空间智能桁架的有限时间振动抑制控制

航天器结构设计需求趋于轻型化,大挠性空间桁架结构的应用日趋广泛,由于其具有低阻尼、大柔性等特性,在轨运行时容易产生大幅度的振荡,从而影响航天器的正常工作.为抑制传感器/作动器一体化的空间智能桁架结构的振动,基于独立模态空间理论并结合动态补偿线性化思想设计了基于终端滑模的有限时间控制方法.首先,基于有限元方法建立桁架动力学模型.然后,基于独立模态空间理论能够对各阶模态响应实现解耦的特点设计模态滤波器,利用扩张状态观测器对由外界环境干扰和模型摄动构成的系统总干扰进行实时估计,采用"动态补偿线性化"的思想将桁架动力学模型进行简化.最后,提出了一种结合双幂次趋近律与终端滑模面的有限时间控制器.仿真结果表明,相比于传统的齐次方法有限时间控制器,所提出的振动抑制控制器能够在较短时间内显著降低空间智能桁架结构在受到瞬态干扰力和周期干扰力作用时的模态振动响应幅值.算法具有良好的鲁棒性和有限时间振动收敛特性.

Finite-time vibration control of space intelligent truss

Due to the lightweight requirements of spacecraft structures, the application of large flexible space truss structure has become increasingly widespread. Since it has low-damping and large-flexible features, large oscillation is easy to be motivated on the orbit and it will affect the normal operation of the spacecraft. A finite-time control scheme based on terminal sliding-mode technique is developed to suppress the vibration of the sensor/actuation-integrated space intelligent truss structure. Based on the modal decoupling characteristics of independent modal space control theory, the extended state observer is utilized to estimate the general system disturbances consisted of external disturbances and model perturbations in real-time. Then, the terminal sliding-mode controller is designed based on "linear dynamics compensation" method. Compared with the traditional finite-time controller based on homogeneous method, simulation results show that the proposed vibration suppression controller can reduce the modal vibration amplitude caused by transient disturbance force and periodic disturbance force significantly in a shorter settling time. The proposed controller has good robustness and finite time vibration convergence characteristics.