地震作用下高层建筑重叠分散控制子结构划分机理研究

针对地震作用下高层建筑振动分散控制问题,引入信息共享的重叠分散策略,研究高层建筑振动重叠分散控制子结构划分机理。基于线型二次型(LQR)最优控制的最优权矩阵和H∞鲁棒控制的最优输出评价矩阵,分析评价高层建筑重叠分散控制子结构不同划分策略时的控制效果。对某20层Benchmark结构模型进行数值模拟与分析,结果表明,本文提出的两种重叠分散控制方法的性能评价方法,可指导任意层数高层建筑振动重叠分散控制子结构的合理划分,既保证控制系统良好的控制效果,又保证控制力在合理的范围内。     

Nonlinear control of electrical flexible-joint robots

This paper is devoted to the nonlinear tracking control of electrically driven flexible-joint manipulators using the voltage control strategy. Despite the torque control laws that are involved in the complexity of manipulator dynamics, the proposed control law is free from manipulator dynamics. This novelty is for adopting the voltage control strategy to derive a simple robust adaptive control under both structured and unstructured uncertainty. The proposed control approach has a fast response with a good tracking performance under the well-behaved control efforts in the form of decentralized control. The control method is justified by the stability analysis and simulated on a flexible-joint electrically driven robot manipulator.     

压电智能结构模糊自学习控制(FSLC)

将模糊逻辑与学习控制的基本思想相结合,根据控制系统的动态输出特性,采用模糊控制对学习控制律中的参数进行实时校正,实现系统的动态学习过程,提出了一种适用于压电智能结构振动控制的模糊自学控制方法FSLC（FuzzySelf-LearningContr01）。分别采用三维8节点实体单元（Solid45）和耦合单元模拟主结构和压电致动器／传感器,基于ANSYS参数化语言编写了压电智能结构振动控制分析的有限元程序。通过数值仿真证明了模糊自学习控制方法能有效控制压电结构的振动,并提高了自学习控制的收敛速度和获得了很好的控制效果。     

航天结构主、被动一体化振动控制技术的研究现状和进展

围绕航天结构振动的被动控制、主动控制、一体化控制和实验研究等几个方面对当前研究的现状和最新进展进行了介绍。将被动控制、主动控制结合,优点互补的体化振动控制技术是当前结构振动控制研究的一个重点。结合工程实际,开发新型振动控制材料及控制元件和装置,发展附加重量代价小、高效、能耗低和可靠性强的一体化振动控制技术,是将来的研究方向。     

用两种功能材料综合控制智能梁的振动

给出了用两种材料对梁进行振动控制的综合控制方法。采用多层分布压电层进行精密主动控制时,将压电传感层和压电致动层分割成若干单元来设计压电模态传感器和压电模态致动器,进而实现了梁的模态控制,同时利用形状记忆合金的超弹性特性对梁进行被动控制来抑制梁的大振幅振动,取得了很好的控制效果。     

考虑时滞的主动悬架系统控制策略对比研究全文替换

本文以二自由度四分之一汽车悬架系统为研究对象,采用不同控制策略对考虑时滞的悬架系统控制特性进行研究,并对控制效果进行对比分析．首先,采用第二类拉氏方程建立考虑时滞的二自由度悬架控制系统的动力学模型;然后分别基于状态变换法和H_∞控制理论,设计系统的时滞反馈控制律．其中状态变换法主要通过系统状态变量的转换,将系统时滞控制方程转换成不显含时滞的动力学方程,然后采用传统的二次型最优控制方法对系统进行控制．H_∞控制主要通过使用Lyapunov-Krasovskii泛函和自由权矩阵法,设计考虑时滞的H_∞控制律;最后在Matlab/Simulink平台上对控制系统进行仿真分析,并在相同时滞下对两种控制结果进行对比．研究表明,两种控制策略在考虑时滞的情况下均可保证系统的稳定性,且H_∞控制相比于状态变换法有更好的控制效果．     

互联结构振动控制元件参数研究

针对双塔结构所具有的模型不精确及承受随机外力作用这一特点，在控制方法选择方面，为保证系统控制的顺利实现，本文引入了能够对模型不精确具有较好控制效果的广义预测控制策略；在优化目标选择方面，为降低控制系统的能量，以控制增益矩阵的Frobenius范数做为优化目标；在优化算法方面，为降低计算工作量，引入并改进了传统的遗传算法。通过优化计算得到系统参数几组次优解，这些解可以供设计者进行选择。最后给出了计算实例。算例表明这一方法是有效的。     

MR阻尼器的状态跳跃控制参数

对MR阻尼器实施状态跳跃控制可以有效地减少结构的地震响应，状态跳跃控制参数对半主动控制效果有很大的影响。本文对状态跳跃控制的相关参数进行了研究。利用两个数值算例，对采用不同类型的控制参数(位移、速度、加速度)、控制参数的大小、输入地震动的大小等相关因素对结构地震响应的控制效果进行了对比，发现采用速度响应作为状态跳跃控制变量对于减少绝对加速度响应是有利的；建议采用试算法确定合适的速度控制参数，通过和LQG控制相联系的方法给出了该控制参数最优值的估算方法。     

静电陀螺测试转台电气部分方案设计

叙述了静电陀螺三环测试转台电气部分的方案设计要点。该电气部分包括静电陀螺启动与控制系统，转台控制系统，计算机三大部分，测角分系统采用粗精耦合式角位置传感器。双轴伺服分系统采用带有纯积分环节的一阶无差控制系统，三轴位置控制分系统采用一阶无差数字控制的方案，从而确保转台满足精度指标。     

Impedance control of robots using voltage control strategy

Impedance control provides a unified solution for the position and force control of robot manipulators. The dynamic behavior of a robotic system in response to environment is prescribed by an impedance model formed as Thevenin model. This model is certain and linear while the robot manipulator is highly nonlinear, coupled, and uncertain. Therefore, impedance control must overcome nonlinearity, coupling, and uncertainty to convert the robotic system to the impedance model. To overcome these problems, this paper presents a novel impedance control for electrically driven robots, which is free from the manipulator dynamics. The novelty of this paper is the use of voltage control strategy to develop the impedance control. Compared with the commonly used impedance control, which is based on the torque control strategy, it is computationally simpler, more efficient, and robust. The mathematical verification and simulation results show the effectiveness of the control method.     

基于进气射流的压气机失速主动控制系统仿真

针对一轴流压气机，构造了利用进气射流对旋转失速进行主动控制的控制系统，发展了以Ｍｏｏｒｅ－Ｇｒｅｉｔｚｅｒ模型为基础的系统数学模型并进行了数值仿真研究。结果表明，该控制系统可有效地抑制压气机中旋转失速的发生。     

A compressed-sensing approach for closed-loop optimal control of nonlinear systems

We present a method that seeks to combine the properties of optimal control with the robust character of closed-loop control. The method relies on the availability of a reduced model of the system to be controlled, in order to express the control problem in a low-dimensional space where the system-state-dependent optimal control law is subsequently approximated in a preprocessing stage. A polynomial expansion is used for the approximation, enabling fast update of the optimal control law each time a new observation of the system state is made available. It results in a real-time compatible, efficient (optimal-like), and robust control strategy. A compressed-sensing approach is proposed to efficiently construct the approximate control law, exploiting the compressible character of the optimal control law in the retained approximation basis. The method is demonstrated for the control of the flow around a cylinder and is shown to perform as well as the much more costly receding-horizon optimal control approach, where the exact optimal control problem is actually recomputed, even in the presence of large aleatoric perturbations. Potential and remaining issues toward application to larger dimensional reduced systems are also discussed, and some directions for improvement are suggested.     

时滞对结构振动半主动控制效果的影响

应用磁流变阻尼器对结构振动进行控制，采用最优控制原理设计了控制器，给出在地震激励下结构半主动控制的仿真计算。研究了时滞对结构振动半主动控制效果的影响。数值结果表明：本文设计的半主动控制策略可有效地减小结构的振动响应，时滞对磁流变半主动控制效果随着时滞的增大而变差，但时滞不会导致该反馈控制系统的失稳。     

Analysis of effects of differential gain on dynamic stability of digital force control

The paper presents an analytical investigation of the dynamics of digital force control. A one degree-of-freedom (DoF) mechanical system with low viscous damping is subjected to proportional-derivative (PD) force control. Analytical results are presented in the form of stability charts in the parameter space of sampling time, control gains and mechanical parameters. Simple closed form results include the largest stable proportional gain and the least steady state force error that provide synthesis of mechanical and control system parameter influences for the design of digital force control. Also, a novel analytical explanation is given why even the properly filtered force derivative signal is rarely used in practice, and why the occurring vibrations have frequencies one range smaller than that of the sampling frequency of the digital control.     

半导体制冷器对SLD光源温控参数的影响

针对光纤陀螺用SLD光源与控制电路的匹配需求,探讨了SLD光源的重要光源组件——半导体制冷器对温度控制参数离散化的影响。结果表明,半导体制冷器(TEC)的等效内阻和制冷/加热效率的特性是目前SLD光源温控参数离散的主要原因;在当前温控模式下,TEC等效内阻对温控参数的影响最为显著,其由于工艺或使用条件变化等原因产生的任何微小差异均直接表现为温控参数的改变;TEC的制冷效率和加热效率对温控参数的影响不同,它们在制冷和加热过程分别促进和阻止温控参数的进一步离散。通过改进光源温控模式、加强光源规范管理、增强TEC的一致性,以及改进TEC制冷/加热效率,可大幅提高光源和温控电路的匹配效果。     

基于最优参数控制方法的齿轮系统混沌控制

基于最优参数控制方法,实现了齿轮传动系统中的混沌控制．以经典的间隙单齿轮副非线性动力学模型为研究对象,以啮合静载荷为控制参数,通过混沌吸引子中轨线的观测近似得到目标周期不动点、系统在目标不动点处的雅克比矩阵以及在控制原始参量处的梯度矩阵．最后运用最优参数控制策略计算得到啮合静载荷的小扰动量,实现了把齿轮系统的混沌运动镇定周期一轨道上的目的．研究结果表明,基于最优参数控制方法的控制过程,只是在控制的前几个周期内需要控制参数产生相对较大的扰动量,随着控制的继续进行,扰动量几乎稳定到了某一固定值,不再需要较大的变动．而且控制参数计算所需要的中间参量可以直接由混沌吸引子中轨线的观测近似得到,因而控制容易实现．     

Nonlinear robust and optimal control of robot manipulators

In this paper, we propose a new optimal control method for robust control of nonlinear robot manipulators. Many industrial robot systems are required to perform relatively large angular movement with sufficient accuracy. In real circumstances, highly nonlinear manipulator dynamics and uncertainties such as unknown load placed on the manipulator, external disturbance, and joint friction make the precise control of manipulators a very challenging task. The main contribution of this work is to develop a new robust control strategy to accomplish the precise control of robot manipulators under load uncertainty using a nonlinear optimal control formulation and solution. This methodology is based on the underlying relation between the robust stability and performance optimality. A class of robust control problems can be transformed to an equivalent optimal control problem by incorporating the uncertainty bounds into the cost functional. The θ-D optimal control approach is utilized to find an approximate closed-form feedback solution to the resultant nonlinear optimal control problem via a perturbation process. Numerical simulations show that the proposed robust controller is able to control the robot manipulator precisely under large load variations.     

On the sliding mode control of mechanical systems

We consider the control of mechanical systems based on sliding mode control techniques. Recently developed simplex control methods are shown to converge in a finite time when applied to nonlinear systems under bounded deterministic uncertainty. Applications are considered to the control of mechanical systems in which the control action is provided by monodirectional devices.     

Hybrid control of Hopf bifurcation in a dual model of Internet congestion control system

In this paper, a hybrid control strategy using both state feedback and parameter perturbation is applied to control the Hopf bifurcation in a dual model of Internet congestion control system. By choosing communication delay as a bifurcation parameter, it is proved that when it passes through a critical value, a Hopf bifurcation occurs. However, by adjusting the control parameters of the hybrid control strategy, the Hopf bifurcation has been delayed without changing the original equilibrium point of the system. Theoretical analysis and numerical results show that this method can delay the onset of bifurcation effectively. Therefore, it can extend the stable range in parameter space and improve the performance of congestion control system.