed by Jiao for an electro-hydraulic load simulator（EHLS）in 2004.In some situations,however,the scheme is limited in the implementation for certain reasons,as is the case when the actuator＇s valve signal is not available or it is seriously polluted by noise.To solve these problems,a＇＇dual-loop scheme＇＇is developed for EHLS.The dual-loop scheme is a combination of a torque loop and a position synchronization loop.The role of the position synchronization loop is to decouple the motion disturbance caused by the actuator system.To verify the feasibility and effectiveness of the proposed scheme,extensive simulations are performed using AMESim.Then,the performance of the developed method is validated by experiments.
基金Program for New Century Excellent Talents in University (NCET-10-0032)
文摘A closed-loop control allocation method is proposed for a class of aircraft with multiple actuators. Nonlinear dynamic inversion is used to design the baseline attitude controller and derive the desired moment increment. And a feedback loop for the moment increment produced by the deflections of actuators is added to the angular rate loop, then the error between the desired and actual moment increment is the input of the dynamic control allocation. Subsequently, the stability of the closed-loop dynamic control allocation system is analyzed in detail. Especially, the closedloop system stability is also analyzed in the presence of two types of actuator failures： loss of effectiveness and lock-in-place actuator failures, where a fault detection subsystem to identify the actuator failures is absent. Finally, the proposed method is applied to a canard rotor/wing （CRW） aircraft model in fixed-wing mode, which has multiple actuators for flight control. The nonlinear simulation demonstrates that this method can guarantee the stability and tracking performance whether the actuators are healthy or fail.
文摘To improve the penetrating ability and the welding quality of keyhole plasma arc welding, a novel penetration closed loop control system was established. In the system, welding current and plasma gas flow rate were selected as adjusting variables. The wavelet method was used to detect penetration status from welding arc voltage in real time. The control strategy of one keyhole per pulse was adapted to fulfill stable and high quality welding process. Experimental results show that the developed system can apparently increase the penetrating force of plasma arc and keyhole plasma arc welding is realized successfully in stainless steel with 10 mm in thickness. Moreover, the disturbances of gradual change and break change from 3 mm to 6 mm in thickness are come over due to the good response property of the developed system.
文摘A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of induStrial parameter closed-loop process controlsystems is improved, and the work quality of the systems bettered.
文摘In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model of closed loop control system including the engine, air fuel mixing and transportation, oxygen sensor and controller, etc., is developed. Various factors that influence the A/F control are studied by simulation. The simulation results show that the reference voltage of oxygen sensor will influence the mean value of A/F ratio, the controller parameters will influence the amplitude of A/F fluctuation, and the operating conditions of the engine determine the frequency of A/F fluctuations, the amplitude of A/F fluctuation can be reduced to within demanded values by logical selection of the signal acquisition method and controller parameters. Higher A/F fluctuation frequency under high speed and load can be reduced through software delay in the controller. The A/F closed loop control system based on the simulation results, accompanied with a rare earth element TWC, gives a better efficiency of conversion against harmful emissions.
