The problem of track control is studied for a class of strict-feedback stochastic nonlinear systems in which unknown virtual control gain function is the main feature. First, the so-called stochastic LaSalle theory is...The problem of track control is studied for a class of strict-feedback stochastic nonlinear systems in which unknown virtual control gain function is the main feature. First, the so-called stochastic LaSalle theory is extended to some extent, and accordingly, the results of global ultimate boundedness for stochastic nonlinear systems are developed. Next, a new design scheme of fuzzy adaptive control is proposed. The advantage of it is that it does not require priori knowledge of virtual control gain function sign, which is usually demanded in many designs. At the same time, the track performance of closed-loop systems is improved by adaptive modifying the estimated error upper bound. By theoretical analysis, the signals of closed-loop systems are globally ultimately bounded in probability and the track error converges to a small residual set around the origin in 4th-power expectation.展开更多
A new concept called intelligent virtual control (IVC), which can be drivenby measuring functions, is put forward. This small 'intelligent measurement instrument unit (IMIU)',carrying with functions of instrum...A new concept called intelligent virtual control (IVC), which can be drivenby measuring functions, is put forward. This small 'intelligent measurement instrument unit (IMIU)',carrying with functions of instrument, consists of different types of intelligent virtualinstrument (IVI) through individual components together as building blocks and can be displayeddirectly on the computer screen. This is a new concept of measuring instrument, and also animportant breakthrough after virtual instrument (VI). Virtual control makes instrument resourcesobtain further exploitation. It brings about a fundamental change to the design and manufacturingmode. The instrument therefore, can not only be produced directly inside a PC, but the product isinvolved in the 'green product' system. So far, all the present digital instruments will grow to bereplaced by intelligent control with green characteristics.展开更多
Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefor...Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefore,in future“double high”power systems,research on the control technology of GFM converters will become an urgent demand.In this paper,we first introduce the basic principle of GFM control and then present five currently used control strategies for GFM converters:droop control,power synchronization control(PSC),virtual synchronous machine control(VSM),direct power control(DPC),and virtual oscillator control(VOC).These five strategies can independently establish voltage phasors to provide inertia to the system.Among these,droop control is the most widely used strategy.PSC and VSM are strategies that simulate the mechanical characteristics of synchronous generators;thus,they are more accurate than droop control.DPC regulates the active power and reactive power directly,with no inner current controller,and VOC is a novel method under study using an oscillator circuit to realize synchronization.Finally,we highlight key technologies and research directions to be addressed in the future.展开更多
Intelligent virtual control (IVC) is an intelligent measurement instrumentunit with the function of actual measurement instruments, and the unit can be used as basic buildingblock for a variety of more complex virtual...Intelligent virtual control (IVC) is an intelligent measurement instrumentunit with the function of actual measurement instruments, and the unit can be used as basic buildingblock for a variety of more complex virtual measurement instruments on a PC. IVC is a furtheradvancement from virtual instrument (VI), and it fuses the function modules and the controls modulesso that the relationship between the functions and controls of an instrument is imbedded in one ormore units. The design, implementation and optimization methods of IVCs are introduced. The computersoftware representation of IVCs is discussed. An example of an actual VI constructed with thebuilding blocks of IVCs is given.展开更多
In order to improve the force tracking performance of hydraulic quadruped robots in uncertain and unstructured environments,an impedance-based adaptive reference trajectory generation scheme is used.Secondly,in order ...In order to improve the force tracking performance of hydraulic quadruped robots in uncertain and unstructured environments,an impedance-based adaptive reference trajectory generation scheme is used.Secondly,in order to improve the robustness to environmental changes and reduce the contact force errors caused by trajectory tracking errors,the backstepping sliding mode controller is combined with the adaptive reference trajectory generator.Finally,a virtual damping control based on velocity and pressure feedback is proposed to solve the problem of contact force disappearance and stall caused by sudden environmental change.The simulation results show that the proposed scheme has higher contact force tracking accuracy when the environment is unchanged;the contact force error can always be guaranteed within an acceptable range when the environment is reasonably changed;when the environment suddenly changes,the drive unit can move slowly until the robot re-contacts the environment.展开更多
The dynamic modeling, finite-time trajectory tracking control and vibration suppression of a flexible two-link space robot are studied. Firstly, the dynamic model of the system is established by combining Lagrange met...The dynamic modeling, finite-time trajectory tracking control and vibration suppression of a flexible two-link space robot are studied. Firstly, the dynamic model of the system is established by combining Lagrange method with assumed mode method. In order to ensure that the base attitude and the joints of space robot can reach the desired positions within a limited time, a non-singular fast terminal sliding mode(NFTSM) controller is designed, which realizes the finite-time convergence of the trajectory tracking errors. Subsequently, for the sake of suppressing the vibrations of flexible links, a hybrid trajectory based on the concept of the virtual control force is developed, which can reflect the flexible modes and the trajectory tracking errors simultaneously. By modifying the original control scheme, a NFTSM hybrid controller is proposed. The hybrid control scheme can not only realized attitude stabilization and trajectory tracking of joints in finite time, but also provide a new method of vibration suppression. The simulation results verify the effectiveness of the designed hybrid control strategy.展开更多
A high fidelity dynamic model of a high-energy hydraulically-actuated shock test machine for heavy weight devices is presented to satisfy the newly-built shock resistance standard and simulate the actual underwater ex...A high fidelity dynamic model of a high-energy hydraulically-actuated shock test machine for heavy weight devices is presented to satisfy the newly-built shock resistance standard and simulate the actual underwater explosion environments in laboratory as well as increase the testing capability of shock test machine. In order to produce the required negative shock pulse in the given time duration, four hydraulic actuators are utilized. The model is then used to formulate an advanced feedforward controller for the system to produce the required negative waveform and to address the motion synchronization of the four cylinders. The model provides a safe and easily controllable way to perform a ＂virtual testing＂ before starting potentially destructive tests on specimen and to predict performance of the system. Simulation results have demonstrated the effectiveness of the controller.展开更多
In order to improve the power of initiating explosive warheads, besides exploring new type of high explosive, multipoint initiation technology becomes the research focus. With research on electronic safety and arming ...In order to improve the power of initiating explosive warheads, besides exploring new type of high explosive, multipoint initiation technology becomes the research focus. With research on electronic safety and arming devices （ESADs）, pulse power devices and slapper detonators, a hardware control circuit was designed for multipoint initiation control system based on complex programmable logic device （ CPLD ）. In addition, a real-time monitoring interface based on virtual instru- ments technology was designed by the prevailing software of Laboratory Virtual Instrument Engineer- ing Workbench （LabVIEW）. It provides users a real-time status of the hardware circuit system. Mo- reover, a series of experiments were done on the software and hardware platform. The results show that the signals transmission, collection, analysis and display can be realized reliably through a serial port line. It is verified that using a serial bus controller for multiple initiators is reasonable. Successful design of the platform will play an important foundation for the theory and engineering of the fu- ture weapon system. Surely, it will become one of the development directions for intelligent initia- tion system.展开更多
As conventional synchronous generators are replaced by large-scale converter-interfaced renewa-ble-energy sources(RESs),the electric power grid en-counters the challenge of low rotational inertia.Conse-quently,system ...As conventional synchronous generators are replaced by large-scale converter-interfaced renewa-ble-energy sources(RESs),the electric power grid en-counters the challenge of low rotational inertia.Conse-quently,system frequency deviation is exacerbated and system instability may occur when the frequency deviates beyond the acceptable range.To mitigate this effect,this study proposes a virtual inertia control(VIC)strategy based on a fractional-order derivative and controller parameter-tuning method.The tuning method uses the stability boundary locus and provides a stability criterion for identifying the stability region in the parameter space.The controller parameters are then optimized within the identified stability region to suppress frequency deviation and enhance system robustness.The proposed controller and tuning method is applied to a battery energy-storage system(BESS)in a low-inertia power system with the integration of RESs.Time-domain simulations are carried out to verify the stability region and compare the per-formance of the optimized proposed controller to that of the traditional integral-order controller.The simulation results show that the stability-analysis method is effective and that the fractional-order VIC,tuned with the pro-posed method,outperforms the traditional method in both frequency-regulation performance and parametric robustness.展开更多
Wind energy systems (WESs) based on doubly-fed induction generators (DFIGs) have enormous potential for meeting the future demands related to clean energy. Due to the low inertia and intermittency of power injection, ...Wind energy systems (WESs) based on doubly-fed induction generators (DFIGs) have enormous potential for meeting the future demands related to clean energy. Due to the low inertia and intermittency of power injection, a WES is equipped with a virtual inertial controller (VIC) to support the system during a frequency deviation event. The frequency deviation measured by a phase locked loop (PLL) installed on a point of common coupling (PCC) bus is the input signal to the VIC. However, a VIC with an improper inertial gain could deteriorate the damping of the power system, which may lead to instability. To address this issue, a mathematical formulation for calculating the synchronizing and damping torque coefficients of a WES-integrated single-machine infinite bus (SMIB) system while considering PLL and VIC dynamics is proposed in this paper. In addition, a power system stabilizer (PSS) is designed for wind energy integrated power systems to enhance electromechanical oscillation damping. A small-signal stability assessment is performed using the infinite bus connected to a synchronous generator of higher-order dynamics integrated with a VIC-equipped WES. Finally, the performance and robustness of the proposed PSS is demonstrated through time-domain simulation in SMIB and nine-bus test systems integrated with WES under several case studies.展开更多
新型脉冲功率设备对直流侧母线电压提出较高的性能要求,为减小脉冲负载对直流电压波动率的影响,建立带脉冲负载三相整流器拓扑结构及数学模型,并在现有无源控制(passivity based control,PBC)设计的基础上,以保证系统稳定性为前提,提出...新型脉冲功率设备对直流侧母线电压提出较高的性能要求,为减小脉冲负载对直流电压波动率的影响,建立带脉冲负载三相整流器拓扑结构及数学模型,并在现有无源控制(passivity based control,PBC)设计的基础上,以保证系统稳定性为前提,提出注入虚拟储能的无源控制算法(virtual energy storage injection PBC,VESI-PBC),该算法以提高能量函数收敛速度为目标,可有效降低直流母线电压波动率,提高抗负载扰动能力。分别基于根轨迹法和时域分析法,讨论VESI-PBC引入储能矩阵后,增大虚拟电感值L_(n)对系统的稳定性和动态性能的影响。为满足直流侧性能要求和保证系统稳定性,利用脉冲负载对直流电压波动率的影响规律,提出L_(n)自适应选取函数f(f_(PL)),使L_(n)自适应平衡系统高频毛刺和低频强脉冲冲击的不同需求。最后,通过仿真及实际试验,验证VESI-PBC算法对减小直流母线电压波动率的有效性,并指出该算法的实质是控制内环电流超前响应直流电压的动态变化及其变化趋势,由此具有较强的抗负载扰动能力,适用于负载脉冲功率等级高、动态特性强烈的场合。展开更多
The increasing adoption of grid-forming converters(GFMCs)stems from their capacity to furnish voltage and frequency support for power grids.Nevertheless,GFMCs employing the current reference saturation limiting method...The increasing adoption of grid-forming converters(GFMCs)stems from their capacity to furnish voltage and frequency support for power grids.Nevertheless,GFMCs employing the current reference saturation limiting method often exhibit instability during various transient disturbances including grid voltage sags,frequency variations,and phase jumps.To address this problem,this paper proposes a virtual power angle synchronous(δv-SYN)control method.The fundamental of this method is to achieve synchronization with the grid using the virtual power angleδv instead of the active power.The transient stability characteristics of the proposed method are theoretically elucidated using a novel virtual power angle-power angle(δv-δ)model.The key benefit of the proposed method is its robustness to various grid strengths and diverse forms of transient disturbances,eliminating the requirement for fault identification or control switching.Moreover,it can offer grid-forming support to the grid during grid faults.Hardware-in-the-loop experimental results validate the theoretical analysis and the performance of the proposed method.展开更多
The control network is an important developmental orientation in the remote control system. As the control network and information network are comparatively alike in the framework and technology, we can build a contro...The control network is an important developmental orientation in the remote control system. As the control network and information network are comparatively alike in the framework and technology, we can build a control network which is similar to the common information network. In the era when the information network is becoming increasingly mature, it is a royal road to construct or rebuild a control information network in the development of the control network by relying on the achievements made in the information network or current information resources. This paper expounds the construction idea of the control information network, gives the idiographic realization method and then researches into the real-time problem encountered in the control information network, and presents a three-closed-loop control system based on virtualized reality. The feasibility of the idea is validated via experiments and simulations separately.展开更多
基金Supported by National Natural Science Foundation of P. R. China (60572070, 60325311, 60534010) Natural Science Foundation of Liaoning Province (20022030)
文摘The problem of track control is studied for a class of strict-feedback stochastic nonlinear systems in which unknown virtual control gain function is the main feature. First, the so-called stochastic LaSalle theory is extended to some extent, and accordingly, the results of global ultimate boundedness for stochastic nonlinear systems are developed. Next, a new design scheme of fuzzy adaptive control is proposed. The advantage of it is that it does not require priori knowledge of virtual control gain function sign, which is usually demanded in many designs. At the same time, the track performance of closed-loop systems is improved by adaptive modifying the estimated error upper bound. By theoretical analysis, the signals of closed-loop systems are globally ultimately bounded in probability and the track error converges to a small residual set around the origin in 4th-power expectation.
基金This project is supported by National Natural Science Foundation of China(No.50135050).
文摘A new concept called intelligent virtual control (IVC), which can be drivenby measuring functions, is put forward. This small 'intelligent measurement instrument unit (IMIU)',carrying with functions of instrument, consists of different types of intelligent virtualinstrument (IVI) through individual components together as building blocks and can be displayeddirectly on the computer screen. This is a new concept of measuring instrument, and also animportant breakthrough after virtual instrument (VI). Virtual control makes instrument resourcesobtain further exploitation. It brings about a fundamental change to the design and manufacturingmode. The instrument therefore, can not only be produced directly inside a PC, but the product isinvolved in the 'green product' system. So far, all the present digital instruments will grow to bereplaced by intelligent control with green characteristics.
基金supported by the National Natural Science Foundation of China(No.52177122)the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 21050100)the Youth Innovation Promotion Association CAS(No.2018170)。
文摘Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefore,in future“double high”power systems,research on the control technology of GFM converters will become an urgent demand.In this paper,we first introduce the basic principle of GFM control and then present five currently used control strategies for GFM converters:droop control,power synchronization control(PSC),virtual synchronous machine control(VSM),direct power control(DPC),and virtual oscillator control(VOC).These five strategies can independently establish voltage phasors to provide inertia to the system.Among these,droop control is the most widely used strategy.PSC and VSM are strategies that simulate the mechanical characteristics of synchronous generators;thus,they are more accurate than droop control.DPC regulates the active power and reactive power directly,with no inner current controller,and VOC is a novel method under study using an oscillator circuit to realize synchronization.Finally,we highlight key technologies and research directions to be addressed in the future.
基金This project is supported by National Natural Science Foundation of China (No.50135050).
文摘Intelligent virtual control (IVC) is an intelligent measurement instrumentunit with the function of actual measurement instruments, and the unit can be used as basic buildingblock for a variety of more complex virtual measurement instruments on a PC. IVC is a furtheradvancement from virtual instrument (VI), and it fuses the function modules and the controls modulesso that the relationship between the functions and controls of an instrument is imbedded in one ormore units. The design, implementation and optimization methods of IVCs are introduced. The computersoftware representation of IVCs is discussed. An example of an actual VI constructed with thebuilding blocks of IVCs is given.
基金Projects(51975376,51505289)supported by the National Natural Science Foundation of ChinaProject(19ZR1435400)supported by the Natural Science Foundation of Shanghai,China。
文摘In order to improve the force tracking performance of hydraulic quadruped robots in uncertain and unstructured environments,an impedance-based adaptive reference trajectory generation scheme is used.Secondly,in order to improve the robustness to environmental changes and reduce the contact force errors caused by trajectory tracking errors,the backstepping sliding mode controller is combined with the adaptive reference trajectory generator.Finally,a virtual damping control based on velocity and pressure feedback is proposed to solve the problem of contact force disappearance and stall caused by sudden environmental change.The simulation results show that the proposed scheme has higher contact force tracking accuracy when the environment is unchanged;the contact force error can always be guaranteed within an acceptable range when the environment is reasonably changed;when the environment suddenly changes,the drive unit can move slowly until the robot re-contacts the environment.
基金supported by the National Natural Science Foundation of China (No. 11372073)。
文摘The dynamic modeling, finite-time trajectory tracking control and vibration suppression of a flexible two-link space robot are studied. Firstly, the dynamic model of the system is established by combining Lagrange method with assumed mode method. In order to ensure that the base attitude and the joints of space robot can reach the desired positions within a limited time, a non-singular fast terminal sliding mode(NFTSM) controller is designed, which realizes the finite-time convergence of the trajectory tracking errors. Subsequently, for the sake of suppressing the vibrations of flexible links, a hybrid trajectory based on the concept of the virtual control force is developed, which can reflect the flexible modes and the trajectory tracking errors simultaneously. By modifying the original control scheme, a NFTSM hybrid controller is proposed. The hybrid control scheme can not only realized attitude stabilization and trajectory tracking of joints in finite time, but also provide a new method of vibration suppression. The simulation results verify the effectiveness of the designed hybrid control strategy.
文摘A high fidelity dynamic model of a high-energy hydraulically-actuated shock test machine for heavy weight devices is presented to satisfy the newly-built shock resistance standard and simulate the actual underwater explosion environments in laboratory as well as increase the testing capability of shock test machine. In order to produce the required negative shock pulse in the given time duration, four hydraulic actuators are utilized. The model is then used to formulate an advanced feedforward controller for the system to produce the required negative waveform and to address the motion synchronization of the four cylinders. The model provides a safe and easily controllable way to perform a ＂virtual testing＂ before starting potentially destructive tests on specimen and to predict performance of the system. Simulation results have demonstrated the effectiveness of the controller.
文摘In order to improve the power of initiating explosive warheads, besides exploring new type of high explosive, multipoint initiation technology becomes the research focus. With research on electronic safety and arming devices （ESADs）, pulse power devices and slapper detonators, a hardware control circuit was designed for multipoint initiation control system based on complex programmable logic device （ CPLD ）. In addition, a real-time monitoring interface based on virtual instru- ments technology was designed by the prevailing software of Laboratory Virtual Instrument Engineer- ing Workbench （LabVIEW）. It provides users a real-time status of the hardware circuit system. Mo- reover, a series of experiments were done on the software and hardware platform. The results show that the signals transmission, collection, analysis and display can be realized reliably through a serial port line. It is verified that using a serial bus controller for multiple initiators is reasonable. Successful design of the platform will play an important foundation for the theory and engineering of the fu- ture weapon system. Surely, it will become one of the development directions for intelligent initia- tion system.
基金supported by the Science and Technology Project of State Grid Corporation of China(No.5419-202199551A-0-5-ZN)the Joint Funds of the National Natural Science Foundation of China(No.U22A6007)the National Excellent Youth Science Fund Project of National Natural Science Foundation of China(No.52222703).
文摘As conventional synchronous generators are replaced by large-scale converter-interfaced renewa-ble-energy sources(RESs),the electric power grid en-counters the challenge of low rotational inertia.Conse-quently,system frequency deviation is exacerbated and system instability may occur when the frequency deviates beyond the acceptable range.To mitigate this effect,this study proposes a virtual inertia control(VIC)strategy based on a fractional-order derivative and controller parameter-tuning method.The tuning method uses the stability boundary locus and provides a stability criterion for identifying the stability region in the parameter space.The controller parameters are then optimized within the identified stability region to suppress frequency deviation and enhance system robustness.The proposed controller and tuning method is applied to a battery energy-storage system(BESS)in a low-inertia power system with the integration of RESs.Time-domain simulations are carried out to verify the stability region and compare the per-formance of the optimized proposed controller to that of the traditional integral-order controller.The simulation results show that the stability-analysis method is effective and that the fractional-order VIC,tuned with the pro-posed method,outperforms the traditional method in both frequency-regulation performance and parametric robustness.
文摘Wind energy systems (WESs) based on doubly-fed induction generators (DFIGs) have enormous potential for meeting the future demands related to clean energy. Due to the low inertia and intermittency of power injection, a WES is equipped with a virtual inertial controller (VIC) to support the system during a frequency deviation event. The frequency deviation measured by a phase locked loop (PLL) installed on a point of common coupling (PCC) bus is the input signal to the VIC. However, a VIC with an improper inertial gain could deteriorate the damping of the power system, which may lead to instability. To address this issue, a mathematical formulation for calculating the synchronizing and damping torque coefficients of a WES-integrated single-machine infinite bus (SMIB) system while considering PLL and VIC dynamics is proposed in this paper. In addition, a power system stabilizer (PSS) is designed for wind energy integrated power systems to enhance electromechanical oscillation damping. A small-signal stability assessment is performed using the infinite bus connected to a synchronous generator of higher-order dynamics integrated with a VIC-equipped WES. Finally, the performance and robustness of the proposed PSS is demonstrated through time-domain simulation in SMIB and nine-bus test systems integrated with WES under several case studies.
文摘新型脉冲功率设备对直流侧母线电压提出较高的性能要求,为减小脉冲负载对直流电压波动率的影响,建立带脉冲负载三相整流器拓扑结构及数学模型,并在现有无源控制(passivity based control,PBC)设计的基础上,以保证系统稳定性为前提,提出注入虚拟储能的无源控制算法(virtual energy storage injection PBC,VESI-PBC),该算法以提高能量函数收敛速度为目标,可有效降低直流母线电压波动率,提高抗负载扰动能力。分别基于根轨迹法和时域分析法,讨论VESI-PBC引入储能矩阵后,增大虚拟电感值L_(n)对系统的稳定性和动态性能的影响。为满足直流侧性能要求和保证系统稳定性,利用脉冲负载对直流电压波动率的影响规律,提出L_(n)自适应选取函数f(f_(PL)),使L_(n)自适应平衡系统高频毛刺和低频强脉冲冲击的不同需求。最后,通过仿真及实际试验,验证VESI-PBC算法对减小直流母线电压波动率的有效性,并指出该算法的实质是控制内环电流超前响应直流电压的动态变化及其变化趋势,由此具有较强的抗负载扰动能力,适用于负载脉冲功率等级高、动态特性强烈的场合。
基金supported in part by the National Natural Science Foundation of China(No.52377186)the Natural Science Foundation of Guangdong Province(No.2024A1515012428)+1 种基金the Science and Technology Planning Project of Guangdong Province,China(No.2023A1111120023)the Basic and Applied Basic Research Foundation of Guangdong Province(No.2022A1515240026)。
文摘The increasing adoption of grid-forming converters(GFMCs)stems from their capacity to furnish voltage and frequency support for power grids.Nevertheless,GFMCs employing the current reference saturation limiting method often exhibit instability during various transient disturbances including grid voltage sags,frequency variations,and phase jumps.To address this problem,this paper proposes a virtual power angle synchronous(δv-SYN)control method.The fundamental of this method is to achieve synchronization with the grid using the virtual power angleδv instead of the active power.The transient stability characteristics of the proposed method are theoretically elucidated using a novel virtual power angle-power angle(δv-δ)model.The key benefit of the proposed method is its robustness to various grid strengths and diverse forms of transient disturbances,eliminating the requirement for fault identification or control switching.Moreover,it can offer grid-forming support to the grid during grid faults.Hardware-in-the-loop experimental results validate the theoretical analysis and the performance of the proposed method.
文摘The control network is an important developmental orientation in the remote control system. As the control network and information network are comparatively alike in the framework and technology, we can build a control network which is similar to the common information network. In the era when the information network is becoming increasingly mature, it is a royal road to construct or rebuild a control information network in the development of the control network by relying on the achievements made in the information network or current information resources. This paper expounds the construction idea of the control information network, gives the idiographic realization method and then researches into the real-time problem encountered in the control information network, and presents a three-closed-loop control system based on virtualized reality. The feasibility of the idea is validated via experiments and simulations separately.
