基于压电作动器的大型空间索网结构动力学分析与振动控制
发布时间：2018-11-04 07:47
【摘要】：大型空间索网结构由于折叠体积小、质量轻、展开后口径大等特点,广泛应用于信号传输、对地观测、深空探测等领域,是世界各国争相研究的热点。由于柔性大,刚度低、阻尼小,一旦受到空间扰动将会长时振荡影响在轨运行精度,因此进行有效的振动主动控制至关重要。首先,采用力密度法对给定几何形态的三向抛物面索网进行了找形分析,并基于复位平衡法确定了均匀分布的索网预拉力。利用有限元法建立了基于预拉力索应力刚化效应及压电作动器等效“压电叠堆-弹簧”力学模型的压电智能索耦合动力学方程。然后,研究了含作动器/传感器的压电智能索的优化配置。在降阶的模态坐标下建立状态空间形式的结构动力学方程,得到模态控制力能量自相关矩阵,并根据该矩阵的秩来优化同位配置的作动器/传感器数目。根据系统总储能积分最小、传感器接收信号能量最大的复合优化准则,利用基于字典序排列组合编码的遗传算法获得作动器/传感器全局最优配置的位置。随后,基于索网动力学方程状态空间描述设计了LQG控制器;建立了含刚度不确定性的索网结构广义受控对象,并通过浮点数编码遗传算法优化得到闭环系统加权函数参数,分析了H?混合灵敏度控制器的鲁棒稳定性;进一步设计了?综合控制器,发现在相同的结构不确定下,?综合控制器有效的降低了控制器保守性,确保了系统的鲁棒稳定性及鲁棒性能;最后就三种控制器的控制效果进行了对比分析,综合考虑选取?综合控制器;针对控制器阶数过高,用Hankle范数近似法对控制器进行了降阶。本文实现了大型空间索网结构的预拉力确定及有限元动力学建模,优化了作动器/传感器数目/配置位置,基于此得到参数优化的加权函数,进一步设计了确保闭环系统鲁棒稳定性及鲁棒性能的主动控制器。
[Abstract]:Large space cable-net structures are widely used in the fields of signal transmission, earth observation and deep space exploration because of their small folding volume, light mass and large caliber. Because of the large flexibility, low stiffness and low damping, once the spatial disturbance will affect the accuracy of orbit operation, it is very important to carry out effective active vibration control. Firstly, the force density method is used to find the shape of the triaxial paraboloid cable network with given geometric shape, and the pretension force of the cable net with uniform distribution is determined based on the reset balance method. Based on the stress hardening effect of the pretension cable and the equivalent "piezoelectric stacked spring" mechanical model of the piezoelectric actuator, the coupled dynamic equations of the piezoelectric intelligent cable are established by using the finite element method. Then, the optimal configuration of piezoelectric intelligent cables with actuators / sensors is studied. The structural dynamics equation in the form of state space is established in the reduced order modal coordinates, and the energy autocorrelation matrix of modal control force is obtained, and the number of actuators / sensors in the same position configuration is optimized according to the rank of the matrix. According to the composite optimization criterion of minimum total energy storage integral and maximum energy of sensor received signal, the position of actuator / sensor global optimal configuration is obtained by genetic algorithm based on dictionary-ordered array and combination coding. Then, the LQG controller is designed based on the state space description of cable network dynamics equation. The generalized controlled object of cable net structure with stiffness uncertainty is established, and the weighted function parameters of closed loop system are obtained by genetic algorithm of floating point coding, and the parameters of the weighted function of the closed-loop system are analyzed. Robust Stability of mixed sensitivity Controller; further designed? Integrated controller, found under the same structure uncertainty,? The integrated controller effectively reduces the conservatism of the controller and ensures the robust stability and robustness of the system. Finally, the control effects of the three controllers are compared and analyzed, and the selection of the controller is considered synthetically. For the controller order is too high, the Hankle norm approximation method is used to reduce the order of the controller. In this paper, the pretension force determination and finite element dynamic modeling of large space cable-net structures are realized, and the actuator / sensor number / configuration position is optimized. Based on this, the weighting function of parameter optimization is obtained. Furthermore, an active controller is designed to ensure the robust stability and robustness of the closed loop system.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：V414;TB535
，
本文编号：2309170
[Abstract]:Large space cable-net structures are widely used in the fields of signal transmission, earth observation and deep space exploration because of their small folding volume, light mass and large caliber. Because of the large flexibility, low stiffness and low damping, once the spatial disturbance will affect the accuracy of orbit operation, it is very important to carry out effective active vibration control. Firstly, the force density method is used to find the shape of the triaxial paraboloid cable network with given geometric shape, and the pretension force of the cable net with uniform distribution is determined based on the reset balance method. Based on the stress hardening effect of the pretension cable and the equivalent "piezoelectric stacked spring" mechanical model of the piezoelectric actuator, the coupled dynamic equations of the piezoelectric intelligent cable are established by using the finite element method. Then, the optimal configuration of piezoelectric intelligent cables with actuators / sensors is studied. The structural dynamics equation in the form of state space is established in the reduced order modal coordinates, and the energy autocorrelation matrix of modal control force is obtained, and the number of actuators / sensors in the same position configuration is optimized according to the rank of the matrix. According to the composite optimization criterion of minimum total energy storage integral and maximum energy of sensor received signal, the position of actuator / sensor global optimal configuration is obtained by genetic algorithm based on dictionary-ordered array and combination coding. Then, the LQG controller is designed based on the state space description of cable network dynamics equation. The generalized controlled object of cable net structure with stiffness uncertainty is established, and the weighted function parameters of closed loop system are obtained by genetic algorithm of floating point coding, and the parameters of the weighted function of the closed-loop system are analyzed. Robust Stability of mixed sensitivity Controller; further designed? Integrated controller, found under the same structure uncertainty,? The integrated controller effectively reduces the conservatism of the controller and ensures the robust stability and robustness of the system. Finally, the control effects of the three controllers are compared and analyzed, and the selection of the controller is considered synthetically. For the controller order is too high, the Hankle norm approximation method is used to reduce the order of the controller. In this paper, the pretension force determination and finite element dynamic modeling of large space cable-net structures are realized, and the actuator / sensor number / configuration position is optimized. Based on this, the weighting function of parameter optimization is obtained. Furthermore, an active controller is designed to ensure the robust stability and robustness of the closed loop system.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：V414;TB535
，
本文编号：2309170
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