The computer numerical control（CNC） system is suited to control varied types of flexible fixtures in aircraft component manufacturing and assembly. The mechanisms and control requirements of flexible fixtures are pr...The computer numerical control（CNC） system is suited to control varied types of flexible fixtures in aircraft component manufacturing and assembly. The mechanisms and control requirements of flexible fixtures are presented and analyzed. The hardware and software architecture and implementation of CNC system are pro- posed. The flexible fixture mechanism is described using configuration parameters. According to the parameters, the CNC system automatically generates the control feature and the human machine interface （HMI） operation function. The CNC system is implemented in a flexible fixture for skin-strlnger assembly, and results show the effectiveness of the system.展开更多
Based on optimM velocity car-following model, in this paper, we propose a new railway tramc model for describing the process of train movement control. In the proposed model, we give an improved form of the optimal ve...Based on optimM velocity car-following model, in this paper, we propose a new railway tramc model for describing the process of train movement control. In the proposed model, we give an improved form of the optimal velocity function V^opt, which is considered as the desired velocity function for train movement control under different control conditions. In order to test the proposed model, we simulate and analyze the trajectories of train movements, moreover, discuss the relationship curves between the train allowable velocity and the site of objective point in detail. Analysis results indicate that the proposed model can well capture some realistic futures of train movement control.展开更多
We study a stochastic control system involving both a standard and a fractional Brownian motion with Hurst parameter less than 1/2.We apply an anticipative Girsanov transformation to transform the system into another ...We study a stochastic control system involving both a standard and a fractional Brownian motion with Hurst parameter less than 1/2.We apply an anticipative Girsanov transformation to transform the system into another one,driven only by the standard Brownian motion with coefficients depending on both the fractional Brownian motion and the standard Brownian motion.We derive a maximum principle and the associated stochastic variational inequality,which both are generalizations of the classical case.展开更多
文摘The computer numerical control（CNC） system is suited to control varied types of flexible fixtures in aircraft component manufacturing and assembly. The mechanisms and control requirements of flexible fixtures are presented and analyzed. The hardware and software architecture and implementation of CNC system are pro- posed. The flexible fixture mechanism is described using configuration parameters. According to the parameters, the CNC system automatically generates the control feature and the human machine interface （HMI） operation function. The CNC system is implemented in a flexible fixture for skin-strlnger assembly, and results show the effectiveness of the system.
基金Supported by the National Natural Science Foundation of China under Grant Nos.60634010 and 60776829the State Key Laboratory of Rail Traffic Control and Safety (Contract No.RCS2008ZZ001 and RCS2010ZZ001),Beijing Jiaotong University
文摘Based on optimM velocity car-following model, in this paper, we propose a new railway tramc model for describing the process of train movement control. In the proposed model, we give an improved form of the optimal velocity function V^opt, which is considered as the desired velocity function for train movement control under different control conditions. In order to test the proposed model, we simulate and analyze the trajectories of train movements, moreover, discuss the relationship curves between the train allowable velocity and the site of objective point in detail. Analysis results indicate that the proposed model can well capture some realistic futures of train movement control.
基金supported by National Natural Science Foundation of China(Grant No11301560)
文摘We study a stochastic control system involving both a standard and a fractional Brownian motion with Hurst parameter less than 1/2.We apply an anticipative Girsanov transformation to transform the system into another one,driven only by the standard Brownian motion with coefficients depending on both the fractional Brownian motion and the standard Brownian motion.We derive a maximum principle and the associated stochastic variational inequality,which both are generalizations of the classical case.
