挠性卫星的姿态快速稳定控制方法研究

发布时间：2018-08-27 20:31

【摘要】：目前,由我国担任发射的航天器大部分都带有挠性附件,挠性附件正朝着结构和体积更加复杂的趋势发展,对这类航天器的控制要求也将变的更加严格。基于此趋势,我们所使用的控制算法应当进一步满足挠性航天器快速机动、快速稳定的需求。新的控制需求主要体现在两方面:第一,航天器因挠性附件的日趋复杂,模型的不确定性增加,控制系统需适应被控对象的不确定性;第二,带有大型挠性附件航天器在快速机动、快速稳定等控制品质方面有待提高。本文针对带有挠性附件的卫星本身存在着模态频率不确定的问题,对挠性卫星控制系统设计了PD和EI的复合控制算法来抑制挠性器件的振动,进而避免了挠性器件组模态直接检测的困难以及因进一步设计观测器而增加的系统复杂性的问题。首先,针对动力学对象确定PD输出反馈控制器,精心设计该控制器的参数,使得姿态控制系统具有很好的动态品质;此外,为了有效抑制挠性结构的振动,进一步将EI输入成型振动抑制方法引入到闭环控制系统的外侧,用来改变输入命令的形状达到抑制挠性结构振动的目的;随后针对模态频率和系统转动惯量的不确定性因素设计了一种基于RBF神经网络自适应的变结构控制器,并且引入了EI输入成型的振动抑制方法,通过改变输入指令的形状来抑制结构的振动,仿真结果证实了设计理论的正确性及所研究方法的可行性。其次,针对挠性卫星在大角度姿态机动时,飞行器带有饱和特性所产生的模态振动问题,本文设计了一种对饱和特性进行分力合成的方法来抑制此类振动,提高了姿态机动的稳定时间和稳态精度。由仿真结果可知,针对执行器带有饱和非线性的模态振动问题,利用PD控制结合分力合成主动振动抑制方法可以有效的减少模态的振动,缩短稳定时间,提高稳态精度,此方法对模态频率变化范围是20%的情况具有较好的鲁棒性。
[Abstract]:At present, most of the spacecraft launched by our country have flexible appendages. The flexible appendages are developing towards more complex structure and volume, and the control requirements of these spacecraft will become more stringent. Based on this trend, the control algorithm we use should further meet the needs of flexible spacecraft for rapid maneuvering and fast stability. The new control requirements are mainly reflected in two aspects: first, because of the increasing complexity of flexible appendages, the uncertainty of the model increases, and the control system needs to adapt to the uncertainty of the controlled object. The control quality of spacecraft with large flexible appendages needs to be improved in terms of fast maneuvering, fast stability and so on. Aiming at the uncertainty of the mode frequency of the satellite with flexible appendages, a compound control algorithm of PD and EI is designed for the flexible satellite control system to suppress the vibration of the flexible device. The difficulty of direct modal detection of flexible device group and the complexity of the system caused by the further design of the observer are avoided. First of all, the PD output feedback controller is determined for the dynamic object, and the parameters of the controller are carefully designed to make the attitude control system have good dynamic quality; in addition, in order to effectively suppress the vibration of the flexible structure, Further, the EI input molding vibration suppression method is introduced to the outside of the closed-loop control system to change the shape of the input command to suppress the vibration of the flexible structure. Then, an adaptive variable structure controller based on RBF neural network is designed for the uncertainty factors of modal frequency and system inertia, and the vibration suppression method of EI input molding is introduced. By changing the shape of the input instruction to suppress the vibration of the structure, the simulation results verify the correctness of the design theory and the feasibility of the proposed method. Secondly, aiming at the modal vibration problem of flexible satellite with saturation characteristics when it maneuvers at large angle, this paper designs a method to combine the saturation characteristics to suppress the vibration. The stability time and steady-state precision of attitude maneuver are improved. The simulation results show that the active vibration suppression method based on PD control combined with component force synthesis can effectively reduce the modal vibration, shorten the stabilization time and improve the steady-state accuracy for the modal vibration problem with saturated nonlinear actuator. This method is robust to the case where the frequency range is 20%.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V448.2

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