发动机初级工况对冷却夹套隔片损伤影响分析

针对可重复使用液体火箭发动机推力室冷却夹套隔片的损伤问题,为确保发动机的工作寿命,对建立了冷却夹套隔片的夹芯梁结构模型、粘塑性模型和细化损伤模型,发动机起动过程中初级工况给冷却夹套隔片损伤发展的影响进行了仿真计算。结果表明:初级工况过高,压力等性能参数振荡明显,振幅也较大,但引起的冷却夹套隔片损伤较小;初级工况选择过低,引起的冷却夹套隔片损伤较大,且压力等性能参数振荡也比较明显,但振幅较小。通过对比分析给出了用于发动机起动的合适初级工况,采用此工况使发动机起动过程中引起的损伤较小,而且压力等性能参数的振荡也较小。     

基于卷取温度预测的层流冷却优化控制模型

卷取温度对带钢的金相组织影响很大,是决定成品带钢加工性能、力学性能、物理性能的重要工艺参数之一;层流冷却过程具有强非线性、不确定性、时变的特点,采用传统的基于传热机理和统计分析的建模方式难以满足卷取温度优化控制要求;针对某钢铁企业热轧板厂卷取温度控制过程中存在的问题,建立了基于神经网络的卷取温度预测模型,综合考虑多种因素对卷取温度的影响,将该模型预测值与目标卷取温度值的偏差作为原有前馈模型的输入,以提高前馈补偿的控制精度;仿真结果表明,模型预测精度高,具有在线应用前景.     

Adaptive control of a CSTR with a neural network model

An adaptive control algorithm with a neural network model, previously proposed in the literature for the control of mechanical manipulators, is applied to a CSTR (Continuous Stirred Tank Reactor). The neural network model uses either radial Gaussian or “Mexican hat” wavelets as basis functions. This work shows that the addition of linear functions to the networks significantly improves the error convergence when the CSTR is operated for long periods of time in a neighborhood of one operating point, a common scenario in chemical process control. Then, a quantitative comparative study based on output errors and control efforts is conducted where adaptive controllers using wavelets or Gaussian basis functions and PID controllers (IMC tuning with fixed parameters and self tuning PID) are compared. From this comparative study, the practicality and advantages of the adaptive controllers over fixed or adaptive PID control is assessed.     

Exact optimal solution for a class of dual control problems

This paper considers a discrete-time stochastic optimal control problem for which only measurement equation is partially observed with unknown constant parameters taking value in a finite set of stochastic systems. Because of the fact that the cost-to-go function at each stage contains variance and the non-separability of the variance is so complicated that the dynamic programming cannot be successfully applied, the optimal solution has not been found. In this paper, a new approach to the optimal solution is proposed by embedding the original non-separable problem into a separable auxiliary problem. The theoretical condition on which the optimal solution of the original problem can be attained from a set of solutions of the auxiliary problem is established. In addition, the optimality of the interchanging algorithm is proved and the analytical solution of the optimal control is also obtained. The performance of this controller is illustrated with a simple example.     

动态优化双估计器的多模型自适应混合控制

针对参数子集个数较多导致计算量较大和由于系统参数发生跳变造成系统暂态性能差的问题,本文提出了基于动态优化双估计器的多模型自适应混合控制方法.首先对多个参数子集进行动态优化得到最优参数子集,减少了需要计算的模型数量,提高了系统收敛速度;其次对被控对象设置一个固定初值的估计器和一个可重新赋值的估计器,固定估计器用于初始时刻对参数的估计,可赋值估计器动态调整估计初值用于减小估计误差,提高系统暂态性能.最后的仿真结果表明了该方法的有效性,并给出了系统的稳定性及收敛性分析.     

混合液温度流量解耦控制算法及系统虚拟

针对一种具体的混合液温度流量非线性控制问题，文中提出了一种解析方式的解耦控制算法。采用MatLab对算法的仿真表明，这种解耦控制算法具有良好的解耦和控制效果。为全面分析该算法，设计了交互式实时混合液温度流量解耦控制系统虚拟软件，该软件的使用结果说明，这种算法可以很好地解决这种解耦控制问题。     

图书馆温湿度智能控制系统研究与设计

针对当前高校图书馆智能化建设中温度调控和湿度调控彼此脱节的现象,设计了基于ZigBee的温度湿度采集系统,从而研究了某高校图书馆内温度和湿度的相关性,提出了该校图书馆内温度和湿度相互关系的经验公式,进而为综合调控图书馆内温度和湿度建立了理论基础。为解决图书馆内温度和湿度自动调控差的现状,在温湿度采集系统的基础上设计了软硬件协同运作的智能温度湿度控制系统,该系统作为该校图书馆智能化楼宇的建设的子系统已经取得了良好的实际运行效果。     

Application of nonlinear dynamic analysis to the identification and control of nonlinear systems-III. n-Dimensional systems

In two previous publications, the authors have shown that normal form theory, a method used extensively in dynamic analysis, can be applied in the structure identification of nonlinear systems. In particular, normal form theory bridges the gap between structure of a nonlinear, low order polynomial dynamical system and the behavior it is able to predict or represent. This is important because knowing a system's dynamic behavior automatically leads to a simple nonlinear normal form model that can be used for (nonlinear) control. Previously, only two-dimensional normal form models were derived. For this paper, simple, n-dimensional, low order polynomial dynamical models will be derived that can represent a nonlinear system with multiple steady states or a limit cycle in the operating region of interest. Using as a plant the nonisothermal Continuous Stirred Tank Reactor with consecutive reactions (A→B→C), it is shown that identification and control of this three-dimensional system using the aforementioned normal form models is feasible.     

圆筒型永磁动圈式直线电动机动态特性仿真

分析了永磁动圈式直线电动机的工作原理,给出了用于驱动电液比例阀的永磁动圈式直线电动机的数学模型,并采用Matlab/Simulink软件建立了该电动机的仿真模型。仿真结果表明,该电动机在位移指令为5 mm时的阶跃响应调节时间小于30 ms,具有较好的高频动态响应特性。     

直接驱动机器人关节的外模模糊控制*

应用文［１］，［２］中提出的外模控制方法组成直接驱动机器人关节外模模糊控制系统，所用模糊控制器为二级规则的三输入－输出模糊控制器，进行了动、静态特性的仿真研究。结果表明系统的性能得到很大的改善。     

一类时变系统的多模型切换动态调节控制算法

当被控对象参数所在的不确定区域未知时,多模型切换调节等控制算法虽然最终可以使系统达到期望特性,但随着不确定区域的增大,系统需要增加大量的模型才能满足快速性等方面上的要求.因此,为了实现一类时变系统在只增加少量模型时便能够满足期望控制性能的目标,提出了多模型切换动态调节控制算法.此算法在不确定区域内分配若干上层模型,在双切换机制的监督下,利用动态分配方法,在最优上层模型所在的子区域分配出若干下层模型,在与自适应模型的协作中,设计最优控制器,保证了系统的暂态和稳态响应.在数值仿真与故障卫星系统的仿真研究中,结果表明了多模型切换动态调节算法在暂态性能方面优于多模型切换调节算法,并验证了此算法的有效性.     

一种双网络架构的煤矿监控系统

针对煤矿井下环境复杂和矿井检测节点、检测参数种类众多的情况,提出了一种双网络架构的煤矿监控系统。该系统根据监控对象的不同,采用不同的网络进行数据传输,视频流数据采用以太网传输,矿井环境监控数据采用CAN网传输;双网络共用同一条物理线路,具有所有监测对象整体组网、统一检测、网络利用率高等优点。