自动套印控制系统的研究与设计

提出了一种凹版印刷机自动套印控制系统。该系统采用滑模变结构理论进行设计,通过永磁同步伺服电机进行套印控制。研究表明,该方法既能有效减少抖动现象,又具有较强的鲁棒性和快速性。     

A novel mixed group preserving scheme for the inverse Cauchy problem of elliptic equations in annular domains

In this paper, the inverse Cauchy problems for elliptic equations, including the Laplace equation, the Poisson equation, and the Helmholtz equation, defined in annular domains are investigated. When the outer boundary of an annulus is imposed by overspecified boundary data, we seek unknown data in the inner boundary through a combination of the spring-damping regularization method (SDRM) and the mixed group-preserving scheme (MGPS). Several numerical examples are examined to show that the MGPS plus the SDRM can overcome the ill-posed behavior of this highly ill-conditioned inverse Cauchy problem. The presently proposed novel algorithm has good efficiency and stability against the disturbance from large random noise even up to 50%, and the computational cost of MGPS is very time saving.     

Direct regularization for system of integral-algebraic equations of index-1

It is known that the coupled system consisting of Volterra integral equations of the first and second kind belongs to the class of moderately ill-posed problems. In the present paper, we are interested in numerical solution of Volterra integral-algebraic equations by a direct regularization method, i.e. an approach which does not make use of the adjoint operator as well as any reduction or remodelling of the original problem. A numerical algorithm based on Lavrentiev’s regularization iterated method is constructed that preserves the Volterra structure of the original problem. The convergence analysis of the proposed method is given and its validity and efficiency are also demonstrated through several numerical experiments.     

机器人灵巧手微型直线驱动器的建模和滑模位置控制

报导了用于机器人多指灵巧手的精密微型直线驱动器,它体积小、输出力大。建立了该驱动器的数学模型,并且基于滑模变结构控制理论设计了微型直线驱动器的位置控制策略。实验结果证明,该控制方案具良好的鲁棒性和快速性。     

一种智能控制方法及其在温度控制系统中的应用

分析了一种基于神经网络的滑模系统,文中首先介绍了滑模控制理论,然后采用小波函数对神经网络参数进行训练,使之能对大滞后被控对象以及复杂工业过程也能进行有效控制。     

高阶数值流形方法中的线性相关问题研究

数值流形方法(NMM)中整体逼近函数是通过单位分解将局部逼近函数进行“粘结”而形成的,当将局部函数取为阶数不低于一阶的多项式时便形成了所谓的高阶流形方法。然而高阶流形方法会导致刚度矩阵亏秩,这种亏秩即使在施加完整的位移约束后仍然存在,从而会导致NMM方程组的多解,但是每个解所对应的位移是唯一的,只要能稳定地求得任何一个特解即可。该文根据刚度矩阵的性质提出了改进的LDLT算法,可快速稳定地求得一个特解。结合典型算例,与摄动解法、最小二乘法和二次规划法进行了对比分析。     

基于MLS-NMM的摩擦接触问题研究

摩擦接触问题的求解是将基于移动最小二乘插值的数值流形法（MLS-NMM）应用到裂纹扩展的必经之路。该文通过结合罚-线性互补方式的施加接触边界条件,并使用拉格朗日乘子法施加本质边界条件,得出一套基于MLS_NMM的摩擦接触问题的求解体系。该方法无需节点与边界重合,则可域外布点和均匀布点,来提高插值精度和降低布点难度,尤其是接触边界处。采用罚-线性互补的方式施加接触条件,使计算格式统一而简洁,利于编程实现。通过算例表明,该方法能准确地模拟接触面的张开、黏结和滑动状态,证明该方法对求解接触摩擦问题是可行的、有效的。     

非线性方程组的牛顿-整体松弛并行多分裂法

松弛技术是提高分裂迭代法收敛速度的一种基本技术。本文在前人工作的基础上,把求解线性方程组的松弛型矩阵多分裂迭代法推广到了求解非线性方程组,并通过引入多个松弛因子,提出了整体松弛的概念和方法。进而,文中研究了牛顿—整体松弛型矩阵多分裂TOR迭代法,建立了其局部收敛性定理,给出了收敛速度的估计。对于本文提出的求解非线性方程组的牛顿—整体松弛型多分裂TOR迭代法,当选取近似最优参数时,我们的方法将比其他方法有更快的收敛速度。     

线性流形上广义次对称矩阵的最佳逼近

讨论了线性流形上广义次对称矩阵的最小二乘解,得到了解的一般表达式,对于任意给定的实对称矩阵A,在最小二乘解集中得到了A的最佳逼近解。     

线性流形上矩阵方程AX=B的一类反问题

设SE={A∈Rn×n|||AY-Z||=min;Y,Z∈Rn×p},Ω={zΩRn|Gz=o,GΩRk×n},R≥Ωn×n={A∈Rn×n|zTaZ≥0,(?)Z∈Ω}考虑问题P:给定X,BΩRn×m,找A∈SE∩R≥Ωn×n使得AX=B。本文给出了问题P有解的充分必要条件,并在有解时,给出了通解的表示。     

极坐标系中弹性力学平面问题的Hamilton正则方程及状态空间有限元法

本文给出了极坐标系下弹性力学平面问题的Hamilton正则方程,并提出一种求解该方程的状态空间有限元法。文中通过对Hellinger-Reissner混和变分原理的修正,导出了Hamilton正则方程及其对应能量泛函,然后采用分离变量法对其场变量进行分离变量,这样就可在θ方向采用通常的有限元插值,而沿半径r方向采用状态空间法给出解析解答,从而实现了有限元法与控论制中状态空间的结合。通过计算表明,本文方法精度高。     

Decentralised stabilising controllers for a class of large-scale linear systems

A simple method for computing decentralised stabilising controllers for a class of large-scale (interconnected) linear systems has been developed. Decentralised controls are optimal controls at subsystem level and are generated from the solution of algebraic Riccati equations for decoupled subsystems resulting from a new aggregation-decomposition technique. The method has been illustrated through a numerical example of a large-scale linear system consisting of three subsystems each of the fourth order