2-D系统理论在开闭环迭代学习控制中的应用

将2-D线性离散系统理论应用于开闭环迭代学习控制中,设计出一种新型的迭代学习控制方案,给出并证明了其控制律及收敛条件.仿真结果表明,据此设计出的迭代学习控制器不仅保持了以往开闭环迭代学习控制的优点,而且在实际应用中放宽了收敛条件.     

离散系统单调收敛高阶迭代学习控制

研究了一类离散线性时不变系统高阶迭代学习控制在相应范数意义下的单调收敛条件,给出了对给定目标函数迭代学习控制参数的最优解,并讨论了其收敛速度。常见的离散P型、D型及PD型ILC算法均可看作是所讨论算法的特例。仿真结果表明采用给出的最优设计具有更好的迭代学习单调收敛性能。     

基于遗传算法的PID型迭代学习控制增益的选取方法

针对PID型迭代学习控制算法,首先讨论了其收敛的充要条件和单调收敛的充分条件,然后给出目前利用单调收敛的充分条件确定PID增益的方法,并指出其不足。在此基础上,提出了基于遗传算法的PID型迭代学习增益选择方法（PID型GA-ILC算法）。利用该算法可以得到不满足PID迭代学习控制系统单调收敛条件但依然能使该系统单调收敛的PID增益,给出了数值仿真实例,证明了PID型GA-ILC算法的有效性。     

非线性系统的改进型迭代学习控制算法研究

针对普通闭环PD型迭代学习控制算法收敛速度慢且收敛精度不高的问题,通过在闭环PD型控制算法中引入动态扩张-收缩因子(dynamic expansion compression coefficient,DECC)的方法,提高闭环PD型算法的收敛速度以及收敛精度。同时将鲁棒控制引入至算法中,进一步提高算法抑制外界干扰的能力。通过构造李雅普诺夫函数证明了在所提改进的控制律作用下的信号是有界且收敛的。最后将改进的迭代学习控制算法应用在一类具有重复运行性质的非线性系统中,证明所提算法是有效的。     

迭代自学习控制算法收敛速度研究

从学习律、学习律参数、输出误差等三方面讨论了迭代自学习算法的收敛速度,为提高该算法的收敛速度得到了一些有用的结论     

初态学习下时滞非线性系统的迭代学习控制

针对在有限时间区间上重复运行的一类状态时滞非线性系统,研究了一种带有初态学习的迭代学习控制算法。基于算子谱理论证明了系统在任意初态条件下经过迭代学习后,其输出能够完全跟踪期望轨迹,得到了该算法谱半径形式的收敛条件,比范数形式的收敛条件放宽了。并通过对系统初态的迭代学习,放松了迭代学习控制算法对初始状态函数的要求。仿真结果验证了所提算法的有效性。最后,将该算法应用到含有状态时滞的非线性间歇过程,结果也表明了该算法的有效性和可靠性。     

应用自解卷积和增量Wiener 波实现迭代盲图像复原

提出了一种基于自解卷积和增量Wiener滤波的迭代盲图像复原算法(SDIWF-IBD).将自解卷积点扩散函数估计法应用于迭代盲目反卷积,准确估计了点扩散函数频域;在图像估计时使用增量Wiener滤波,确保算法稳定收敛.为进一步控制算法收敛速度,引入内迭代加速方法,有效减少了算法的外部迭代次数.实验结果表明,复原后图像细...     

压电驱动器的开闭环迭代学习控制

由于开闭环迭代学习控制方法能在加快收敛速度的情况下降低跟踪误差,本文利用该控制方法来提高压电驱动器(PZT)的高频轨迹跟踪精度。首先,提出了离散时间下的开环P型结合闭环PI型的迭代学习律,并且给出了基于该学习律的收敛性条件。然后,设计了用于PZT系统的离散开闭环迭代学习控制器。最后,针对50Hz单频和25Hz+50Hz复频三角波轨迹进行了跟踪控制实验。实验结果表明:所提出的迭代学习控制器对上述2种轨迹的最大跟踪误差分别为10.6nm和12.5nm,相对于PID控制器,分别降低了96.25%和95.62%。结果显示:提出的控制方法易于实现,无需准确的PZT迟滞和系统模型就可以获得很高的跟踪精度,能有效地满足高频和复频轨迹跟踪的精度要求。     

即时学习型迭代学习控制在励磁控制中的应用

将即时学习算法型迭代学习控制引入发电机的励磁控制。运用即时学习算法来解决系统的迭代学习控制初值问题,有效地估计初始控制量,加快了算法的收敛速度。仿真结果表明,所设计的励磁控制器与常规PID控制器和非即时学习型励磁控制器相比其收敛速度明显加快,具有更强的维持机端电压的能力。     

迭代学习在音圈电机轨迹跟踪中的应用研究

为实现高密度LED焊线机上邦头运动轨迹的精确跟踪,降低因其轨迹偏差而产生的废品率。提出了一种基于迭代学习做前馈控制的前馈+反馈二自由度控制算法。首先对音圈电机进行机理分析,建立了其数学模型,以此为基础,给出了音圈电机轨迹跟踪的整体控制方案,并且结合焊线机上邦头超高加速度(20g)和整定时间短的运动特点后设计了带遗忘因子的PD型闭环迭代学习控制算法。对所提出的带遗忘因子的PD型闭环迭代学习控制的收敛性进行了理论分析,并且通过MATLAB中的SIMULINK模块进行了动态仿真,验证了该算法下的音圈电机系统响应速度显著提升,位置误差的收敛稳定可靠,改善了高密度LED焊线机上邦头的轨迹跟踪性能。     

WiMAX上行功率控制的研究

将路径损耗应用到可变步长的功率控制算法中,使得闭环功率控制的控制精度和收敛速度有了更大的提高,并加入依据下行信道的质量估计上行信道的损耗和噪声干扰量的机制,从而对MS的发射功率进行迅速调整,然后利用闭环功率控制进一步调节,最后仿真对比3种算法的控制精度和收敛性速度。仿真结果表明改进后的变步长功率控制算法具有更好的功率控制精度和收敛速度。     

Reference model iterative learning control for nonlinear systems with repeatable and non-repeatable uncertainties

This paper deals with iterative learning control (ILC) design for nonlinear systems with repeatable and non-repeatable uncertainties and performing repetitive tasks to follow a reference model (also called desired system). This desired system does not necessarily have the same structure, nor the same parameters as the real systems (there is no dependence between the reference model system and the real system). For this purpose, two ILC schemes are considered and analysed. The first controller assures the asymptotic stability with a simple condition to verify, whereas the second assures this stability without condition to verify. The λ-norm is adopted as the topological measure in our proof of the asymptotic stability of the closed loop system over the whole finite time interval when the iteration number tends to infinity. Finally, two simulation results on nonlinear system are provided to illustrate the effectiveness of the proposed controllers.     

B-spline network-based iterative learning control for trajectory tracking of a piezoelectric actuator

This paper presents the trajectory tracking approach of a piezoelectric actuator using an iterative learning control (ILC) scheme based on B-spline network (BSN) filtering. The ILC scheme adopts a state-compensated iterative learning formula, which compensates for the state difference between two consecutive iterations in order that the iterative learning can learn from the tracking errors of the previous iteration effectively. The BSN is used to attenuate the noises and retrieve the signals of the tracking errors for the ILC. The BSN serves as a unique filter which generally does not have zero-phase responses. Design details on the ILC scheme using BSN filtering are discussed in the paper. Extensive experiments of tracking two desired trajectories for a piezoelectric actuator are presented. The experimental results show that the state-compensated ILC scheme using BSN filtering can achieve fast error convergence and keep small steady-state tracking errors close to the system noise level. This research thus relaxes the restriction of the zero-phase criterion commonly applied to the ILC filtering in the literature.     

Finite-time control for nonlinear spacecraft attitude based on terminal sliding mode technique

In this paper, a fast terminal sliding mode control (FTSMC) scheme with double closed loops is proposed for the spacecraft attitude control. The FTSMC laws are included both in an inner control loop and an outer control loop. Firstly, a fast terminal sliding surface (FTSS) is constructed, which can drive the inner loop tracking-error and the outer loop tracking-error on the FTSS to converge to zero in finite time. Secondly, FTSMC strategy is designed by using Lyaponov's method for ensuring the occurrence of the sliding motion in finite time, which can hold the character of fast transient response and improve the tracking accuracy. It is proved that FTSMC can guarantee the convergence of tracking-error in both approaching and sliding mode surface. Finally, simulation results demonstrate the effectiveness of the proposed control scheme.     

板形自动检测及闭环控制技术的应用

介绍冷连轧机组设计中应用板形辊的几种形式、板形自动检测装置和闭环控制系统功能。     

基于“位移—力闭环控制系统”的铝合金车轮圆度校形

铝合金车轮的热处理变形是不可避免的,变形会带来诸多不利因素。文章分析了铝合金车轮产生变形的原因,讲解了控制变形的积极意义,并根据“位移—力闭环控制系统”的数学模型,阐述了圆度校形的判定准则和具体的实施方式。     

Model reference adaptive control of a flexible structure

In this paper, the model reference adaptive control (MRAC) of a flexible structure is investigated. Any mechanically flexible structure is inherently distributed parameter in nature, so that its dynamics are described by a partial, rather than ordinary, differential equation. The MRAC problem is formulated as an initial value problem of coupled partial and ordinary differential equations in weak form. The well-posedness of the initial value problem is proved. The control law is derived by using the Lyapunov redesign method on an infinite dimensional Hilbert space. Uniform asymptotic stability of the closed loop system is established, and asymptotic tracking, i.e., convergence of the state-error to zero, is obtained. With an additional persistence of excitation condition for the reference model, parameter-error convergence to zero is also shown. Numerical simulations are provided.     

Multibody dynamics of closed,open, and switching loop mechanical systems

The vast mechanical systems could be classified as closed loop system, open loop system and open & closed (switching) system In the closed loop system, the kinematics and dynamics of 3-D mechanisms will be reviewed and closed form solutions using the direction cosine matrix method and reflection transformation method will be introduced In the open loop system, kinematic & dynamic analysis methods regarding the redundant system which has more degrees of freedom in joint space than those of task space are leviewed and discussed Finally, switching system which changes its phase between closed and open loop motion is investigated with the pinciple of dynamical balance Among switching systems, the human gait in biomechanics and humanoid in robotics are presented