Chemical processes are usually nonlinear singular systems.In this study,a soft sensor using nonlinear singular state observer is established for unknown inputs and uncertain model parameters in chemical processes,whic...Chemical processes are usually nonlinear singular systems.In this study,a soft sensor using nonlinear singular state observer is established for unknown inputs and uncertain model parameters in chemical processes,which are augmented as state variables.Based on the observability of the singular system,this paper presents a simplified observability criterion under certain conditions for unknown inputs and uncertain model parameters.When the observability is satisfied,the unknown inputs and the uncertain model parameters are estimated online by the soft sensor using augmented nonlinear singular state observer.The riser reactor of fluid catalytic cracking unit is used as an example for analysis and simulation.With the catalyst circulation rate as the only unknown input without model error,one temperature sensor at the riser reactor outlet will ensure the correct estimation for the catalyst circulation rate.However,when uncertain model parameters also exist,additional temperature sensors must be used to ensure correct estimation for unknown inputs and uncertain model parameters of chemical processes.展开更多
In this paper,an active fault-tolerant control(FTC)strategy of aerial manipulators based on non-singular terminal sliding mode(NTSM)and extended state observer(ESO)is proposed.Firstly,back-stepping technology is adopt...In this paper,an active fault-tolerant control(FTC)strategy of aerial manipulators based on non-singular terminal sliding mode(NTSM)and extended state observer(ESO)is proposed.Firstly,back-stepping technology is adopted as the control framework to ensure the global asymptotic stability of the closed-loop system.Next,the NTSM with estimated parameters of actuator faults is used as main robustness controller to deal with actuator faults.Then,the ESO is utilized to estimate and compensate the complex coupling effects and external disturbances.The Lyapunov stability theory can guarantee the asymptotic stability of aerial manipulators system with actuator faults and external disturbances.The proposed FTC scheme considers both actuator fault and modelling errors,combined with the adaptive law of actuator fault,which has better performance than traditional FTC scheme,such as NTSM.Finally,several comparative simulations are conducted to illustrate the effectiveness of the proposed FTC scheme.展开更多
Aiming at the problem that the traditional control strategy of permanent magnet synchronous motor(PMSM)for electric vehicles has low control performance,a novel adaptive non-singular fast terminal sliding mode control...Aiming at the problem that the traditional control strategy of permanent magnet synchronous motor(PMSM)for electric vehicles has low control performance,a novel adaptive non-singular fast terminal sliding mode control(ANFTSMC)model predictive torque control(MPTC)strategy is proposed.A new adaptive exponential approach rate is designed,and the traditional switching function sgn()is replaced by the hyperbolic tangent function tanh().A new ANFTSMC with extended state observer(ESO)is constructed as the speed regulator of the system,and ESO can observe disturbances.This improved method weakens chattering and improves the robustness of the system.To realize sensorless control of the speed control system,an ESO speed observer based on tanh(Fal)is constructed.Compared with the traditional ESO based on Fal function,the observation error is smaller,and the observation accuracy is higher.Finally,aiming at the model predictive torque control strategy used,a new objective function construction method is proposed,which avoids the design of weight coefficient,and the traditional voltage vector selection method is improved and optimized,which reduces the calculation amount of the algorithm.展开更多
Using linear state feedback and linear feedforward control of the disturbances, the problem of achieving the distrubance rejection in a linear time invariant singular system is treated and a constructive solvability c...Using linear state feedback and linear feedforward control of the disturbances, the problem of achieving the distrubance rejection in a linear time invariant singular system is treated and a constructive solvability condition is presented.展开更多
The massive neutron star discoverer announced that strange particles, such as hyperons should be ruled out in the neutron star core as the soft Equation of State(EOS) can-not support a massive neutron star. However, m...The massive neutron star discoverer announced that strange particles, such as hyperons should be ruled out in the neutron star core as the soft Equation of State(EOS) can-not support a massive neutron star. However, many of the nuclear theories and laboratory experiments support that at high density the strange particles will appear and the corresponding EOS of super-dense matters will become soft. This situation promotes a challenge between the astro-observation and nuclear physics. In this work, we introduce an effective mechanism to answer this challenge, that is, if a neutron star is electrically charged, a soft EOS will be equivalently stiffened and thus can support a massive neutron star. By employing a representative soft EOS, it is found that in order to obtain an evident effect on the EOS and thus increasing the maximum stellar mass by the electrostatic field, the total net charge should be in an order of 1020 C. Moreover, by comparing the results of two kind of charge distributions, it is found that even for different distributions, a similar total charge:～2.3×1020C is needed to support a～2.0M⊙neutron star.展开更多
State feedback and pole assignment of the second order coupled singular distributed parameter systems are discussed via functional analysis and operator theory in Hilbert space, in which infinite many poles are change...State feedback and pole assignment of the second order coupled singular distributed parameter systems are discussed via functional analysis and operator theory in Hilbert space, in which infinite many poles are changed. The solutions of the problem and the constructive expression of the solutions are given by the generalized inverse of bounded linear operator. This research is theoretically important for studying the pole assignment and stabilization of the singular distributed parameter systems.展开更多
基金Supported by the National Natural Science Foundation of China （21006127）, the National Basic Research Program of China （2012CB720500） and the Science Foundation of China University of Petroleum, Beijing （KYJJ2012-05-28）.
文摘Chemical processes are usually nonlinear singular systems.In this study,a soft sensor using nonlinear singular state observer is established for unknown inputs and uncertain model parameters in chemical processes,which are augmented as state variables.Based on the observability of the singular system,this paper presents a simplified observability criterion under certain conditions for unknown inputs and uncertain model parameters.When the observability is satisfied,the unknown inputs and the uncertain model parameters are estimated online by the soft sensor using augmented nonlinear singular state observer.The riser reactor of fluid catalytic cracking unit is used as an example for analysis and simulation.With the catalyst circulation rate as the only unknown input without model error,one temperature sensor at the riser reactor outlet will ensure the correct estimation for the catalyst circulation rate.However,when uncertain model parameters also exist,additional temperature sensors must be used to ensure correct estimation for unknown inputs and uncertain model parameters of chemical processes.
基金Project(51705243)supported by National Natural Science Foundation of ChinaProject(NS2020052)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(GZKF-201915)supported by the Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems,China。
文摘In this paper,an active fault-tolerant control(FTC)strategy of aerial manipulators based on non-singular terminal sliding mode(NTSM)and extended state observer(ESO)is proposed.Firstly,back-stepping technology is adopted as the control framework to ensure the global asymptotic stability of the closed-loop system.Next,the NTSM with estimated parameters of actuator faults is used as main robustness controller to deal with actuator faults.Then,the ESO is utilized to estimate and compensate the complex coupling effects and external disturbances.The Lyapunov stability theory can guarantee the asymptotic stability of aerial manipulators system with actuator faults and external disturbances.The proposed FTC scheme considers both actuator fault and modelling errors,combined with the adaptive law of actuator fault,which has better performance than traditional FTC scheme,such as NTSM.Finally,several comparative simulations are conducted to illustrate the effectiveness of the proposed FTC scheme.
基金Project of National Natural Science Foundation of China(No.61863023)。
文摘Aiming at the problem that the traditional control strategy of permanent magnet synchronous motor(PMSM)for electric vehicles has low control performance,a novel adaptive non-singular fast terminal sliding mode control(ANFTSMC)model predictive torque control(MPTC)strategy is proposed.A new adaptive exponential approach rate is designed,and the traditional switching function sgn()is replaced by the hyperbolic tangent function tanh().A new ANFTSMC with extended state observer(ESO)is constructed as the speed regulator of the system,and ESO can observe disturbances.This improved method weakens chattering and improves the robustness of the system.To realize sensorless control of the speed control system,an ESO speed observer based on tanh(Fal)is constructed.Compared with the traditional ESO based on Fal function,the observation error is smaller,and the observation accuracy is higher.Finally,aiming at the model predictive torque control strategy used,a new objective function construction method is proposed,which avoids the design of weight coefficient,and the traditional voltage vector selection method is improved and optimized,which reduces the calculation amount of the algorithm.
文摘Using linear state feedback and linear feedforward control of the disturbances, the problem of achieving the distrubance rejection in a linear time invariant singular system is treated and a constructive solvability condition is presented.
基金supported by National Natural Science Foundation of China(Grant Nos.10947023,11275073,and 11305063)the Fundamental Research Funds for the Central University of China(Grant Nos.2013ZG0036and 2013ZM107)University of China(Grant Nos.2013ZG0036 and2013ZM107)
文摘The massive neutron star discoverer announced that strange particles, such as hyperons should be ruled out in the neutron star core as the soft Equation of State(EOS) can-not support a massive neutron star. However, many of the nuclear theories and laboratory experiments support that at high density the strange particles will appear and the corresponding EOS of super-dense matters will become soft. This situation promotes a challenge between the astro-observation and nuclear physics. In this work, we introduce an effective mechanism to answer this challenge, that is, if a neutron star is electrically charged, a soft EOS will be equivalently stiffened and thus can support a massive neutron star. By employing a representative soft EOS, it is found that in order to obtain an evident effect on the EOS and thus increasing the maximum stellar mass by the electrostatic field, the total net charge should be in an order of 1020 C. Moreover, by comparing the results of two kind of charge distributions, it is found that even for different distributions, a similar total charge:～2.3×1020C is needed to support a～2.0M⊙neutron star.
基金supported by the National Nature Science Foundation of China under Grant No.60674018
文摘State feedback and pole assignment of the second order coupled singular distributed parameter systems are discussed via functional analysis and operator theory in Hilbert space, in which infinite many poles are changed. The solutions of the problem and the constructive expression of the solutions are given by the generalized inverse of bounded linear operator. This research is theoretically important for studying the pole assignment and stabilization of the singular distributed parameter systems.
