Signal filtering and differential acquisition are classic yet challenging issues in control engineering.The discrete-time optimal control(DTOC)based on classic tracking differentiator(TD)can effectively extract differ...Signal filtering and differential acquisition are classic yet challenging issues in control engineering.The discrete-time optimal control(DTOC)based on classic tracking differentiator(TD)can effectively extract differentiation signals and filter signals,while eliminating the chattering problem that arises during the discretization of the continuous solution.However,under external disturbance,the convergence mode may change,leading to overshoot and noise amplification.In this paper,a dual-switching strategy is proposed,which can alternate between the base double-integral system and its dual system according to the quadrant of the system’s state.And a novel linearized control law is also introduced,deriving a novel dual-switch tracking differentiator.Further analysis of system convergence and time optimality is provided.Simulation results show that the application of this dual-switching strategy notably reduces overshoot in both tracking and differential signals while enhancing noise filtering performance.Moreover,experiments conducted on a permanent magnet synchronous motor(PMSM)platform,where the proposed TD acts as a filter in the speed feedback loop,demonstrate that the standard deviation between the reference speed and the target speed(at a constant speed of 378 r/min)decreased from 5.63 r/min to 4.93 r/min,compared to the moving average algorithm.展开更多
In this paper,some kinds of linear and nonlinear tracking-differentiators are designed by using suitable exponent functions instead of switch functions,and the stability of these tracking-differentiators is proved.Fro...In this paper,some kinds of linear and nonlinear tracking-differentiators are designed by using suitable exponent functions instead of switch functions,and the stability of these tracking-differentiators is proved.From the result of simulations,it is manifest that the tracking speeds of these kinds of linear and nonlinear tracking-differentiators are very high,and their design procedures are simple.展开更多
Since the quadruped robot possesses predominant environmental adaptability,it is expected to be employed in nature environments. In some situations,such as ice surface and tight space,the quadruped robot is required t...Since the quadruped robot possesses predominant environmental adaptability,it is expected to be employed in nature environments. In some situations,such as ice surface and tight space,the quadruped robot is required to lower the height of center of gravity( COG) to enhance the stability and maneuverability. To properly handle these situations,a quadruped controller based on the central pattern generator( CPG) model,the discrete tracking differentiator( TD) and proportional-derivative( PD) sub-controllers is presented. The CPG is used to generate basic rhythmic motion for the quadruped robot. The discrete TD is not only creatively employed to implement the transition between two different rhythmic medium values of the CPG which results in the adjustment of the height of COG of the quadruped robot,but also modified to control the transition duration which enables the quadruped robot to achieve the stable transition. Additionally,two specific PD sub-controllers are constructed to adjust the oscillation amplitude of the CPG,so as to avoid the severe deviation in the transverse direction during transition locomotion. Finally,the controller is validated on a quadruped model. A tunnel with variable height is built for the quadruped model to travel through. The simulation demonstrates the severe deviation without the PD sub-controllers,and the reduced deviation with the PD sub-controllers.展开更多
A modified tracking differentiator is proposed. Firstly, a nonlinear odd exponent continuous function is adopted which is only stable at one equilibrium point and proved the global asymptotic stability of the modified...A modified tracking differentiator is proposed. Firstly, a nonlinear odd exponent continuous function is adopted which is only stable at one equilibrium point and proved the global asymptotic stability of the modified tracking differentiator by select a Lyapunov function. Through combining of the nonlinear and linear function properly, it can be sure that the state converges to the equilibrium point with high speed automatically no matter that the state was far away from the equilibrium point or near to it, and it can prevent the chattering.?Simulation results show that the modified tracking differentiator tracking results?are?superior to the classical nonlinear tracking differentiator, and the response?of state variables tracking differentiator estimated?is?almost coincide with the real state of the variables of the given system.展开更多
Differential signals are key in control engineering as they anticipate future behavior of process variables and therefore are critical in formulating control laws such as proportional-integral-derivative(PID).The prac...Differential signals are key in control engineering as they anticipate future behavior of process variables and therefore are critical in formulating control laws such as proportional-integral-derivative(PID).The practical challenge,however,is to extract such signals from noisy measurements and this difficulty is addressed first by J.Han in the form of linear and nonlinear tracking differentiator(TD).While improvements were made,TD did not completely resolve the conflict between the noise sensitivity and the accuracy and timeliness of the differentiation.The two approaches proposed in this paper start with the basic linear TD,but apply iterative learning mechanism to the historical data in a moving window(MW),to form two new iterative learning tracking differentiators(IL-TD):one is a parallel IL-TD using an iterative ladder network structure which is implementable in analog circuits;the other a serial IL-TD which is implementable digitally on any computer platform.Both algorithms are validated in simulations which show that the proposed two IL-TDs have better tracking differentiation and de-noise performance compared to the existing linear TD.展开更多
This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the ...This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the lateral component of the centrifugal force acting on the tank on the basis of modeling and analyzing the dynamic model of the low-speed steering system.Secondly,we propose a differential-flatness ADRC approach by converting the under-actuated system to a fully driven flat one.Moreover,we prove the differential flatness of the steering system,which facilitates a two-channel ADRC development.Finally,we show that both the states of the flat system and the original under-actuated system can track the reference trajectory.On the external interference condition,the system is observed to re-track the target signal within 2 s.展开更多
The tracking problem for a class of differential inclusion systems is investigated. Using global sliding mode control approach, a tracking control is proposed such that the output of a differential inclusion system tr...The tracking problem for a class of differential inclusion systems is investigated. Using global sliding mode control approach, a tracking control is proposed such that the output of a differential inclusion system tracks the desired trajectory asymptotically.An extensive reaching law is proposed to achieve the chattering reduction. Finally, an example is given to illustrate the validity of the proposed design.展开更多
The large-range uncertainties of specific impulse,mass flow per second,aerodynamic coefficients and atmospheric density during rapid turning in solid launch vehicles(SLVs) ascending leads to the deviation of the actua...The large-range uncertainties of specific impulse,mass flow per second,aerodynamic coefficients and atmospheric density during rapid turning in solid launch vehicles(SLVs) ascending leads to the deviation of the actual trajectory from the reference one.One of the traditional trajectory tracking methods is to observe the uncertainties by Extended State Observer(ESO) and then modify the control commands.However,ESO cannot accurately estimate the uncertainties when the uncertainty ranges are large,which reduces the guidance accuracy.This paper introduces differential inclusion(DI) and designs a controller to solve the large-range parameter uncertainties problem.When above uncertainties have large ranges,it can be combined with the ascent dynamic equation and described as a DI system in the mathematical form of a set.If the DI system is stabilized,all the subsets are stabilized.Different from the traditional controllers,the parameters of the designed controller are calculated by the uncertain boundaries.Therefore,the controller can solve the problem of large-range parameter uncertainties of in ascending.Firstly,the ascent deviation system is obtained by linearization along the reference trajectory.The trajectory tracking system with engine parameters and aerodynamic uncertainties is described as an ascent DI system with respect to state deviation,which is called DI system.A DI adaptive saturation tracking controller(DIAST) is proposed to stabilize the DI system.Secondly,an improved barrier Lyapunov function(named time-varying tangent-log barrier Lyapunov function) is proposed to constrain the state deviations.Compared with traditional barrier Lyapunov function,it can dynamically adjust the boundary of deviation convergence,which improve the convergence rate and accuracy of altitude,velocity and LTIA deviation.In addition,the correction amplitudes of angle of attack(AOA) and angle of sideslip(AOS) need to be limited in order to guarantee that the overload constraint is not violated during actual flight.In this paper,a fixed time adaptive saturation compensation auxiliary system is designed to shorten the saturation time and accelerate the convergence rate,which eliminates the adverse effects caused by the saturation.Finally,it is proved that the state deviations are ultimately uniformly bounded under the action of DIAST controller.Simulation results show that the DI ascent tracking system is stabilized within the given uncertainty boundary values.The feasible bounds of uncertainty is broadened compared with Integrated Guidance and Control algorithm.Compared with Robust Gain-Scheduling Control method,the robustness to the engine parameters are greatly improved and the control variable is smoother.展开更多
In this paper,a prescribed fast tracking control scheme is proposed for Flexible Airbreathing Hypersonic Vehicles(FAHV)subject to lumped disturbances and limited resources.To maintain tracking errors of velocity and a...In this paper,a prescribed fast tracking control scheme is proposed for Flexible Airbreathing Hypersonic Vehicles(FAHV)subject to lumped disturbances and limited resources.To maintain tracking errors of velocity and altitude converge to a predefined region with a prescribed time and release the transient intense fluctuations encountered in classical Prescribed Performance Control(PPC)using a fast decaying rate,a tracking differentiator-based PPC is presented,where the reaching time and the maximum time differentiation of preselected envelopes can be regulated as a prior via fixing an acceleration factor,so that a guaranteed fast convergence speed can be realized with reduced oscillations.Besides,to avoid the excessive occupation of limited resources(energy and communication)and guarantee a remarkable tracking accuracy,switching event-triggered mechanisms are constructed for FAHV control realization,which provide a promising way to pursue a desired level of tracking performance with a low energy consumption.Subsequently,Uncertainty and Disturbance Estimators(UDE)and Sigmoid function-based Tracking Differentiators(STD)are employed to provide disturbance estimation and reference derivation with a low computational complexity.Finally,robust control laws are designed to compensate for the sampling error induced by event-triggered conditions,meanwhile Zeno phenomena can be effectively eliminated.The simulation results and comparisons validate the effectiveness of the proposed scheme.展开更多
This paper proposes a rail pressure tracking controller based on a novel common rail system. A mathematical model, based on physical equations, is developed and used for feed forward control design. Rail pressure peak...This paper proposes a rail pressure tracking controller based on a novel common rail system. A mathematical model, based on physical equations, is developed and used for feed forward control design. Rail pressure peak sampling mechanism is designed to remove the disturbance of rail pressure due to fuel injection. All enhanced tracking differentiator is designed to get smooth tracking signal and exact differential signal from signal with noise. Double loop control strategy is designed to decouple the system and to improve dynamic performance of the system. Experimental results indicate that fluctuation of rail pressure is within il MPa in steady condition, while within ±3 MPa in transient condition, which verifies the effectiveness of the proposed rail pressure control strategy.展开更多
One of the challenging problems with evolutionary computing algorithms is to maintain the balance between exploration and exploitation capability in order to search global optima.A novel convergence track based adapti...One of the challenging problems with evolutionary computing algorithms is to maintain the balance between exploration and exploitation capability in order to search global optima.A novel convergence track based adaptive differential evolution(CTbADE)algorithm is presented in this research paper.The crossover rate and mutation probability parameters in a differential evolution algorithm have a significant role in searching global optima.A more diverse population improves the global searching capability and helps to escape from the local optima problem.Tracking the convergence path over time helps enhance the searching speed of a differential evolution algorithm for varying problems.An adaptive powerful parameter-controlled sequences utilized learning period-based memory and following convergence track over time are introduced in this paper.The proposed algorithm will be helpful in maintaining the equilibrium between an algorithm’s exploration and exploitation capability.A comprehensive test suite of standard benchmark problems with different natures,i.e.,unimodal/multimodal and separable/non-separable,was used to test the convergence power of the proposed CTbADE algorithm.Experimental results show the significant performance of the CTbADE algorithm in terms of average fitness,solution quality,and convergence speed when compared with standard differential evolution algorithms and a few other commonly used state-of-the-art algorithms,such as jDE,CoDE,and EPSDE algorithms.This algorithm will prove to be a significant addition to the literature in order to solve real time problems and to optimize computationalmodels with a high number of parameters to adjust during the problem-solving process.展开更多
Smweillance system using active tracking camera has no distance limitation of surveillance range compared to supersonic or sound sensors. However, complex motion tracking algorithm requires huge amount of computation,...Smweillance system using active tracking camera has no distance limitation of surveillance range compared to supersonic or sound sensors. However, complex motion tracking algorithm requires huge amount of computation, and it often requires exfmasive DSPs or embedded processors. This paper proposes a novel motion tracking trait based on different image for fast and simple motion tracking. It uses configuration factor to avoid noise and inaccuracy. It reduces the required computation significantly, so as to be implemented on Field Programmable Gate Array（FFGAs ） instead of expensive Digital Signal Processing（DSPs）. It also performs calculation for motion estimation in video compression, so it can be easily combined with surveil system with video recording functionality based on video compression. The proposed motion tracking system implemented on Xilinx Vertex-4 FPGA can process 48 frames per second, and operating frequency of motion tracking trait is 100 MHz.展开更多
In this paper, a novel method to model, track control and synchronize the Rossler’s chaotic system is proposed. The fuzzy logical system is used so that the fuzzy inference rule is transferred into a type of variable...In this paper, a novel method to model, track control and synchronize the Rossler’s chaotic system is proposed. The fuzzy logical system is used so that the fuzzy inference rule is transferred into a type of variable coefficient nonlinear ordinary differential equation. Consequently the model of the chaotic system is obtained. Then a fuzzy tracking control and a fuzzy synchronization for chaotic systems is proposed as well. First, a known tracking control for the Rossler’s system is used in this paper. We represent the Rossler’s chaotic and control systems into fuzzy inference rules. Then the variable coefficient nonlinear ordinary differential equation is also got. Simulation results show that such an approach is effective and has a high precision.展开更多
Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed contr...Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed controller is designed by a transfer function model,which is obtained by adaptive differential evolution. Model error,friction and nonlinear factor existing in position loop are treated as ‘disturbance',which is estimated and compensated by generalized proportional integral( GPI)observer. Comparative results are provided to demonstrate the remarkable performance of the proposed method. It turns out that the proposed scheme is successful and has superior features,such as quick dynamic response,low overshoot and high tracking precision. Furthermore,with the proposed method,friction is suppressed effectively.展开更多
Subgrade settlement is a common issue in soil ground within earthquake-prone regions,posing a threat to the safe operation of train-slab track coupled system(TSCS)in high-speed railways(HSRs).This study aims to analyz...Subgrade settlement is a common issue in soil ground within earthquake-prone regions,posing a threat to the safe operation of train-slab track coupled system(TSCS)in high-speed railways(HSRs).This study aims to analyze the mechanical behavior evolution of TSCS under subgrade settlement and earthquake excitation.The refined numerical model of slab track under subgrade differential settlement is established.The short settlement wavelength of 10 m causes the separation between the base and subgrade.The dynamic model of TSCS under subgrade settlement and earthquake excitation is developed.The dynamic response of TSCS exhibits more pronounced fluctuations under the combined effects of subgrade settlement and earthquake excitation than under the effects of settlement or earthquake alone.The evaluation indexes for the running safety of train on slab track under different settlement wavelengths exhibit varying degrees of increase with settlement amplitude and are particularly sensitive to the short settlement wavelength of 10 m.The wheel unloading rate and derailment coefficient of TSCS increase with earthquake intensity.Under the settlement wavelength of 10 m and amplitude of 20 mm,the wheel unloading rate of TSCS exceeds the allowable limit when the earthquake intensity exceeds 0.17g,and the derailment coefficient exceeds the allowable limit when the earthquake intensity surpasses 0.29g.展开更多
基金Project(QZKFKT2023-012)supported by the State Key Laboratory of Heavy-duty and Express High-power Electric Locomotive,China。
文摘Signal filtering and differential acquisition are classic yet challenging issues in control engineering.The discrete-time optimal control(DTOC)based on classic tracking differentiator(TD)can effectively extract differentiation signals and filter signals,while eliminating the chattering problem that arises during the discretization of the continuous solution.However,under external disturbance,the convergence mode may change,leading to overshoot and noise amplification.In this paper,a dual-switching strategy is proposed,which can alternate between the base double-integral system and its dual system according to the quadrant of the system’s state.And a novel linearized control law is also introduced,deriving a novel dual-switch tracking differentiator.Further analysis of system convergence and time optimality is provided.Simulation results show that the application of this dual-switching strategy notably reduces overshoot in both tracking and differential signals while enhancing noise filtering performance.Moreover,experiments conducted on a permanent magnet synchronous motor(PMSM)platform,where the proposed TD acts as a filter in the speed feedback loop,demonstrate that the standard deviation between the reference speed and the target speed(at a constant speed of 378 r/min)decreased from 5.63 r/min to 4.93 r/min,compared to the moving average algorithm.
基金Supported by the National Natural Science Foundation of China (6 0 1 740 2 1 ) and Tianjin Key NaturalScience Foundation(0 1 3 80 0 71 1 )
文摘In this paper,some kinds of linear and nonlinear tracking-differentiators are designed by using suitable exponent functions instead of switch functions,and the stability of these tracking-differentiators is proved.From the result of simulations,it is manifest that the tracking speeds of these kinds of linear and nonlinear tracking-differentiators are very high,and their design procedures are simple.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61375101)
文摘Since the quadruped robot possesses predominant environmental adaptability,it is expected to be employed in nature environments. In some situations,such as ice surface and tight space,the quadruped robot is required to lower the height of center of gravity( COG) to enhance the stability and maneuverability. To properly handle these situations,a quadruped controller based on the central pattern generator( CPG) model,the discrete tracking differentiator( TD) and proportional-derivative( PD) sub-controllers is presented. The CPG is used to generate basic rhythmic motion for the quadruped robot. The discrete TD is not only creatively employed to implement the transition between two different rhythmic medium values of the CPG which results in the adjustment of the height of COG of the quadruped robot,but also modified to control the transition duration which enables the quadruped robot to achieve the stable transition. Additionally,two specific PD sub-controllers are constructed to adjust the oscillation amplitude of the CPG,so as to avoid the severe deviation in the transverse direction during transition locomotion. Finally,the controller is validated on a quadruped model. A tunnel with variable height is built for the quadruped model to travel through. The simulation demonstrates the severe deviation without the PD sub-controllers,and the reduced deviation with the PD sub-controllers.
文摘A modified tracking differentiator is proposed. Firstly, a nonlinear odd exponent continuous function is adopted which is only stable at one equilibrium point and proved the global asymptotic stability of the modified tracking differentiator by select a Lyapunov function. Through combining of the nonlinear and linear function properly, it can be sure that the state converges to the equilibrium point with high speed automatically no matter that the state was far away from the equilibrium point or near to it, and it can prevent the chattering.?Simulation results show that the modified tracking differentiator tracking results?are?superior to the classical nonlinear tracking differentiator, and the response?of state variables tracking differentiator estimated?is?almost coincide with the real state of the variables of the given system.
基金supported by National Natural Science Foundation of China(61773170,62173151)the Natural Science Foundation of Guangdong Province(2023A1515010949,2021A1515011850).
文摘Differential signals are key in control engineering as they anticipate future behavior of process variables and therefore are critical in formulating control laws such as proportional-integral-derivative(PID).The practical challenge,however,is to extract such signals from noisy measurements and this difficulty is addressed first by J.Han in the form of linear and nonlinear tracking differentiator(TD).While improvements were made,TD did not completely resolve the conflict between the noise sensitivity and the accuracy and timeliness of the differentiation.The two approaches proposed in this paper start with the basic linear TD,but apply iterative learning mechanism to the historical data in a moving window(MW),to form two new iterative learning tracking differentiators(IL-TD):one is a parallel IL-TD using an iterative ladder network structure which is implementable in analog circuits;the other a serial IL-TD which is implementable digitally on any computer platform.Both algorithms are validated in simulations which show that the proposed two IL-TDs have better tracking differentiation and de-noise performance compared to the existing linear TD.
基金supported by the National Natural Science Foundation of China(62422305,62373049).
文摘This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the lateral component of the centrifugal force acting on the tank on the basis of modeling and analyzing the dynamic model of the low-speed steering system.Secondly,we propose a differential-flatness ADRC approach by converting the under-actuated system to a fully driven flat one.Moreover,we prove the differential flatness of the steering system,which facilitates a two-channel ADRC development.Finally,we show that both the states of the flat system and the original under-actuated system can track the reference trajectory.On the external interference condition,the system is observed to re-track the target signal within 2 s.
基金supported by National Natural Science Foundation of China(Nos.61374077 and 61203047)fundamental research project(No.142300410293)in the Science and Technology Department of Henan province+1 种基金the science and technology research key project(No.14A413001)in the Education Department of Henan provinceinnovation ability cultivation fund(No.2014ZCX015)in Henan University of Science and Technology
文摘The tracking problem for a class of differential inclusion systems is investigated. Using global sliding mode control approach, a tracking control is proposed such that the output of a differential inclusion system tracks the desired trajectory asymptotically.An extensive reaching law is proposed to achieve the chattering reduction. Finally, an example is given to illustrate the validity of the proposed design.
基金supported by the National Natural Science Foundation of China (Grant Nos.61627810, 61790562 and 61403096)。
文摘The large-range uncertainties of specific impulse,mass flow per second,aerodynamic coefficients and atmospheric density during rapid turning in solid launch vehicles(SLVs) ascending leads to the deviation of the actual trajectory from the reference one.One of the traditional trajectory tracking methods is to observe the uncertainties by Extended State Observer(ESO) and then modify the control commands.However,ESO cannot accurately estimate the uncertainties when the uncertainty ranges are large,which reduces the guidance accuracy.This paper introduces differential inclusion(DI) and designs a controller to solve the large-range parameter uncertainties problem.When above uncertainties have large ranges,it can be combined with the ascent dynamic equation and described as a DI system in the mathematical form of a set.If the DI system is stabilized,all the subsets are stabilized.Different from the traditional controllers,the parameters of the designed controller are calculated by the uncertain boundaries.Therefore,the controller can solve the problem of large-range parameter uncertainties of in ascending.Firstly,the ascent deviation system is obtained by linearization along the reference trajectory.The trajectory tracking system with engine parameters and aerodynamic uncertainties is described as an ascent DI system with respect to state deviation,which is called DI system.A DI adaptive saturation tracking controller(DIAST) is proposed to stabilize the DI system.Secondly,an improved barrier Lyapunov function(named time-varying tangent-log barrier Lyapunov function) is proposed to constrain the state deviations.Compared with traditional barrier Lyapunov function,it can dynamically adjust the boundary of deviation convergence,which improve the convergence rate and accuracy of altitude,velocity and LTIA deviation.In addition,the correction amplitudes of angle of attack(AOA) and angle of sideslip(AOS) need to be limited in order to guarantee that the overload constraint is not violated during actual flight.In this paper,a fixed time adaptive saturation compensation auxiliary system is designed to shorten the saturation time and accelerate the convergence rate,which eliminates the adverse effects caused by the saturation.Finally,it is proved that the state deviations are ultimately uniformly bounded under the action of DIAST controller.Simulation results show that the DI ascent tracking system is stabilized within the given uncertainty boundary values.The feasible bounds of uncertainty is broadened compared with Integrated Guidance and Control algorithm.Compared with Robust Gain-Scheduling Control method,the robustness to the engine parameters are greatly improved and the control variable is smoother.
基金supported by National Natural Science Foundation of China(No.61803348)National Nature Science Foundation of China as National Major Scientific Instruments Development Project(No.61927807)+5 种基金State Key Laboratory of Deep Buried Target Damage,China(No.DXMBJJ2019-02)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China(No.2020L0266)Shanxi Province Science Foundation for Youths,China(No.201701D221123)Youth Academic North University of China(No.QX201803)Program for the Innovative Talents of Higher Education Institutions of ShanxiShanxi“1331 Project” Key Subjects Construction,China(1331KSC)。
文摘In this paper,a prescribed fast tracking control scheme is proposed for Flexible Airbreathing Hypersonic Vehicles(FAHV)subject to lumped disturbances and limited resources.To maintain tracking errors of velocity and altitude converge to a predefined region with a prescribed time and release the transient intense fluctuations encountered in classical Prescribed Performance Control(PPC)using a fast decaying rate,a tracking differentiator-based PPC is presented,where the reaching time and the maximum time differentiation of preselected envelopes can be regulated as a prior via fixing an acceleration factor,so that a guaranteed fast convergence speed can be realized with reduced oscillations.Besides,to avoid the excessive occupation of limited resources(energy and communication)and guarantee a remarkable tracking accuracy,switching event-triggered mechanisms are constructed for FAHV control realization,which provide a promising way to pursue a desired level of tracking performance with a low energy consumption.Subsequently,Uncertainty and Disturbance Estimators(UDE)and Sigmoid function-based Tracking Differentiators(STD)are employed to provide disturbance estimation and reference derivation with a low computational complexity.Finally,robust control laws are designed to compensate for the sampling error induced by event-triggered conditions,meanwhile Zeno phenomena can be effectively eliminated.The simulation results and comparisons validate the effectiveness of the proposed scheme.
基金the National Natural Science Foundation of China (No. 51179102)
文摘This paper proposes a rail pressure tracking controller based on a novel common rail system. A mathematical model, based on physical equations, is developed and used for feed forward control design. Rail pressure peak sampling mechanism is designed to remove the disturbance of rail pressure due to fuel injection. All enhanced tracking differentiator is designed to get smooth tracking signal and exact differential signal from signal with noise. Double loop control strategy is designed to decouple the system and to improve dynamic performance of the system. Experimental results indicate that fluctuation of rail pressure is within il MPa in steady condition, while within ±3 MPa in transient condition, which verifies the effectiveness of the proposed rail pressure control strategy.
基金This work was supported by the Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia,which funded this research work through project number 959.
文摘One of the challenging problems with evolutionary computing algorithms is to maintain the balance between exploration and exploitation capability in order to search global optima.A novel convergence track based adaptive differential evolution(CTbADE)algorithm is presented in this research paper.The crossover rate and mutation probability parameters in a differential evolution algorithm have a significant role in searching global optima.A more diverse population improves the global searching capability and helps to escape from the local optima problem.Tracking the convergence path over time helps enhance the searching speed of a differential evolution algorithm for varying problems.An adaptive powerful parameter-controlled sequences utilized learning period-based memory and following convergence track over time are introduced in this paper.The proposed algorithm will be helpful in maintaining the equilibrium between an algorithm’s exploration and exploitation capability.A comprehensive test suite of standard benchmark problems with different natures,i.e.,unimodal/multimodal and separable/non-separable,was used to test the convergence power of the proposed CTbADE algorithm.Experimental results show the significant performance of the CTbADE algorithm in terms of average fitness,solution quality,and convergence speed when compared with standard differential evolution algorithms and a few other commonly used state-of-the-art algorithms,such as jDE,CoDE,and EPSDE algorithms.This algorithm will prove to be a significant addition to the literature in order to solve real time problems and to optimize computationalmodels with a high number of parameters to adjust during the problem-solving process.
基金sponsored by the MKE(The Ministry of Knowledge Economy,Korea),the ITRC(Information Technology Research Center)support program(NIPA-2009-(C1090-0902-0007))the System Semiconductor Industry Development Center,Human Resource Development Project for IT SOC Architecture
文摘Smweillance system using active tracking camera has no distance limitation of surveillance range compared to supersonic or sound sensors. However, complex motion tracking algorithm requires huge amount of computation, and it often requires exfmasive DSPs or embedded processors. This paper proposes a novel motion tracking trait based on different image for fast and simple motion tracking. It uses configuration factor to avoid noise and inaccuracy. It reduces the required computation significantly, so as to be implemented on Field Programmable Gate Array（FFGAs ） instead of expensive Digital Signal Processing（DSPs）. It also performs calculation for motion estimation in video compression, so it can be easily combined with surveil system with video recording functionality based on video compression. The proposed motion tracking system implemented on Xilinx Vertex-4 FPGA can process 48 frames per second, and operating frequency of motion tracking trait is 100 MHz.
文摘In this paper, a novel method to model, track control and synchronize the Rossler’s chaotic system is proposed. The fuzzy logical system is used so that the fuzzy inference rule is transferred into a type of variable coefficient nonlinear ordinary differential equation. Consequently the model of the chaotic system is obtained. Then a fuzzy tracking control and a fuzzy synchronization for chaotic systems is proposed as well. First, a known tracking control for the Rossler’s system is used in this paper. We represent the Rossler’s chaotic and control systems into fuzzy inference rules. Then the variable coefficient nonlinear ordinary differential equation is also got. Simulation results show that such an approach is effective and has a high precision.
基金Supported by the National High Technology Research and Development Programme of China(No.2015AA8082065)the National Natural Science Foundation of China(No.61205143)
文摘Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed controller is designed by a transfer function model,which is obtained by adaptive differential evolution. Model error,friction and nonlinear factor existing in position loop are treated as ‘disturbance',which is estimated and compensated by generalized proportional integral( GPI)observer. Comparative results are provided to demonstrate the remarkable performance of the proposed method. It turns out that the proposed scheme is successful and has superior features,such as quick dynamic response,low overshoot and high tracking precision. Furthermore,with the proposed method,friction is suppressed effectively.
基金Project(52078501)supported by the National Natural Science Foundation of ChinaProject(2022-Major-14)supported by the Science and Technology Research and Development Program Project of China Railway Group LimitedProject(2023ZZTS0342)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Subgrade settlement is a common issue in soil ground within earthquake-prone regions,posing a threat to the safe operation of train-slab track coupled system(TSCS)in high-speed railways(HSRs).This study aims to analyze the mechanical behavior evolution of TSCS under subgrade settlement and earthquake excitation.The refined numerical model of slab track under subgrade differential settlement is established.The short settlement wavelength of 10 m causes the separation between the base and subgrade.The dynamic model of TSCS under subgrade settlement and earthquake excitation is developed.The dynamic response of TSCS exhibits more pronounced fluctuations under the combined effects of subgrade settlement and earthquake excitation than under the effects of settlement or earthquake alone.The evaluation indexes for the running safety of train on slab track under different settlement wavelengths exhibit varying degrees of increase with settlement amplitude and are particularly sensitive to the short settlement wavelength of 10 m.The wheel unloading rate and derailment coefficient of TSCS increase with earthquake intensity.Under the settlement wavelength of 10 m and amplitude of 20 mm,the wheel unloading rate of TSCS exceeds the allowable limit when the earthquake intensity exceeds 0.17g,and the derailment coefficient exceeds the allowable limit when the earthquake intensity surpasses 0.29g.
