An iterative identification and control design method based on v-gap is given to ensure the stability of closed-loop system and control performance improvement. The whole iterative procedure includes three parts： the...An iterative identification and control design method based on v-gap is given to ensure the stability of closed-loop system and control performance improvement. The whole iterative procedure includes three parts： the optimal excitation signals design, the uncertainty model set identification and the stable controller design. Firstly the worst case v-gap is used as the criterion of the optimal excitation signals design, and the design is performed via the power spectrum optimization. And then, an uncertainty model set is attained by system identification on the basis of the measure signals. The controller is designed to ensure the stability of closed-loop system and the closed-loop performance improvement. Simulation result shows that the proposed method has good convergence and closed-loop control performance.展开更多
利用石河子c波段多普勒天气雷达资料,对2007年7月3日下午发生在石河子垦区南部山脉与平原交界区151团的冰雹等强对流风暴的多普勒雷达回波演变特征进行分析。结果表明:该强对流风暴具有超级单体风暴的典型特征,强风暴前进方向的右侧出...利用石河子c波段多普勒天气雷达资料,对2007年7月3日下午发生在石河子垦区南部山脉与平原交界区151团的冰雹等强对流风暴的多普勒雷达回波演变特征进行分析。结果表明:该强对流风暴具有超级单体风暴的典型特征,强风暴前进方向的右侧出现钩状回波,西北侧呈现出"V"型缺口;反射率因子垂直剖面呈现出弱回波区、回波悬垂和弱回波区左侧的回波墙,最大回波强度超过65 dB z,垂直累积液态水含量超过70 kg/m2;相应的径向速度图上出现中气旋。该超级单体的移动方向在盛行风向的右侧约30,°属于右移风暴。展开更多
In this paper, a systematic robust control design and analysis for a single axis precise positioner is presented. The effects of uncertainties on closed-loop stability and performance are considered in the H∞ robust ...In this paper, a systematic robust control design and analysis for a single axis precise positioner is presented. The effects of uncertainties on closed-loop stability and performance are considered in the H∞ robust controllers design. v-gap metric is utilized to validate the intelligently estimated uncertainty. The robust controllers are formulated within the frame- work of the standard H∞ mixed sensitivity optimization problem. Furthermore, a specially designed integral-H∞ and two-degree-of-freedom 2 DOF H∞ controllers are developed to provide improved robust performance and resolution properties. It is shown that the proposed design schemes are very effective for robust control and precise tracking performance of the servo positioning system.展开更多
Faults in traction system rectifiers can cause deterioration in system performance,robustness,and continuity.A single fault may propagate and cause the whole system to be shut down.Therefore,improving the robust stabi...Faults in traction system rectifiers can cause deterioration in system performance,robustness,and continuity.A single fault may propagate and cause the whole system to be shut down.Therefore,improving the robust stability and reliability of the control system is becoming more important.This study presents a robust current control based on a generalized internal model control(GIMC)for single-phase pulse width modulation(PWM)rectifier.The study aims to simultaneously achieve decent dynamic performance and robustness for the rectifiers under current sensor gain faults using generalized internal model control.H∞loop shaping can maintain robustness and achieve acceptable performance for the system in such cases.However,this controller will be conservative during an increase of sensor gain faults.That is,we sacrifice performance for robustness.Therefore,the GIMC structure is proposed to balance robustness and dynamic performance in such cases.The proposed control scheme during sensor gain faults is investigated.Furthermore,the robustness is analyzed using the v-gap metric.The proposed GIMC control framework consists of two parts,nominal and robustness controllers.The system is controlled solely by the nominal controller in normal operation in the absence of current sensor gain faults.If they occur,then the robustness controller will be active to maintain system robustness and achieve acceptable performance.The nominal controller is chosen as H∞loop shaping to assure nominal performance,while the robustness controller is chosen as the plant inverse cascaded by low pass filter to compensate for the sensor gain faults.Hardware-in-loop experimental results indicate that the suggested fault-tolerant control achieves good performance and robustness in comparison to the H∞loop shaping controller.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 60574055, 60874073)the Specialized Research Fund for Doctoral Program of Higher Education of China (Grant No. 20050056037)the Tianjin Science and Technology Keystone Project (Grant No.08ZCKFJC27900)
文摘An iterative identification and control design method based on v-gap is given to ensure the stability of closed-loop system and control performance improvement. The whole iterative procedure includes three parts： the optimal excitation signals design, the uncertainty model set identification and the stable controller design. Firstly the worst case v-gap is used as the criterion of the optimal excitation signals design, and the design is performed via the power spectrum optimization. And then, an uncertainty model set is attained by system identification on the basis of the measure signals. The controller is designed to ensure the stability of closed-loop system and the closed-loop performance improvement. Simulation result shows that the proposed method has good convergence and closed-loop control performance.
基金Supported by National Natural Science Foundation of China(61203119,61304153)Key Program of Tianjin Natural Science Foundation,China(14JCZDJC36300)Tianjin University of Technology and Education Funded Project(RC14-48)
文摘利用石河子c波段多普勒天气雷达资料,对2007年7月3日下午发生在石河子垦区南部山脉与平原交界区151团的冰雹等强对流风暴的多普勒雷达回波演变特征进行分析。结果表明:该强对流风暴具有超级单体风暴的典型特征,强风暴前进方向的右侧出现钩状回波,西北侧呈现出"V"型缺口;反射率因子垂直剖面呈现出弱回波区、回波悬垂和弱回波区左侧的回波墙,最大回波强度超过65 dB z,垂直累积液态水含量超过70 kg/m2;相应的径向速度图上出现中气旋。该超级单体的移动方向在盛行风向的右侧约30,°属于右移风暴。
文摘In this paper, a systematic robust control design and analysis for a single axis precise positioner is presented. The effects of uncertainties on closed-loop stability and performance are considered in the H∞ robust controllers design. v-gap metric is utilized to validate the intelligently estimated uncertainty. The robust controllers are formulated within the frame- work of the standard H∞ mixed sensitivity optimization problem. Furthermore, a specially designed integral-H∞ and two-degree-of-freedom 2 DOF H∞ controllers are developed to provide improved robust performance and resolution properties. It is shown that the proposed design schemes are very effective for robust control and precise tracking performance of the servo positioning system.
基金supported by the National Natural Science Foundation of China(No.61733015)High-Speed Railway Joint Funds of the National Science Foundation of China(No.U1934204).
文摘Faults in traction system rectifiers can cause deterioration in system performance,robustness,and continuity.A single fault may propagate and cause the whole system to be shut down.Therefore,improving the robust stability and reliability of the control system is becoming more important.This study presents a robust current control based on a generalized internal model control(GIMC)for single-phase pulse width modulation(PWM)rectifier.The study aims to simultaneously achieve decent dynamic performance and robustness for the rectifiers under current sensor gain faults using generalized internal model control.H∞loop shaping can maintain robustness and achieve acceptable performance for the system in such cases.However,this controller will be conservative during an increase of sensor gain faults.That is,we sacrifice performance for robustness.Therefore,the GIMC structure is proposed to balance robustness and dynamic performance in such cases.The proposed control scheme during sensor gain faults is investigated.Furthermore,the robustness is analyzed using the v-gap metric.The proposed GIMC control framework consists of two parts,nominal and robustness controllers.The system is controlled solely by the nominal controller in normal operation in the absence of current sensor gain faults.If they occur,then the robustness controller will be active to maintain system robustness and achieve acceptable performance.The nominal controller is chosen as H∞loop shaping to assure nominal performance,while the robustness controller is chosen as the plant inverse cascaded by low pass filter to compensate for the sensor gain faults.Hardware-in-loop experimental results indicate that the suggested fault-tolerant control achieves good performance and robustness in comparison to the H∞loop shaping controller.
