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991.
针对一类机器人操作手,提出了一种设计机器人操作手迭代学习控制的新方法,与其它现有的迭代学习控制方法相比较,当折合到机器人操作手关节轴上的驱动装置惯量足够大时,可以用驱动装置的动力学特性参数确定学习增益,克服了传统迭代学习控制方法由多次尝试选取学习增益的缺点,增强了实用性。在实际机器人操作手上的实验结果充分表明了新提出方法可获得较高学习速度和控制精度的优越性。 相似文献
992.
大型低速二元风洞侧壁边界层控制及对单段翼型实验结果的影响 总被引:1,自引:0,他引:1
本文简述了NF-3风洞二元实验段侧壁边界层吹除控制系统及具有吹气的模型实验方法,给出了不同吹气系数对风洞边界层的控制效果以及对相对厚度为7%的单段翼型实验结果的影响。初步实验研究结果表明,该控制系统能有效地改善风洞侧壁边界层的流动状态,减小侧壁干扰,改善翼型实验中的二元流动特性 相似文献
993.
K. S. Matviichuk 《International Applied Mechanics》2006,42(6):699-713
Sufficient conditions for the technical stability in measure of a nonstationary control system with variable structure are
established. The controller of the system has feedback-switched filters functioning together with shaper and actuator. It
is assumed that the nonstationary parameters of the system vary within given ranges, at a finite rate, with appropriate control
laws, with adjustment against mismatch signal, its derivatives of finite order, and all variable parameters of the filter.
The parameters of the switching hyperplane remain constant. This approach for analysis of technical stability does not involve
sliding mode conditions. Criteria of technical instability in measure for the control system under consideration are formulated
using the properties of systems of comparison from below. The general criteria of technical stability and instability are
applied to nonstationary filtered-control systems of variable structure of the third order. The comparison method based on
normalized Lyapunov functions is used
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 6, pp. 110–127, June 2006. 相似文献
994.
在斜支撑和Ⅴ形支撑的基础上,提出了安装阻尼器的三种新型附加联动机构支撑形式;并对这三种支撑形式下的阻尼器行程和控制力的计算进行了分析,采用放大系数的形式使计算公式得以简化;以SMA耗能阻尼器为对象,利用笔者编写的计算机程序,对包括斜支撑和Ⅴ形支撑在内的五种阻尼器安装方式进行了仿真计算。结果表明:(1)不同安装方式的振动控制效果各不相同,上肢联动机构的放大作用最大;(2)SMA耗能阻尼器的控制效果受SMA丝材长度的影响较大;(3)对不同的结构和不同的阻尼器应选择不同的阻尼器安装方式,才能使整体控制效果达到最佳。 相似文献
995.
探索用系统科学原理和方法分析工业化住宅的形成过程,讨论了工业化住宅系统的结构模型,邻接矩阵,数学模型及知识模型,构建了工业化住宅系统的集成模型,提出了工业化住宅系统优化设计原则和目标函数,分析了工业化住宅形成过程的多级递阶协调控制结构.为住宅工业化提供相关的理论指导. 相似文献
996.
G. V. Alekseev 《Journal of Applied Mechanics and Technical Physics》2003,44(6):890-899
Control problems for a steady-state model of the magnetohydrodynamics of a viscous incompressible fluid in a bounded domain with an impermeable, perfectly conducting boundary are formulated. The resolvability of the problems is studied, the use of the Lagrange principle is justified, and optimality systems are analyzed. 相似文献
997.
自适应结构多工况下强度控制的研究 总被引:4,自引:0,他引:4
对自适应超静定桁架结构的强度控制问题进行了研究,把模型从单一工况推广到了多工况,实现了理论的完整性,定义了结构工作状态系数, 分析了作动器的联入对结构强度的影响,利用超静定桁架的耦合特性和作动器的调节功能,把强度控制问题转化为数学规划问题,方法简单有效。 相似文献
998.
Nonlinear Oscillations of a Nonresonant Cable under In-Plane Excitation with a Longitudinal Control 总被引:1,自引:0,他引:1
The nonlinear oscillations of a controlled suspended elastic cable under in-plane excitation are considered. Active control realized by longitudinal displacement of one support is introduced in order to reduce the transverse in-plane and out-of-plane vibrations. Linear and quadratic enhanced velocity feedback control laws are chosen and their effects on the cable motion are investigated using a two degree-of-freedom model. Perturbation analysis is performed to determine the in-plane steady-state solutions and their stability under an out-of-plane disturbance. The analysis is extended to the bifurcated two-mode steady-state oscillations in the region of parametric excitation. The dependence of the control effectiveness on the system parameters is investigated in the case of the first symmetric mode and the range of oscillation amplitudes in which the proposed control ensures a dissipation of energy is determined. Although control based only on in-plane response quantities is effective in reducing oscillations with a prevailing in-plane component, addition of out-of-plane measures has to be considered when the motion is characterized by two comparable components. 相似文献
999.
The baseline and forced flow around a bluff body with semi-elliptical D-shape was investigated by solving the 2D Navier–Stokes
equations at low Reynolds numbers. A D-shape rather than the canonic circular-cylinder was selected due to the fixed separation
points in the latter, enabling to study a pure wake rather than boundary-layer control. The correlation between Strouhal and
Reynolds numbers, the mean drag, the lift and drag oscillations vs. the Reynolds number and wake structure were investigated
and compared to experimental and numerical data. Effects of open-loop forcing, resulting from the influence of zero-mass-flux
actuators located at the fixed separation points, were studied at a Reynolds number of 150. Fluidic rather than body motion
or volume forcing was selected due to applicability considerations. The motivation for the study was to quantify the changes
in the flow field features, as captured by Proper Orthogonal Decomposition (POD) analysis, due to open-loop forcing, inside
and outside the “lock-in” regime. This is done in order to evaluate the suitability of low-order-models based on POD modes
of this changing flow field, for future feed-back flow control studies. The evolution of the natural and the excited vortices
in the Kármán wake were also investigated. The formation and convection regions of the vortex evolution were documented. It
was found that the forcing causes an earlier detachment of the vortices from the boundary-layers, but does not affect their
circulation or convection speeds. The results of the POD analysis of the near-wake flow show that the influence of the bluff
body shape (“D”-shaped versus circular cylinder) on the baseline POD wake modes is small. It was found that the eigenfunctions
(mode-shapes) of the POD velocity modes are less sensitive to slot excitation than the vorticity modes. As a result of the
open-loop excitation, two types of mode-shape-change were observed: a mode can be exchanged with a lower-energy mode or shifted
to a low energy level. In the latter case, the most energetic mode becomes the “actuator” mode. The evolution of one-slot
excitation on still fluid (“Synthetic jet”) was studied and compared to published data and to “actuator” modes with external
flow present. Based on the current findings, it is hypothesized that the cross-flow velocity POD modes are suitable for feedback
control of wake flow using periodic excitation, due to their low sensitivity to the excitation as compared to the streamwise
velocity or vorticity modes. 相似文献
1000.
The Fourier series method was extended for the exact analysis of wave propagation in an infinite rectangular beam. Initially, by solving the three-dimensional elastodynamic equations a general analytic solution was derived for wave motion within the beam. And then for the beam with stress-free boundaries, the propagation characteristics of elastic waves were presented. This accurate wave propagation model lays a solid foundation of simultaneous control of coupled waves in the beam. 相似文献