The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical ...The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.展开更多
Underwater gliders are recent innovative types of autonomous underwater vehicles （AUVs） used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the ch...Underwater gliders are recent innovative types of autonomous underwater vehicles （AUVs） used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the change of altitude, they use the hydrodynamic forces developed by their wings to move forward. Their flights are controlled by changing the position of their centers of gravity and their buoyancy to adjust their trim and heel angles. For better flight control, the understanding of the hydrodynamic behavior and the flight mechanics of the underwater glider is necessary. A 6-DOF motion simulator is coupled with an unsteady potential flow model for this purpose. In some specific cases, the numerical study demonstrates that an inappropriate stabilizer dimension can cause counter-steering behavior. The simulator can be used to improve the automatic flight control. It can also be used for the hydrodynamic design optimization of the devices.展开更多
This paper gives details about the controller design that aims to stabilize the novel twinrotor flying robot, Toruk. Toruk is an experimental test bench to study center of gravity steering, effect of the location of t...This paper gives details about the controller design that aims to stabilize the novel twinrotor flying robot, Toruk. Toruk is an experimental test bench to study center of gravity steering, effect of the location of the center of gravity, controller design and implementation, etc. Physical components are also briefly discussed in this paper. Attitude dynamics of the system is inherently unstable. It is stabilized by a regulator. In addition, an observer is designed and utilized to estimate the unmeasured states. Thrust force generated by the propulsion unit is estimated by using the identified mathematical model of the unit. An experimental setup is employed to identify the mathematical model that expresses the relation between the applied input voltage to the propulsion unit and thrust produced by the propeller. Mathematical model for the attitude dynamics of Toruk is built. Then controllability and observability analysis are carried out for the system. Dynamic compensator composed of a state observer and a regulator, is designed on the mathematical model. Physical implementation on the system will be performed.展开更多
基金Project supported by the Science Foundation of Shanghai Municipal Commission of Education (Grant No.98AJ01)the Natural Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No.03ZR14032)
文摘The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.
文摘Underwater gliders are recent innovative types of autonomous underwater vehicles （AUVs） used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the change of altitude, they use the hydrodynamic forces developed by their wings to move forward. Their flights are controlled by changing the position of their centers of gravity and their buoyancy to adjust their trim and heel angles. For better flight control, the understanding of the hydrodynamic behavior and the flight mechanics of the underwater glider is necessary. A 6-DOF motion simulator is coupled with an unsteady potential flow model for this purpose. In some specific cases, the numerical study demonstrates that an inappropriate stabilizer dimension can cause counter-steering behavior. The simulator can be used to improve the automatic flight control. It can also be used for the hydrodynamic design optimization of the devices.
文摘This paper gives details about the controller design that aims to stabilize the novel twinrotor flying robot, Toruk. Toruk is an experimental test bench to study center of gravity steering, effect of the location of the center of gravity, controller design and implementation, etc. Physical components are also briefly discussed in this paper. Attitude dynamics of the system is inherently unstable. It is stabilized by a regulator. In addition, an observer is designed and utilized to estimate the unmeasured states. Thrust force generated by the propulsion unit is estimated by using the identified mathematical model of the unit. An experimental setup is employed to identify the mathematical model that expresses the relation between the applied input voltage to the propulsion unit and thrust produced by the propeller. Mathematical model for the attitude dynamics of Toruk is built. Then controllability and observability analysis are carried out for the system. Dynamic compensator composed of a state observer and a regulator, is designed on the mathematical model. Physical implementation on the system will be performed.
