The location of model errors in a stiffness matrix by using test data has been investigated by the others.The present paper deals with the problem of updating stiffness elements in the erroneous areas. Firstly,a model...The location of model errors in a stiffness matrix by using test data has been investigated by the others.The present paper deals with the problem of updating stiffness elements in the erroneous areas. Firstly,a model that bears relation to erroneous elements only is derived.This model is termed local errors model,which reduces orders and computational loads compared with global stiffness matrix. Secondly,an inverse eigenvalue method is used to update model errors. The results of a numerical experiment demonstrate that the method is quite effective.展开更多
In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces wit...In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces with aerodynamic redundancy.This paper studies a control reconfiguration scheme based on Control Mixer Concept.A technique for the design of a control mixer for an aircraft with damaged surfaces/actuators using the pseudo-inverse is developed and applied.This paper discusses its applications and limitations based on linear analysis and computer simulation.展开更多
It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the ...It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the linear control is realized by the dynamic inverse nonlinear controlling theory and the three-time-scale separation method.The control ability and the simulation results are also tested and verified.The results show that the output responses of system track the expected curve well and the error is controlled in a given margin.The maximum correction is about±314 m in the lengthwise direction and±1 212 m in the crosswise direction from the moment of 5 s to the drop-point time when the angle of fire is 55°.Thus,based on the dynamic inverse control of feedback linearization,the trajectory correction capability of nose cone swinging can satisfy the requirements of two-dimensional ballistic correction,and the validity and effectiveness of the method are proved.展开更多
In this paper, we show the direct and converse theorems of strong type of approximation for modified Szasz operators. Rom these theorems, the characterization of approximation for these operators is derived. The obtai...In this paper, we show the direct and converse theorems of strong type of approximation for modified Szasz operators. Rom these theorems, the characterization of approximation for these operators is derived. The obtained results are similar to the corresponding ones of the Szasz operators.展开更多
文摘The location of model errors in a stiffness matrix by using test data has been investigated by the others.The present paper deals with the problem of updating stiffness elements in the erroneous areas. Firstly,a model that bears relation to erroneous elements only is derived.This model is termed local errors model,which reduces orders and computational loads compared with global stiffness matrix. Secondly,an inverse eigenvalue method is used to update model errors. The results of a numerical experiment demonstrate that the method is quite effective.
文摘In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces with aerodynamic redundancy.This paper studies a control reconfiguration scheme based on Control Mixer Concept.A technique for the design of a control mixer for an aircraft with damaged surfaces/actuators using the pseudo-inverse is developed and applied.This paper discusses its applications and limitations based on linear analysis and computer simulation.
基金Project(9140A05030109HK01)supported by Equipment Pre-research Foundation,China
文摘It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the linear control is realized by the dynamic inverse nonlinear controlling theory and the three-time-scale separation method.The control ability and the simulation results are also tested and verified.The results show that the output responses of system track the expected curve well and the error is controlled in a given margin.The maximum correction is about±314 m in the lengthwise direction and±1 212 m in the crosswise direction from the moment of 5 s to the drop-point time when the angle of fire is 55°.Thus,based on the dynamic inverse control of feedback linearization,the trajectory correction capability of nose cone swinging can satisfy the requirements of two-dimensional ballistic correction,and the validity and effectiveness of the method are proved.
基金Supported by the Foundation of Key Item of Science and Technology of Education Ministry of China(03142)Foundation of Higher School of Ningxia(JY2002107)
文摘In this paper, we show the direct and converse theorems of strong type of approximation for modified Szasz operators. Rom these theorems, the characterization of approximation for these operators is derived. The obtained results are similar to the corresponding ones of the Szasz operators.
