The paper presents a method of using single neuron adaptive PID control for adjusting system or servo system to implement timber drying process control, which combines the thought of parameter adaptive PID control and...The paper presents a method of using single neuron adaptive PID control for adjusting system or servo system to implement timber drying process control, which combines the thought of parameter adaptive PID control and the character of neural network on exactly describing nonlinear and uncertainty dynamic process organically. The method implements functions of adaptive and self-learning by adjusting weighting parameters. Adaptive neural network can make some output trail given hoping value to decouple in static state. The simulation result indicates the validity, veracity and robustness of the method used in the timber drying process展开更多
In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is sing...In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current(DC)bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.展开更多
The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg)...The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg) and immediate release tablets (IRMS, 20 mg). The plasma concentration of morphine was determined by GC MS. The pharmacokinetic parameters of controlled release tablets and immediate release tablets were calculated∶ C max was 19.38±3.80 and 21.27±6.21 ng/ml, t max was 2.36 ±0.37 h and 0.56±0.16 h, t 1/2β was 3.53±0.87 and 3.03±0.74 h, AUC was 145.15±17.65 and 93.08±16.65 ng/ml, respectively. The steady state plasma concentration of morphine sulphate in cancer patients after multiple doses was achieved, C max of CRMS and IRMS was 27.43±0.33 ng/ml and 22.68±0.16 ng/ml, C min of CRMS and IRMS was 19.45±1.44 ng/ml and 18.14±0.49 ng/ml, respectively.展开更多
Flatness is one of the most important criterion factors to evaluate the quality of the steel strip. To improve the strip' s flatness quality, the most frequently used methodology is to employ the closed-loop automati...Flatness is one of the most important criterion factors to evaluate the quality of the steel strip. To improve the strip' s flatness quality, the most frequently used methodology is to employ the closed-loop automatic shape control system. However, in the shape control system, the shape-meter is always installed at the down way of the exit of the cold rolling mill and can not sense the changes of the strip flatness in the rolling gap directly. This kind of installation results in the delay of the feedback in the control system. Therefore, the stability and response performance of the system are strongly affected by the delay. At present, there is still no mature way to design controllers for systems with time delay. Although the conventional PID controller used in most practical applications has the capability to compensate the delay, the effect of the compensation is limited, especially for the systems with long time delay. Smith predictor, as a compensator for solving this problem, is now widely used in industry systems. However, the request of highly precise model of the system and the poor adaptive performance to the changes of related parameters limit the application of the Smith predictor in practice. In order to overcome the drawbacks of the Smith predictor, a new Smith predictor based on single neural network PID (SNN-PID) is proposed. Because the single neural network is employed into the Smith predictor to improve the controller's self-adaptability, the adaptive capability to the varying parameters of the system is improved. Meanwhile, for the purpose of solving the problems such as time-consuming and complicated calculation of the neural networks in real time, the learning coefficient of neural network is divided into several stages as usually done in expert control system. Therefore, the control system can obtain fast response due to the improved calculation speed of the neural networks. In order to validate the performance of the proposed controller, the experiment is conducted on the shape control system in a 300 mm four-high reversing cold rolling mill. The experimental results show that the SNN-PID with Smith predictor controller can effectively compensate the delay effects and achieve better control performance than the conventional PID controller.展开更多
The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n tim...The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n time state vector. An estimating algorithm, is developed from this to solve the problem of active control with time delay compensation. The estimating algorithm based on this high order single step β method (HSM) foundation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control with time delay compensation.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
Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros (SGCMGs) as actuators is investigated. First of all, the dy...Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros (SGCMGs) as actuators is investigated. First of all, the dynamic model of the underactuated spacecraft is established and the singularity of different configurations with the two SGCMGs is analyzed. Under the assumption that the gimbal axes of the two SGCMGs are installed in any direction, and that the total system angular momentum is not zero, a state feedback control law via Lyapunov method is designed to globally asymptotically stabilize the angular velocity of spacecraft. Under the assumption that the gimbal axes of the two SGCMGs are coaxially installed along anyone of the three principal axes of spacecraft inertia, and that the total system angular momentum is zero, a discontinuous state feedback control law is designed to stabilize three-axis attitude of spacecraft with respect to the inertial frame. Furthermore, the singularity escape of SGCMGs for the above two control problems is also studied. Simulation results demonstrate the validity of the control laws.展开更多
Presents a one grade adaptive controller with one reference model which is built according to δ MRACS adaptive control theory and used to control an actual high order hydraulic system, and the whole hardware system u...Presents a one grade adaptive controller with one reference model which is built according to δ MRACS adaptive control theory and used to control an actual high order hydraulic system, and the whole hardware system used, which includes a AT89C51 single chip microcomputer, 74Ls373 flip latch, 6116 store, eight bit ADC0809, and so on, and the satisfactory results obtained in study on hydraulic control system.展开更多
Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbi...Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbine(MCT)system,the nonlinear controllers which rely on precise mathematical models show poor performance under a high level of parameters’uncertainties.This paper proposes an adaptive single neural control(ASNC)strategy for variable step-size perturb and observe(P&O)maximum power point tracking(MPPT)control.Firstly,to automatically update the neuron weights of SNC for the nonlinear systems,an adaptive mechanism is proposed to adaptively adjust the weighting and learning coefficients.Secondly,aiming to generate the exact reference speed for ASNC to extract the maximum power,a variable step-size law based on speed increment is designed to strike a balance between tracking speed and accuracy of P&O MPPT.The robust stability of the MCT control system is guaranteed by the Lyapunov theorem.Comparative simulation results show that this strategy has favorable adaptive performance under variable velocity conditions,and the MCT system operates at maximum power point steadily.展开更多
This paper is concerned with the problem of network power quality when grid connected systems are used to feed the grid. These systems use power electronic components such as inverters that produce harmonics which adv...This paper is concerned with the problem of network power quality when grid connected systems are used to feed the grid. These systems use power electronic components such as inverters that produce harmonics which adversely affect the power quality of the distribution network. Instead of using a conventional PI current controller with a fixed proportional and integral gain, development of new control method is considered to overcome the total harmonic emissions in PV inverters. It considers a modification to the controller where a random integral gain is used in the system. Experimental hardware is developed and result shows a reduced total harmonic distortion (THD) of the output current when tested with a resistive load.展开更多
Because of hydraulic-electromagnetic double supporting forms,the supporting capacity and stiffness of magnetic-liquid double suspension bearing(MLDSB)can be improved sharply and then it is more suitable for medium spe...Because of hydraulic-electromagnetic double supporting forms,the supporting capacity and stiffness of magnetic-liquid double suspension bearing(MLDSB)can be improved sharply and then it is more suitable for medium speed,heavy load and frequent-starting occasions.Due to the multiple uncertainty,such as the coupling,the unmodeled dynamics,the parameter perturbation and the external disturbance perturbation,the robust stability and stiffness of control system of MLDSB are hard to meet the design requirements.Firstly,the structural features and the regulation mechanisms of MLDSB are presented and the radial 4-DOF kinetic equations are established.Secondly,the influence factors of the control system's coupling on unbalanced vibration caused by the deviation of the rotor center of mass are revealed,and then the weighting function of suppressing the unbalanced vibration can be obtained.Finally,H∞ controller of MLDSB is designed with H∞ mixed-sensitivity method,and the control performances of H∞ controller is compared with the state feedback controller.The simulation results show that single degree of freedom(DOF)supporting system of MLDSB with H∞ controller has good robust stability,stiffness and the ability to suppress unbalanced external disturbances.This study can provide the theoretical reference for stabilized suspension and control of MLDSB.展开更多
This research is focused on the singularity analysis for single-gimbal control moment gyros systems (SCMGs) which include two types, with constant speed (CSCMG) or variable speed (VSCMG) rotors. Through angular ...This research is focused on the singularity analysis for single-gimbal control moment gyros systems (SCMGs) which include two types, with constant speed (CSCMG) or variable speed (VSCMG) rotors. Through angular momentum hypersurfaces of singular states, the passable and impassable singular points are discriminated easily, meanwhile the information about how much the angular momentum workspace as well as the steering capability available is provided directly. It is obvious that the null motions of steering laws are more effective for the five pyramid configuration(FPC) than for the pyramid configuration(PC) from the singular plots. The possible degenerate hyperbolic singular points of the preceding configurations are calculated and the distinctness of them is denoted by the Gaussian curvature. Furthermore, failure problems to steer integrated power and attitude control system (IPACS) are also analyzed. A sufficient condition of choosing configurations of VSCMGs to guarantee the IPACS steering is given. The angular momentum envelops of VSCMGs, in a given energy and a limited range of rotor speeds, are plotted. The connection and distinctness between CSCMGs and VSCMGs are obtained from the point of view of envelops.展开更多
The trajectory of the controlled system in phase space has been investigated, and different learning methods are applied to the single adaptive neuron controller according to the pattem of the control system. The adva...The trajectory of the controlled system in phase space has been investigated, and different learning methods are applied to the single adaptive neuron controller according to the pattem of the control system. The advantage of the controller presented has been shown by simulation of a satellite attitude stability control system.展开更多
This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice (Oryza sativa L.). Pot trials and cylinder trials were carried out from 2002 to 2005...This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice (Oryza sativa L.). Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance (CRF1) and polymer materials (CRF3) increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer (RSF1). Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.展开更多
An improved single-neuron proportional integral derivative ( PID ) controller and a new method to build the DC motor system were presented in the article. In the simulation, the robot arm is considered as an externa...An improved single-neuron proportional integral derivative ( PID ) controller and a new method to build the DC motor system were presented in the article. In the simulation, the robot arm is considered as an external load to DC motor. Both the motor module and the load module are crea- ted in Simulink to achieve simulation results closer to real robot system. In this way, it can well veri- fy the performance of the improved single-neuron PID controller, which is a combined controller of normal PID controller and single-neuron PID controller. Besides, an intelligent switcher can help to realize the function of choosing a better control algorithm according to motor' s velocity output. Sim- ulated results confirm the rapid and stable response of the improved PID controller. Moreover, the improved single-neuron PID controller has an excellent ability to overcome the load impact and su- press the jamming signals. At last, a GUI interface platform is built to make the controller easier to be applied in other robot systems.展开更多
This paper introduces a SF vector control system of a slip frequency controlled induction mo-tor with simple structure,fair performance and convenient operation.It is realized by two singlechip microprocessors and fed...This paper introduces a SF vector control system of a slip frequency controlled induction mo-tor with simple structure,fair performance and convenient operation.It is realized by two singlechip microprocessors and fed from SPWM-GTR inverter.The whole system is combined by twosubsystems,both of them are 8031 single chip microprocessors.The communication between themis coordinated by the full duplex serial port within the chip and ask-and-answer communicationmanner.The error-corrected means adopted has improved the operation reliability of the system.A series of experimental results on a 3 kW induction motor are given at the end of this paper.展开更多
In this paper we investigate the synchronization of a class of three-dimensional fractional-order chaotic systems. Based on the Lyapunov stability theory and adaptive control technique, a single adaptive-feedback cont...In this paper we investigate the synchronization of a class of three-dimensional fractional-order chaotic systems. Based on the Lyapunov stability theory and adaptive control technique, a single adaptive-feedback controller is developed to synchronize a class of fractional-order chaotic systems. The presented controller which only contains a single driving variable is simple both in design and in implementation. Numerical simulation and circuit experimental results for fractional-order chaotic system are provided to illustrate the effectiveness of the proposed scheme.展开更多
This paper mainly concentrates on design of improved controller and its implementation based on single phase synchronous reference frame theory (SRFT) for Dynamic Voltage Restorer (DVR) compensating voltage sag partic...This paper mainly concentrates on design of improved controller and its implementation based on single phase synchronous reference frame theory (SRFT) for Dynamic Voltage Restorer (DVR) compensating voltage sag particularly for nonlinear load. In case of single phase distribution line with nonlinear load, the complexity of controller’s design becomes more serious issue. The present single phase and/or three phase theories applicable to DVR shows poor response to restore voltage sag in case of nonlinear load due to presence of harmonics. Hence restoration of voltage sag in single phase nonlinear load connected system has been a serious concern. Therefore, new controller for DVR has been proposed incorporating effective design concept for fundamental component extraction in case of nonlinear load. The single phase SRFT based main controller for DVR works on two separate closed path viz. feed forward path for quick transient response and feedback path for reducing the steady state error. Moreover, pre-sag mitigation strategy of DVR has been adapted through these two aforementioned paths. Complete design of proposed controller is based on phasor analysis. It also consist of proportional integral (PI) controller to reduce the error in the DC-link voltage during compensation time. The controller performance has been verified in MATLAB Simulink for both types (linear and nonlinear) of load. The results obtained indicates that the proposed controller is effective in its performance.展开更多
Taking a specific production process as an example, this paper introduces the design of multi slot and unequal temperature PID controller based on single chip microcomputer. The mathematical implementation method...Taking a specific production process as an example, this paper introduces the design of multi slot and unequal temperature PID controller based on single chip microcomputer. The mathematical implementation method of PID algorithm and the design method of the hardware and software are discussed, The principle diagram of the hardware circuit implementing the control algorithm and the features of the software possessed are also presented.展开更多
单边短初级长次级直线感应电机己普遍应用于低速磁悬浮的驱动系统。由于在动态纵向边端效应影响下等效电路不对称,单边直线感应电机(single-sided linear inductionmotor,SLIM)的一些参数非线性变化。传统的应用于旋转电机的无速度...单边短初级长次级直线感应电机己普遍应用于低速磁悬浮的驱动系统。由于在动态纵向边端效应影响下等效电路不对称,单边直线感应电机(single-sided linear inductionmotor,SLIM)的一些参数非线性变化。传统的应用于旋转电机的无速度传感器方法不再适用。首先分析了SLIM的M/T轴等效电路,选择次级磁链作为速度观测器状态变量。根据李雅普诺夫系统稳定性判据,推导出适用于SLIM的无速度传感器辨识;然后,采用反馈广义积分观测器控制稳态辨识速度的双幅脉振幅值;引入虚拟期望变量(virtualdesiredvariable,VDV)法,利用估算速度参与SLIM的恒滑差频率矢量控制。仿真与实验对所提控制算法的有效性和实用性进行了验证,所得结论可为磁悬浮的无速度传感器控制提供参考。展开更多
基金the Key Technologies R&D Program of Harbin (0111211102).
文摘The paper presents a method of using single neuron adaptive PID control for adjusting system or servo system to implement timber drying process control, which combines the thought of parameter adaptive PID control and the character of neural network on exactly describing nonlinear and uncertainty dynamic process organically. The method implements functions of adaptive and self-learning by adjusting weighting parameters. Adaptive neural network can make some output trail given hoping value to decouple in static state. The simulation result indicates the validity, veracity and robustness of the method used in the timber drying process
基金Natural Science Foundation of Gansu Province(Joint)Project(No.213244)Natural Science Foundation of Gansu Province(No.145RJZA136)Youth Science Foundation of Lanzhou Jiaotong University(No.2013040)
文摘In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current(DC)bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.
文摘The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg) and immediate release tablets (IRMS, 20 mg). The plasma concentration of morphine was determined by GC MS. The pharmacokinetic parameters of controlled release tablets and immediate release tablets were calculated∶ C max was 19.38±3.80 and 21.27±6.21 ng/ml, t max was 2.36 ±0.37 h and 0.56±0.16 h, t 1/2β was 3.53±0.87 and 3.03±0.74 h, AUC was 145.15±17.65 and 93.08±16.65 ng/ml, respectively. The steady state plasma concentration of morphine sulphate in cancer patients after multiple doses was achieved, C max of CRMS and IRMS was 27.43±0.33 ng/ml and 22.68±0.16 ng/ml, C min of CRMS and IRMS was 19.45±1.44 ng/ml and 18.14±0.49 ng/ml, respectively.
基金supported by National Natural Science Foundation of China (Grant No. 604740044)Hebei Provincial Natural Science Foundation of China (Grant No. E2004000221)
文摘Flatness is one of the most important criterion factors to evaluate the quality of the steel strip. To improve the strip' s flatness quality, the most frequently used methodology is to employ the closed-loop automatic shape control system. However, in the shape control system, the shape-meter is always installed at the down way of the exit of the cold rolling mill and can not sense the changes of the strip flatness in the rolling gap directly. This kind of installation results in the delay of the feedback in the control system. Therefore, the stability and response performance of the system are strongly affected by the delay. At present, there is still no mature way to design controllers for systems with time delay. Although the conventional PID controller used in most practical applications has the capability to compensate the delay, the effect of the compensation is limited, especially for the systems with long time delay. Smith predictor, as a compensator for solving this problem, is now widely used in industry systems. However, the request of highly precise model of the system and the poor adaptive performance to the changes of related parameters limit the application of the Smith predictor in practice. In order to overcome the drawbacks of the Smith predictor, a new Smith predictor based on single neural network PID (SNN-PID) is proposed. Because the single neural network is employed into the Smith predictor to improve the controller's self-adaptability, the adaptive capability to the varying parameters of the system is improved. Meanwhile, for the purpose of solving the problems such as time-consuming and complicated calculation of the neural networks in real time, the learning coefficient of neural network is divided into several stages as usually done in expert control system. Therefore, the control system can obtain fast response due to the improved calculation speed of the neural networks. In order to validate the performance of the proposed controller, the experiment is conducted on the shape control system in a 300 mm four-high reversing cold rolling mill. The experimental results show that the SNN-PID with Smith predictor controller can effectively compensate the delay effects and achieve better control performance than the conventional PID controller.
文摘The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n time state vector. An estimating algorithm, is developed from this to solve the problem of active control with time delay compensation. The estimating algorithm based on this high order single step β method (HSM) foundation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control with time delay compensation.
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Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros (SGCMGs) as actuators is investigated. First of all, the dynamic model of the underactuated spacecraft is established and the singularity of different configurations with the two SGCMGs is analyzed. Under the assumption that the gimbal axes of the two SGCMGs are installed in any direction, and that the total system angular momentum is not zero, a state feedback control law via Lyapunov method is designed to globally asymptotically stabilize the angular velocity of spacecraft. Under the assumption that the gimbal axes of the two SGCMGs are coaxially installed along anyone of the three principal axes of spacecraft inertia, and that the total system angular momentum is zero, a discontinuous state feedback control law is designed to stabilize three-axis attitude of spacecraft with respect to the inertial frame. Furthermore, the singularity escape of SGCMGs for the above two control problems is also studied. Simulation results demonstrate the validity of the control laws.
文摘Presents a one grade adaptive controller with one reference model which is built according to δ MRACS adaptive control theory and used to control an actual high order hydraulic system, and the whole hardware system used, which includes a AT89C51 single chip microcomputer, 74Ls373 flip latch, 6116 store, eight bit ADC0809, and so on, and the satisfactory results obtained in study on hydraulic control system.
基金financially supported by the National Natural Science Foundation of China(Grant No.61673260)。
文摘Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbine(MCT)system,the nonlinear controllers which rely on precise mathematical models show poor performance under a high level of parameters’uncertainties.This paper proposes an adaptive single neural control(ASNC)strategy for variable step-size perturb and observe(P&O)maximum power point tracking(MPPT)control.Firstly,to automatically update the neuron weights of SNC for the nonlinear systems,an adaptive mechanism is proposed to adaptively adjust the weighting and learning coefficients.Secondly,aiming to generate the exact reference speed for ASNC to extract the maximum power,a variable step-size law based on speed increment is designed to strike a balance between tracking speed and accuracy of P&O MPPT.The robust stability of the MCT control system is guaranteed by the Lyapunov theorem.Comparative simulation results show that this strategy has favorable adaptive performance under variable velocity conditions,and the MCT system operates at maximum power point steadily.
文摘This paper is concerned with the problem of network power quality when grid connected systems are used to feed the grid. These systems use power electronic components such as inverters that produce harmonics which adversely affect the power quality of the distribution network. Instead of using a conventional PI current controller with a fixed proportional and integral gain, development of new control method is considered to overcome the total harmonic emissions in PV inverters. It considers a modification to the controller where a random integral gain is used in the system. Experimental hardware is developed and result shows a reduced total harmonic distortion (THD) of the output current when tested with a resistive load.
基金Supported by the National Nature Science Foundation of China(No.51705445,52075468)General Project of Natural Science Foundation of Hebei Province(E2020203052)+1 种基金Youth Fund Project of Scientific Research Project of Hebei University(QN202013)Open Project Funding of Jiangsu Provincial Key Laboratory of Advanced Manufacture and Process for Marine Mechanical Equipment and Open Project Funding of Fluid Power Transmission Control Laboratory of Yanshan University.
文摘Because of hydraulic-electromagnetic double supporting forms,the supporting capacity and stiffness of magnetic-liquid double suspension bearing(MLDSB)can be improved sharply and then it is more suitable for medium speed,heavy load and frequent-starting occasions.Due to the multiple uncertainty,such as the coupling,the unmodeled dynamics,the parameter perturbation and the external disturbance perturbation,the robust stability and stiffness of control system of MLDSB are hard to meet the design requirements.Firstly,the structural features and the regulation mechanisms of MLDSB are presented and the radial 4-DOF kinetic equations are established.Secondly,the influence factors of the control system's coupling on unbalanced vibration caused by the deviation of the rotor center of mass are revealed,and then the weighting function of suppressing the unbalanced vibration can be obtained.Finally,H∞ controller of MLDSB is designed with H∞ mixed-sensitivity method,and the control performances of H∞ controller is compared with the state feedback controller.The simulation results show that single degree of freedom(DOF)supporting system of MLDSB with H∞ controller has good robust stability,stiffness and the ability to suppress unbalanced external disturbances.This study can provide the theoretical reference for stabilized suspension and control of MLDSB.
文摘This research is focused on the singularity analysis for single-gimbal control moment gyros systems (SCMGs) which include two types, with constant speed (CSCMG) or variable speed (VSCMG) rotors. Through angular momentum hypersurfaces of singular states, the passable and impassable singular points are discriminated easily, meanwhile the information about how much the angular momentum workspace as well as the steering capability available is provided directly. It is obvious that the null motions of steering laws are more effective for the five pyramid configuration(FPC) than for the pyramid configuration(PC) from the singular plots. The possible degenerate hyperbolic singular points of the preceding configurations are calculated and the distinctness of them is denoted by the Gaussian curvature. Furthermore, failure problems to steer integrated power and attitude control system (IPACS) are also analyzed. A sufficient condition of choosing configurations of VSCMGs to guarantee the IPACS steering is given. The angular momentum envelops of VSCMGs, in a given energy and a limited range of rotor speeds, are plotted. The connection and distinctness between CSCMGs and VSCMGs are obtained from the point of view of envelops.
文摘The trajectory of the controlled system in phase space has been investigated, and different learning methods are applied to the single adaptive neuron controller according to the pattem of the control system. The advantage of the controller presented has been shown by simulation of a satellite attitude stability control system.
文摘This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice (Oryza sativa L.). Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance (CRF1) and polymer materials (CRF3) increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer (RSF1). Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.
文摘An improved single-neuron proportional integral derivative ( PID ) controller and a new method to build the DC motor system were presented in the article. In the simulation, the robot arm is considered as an external load to DC motor. Both the motor module and the load module are crea- ted in Simulink to achieve simulation results closer to real robot system. In this way, it can well veri- fy the performance of the improved single-neuron PID controller, which is a combined controller of normal PID controller and single-neuron PID controller. Besides, an intelligent switcher can help to realize the function of choosing a better control algorithm according to motor' s velocity output. Sim- ulated results confirm the rapid and stable response of the improved PID controller. Moreover, the improved single-neuron PID controller has an excellent ability to overcome the load impact and su- press the jamming signals. At last, a GUI interface platform is built to make the controller easier to be applied in other robot systems.
文摘This paper introduces a SF vector control system of a slip frequency controlled induction mo-tor with simple structure,fair performance and convenient operation.It is realized by two singlechip microprocessors and fed from SPWM-GTR inverter.The whole system is combined by twosubsystems,both of them are 8031 single chip microprocessors.The communication between themis coordinated by the full duplex serial port within the chip and ask-and-answer communicationmanner.The error-corrected means adopted has improved the operation reliability of the system.A series of experimental results on a 3 kW induction motor are given at the end of this paper.
基金Project supported by the Natural Science Foundation of Hebei Province,China (Grant No. A2010000343)
文摘In this paper we investigate the synchronization of a class of three-dimensional fractional-order chaotic systems. Based on the Lyapunov stability theory and adaptive control technique, a single adaptive-feedback controller is developed to synchronize a class of fractional-order chaotic systems. The presented controller which only contains a single driving variable is simple both in design and in implementation. Numerical simulation and circuit experimental results for fractional-order chaotic system are provided to illustrate the effectiveness of the proposed scheme.
文摘This paper mainly concentrates on design of improved controller and its implementation based on single phase synchronous reference frame theory (SRFT) for Dynamic Voltage Restorer (DVR) compensating voltage sag particularly for nonlinear load. In case of single phase distribution line with nonlinear load, the complexity of controller’s design becomes more serious issue. The present single phase and/or three phase theories applicable to DVR shows poor response to restore voltage sag in case of nonlinear load due to presence of harmonics. Hence restoration of voltage sag in single phase nonlinear load connected system has been a serious concern. Therefore, new controller for DVR has been proposed incorporating effective design concept for fundamental component extraction in case of nonlinear load. The single phase SRFT based main controller for DVR works on two separate closed path viz. feed forward path for quick transient response and feedback path for reducing the steady state error. Moreover, pre-sag mitigation strategy of DVR has been adapted through these two aforementioned paths. Complete design of proposed controller is based on phasor analysis. It also consist of proportional integral (PI) controller to reduce the error in the DC-link voltage during compensation time. The controller performance has been verified in MATLAB Simulink for both types (linear and nonlinear) of load. The results obtained indicates that the proposed controller is effective in its performance.
文摘Taking a specific production process as an example, this paper introduces the design of multi slot and unequal temperature PID controller based on single chip microcomputer. The mathematical implementation method of PID algorithm and the design method of the hardware and software are discussed, The principle diagram of the hardware circuit implementing the control algorithm and the features of the software possessed are also presented.
文摘单边短初级长次级直线感应电机己普遍应用于低速磁悬浮的驱动系统。由于在动态纵向边端效应影响下等效电路不对称,单边直线感应电机(single-sided linear inductionmotor,SLIM)的一些参数非线性变化。传统的应用于旋转电机的无速度传感器方法不再适用。首先分析了SLIM的M/T轴等效电路,选择次级磁链作为速度观测器状态变量。根据李雅普诺夫系统稳定性判据,推导出适用于SLIM的无速度传感器辨识;然后,采用反馈广义积分观测器控制稳态辨识速度的双幅脉振幅值;引入虚拟期望变量(virtualdesiredvariable,VDV)法,利用估算速度参与SLIM的恒滑差频率矢量控制。仿真与实验对所提控制算法的有效性和实用性进行了验证,所得结论可为磁悬浮的无速度传感器控制提供参考。