针对主动电磁轴承(active magnetic bearing,AMB)刚性转子系统在全转速范围内的不平衡振动控制,提出一种基于干扰观测器和变极性跟踪滤波器的振动抑制方法。虽然在AMB刚性转子系统刚体临界转速区间前/后分别采用变极性跟踪滤波器(polari...针对主动电磁轴承(active magnetic bearing,AMB)刚性转子系统在全转速范围内的不平衡振动控制,提出一种基于干扰观测器和变极性跟踪滤波器的振动抑制方法。虽然在AMB刚性转子系统刚体临界转速区间前/后分别采用变极性跟踪滤波器(polarity switching tracking filter,PSTF)可以降低转子在刚体临界转速区间前后的振动,但在刚体临界转速区间内,转子的振动明显增大,甚至导致系统失稳。因此,将刚体临界转速区间内的转子振动看成一种干扰,引入干扰观测器(disturbance observer,DO)将转子的振动信息观测出来,实现基于跟踪滤波器的全转速范围内的转子振动抑制。最后,仿真和实验结果说明不同工况下基于干扰观测器和变极性跟踪滤波器的振动抑制方法能有效地抑制转子系统全转速范围内的同频扰动。展开更多
Exact solutions for the flexural vibrations of circular plates having elastic edge conditions along with rigid concentric ring support have been presented in this paper. Values of frequency parameter for the considere...Exact solutions for the flexural vibrations of circular plates having elastic edge conditions along with rigid concentric ring support have been presented in this paper. Values of frequency parameter for the considered circular plate are computed for different sets of values of elastic rotational and translation restraints and the radius of internal rigid ring support. The results for the first three modes of plate vibrations are computed and are presented in tabular form. The effects of rotational and linear restraints and the radius of the rigid ring support on the vibration behavior of circular plates are studied over a wide range of non-dimensional parametric values. The values of the exact frequency parameter presented in this paper for varying values of restraint parameters and the radius of the rigid ring support can better serve in design and as benchmark solutions to validate the numerical methods obtained by using other methods of solution.展开更多
The primary sensor of astronomy observation satellite （AOS） is mounted on a gimbal base which connects directly with the satellite platform and has two degrees of freedom. Attitude control for AOS with a swinging se...The primary sensor of astronomy observation satellite （AOS） is mounted on a gimbal base which connects directly with the satellite platform and has two degrees of freedom. Attitude control for AOS with a swinging sensor will be highlighted in this paper. Due to the non-negligible mass and length of the sensor, the internal motion between the satellite and the sensor will change the attitude, the position of center of mass and moment of inertia of the SYSTEM （consists of the satellite and the sen- sor）. According to moment of momentum theorem, a rigid two-body dynamic model is derived, which can he used to determine the inertial tensor of the SYSTEM. Modulating the satellite＇s present and desired quaternions results in quasi-Euler angles and normalizing these resultant parameters can ensure that the channel corresponding to each quasi-Euler angle is in the charge of each component of the control torque. Based on the normalized quasi-Euler angles, a switching attitude control law is proposed. With the control law, the corresponding phase trajectory will slide along the switching surface to the origin （corresponding to the desired states）. Simulation results show that the satellite can be controlled perfectly by thrusters with the proposed control law, even in the case of structural asymmetry and serious coupling between the control channels.展开更多
文摘Exact solutions for the flexural vibrations of circular plates having elastic edge conditions along with rigid concentric ring support have been presented in this paper. Values of frequency parameter for the considered circular plate are computed for different sets of values of elastic rotational and translation restraints and the radius of internal rigid ring support. The results for the first three modes of plate vibrations are computed and are presented in tabular form. The effects of rotational and linear restraints and the radius of the rigid ring support on the vibration behavior of circular plates are studied over a wide range of non-dimensional parametric values. The values of the exact frequency parameter presented in this paper for varying values of restraint parameters and the radius of the rigid ring support can better serve in design and as benchmark solutions to validate the numerical methods obtained by using other methods of solution.
文摘The primary sensor of astronomy observation satellite （AOS） is mounted on a gimbal base which connects directly with the satellite platform and has two degrees of freedom. Attitude control for AOS with a swinging sensor will be highlighted in this paper. Due to the non-negligible mass and length of the sensor, the internal motion between the satellite and the sensor will change the attitude, the position of center of mass and moment of inertia of the SYSTEM （consists of the satellite and the sen- sor）. According to moment of momentum theorem, a rigid two-body dynamic model is derived, which can he used to determine the inertial tensor of the SYSTEM. Modulating the satellite＇s present and desired quaternions results in quasi-Euler angles and normalizing these resultant parameters can ensure that the channel corresponding to each quasi-Euler angle is in the charge of each component of the control torque. Based on the normalized quasi-Euler angles, a switching attitude control law is proposed. With the control law, the corresponding phase trajectory will slide along the switching surface to the origin （corresponding to the desired states）. Simulation results show that the satellite can be controlled perfectly by thrusters with the proposed control law, even in the case of structural asymmetry and serious coupling between the control channels.
