This paper presented a hybrid control scheme to vibration reduction of flexible spacecraft during rotational maneuver by using variable structure output feedback control （VSOFC） and piezoelectric materials. The cont...This paper presented a hybrid control scheme to vibration reduction of flexible spacecraft during rotational maneuver by using variable structure output feedback control （VSOFC） and piezoelectric materials. The control configuration included the attitude controller based on VSOFC method and vibration attenuator designed by constant-gain negative velocity feedback control. The attitude controller consisted of a linear feedback term and a discontinuous feedback term. With the presence of this attitude controller, an additional flexible control system acting on the flexible parts can be designed for vibration control. Compared with conventional proportional-derivative （PD） control, the developed control scheme guarantees not only the stability of the closed-loop system, but also yields better performance and robustness in the presence of parametric uncertainties and externai disturbance. Simulation results are presented for the spacecraft model to show the effectiveness of the proposed control techniques.展开更多
It is concluded that Communicative Language Teaching(CLT) is a more practical approach to develop communication ability. In the process of applying this approach on oral communication ability, techniques based on CLT ...It is concluded that Communicative Language Teaching(CLT) is a more practical approach to develop communication ability. In the process of applying this approach on oral communication ability, techniques based on CLT are explored and classified as structured output activities and communicative output activities.展开更多
Synthesis and design of output variable structure controller for time-invariant linear timedelay singular system are studied. In the case that the system is regular and the system index is one, switching function with...Synthesis and design of output variable structure controller for time-invariant linear timedelay singular system are studied. In the case that the system is regular and the system index is one, switching function with integral compensator and variable structure controller are designed, which guarantee that the sliding mode is asymptotically stable and the solution trajectory of the system arrives at the switching manifold in limited time. The design method is applicable to the systems which can be regularized. Finally, a numerical example is given to demonstrate effectiveness and simplicity of the design method.展开更多
基金Sponsored by Program for Young Excellent Talents in Harbin Institute of Technology(Grant No.HITQNJS.2007.001)National Natural Science Founda-tion of China(Grant No.60674101)Research Fund for the Doctoral Program of Higher Education of China(Grant No.20050213010).
文摘This paper presented a hybrid control scheme to vibration reduction of flexible spacecraft during rotational maneuver by using variable structure output feedback control （VSOFC） and piezoelectric materials. The control configuration included the attitude controller based on VSOFC method and vibration attenuator designed by constant-gain negative velocity feedback control. The attitude controller consisted of a linear feedback term and a discontinuous feedback term. With the presence of this attitude controller, an additional flexible control system acting on the flexible parts can be designed for vibration control. Compared with conventional proportional-derivative （PD） control, the developed control scheme guarantees not only the stability of the closed-loop system, but also yields better performance and robustness in the presence of parametric uncertainties and externai disturbance. Simulation results are presented for the spacecraft model to show the effectiveness of the proposed control techniques.
文摘It is concluded that Communicative Language Teaching(CLT) is a more practical approach to develop communication ability. In the process of applying this approach on oral communication ability, techniques based on CLT are explored and classified as structured output activities and communicative output activities.
基金The project is supported by National Nature Science Foundation of China under Grant No.60574005.
文摘Synthesis and design of output variable structure controller for time-invariant linear timedelay singular system are studied. In the case that the system is regular and the system index is one, switching function with integral compensator and variable structure controller are designed, which guarantee that the sliding mode is asymptotically stable and the solution trajectory of the system arrives at the switching manifold in limited time. The design method is applicable to the systems which can be regularized. Finally, a numerical example is given to demonstrate effectiveness and simplicity of the design method.
