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基于飞轮的欠驱动航天器姿态控制器设计 总被引:1,自引:0,他引:1
在以飞轮作为姿态控制执行机构的航天器中,如果部分飞轮发生故障而使得航天器欠驱动时,姿态控制性能会急剧下降.本文对两个匕轮的刚性航天器,研究了姿态控制问题.在零动量的假设下,利用Backstepping方法,为欠驱动姿态控制系统设计了一个新型的姿态控制器.设计过程分两步进行:首先,根据姿态运动学模型,设计出可使航天器姿态全局渐近稳定的控制角速率;然后,根据姿态动力学模型,得到使航天器姿态全局渐近稳定的控制力矩.该控制器为非连续控制器,可使航天器姿态误差全局一致渐近收敛为零,并使系统具有良好的动态性能.计算机仿真表明,本文所设计出的控制器是可行的. 相似文献
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针对存在不确定惯量矩阵和外干扰的刚体航天器姿态跟踪系统,提出了一种自适应滑模控制方法。首先建立了姿态跟踪误差动力学方程,并对刚体航天器跟踪误差动力学定义了滑模,设计了自适应滑模控制律,该控制律的优点在于可以估计系统不确定块,消除了传统滑模控制中对不确定界的要求。Lyapunov分析表明了提出的自适应滑模控制器确保闭环系统取得渐近稳定性。仿真结果验证了提出的控制策略的有效性。 相似文献
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针对存在时变干扰和通信受限的船舶艏向保持控制问题, 本文设计了一种基于混合阈值事件触发机制的船舶自适应神经滑模控制算法. 首先, 采用径向基函数神经网络(RBF-NNs)对控制系统的模型不确定部分进行在线逼近. 其次, 构造了一种比例积分滑模面和基于混合阈值参数的事件触发规则来降低时变干扰引起的系统抖振和减少传输信道的通信资源占用. 并且在理论上分析了事件触发技术能够增强闭环控制系统对低频扰动的抗扰性. 最后, 通过Lyapunov理论证明了所提控制算法能够保证所有误差信号满足半全局一致最终有界稳定(SGUUB). 在时变干扰条件下进行数值仿真, 并且与现有控制技术进行对比, 仿真结果表明, 所提控制算法能够明显减少系统抖振和控制输入频率. 相似文献
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对主从航天器的相对姿态控制问题,考虑从航天器系统不确定因素,提出了一种基于反步法的姿态控制方法,并引入自适应控制律.该方法首先根据主从航天器的相对位置信息,解算出从航天器观测轴指向主航天器以及从航天器跟踪主航天器轨道坐标系等两种任务的期望姿态;然后基于修正罗德里格参数(MI(P)描述的从航天器姿态误差动力学模型设计了姿态控制器以及针对航天器惯量的不确定性设计了自适应控制律;并基于Lyapunov方法从理论上证明了该方法能够实现全局渐近稳定的相对姿态控制.最后将该方法应用于某编队飞行任务,仿真结果表明此控制器能够实现其编队飞行控制,具有良好的控制性能. 相似文献
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针对存在外界未知干扰、参数不确定问题的刚-液-柔多体耦合航天器姿态控制进行了研究.将液体燃料的晃动等效为球摆模型,挠性附件假设为欧拉-伯努利梁,建立了多体耦合航天器动力学方程.首先,设计了积分滑模干扰观测器,使其能够在有限的时间范围内对控制系统的集总扰动实现准确估计;其次,以此干扰观测器为基础,设计了一种时变滑模控制方法,该控制运用双曲正切函数;最后,结合光滑整形技术,设计出零振动指令光滑器,从而抑制液体晃动和挠性附件振动.数值仿真结果表明:本文所设计的控制方案具有可行性和有效性,多模态充液挠性航天器在姿态机动过程中所引起的残余振动可以得到有效抑制. 相似文献
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Bi-Objective Optimal Control Modification Adaptive Control for Systems with Input Uncertainty
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Nhan T. Nguyen Sivasubramanya N. Balakrishnan 《IEEE/CAA Journal of Automatica Sinica》2014,1(4):423-434
This paper presents a new model-reference adaptive control method based on a bi-objective optimal control formulation for systems with input uncertainty. A parallel predictor model is constructed to relate the predictor error to the estimation error of the control effectiveness matrix. In this work, we develop an optimal control modification adaptive control approach that seeks to minimize a bi-objective linear quadratic cost function of both the tracking error norm and the predictor error norm simultaneously. The resulting adaptive laws for the parametric uncertainty and control effectiveness uncertainty are dependent on both the tracking error and the predictor error, while the adaptive laws for the feedback gain and command feedforward gain are only dependent on the tracking error. The optimal control modification term provides robustness to the adaptive laws naturally from the optimal control framework. Simulations demonstrate the effectiveness of the proposed adaptive control approach. 相似文献
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李善姬 《计算技术与自动化》2005,24(4):16-18
变结构控制系统是一类特殊的非线性控制系统,滑模控制就是其中一种。滑模控制对系统参数及扰动的变化反应迟钝,具有很强的鲁棒性,该类控制方法特别适合于机械臂系统的控制。本文中采用奇异摄动方法将双连杆柔性机械臂系统分解为慢变和快变两个子系统,并对慢变子系统采用滑模控制方法设计了控制器。采用MATLAB进行的数值仿真结果表明了所设计控制器的有效性; 相似文献
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In this paper, we present a new approach of designing adaptive inverse controller for synchronous generator excitation system
containing nonsmooth nonlinearities in actuator device. The proposed controller considers not only the dynamics of generator
but also nonlinearities in actuator. To address such a challenge, support vector machines (SVM) is adopted to identify the
plant and to construct the inverse controller. SVM networks, used to compensate nonlinearities in synchronous generator as
well as in actuator, are adjusted online by an adaptive law via back propagation (BP) algorithm. To guarantee convergence
and for fast learning, adaptive learning rate and convergence theorem are developed. Simulation results are given, showing
satisfactory control performance and illustrate the potential of the proposed adaptive inverse controller as useful for practical
purpose. 相似文献
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Characteristic Model-based Discrete-time Sliding Mode Control for Spacecraft with Variable Tilt of Flexible Structures
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In this paper, the finite-time attitude tracking control problem for the spacecrafts with variable tilt of flexible appendages in the conditions of exogenous disturbances and inertia uncertainties is addressed. First the characteristic modeling method is applied to the problem of the spacecraft modeling. Second, a novel adaptive sliding mode surface is designed based on the characteristic model. Furthermore, a discrete-time sliding mode control (DTSMC) law, which makes the tracking error converge into a predefined bound in finite time, is proposed by employing the parameters of characteristic model associated with the sliding mode surface to provide better performances, robustness, faster response, and higher control precision. The designed DTSMC includes the adaptive control architecture and is chattering-free. Finally, digital simulations of a sun synchronous orbit satellite (SSOS) are presented to illustrate effectiveness of the control strategies as well as to verify the practical feasibility of the rapid maneuver mission. 相似文献
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Robust Adaptive Gain Higher Order Sliding Mode Observer Based Control-constrained Nonlinear Model Predictive Control for Spacecraft Formation Flying
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Ranjith Ravindranathan Nair Laxmidhar Behera 《IEEE/CAA Journal of Automatica Sinica》2018,5(1):367-381
This work deals with the development of a decentralized optimal control algorithm, along with a robust observer, for the relative motion control of spacecraft in leader-follower based formation. An adaptive gain higher order sliding mode observer has been proposed to estimate the velocity as well as unmeasured disturbances from the noisy position measurements. A differentiator structure containing the Lipschitz constant and Lebesgue measurable control input, is utilized for obtaining the estimates. Adaptive tuning algorithms are derived based on Lyapunov stability theory, for updating the observer gains, which will give enough flexibility in the choice of initial estimates. Moreover, it may help to cope with unexpected state jerks. The trajectory tracking problem is formulated as a finite horizon optimal control problem, which is solved online. The control constraints are incorporated by using a nonquadratic performance functional. An adaptive update law has been derived for tuning the step size in the optimization algorithm, which may help to improve the convergence speed. Moreover, it is an attractive alternative to the heuristic choice of step size for diverse operating conditions. The disturbance as well as state estimates from the higher order sliding mode observer are utilized by the plant output prediction model, which will improve the overall performance of the controller. The nonlinear dynamics defined in leader fixed Euler-Hill frame has been considered for the present work and the reference trajectories are generated using Hill-Clohessy-Wiltshire equations of unperturbed motion. The simulation results based on rigorous perturbation analysis are presented to confirm the robustness of the proposed approach. 相似文献
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This paper presents the finite‐time attitude synchronization and tracking control method of undirected multi‐spacecraft formation with external disturbances. First, a modified adaptive nonsingular fast terminal sliding mode surface (ANFTSMS) is designed by introducing a user‐defined function, both of which avoid the singularity problem and continuous sliding surface, and, therefore, can freely adjust relative weighting between angular velocity error and attitude error adaptively, such that the controller can provide sufficient maneuvers and precision. This provides designers with a new technique to adjust and improve formation control performance. Second, by applying the ANFTSMS associated with adaptation, two proposed decentralized ANFTSM‐controllers provide finite‐time convergence, robustness to disturbance, and chattering free for continuous design. Finally, simulation results validate the proposed algorithms. 相似文献