In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is sing...In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current(DC)bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.展开更多
Access control in multi-domain environments is one of the important questions of building coalition between domains. On the basis of RBAC access control model, the concepts of role delegation and role mapping are prop...Access control in multi-domain environments is one of the important questions of building coalition between domains. On the basis of RBAC access control model, the concepts of role delegation and role mapping are proposed, which support the third-party authorization. Then, a distributed RBAC model is presented. Finally the implementation issues are discussed.展开更多
In this paper, the variable universe adaptive fuzzy controller based on variable gain Ha regulator (VGH∞R) is designed to stabilize a quadruple inverted pendulum. The VGH∞R is a novel robust gain-scheduling approa...In this paper, the variable universe adaptive fuzzy controller based on variable gain Ha regulator (VGH∞R) is designed to stabilize a quadruple inverted pendulum. The VGH∞R is a novel robust gain-scheduling approach. By utilizing VGH∞R technique, a more precise real-time feedback gain matrix, which is changing with states, is obtained, Via the variable gain matrix 10 state variables of quadruple inverted pendulum are transformed into a kind of synthesis error (E) and synthesis rate of change of error (EC) at sampling time. Therefore, the dimension of the multivariable system is reduced and the variable universe adaptive fuzzy controller is built. Experiments illustrate the effectiveness of the proposed control scheme.展开更多
基金Natural Science Foundation of Gansu Province(Joint)Project(No.213244)Natural Science Foundation of Gansu Province(No.145RJZA136)Youth Science Foundation of Lanzhou Jiaotong University(No.2013040)
文摘In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current(DC)bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.
文摘Access control in multi-domain environments is one of the important questions of building coalition between domains. On the basis of RBAC access control model, the concepts of role delegation and role mapping are proposed, which support the third-party authorization. Then, a distributed RBAC model is presented. Finally the implementation issues are discussed.
基金supported by the National Natural Science Foundation of China under Grant Nos.61074044, 61104038,and 60834004Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No.20090041110003the National 973 Basic Research Program of China under Grant Nos. 2009CB320602 and 2002CB312200
文摘In this paper, the variable universe adaptive fuzzy controller based on variable gain Ha regulator (VGH∞R) is designed to stabilize a quadruple inverted pendulum. The VGH∞R is a novel robust gain-scheduling approach. By utilizing VGH∞R technique, a more precise real-time feedback gain matrix, which is changing with states, is obtained, Via the variable gain matrix 10 state variables of quadruple inverted pendulum are transformed into a kind of synthesis error (E) and synthesis rate of change of error (EC) at sampling time. Therefore, the dimension of the multivariable system is reduced and the variable universe adaptive fuzzy controller is built. Experiments illustrate the effectiveness of the proposed control scheme.