Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros (SGCMGs) as actuators is investigated. First of all, the dy...Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros (SGCMGs) as actuators is investigated. First of all, the dynamic model of the underactuated spacecraft is established and the singularity of different configurations with the two SGCMGs is analyzed. Under the assumption that the gimbal axes of the two SGCMGs are installed in any direction, and that the total system angular momentum is not zero, a state feedback control law via Lyapunov method is designed to globally asymptotically stabilize the angular velocity of spacecraft. Under the assumption that the gimbal axes of the two SGCMGs are coaxially installed along anyone of the three principal axes of spacecraft inertia, and that the total system angular momentum is zero, a discontinuous state feedback control law is designed to stabilize three-axis attitude of spacecraft with respect to the inertial frame. Furthermore, the singularity escape of SGCMGs for the above two control problems is also studied. Simulation results demonstrate the validity of the control laws.展开更多
The attitude control problem of a spacecraft underactuated by two single-gimbal control moment gyros (SGCMGs) is investigated. Small-time local controllability (STLC) of the attitude dynamics of the spacecraft-SGC...The attitude control problem of a spacecraft underactuated by two single-gimbal control moment gyros (SGCMGs) is investigated. Small-time local controllability (STLC) of the attitude dynamics of the spacecraft-SGCMGs system is analyzed via nonlinear controllability theory. The conditions that guarantee STLC of the spacecraft attitude by two non-coaxial SGCMGs are obtained with the momentum of the SGCMGs as inputs, implying that the spacecraft attitude is STLC when the total angular momentum of the whole system is zero. Moreover, our results indi- cate that under the zero-momentum restriction, full attitude stabilization is possible for a spacecraft using two non-coaxial SGCMGs. For the case of two coaxial SGCMGs, the STLC property of the spacecraft cannot be determined. In this case, an improvement to the previous full attitude stabilizing control law, which requires zero-momentum presumption, is proposed to account for the singu- larity of SGCMGs and enhance the steady state performance. Numerical simulation results demonstrate the effectiveness and advantages of the new control law.展开更多
Attitude control system is one of the most important subsystems in a spacecraft.As a key actuator,the control moment gyroscope(CMG)mainly determines the performance of attitude control system.Whereas,the control accur...Attitude control system is one of the most important subsystems in a spacecraft.As a key actuator,the control moment gyroscope(CMG)mainly determines the performance of attitude control system.Whereas,the control accuracy and output torque smoothness of the CMG depends more on its gimbal servo system.Considering the constraints of size,mass and power consumption for a small satellite,here,a mini-CMG is designed,in which the gimbal servo system is driven by an ultrasonic motor.The good performances of the CMG are obtained by both the ultrasonic motor and the rotary inductosyn.The direct drive of gimbal improves its dynamic performance,with the output bandwidth above 20 Hz.The angular and speed closed-loop control obtains the 0.02°/s gimbal rate,and the output torque resolution better than 2×10^(-3) N·m.The ultrasonic motor provides 1.0N·m self-lock torque during power-off,with 12arc-second position accuracy.展开更多
Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gim...Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gimbal control moment gyros (SGCMGs) as the actuator for the attitude control system.The expression of output-torque error is given at the point of singularity,proving the incompatible relationship between the gimbal rate and the output-torque error.The method of establishing a balance between the gimbal rate and the output-torque error is discussed,and a new steering law is designed.Simulation results show that the proposed steering law can effectively drive SGCMGs to escape away from singularities.展开更多
A system model is developed to describe the translational and rotational motion of an active-magnetic-bearing-suspended rigid rotor in a single-gimbal control moment gyro onboard a rigid satellite. This model strictly...A system model is developed to describe the translational and rotational motion of an active-magnetic-bearing-suspended rigid rotor in a single-gimbal control moment gyro onboard a rigid satellite. This model strictly reflects the motion characteristics of the rotor by considering the dynamic and static imbalance as well as the coupling between the gimbal's and the rotor's motion on a satellite platform. Adaptive auto-centering control is carefully constructed for the rotor with unknown dynamic and static imbalance. The rotor makes its rotation about the principal axis of inertia through identifying the small rotational angles between the geometric axis and the principal axis as well as the displacements from the geometric center to the mass center so as to tune a stabilizing controller composed of a decentralized PD controller with cross-axis proportional gains and high- and low-pass filters. The main disturbance in the wheel spinning can thereby be completely removed and the vibration acting on the satellite attenuated.展开更多
双框架磁悬浮控制力矩陀螺(Double gimbal magnetically suspended control moment gyroscope,DGMSCMG)是由磁悬浮高速转子系统与内框架、外框架速率伺服系统构成的航天器新型姿控执行机构。由于非线性及三个子系统间的强耦合,框架转动...双框架磁悬浮控制力矩陀螺(Double gimbal magnetically suspended control moment gyroscope,DGMSCMG)是由磁悬浮高速转子系统与内框架、外框架速率伺服系统构成的航天器新型姿控执行机构。由于非线性及三个子系统间的强耦合,框架转动时磁悬浮转子位移急剧增大影响稳定性,同时框架系统的响应速度显著下降,称之为动框架效应。该效应严重影响了DGMSCMG的功能,必须加以抑制。建立DGMSCMG的动力学模型,分析三个子系统间的动力学耦合机理,提出一种基于复合控制的补偿方法,引入针对陀螺项的反馈和针对框架角速率给定的前馈消除磁悬浮转子附加位移,提高框架系统响应速度,并对补偿后系统做全局稳定性分析。仿真和试验结果表明,该方法能在保证系统稳定性的前提下有效抑制动框架效应,满足DGMSCMG的功能要求。展开更多
针对挠性航天器系统中同时存在单框架控制力矩陀螺群(Single gimbaled control moment gyroscopes,SGCMGs)摩擦非线性、电磁干扰力矩、惯量摄动以及外部干扰等问题,提出了一种有限时间自适应鲁棒控制(Finite-time adaptive robust contr...针对挠性航天器系统中同时存在单框架控制力矩陀螺群(Single gimbaled control moment gyroscopes,SGCMGs)摩擦非线性、电磁干扰力矩、惯量摄动以及外部干扰等问题,提出了一种有限时间自适应鲁棒控制(Finite-time adaptive robust control,FTARC)方法.针对系统中存在未知参数的情况,分别设计自适应更新律,使得控制器的设计不依赖参数信息,同时减小外部干扰对系统的不利影响.应用Lyapunov稳定性理论证明了闭环系统姿态角误差和姿态角速度误差可在有限时间内收敛到原点附近的邻域内.仿真结果表明,所提控制律可实现挠性航天器姿态快速机动,并获得甚高指向精度.展开更多
文摘Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros (SGCMGs) as actuators is investigated. First of all, the dynamic model of the underactuated spacecraft is established and the singularity of different configurations with the two SGCMGs is analyzed. Under the assumption that the gimbal axes of the two SGCMGs are installed in any direction, and that the total system angular momentum is not zero, a state feedback control law via Lyapunov method is designed to globally asymptotically stabilize the angular velocity of spacecraft. Under the assumption that the gimbal axes of the two SGCMGs are coaxially installed along anyone of the three principal axes of spacecraft inertia, and that the total system angular momentum is zero, a discontinuous state feedback control law is designed to stabilize three-axis attitude of spacecraft with respect to the inertial frame. Furthermore, the singularity escape of SGCMGs for the above two control problems is also studied. Simulation results demonstrate the validity of the control laws.
基金supported by the National Natural Science Foundation of China (No.10902003)
文摘The attitude control problem of a spacecraft underactuated by two single-gimbal control moment gyros (SGCMGs) is investigated. Small-time local controllability (STLC) of the attitude dynamics of the spacecraft-SGCMGs system is analyzed via nonlinear controllability theory. The conditions that guarantee STLC of the spacecraft attitude by two non-coaxial SGCMGs are obtained with the momentum of the SGCMGs as inputs, implying that the spacecraft attitude is STLC when the total angular momentum of the whole system is zero. Moreover, our results indi- cate that under the zero-momentum restriction, full attitude stabilization is possible for a spacecraft using two non-coaxial SGCMGs. For the case of two coaxial SGCMGs, the STLC property of the spacecraft cannot be determined. In this case, an improvement to the previous full attitude stabilizing control law, which requires zero-momentum presumption, is proposed to account for the singu- larity of SGCMGs and enhance the steady state performance. Numerical simulation results demonstrate the effectiveness and advantages of the new control law.
基金supported by the National Natural Science Foundation of China(No.51575260)the Fundamental Research Funds for the Central Universities(No.NJ20160001)
文摘Attitude control system is one of the most important subsystems in a spacecraft.As a key actuator,the control moment gyroscope(CMG)mainly determines the performance of attitude control system.Whereas,the control accuracy and output torque smoothness of the CMG depends more on its gimbal servo system.Considering the constraints of size,mass and power consumption for a small satellite,here,a mini-CMG is designed,in which the gimbal servo system is driven by an ultrasonic motor.The good performances of the CMG are obtained by both the ultrasonic motor and the rotary inductosyn.The direct drive of gimbal improves its dynamic performance,with the output bandwidth above 20 Hz.The angular and speed closed-loop control obtains the 0.02°/s gimbal rate,and the output torque resolution better than 2×10^(-3) N·m.The ultrasonic motor provides 1.0N·m self-lock torque during power-off,with 12arc-second position accuracy.
基金supported by the National Natural Science Foundation of China (10872029)the Excellent Young Scholars Research Fund of the Beijing Institute of Technology (2007YS0202)
文摘Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gimbal control moment gyros (SGCMGs) as the actuator for the attitude control system.The expression of output-torque error is given at the point of singularity,proving the incompatible relationship between the gimbal rate and the output-torque error.The method of establishing a balance between the gimbal rate and the output-torque error is discussed,and a new steering law is designed.Simulation results show that the proposed steering law can effectively drive SGCMGs to escape away from singularities.
文摘A system model is developed to describe the translational and rotational motion of an active-magnetic-bearing-suspended rigid rotor in a single-gimbal control moment gyro onboard a rigid satellite. This model strictly reflects the motion characteristics of the rotor by considering the dynamic and static imbalance as well as the coupling between the gimbal's and the rotor's motion on a satellite platform. Adaptive auto-centering control is carefully constructed for the rotor with unknown dynamic and static imbalance. The rotor makes its rotation about the principal axis of inertia through identifying the small rotational angles between the geometric axis and the principal axis as well as the displacements from the geometric center to the mass center so as to tune a stabilizing controller composed of a decentralized PD controller with cross-axis proportional gains and high- and low-pass filters. The main disturbance in the wheel spinning can thereby be completely removed and the vibration acting on the satellite attenuated.
文摘双框架磁悬浮控制力矩陀螺(Double gimbal magnetically suspended control moment gyroscope,DGMSCMG)是由磁悬浮高速转子系统与内框架、外框架速率伺服系统构成的航天器新型姿控执行机构。由于非线性及三个子系统间的强耦合,框架转动时磁悬浮转子位移急剧增大影响稳定性,同时框架系统的响应速度显著下降,称之为动框架效应。该效应严重影响了DGMSCMG的功能,必须加以抑制。建立DGMSCMG的动力学模型,分析三个子系统间的动力学耦合机理,提出一种基于复合控制的补偿方法,引入针对陀螺项的反馈和针对框架角速率给定的前馈消除磁悬浮转子附加位移,提高框架系统响应速度,并对补偿后系统做全局稳定性分析。仿真和试验结果表明,该方法能在保证系统稳定性的前提下有效抑制动框架效应,满足DGMSCMG的功能要求。
文摘针对挠性航天器系统中同时存在单框架控制力矩陀螺群(Single gimbaled control moment gyroscopes,SGCMGs)摩擦非线性、电磁干扰力矩、惯量摄动以及外部干扰等问题,提出了一种有限时间自适应鲁棒控制(Finite-time adaptive robust control,FTARC)方法.针对系统中存在未知参数的情况,分别设计自适应更新律,使得控制器的设计不依赖参数信息,同时减小外部干扰对系统的不利影响.应用Lyapunov稳定性理论证明了闭环系统姿态角误差和姿态角速度误差可在有限时间内收敛到原点附近的邻域内.仿真结果表明,所提控制律可实现挠性航天器姿态快速机动,并获得甚高指向精度.