Palladium(Pd)-based sulfides have triggered extensive interest due to their unique properties and potential applications in the fields of electronics and optoelectronics.However,the synthesis of large-scale uniform Pd...Palladium(Pd)-based sulfides have triggered extensive interest due to their unique properties and potential applications in the fields of electronics and optoelectronics.However,the synthesis of large-scale uniform PdS and PdS_(2)nanofilms(NFs)remains an enormous challenge.In this work,2-inch wafer-scale PdS and PdS_(2) NFs with excellent stability can be controllably prepared via chemical vapor deposition combined with electron beam evaporation technique.The thickness of the pre-deposited Pd film and the sulfurization temperature are critical for the precise synthesis of PdS and PdS_(2) NFs.A corresponding growth mechanism has been proposed based on our experimental results and Gibbs free energy calculations.The electrical transport properties of PdS and PdS_(2) NFs were explored by conductive atomic force microscopy.Our findings have achieved the controllable growth of PdS and PdS_(2) NFs,which may provide a pathway to facilitate PdS and PdS_(2) based applications for next-generation high performance optoelectronic devices.展开更多
Long-period pulses in near-field earthquakes lead to large displacements in the base of isolated structures.To dissipate energy in isolated structures using semi-active control,piezoelectric friction dampers（PFD） ca...Long-period pulses in near-field earthquakes lead to large displacements in the base of isolated structures.To dissipate energy in isolated structures using semi-active control,piezoelectric friction dampers（PFD） can be employed.The performance of a PFD is highly dependent on the strategy applied to adjust its contact force.In this paper,the seismic control of a benchmark isolated building equipped with PFD using PD/PID controllers is developed.Using genetic algorithms,these controllers are optimized to create a balance between the performance and robustness of the closed-loop structural system.One advantage of this technique is that the controller forces can easily be estimated.In addition,the structure is equipped with only a single sensor at the base floor to measure the base displacement.Considering seven pairs of earthquakes and nine performance indices,the performance of the closed-loop system is evaluated.Then,the results are compared with those given by two well-known methods：the maximum possive operation of piezoelectric friction dampers and LQG controllers.The simulation results show that the proposed controllers perform better than the others in terms of simultaneous reduction of floor acceleration and maximum displacement of the isolator.Moreover,they are able to reduce the displacement of the isolator systems for different earthquakes without losing the advantages of isolation.展开更多
A novel repetitive control strategy for the output waveform of single-phase CVCF inverters is presented. In this scheme, the inverse transfer function of inverter is used as a compensator to obtain stable and satisfy ...A novel repetitive control strategy for the output waveform of single-phase CVCF inverters is presented. In this scheme, the inverse transfer function of inverter is used as a compensator to obtain stable and satisfy harmonic rejection. Besides, PD controller is adopted to improve transient performance. Simulation and experimental results, which are gotten from a DSP-based 400Hz, 5.5KW inverter, indicate that the proposed control scheme can achieve not only low THD during steady-state operation but also fast transient response during load step change.展开更多
In this paper, a decentralized proportional-derivative （PD） controller design for non-uniform motion of a Hamiltonian hybrid system is considered. A Hamiltonian hybrid system with the capability of producing a non-u...In this paper, a decentralized proportional-derivative （PD） controller design for non-uniform motion of a Hamiltonian hybrid system is considered. A Hamiltonian hybrid system with the capability of producing a non-uniform motion is developed. The structural properties of the system are investigated by means of the theory of Hamiltonian systems. A relationship between the parameters of the system and the parameters of the proposed decentralized PD controller is shown to ensure local stability and tracking performance. Simulation results are included to show the obtained non-uniform motion.展开更多
A novel type of control law was adopted to reduce the vertical acceleration of a fast ferry as well as the motion sickness incidence suffered by the passengers onboard by means of a submerged T-foil.Considering the sy...A novel type of control law was adopted to reduce the vertical acceleration of a fast ferry as well as the motion sickness incidence suffered by the passengers onboard by means of a submerged T-foil.Considering the system changing characteristics under high disturbances,a model-free approach was adopted.In addition,an upgraded proportional-derivative(PD)controller with correction terms resulting from a fast-online estimation of the system dynamics was designed.The overall controller,known as intelligent PD(i-PD)controller,was tested,and the obtained results were compared with those of a classic PD controller.The controllers were also tested in a changing environment and at different operating velocities.The results confirmed the effectiveness of the i-PD controller to smooth the motions with low computational cost control schemes.Furthermore,thanks to ability of the i-PD controller to continually update the estimated dynamics of the system,it showed a better reduction in both vertical motions and the seasickness level of the passengers with the needed robustness under external disturbances and system changing parameters.展开更多
针对四轮全向机器人数学模型中未知因数的干扰,提出了一种基于神经滑模的比例微分(Proportional plus Derivative,PD)自适应跟踪控制策略。首先,对机器人的动力学模型进行分析;其次,利用反步轨迹跟踪控制器得到虚拟速度,基于虚拟输入与...针对四轮全向机器人数学模型中未知因数的干扰,提出了一种基于神经滑模的比例微分(Proportional plus Derivative,PD)自适应跟踪控制策略。首先,对机器人的动力学模型进行分析;其次,利用反步轨迹跟踪控制器得到虚拟速度,基于虚拟输入与实际输入的误差设计PD控制器;接着,采用神经网络来逼近动力学模型中的不确定性,并利用Lyapunov定理证明了系统的稳定性。仿真和实验结果表明,该控制策略具有有效性。展开更多
This paper presents the formulation of novel implementation method based on parameter varying PD controller for fuzzy servo controllers. This formulation uses the approximation of fuzzy nonlinear function including er...This paper presents the formulation of novel implementation method based on parameter varying PD controller for fuzzy servo controllers. This formulation uses the approximation of fuzzy nonlinear function including error and error derivation in operation point. Obtained fuzzy control law has been employed to control angular position of servo using digital control technique applied to a typical microcontroller like AVR. The performance and robustness of modified fuzzy controller in comparison with PID controller evaluated in no load, applied external disturbance with different magnitude conditions has been studied. The simulation results showed that the proposed fuzzy controller has a considerable advantage in rise time, settling time and overshoot respect to PID controller when the servo system encounters with nonlinear features like saturation and friction.展开更多
In conjunction with a second order uncertain nonlinear system, this paper makes some comparisons between PID control and general-integral-proportional-derivative (GI-PD) control;that is, by Routh’s stability criterio...In conjunction with a second order uncertain nonlinear system, this paper makes some comparisons between PID control and general-integral-proportional-derivative (GI-PD) control;that is, by Routh’s stability criterion, we demonstrate that the system matrix under GI-PD control can be stabilized more easily;by linear system theory and Lyapunov method, we demonstrate that GI-PD control can deal with the uncertain nonlinearity more effectively;by analyzing and comparing the integral control action, we demonstrate that GI-PD control has the better control performance. Design example and simulation results verify the justification of our conclusions again. All these mean that GI-PD control has the stronger robustness and higher control performance than PID control. Consequently, GI-PD control has broader application prospects than PID control.展开更多
基金supported by National Natural Science Foundation of China (No.11974301)Key Research and Development Program of Hunan Province (No.2022GK2007)+2 种基金Key Project from Department Education of Hunan Province (No.22A0123)Scientific Research Fund of Hunan Provincial Education Department (No.21B0136)National college students innovation and entrepreneurship training program (No.S202310530016)。
文摘Palladium(Pd)-based sulfides have triggered extensive interest due to their unique properties and potential applications in the fields of electronics and optoelectronics.However,the synthesis of large-scale uniform PdS and PdS_(2)nanofilms(NFs)remains an enormous challenge.In this work,2-inch wafer-scale PdS and PdS_(2) NFs with excellent stability can be controllably prepared via chemical vapor deposition combined with electron beam evaporation technique.The thickness of the pre-deposited Pd film and the sulfurization temperature are critical for the precise synthesis of PdS and PdS_(2) NFs.A corresponding growth mechanism has been proposed based on our experimental results and Gibbs free energy calculations.The electrical transport properties of PdS and PdS_(2) NFs were explored by conductive atomic force microscopy.Our findings have achieved the controllable growth of PdS and PdS_(2) NFs,which may provide a pathway to facilitate PdS and PdS_(2) based applications for next-generation high performance optoelectronic devices.
文摘Long-period pulses in near-field earthquakes lead to large displacements in the base of isolated structures.To dissipate energy in isolated structures using semi-active control,piezoelectric friction dampers（PFD） can be employed.The performance of a PFD is highly dependent on the strategy applied to adjust its contact force.In this paper,the seismic control of a benchmark isolated building equipped with PFD using PD/PID controllers is developed.Using genetic algorithms,these controllers are optimized to create a balance between the performance and robustness of the closed-loop structural system.One advantage of this technique is that the controller forces can easily be estimated.In addition,the structure is equipped with only a single sensor at the base floor to measure the base displacement.Considering seven pairs of earthquakes and nine performance indices,the performance of the closed-loop system is evaluated.Then,the results are compared with those given by two well-known methods：the maximum possive operation of piezoelectric friction dampers and LQG controllers.The simulation results show that the proposed controllers perform better than the others in terms of simultaneous reduction of floor acceleration and maximum displacement of the isolator.Moreover,they are able to reduce the displacement of the isolator systems for different earthquakes without losing the advantages of isolation.
基金This work was supported by the National Natural Science Foundation of China (No. 50007004)
文摘A novel repetitive control strategy for the output waveform of single-phase CVCF inverters is presented. In this scheme, the inverse transfer function of inverter is used as a compensator to obtain stable and satisfy harmonic rejection. Besides, PD controller is adopted to improve transient performance. Simulation and experimental results, which are gotten from a DSP-based 400Hz, 5.5KW inverter, indicate that the proposed control scheme can achieve not only low THD during steady-state operation but also fast transient response during load step change.
文摘In this paper, a decentralized proportional-derivative （PD） controller design for non-uniform motion of a Hamiltonian hybrid system is considered. A Hamiltonian hybrid system with the capability of producing a non-uniform motion is developed. The structural properties of the system are investigated by means of the theory of Hamiltonian systems. A relationship between the parameters of the system and the parameters of the proposed decentralized PD controller is shown to ensure local stability and tracking performance. Simulation results are included to show the obtained non-uniform motion.
文摘A novel type of control law was adopted to reduce the vertical acceleration of a fast ferry as well as the motion sickness incidence suffered by the passengers onboard by means of a submerged T-foil.Considering the system changing characteristics under high disturbances,a model-free approach was adopted.In addition,an upgraded proportional-derivative(PD)controller with correction terms resulting from a fast-online estimation of the system dynamics was designed.The overall controller,known as intelligent PD(i-PD)controller,was tested,and the obtained results were compared with those of a classic PD controller.The controllers were also tested in a changing environment and at different operating velocities.The results confirmed the effectiveness of the i-PD controller to smooth the motions with low computational cost control schemes.Furthermore,thanks to ability of the i-PD controller to continually update the estimated dynamics of the system,it showed a better reduction in both vertical motions and the seasickness level of the passengers with the needed robustness under external disturbances and system changing parameters.
文摘针对四轮全向机器人数学模型中未知因数的干扰,提出了一种基于神经滑模的比例微分(Proportional plus Derivative,PD)自适应跟踪控制策略。首先,对机器人的动力学模型进行分析;其次,利用反步轨迹跟踪控制器得到虚拟速度,基于虚拟输入与实际输入的误差设计PD控制器;接着,采用神经网络来逼近动力学模型中的不确定性,并利用Lyapunov定理证明了系统的稳定性。仿真和实验结果表明,该控制策略具有有效性。
文摘This paper presents the formulation of novel implementation method based on parameter varying PD controller for fuzzy servo controllers. This formulation uses the approximation of fuzzy nonlinear function including error and error derivation in operation point. Obtained fuzzy control law has been employed to control angular position of servo using digital control technique applied to a typical microcontroller like AVR. The performance and robustness of modified fuzzy controller in comparison with PID controller evaluated in no load, applied external disturbance with different magnitude conditions has been studied. The simulation results showed that the proposed fuzzy controller has a considerable advantage in rise time, settling time and overshoot respect to PID controller when the servo system encounters with nonlinear features like saturation and friction.
文摘In conjunction with a second order uncertain nonlinear system, this paper makes some comparisons between PID control and general-integral-proportional-derivative (GI-PD) control;that is, by Routh’s stability criterion, we demonstrate that the system matrix under GI-PD control can be stabilized more easily;by linear system theory and Lyapunov method, we demonstrate that GI-PD control can deal with the uncertain nonlinearity more effectively;by analyzing and comparing the integral control action, we demonstrate that GI-PD control has the better control performance. Design example and simulation results verify the justification of our conclusions again. All these mean that GI-PD control has the stronger robustness and higher control performance than PID control. Consequently, GI-PD control has broader application prospects than PID control.
