新型辐照容器内部流场及温度场数值计算

辐照容器属于核级设备辐照鉴定试验装置的一个重要组成部件，是承载需要辐照的1E级设备的压力容器。针对新型辐照容器，采用ANSYS软件对容器内部流场及温度场进行了数值计算，研究了在实际工况下，辐照容器不同截面位置的温度分布和气流运动轨迹，以及分流板对温度分布和气流运动的影响，并经由试验验证了模拟结论。结果表明：增加分流板的辐照容器内部温度分布和气流运动更均匀，气流运动轨迹更集中于中间区域；内部温度分布更均衡，温差在5K以内，为新型辐照容器的设计提供了理论依据。     

密闭容器内压力控制系统研制

介绍一种用单片机作为控制器，实现对密闭容器内汽液混合状态下的蒸汽压力和炉壁温度进行控制的方案。该控制器采用模糊控制技术，适用于非线性、时变和时滞系统。实验结果表明，它具有无超调、无静差、鲁棒性强等特点。     

等温容器内多孔介质分布对强化导热以及等温性能的影响

为了提高等温容器的等温性能,基于拓扑方法将内部细铜丝的分布对强化容器壁向中心导热的影响进行研究。建立导热模型,计算在均匀填充下横截面上的温度场以及容器中心温度。在容器壁温度、中心初始温度和细铜丝平均孔隙率一定的情况下,导热时间15 s,以中心温度最高为优化目标,分别采用线性变密度填充法和自适应成长法优化铜丝分布。两种优化结果的中心温度与均匀填充相比分别提高了0.6℃和2.62℃,并且得到了相应的铜丝分布曲线。将等温容器内部的铜丝根据优化结果进行分层填充后进行试验验证,先用导热试验说明改变细铜丝分布可以强化容器壁向中心的导热,接着用等温容器放气试验例证了该填充方案能够有效提高等温容器的等温性能。     

双层容器温度控制的研究

以某双层容器热交换器为受控对象,分别设计了PID控制器、自校正控制器和两种不同的模糊控制器。通过仿真和现场实验,对采用不同方案的闭环系统性能进行了比较。总结了各种控制方案的特点。给出了应用范围。     

芬顿流化床COD去除率影响因素研究

针对芬顿反应参数设置不合理、内部流态不均匀导致COD(化学需氧量(Chemical Oxygen Demand),以化学方法测量水样中需要被氧化的还原性物质的量)去除率不高的问题,通过容器反应条件对COD去除率的影响,确定容器反应的运行条件;优化设计分布管式布水,运用CFD数值模拟的方法进行验证,发现分布管式布水使反应容器内部流化状态均匀无死区,间接使得COD去除率约提升6%。     

菱形与圆形绕丝式超高压容器应力对比分析

提出了一种新型菱形绕丝式超高压容器结构,并与已经在工程实践中应用的两种常见的超高压容器进行了比较.结合相关的强度理论及设计方法,分别对三种结构进行了有限元分析,并给出了对比结果.结果表明,在同样径比、工况及边界条件下,菱形绕丝容器的承载能力更高,沿壁厚方向的应力分布更均匀.     

微流控芯片凝血检测装置的设计

在传统检测原理及方法的基础上,设计了一种凝血检测装置。重点对检测装置的机械部分进行了改善,选择微流控芯片替代传统的玻璃试管作为检测容器。实验结果表明,与传统玻璃试管相比,采用微流控芯片作为检测容器,试剂混合均匀,检测结果的重复性好。     

基于模糊自整定的电伴加热装置应用

通过对供料净化操作电伴加热温度控制进行实验，证明了模糊自整定PID控制器在进行供料净化容器入口连接管电伴加热带温度控制时，具有温度控制迅速、控制效果稳定等优势，为今后电伴加热系统的设计和应用提供了参考。     

可燃容器抽滤模具流量分布优化方法研究

由于抽滤工艺形成的薄壁可燃容器毛坯厚度与质量分布不均匀、产品合格率低,且严重影响模压容器的强度和燃尽性,提出可燃容器抽滤模具结构优化方法,通过有限元分析模具内腔流量分布规律,依据细长孔流量公式建立模具内腔各层域流量补偿数学模型,进行流量采集试验,试验结果与流量补偿数学模型计算结果基本一致。利用流量补偿数学模型计算得到了模具内腔流量补偿管道关键尺寸,采用3D打印技术制作了模具样机,并进行了毛坯抽滤试验,获得厚度与质量分布均匀的合格毛坯,验证了所提方法的可行性。     

扁平绕带压力容器内爆炸动力响应数值模拟

运用ANSYS／LS—DYNA非线性显示动力学有限元软件,采用流固耦合方法,对10°,15°,20°倾角的扁平绕带压力容器在内部中心处爆炸作用下的动力响应进行了数值模拟。分析了缠绕倾角对容器的抗爆性能的影响和装药形状对容器爆炸作用产生的影响。结果表明：缠绕倾角越小,容器的抗爆特性越好;同等重量下,球形装药在爆心处产生的冲击载荷要比柱形装药产生的小,并且产生的爆炸作用更加均匀。     

Buck 变换器导通模式转换滑模 PI 混合控制策略

为了满足Buck变换器由待机或轻载向较大负载状态快速转换的需求,基于对传统平均电流控制Buck变换器的动态性能分析,提出了一种改进的适用于断续导通模式/连续导通模式过程的滑模PI混合控制策略。该策略电压外环依据系统状态和导通模式分别采用PI控制器和滑模控制器,其中稳态工况应用PI控制器,负载增大动态工况根据导通模式转换为滑模控制器,并通过统一校正的平均电感电流实现导通模式的准确判断。该混合控制策略可以有效结合PI控制与滑模控制各自的稳态与动态性能优势。仿真和实验结果表明,相比于传统平均电流控制,本策略动态响应时间缩短约65%,电压跌落减小35%以上。     

分布式电驱动汽车稳定性控制策略设计与试验

研究分布式驱动电动汽车操纵稳定性控制问题。基于模型跟踪控制的思想,采用分层控制结构设计控制器。控制器包含参考模型、运动跟踪控制器、控制分配器、参数估计模块。采用带质心侧偏角约束的2自由度车辆模型作为参考模型,设计非线性滑模变结构运动跟踪控制器;针对过驱动系统引入控制分配理论,采用二次规划法设计控制分配器,利用有效集方法进行求解;设计相关动力学参量的估计模块。利用实车平台对稳定性策略进行实车验证,双移线试验与蛇形绕桩试验结果表明：滑模变结构控制器具有较好的收敛性,控制分配模块可以实现四轮纵向力的优化分配,车辆横摆角速度能够较好地跟踪参考横摆角速度。相比无控制车辆,提高平均通过车速,提高平均峰值横摆角速度响应,增加车辆在极限工况下的稳定性。     

Active vibration control of trim panel using a hybrid controller to regulate sound transmission

This paper presents a method for actively controlling the sound transmission through an aircraft trim panel using a hybrid feedforward/feedback control technique. The method involves measuring the frequency transfer function of the trim panel system and then creating an autoregressive moving average model using frequency domain curve fitting. The control technique is designed to minimize the vibration of a panel that has a limited piston-like motion. The hybrid controller consists of an adaptive feedforward controller that operates in conjunction with a linear quadratic Gaussian feedback controller. The feedback controller increases the damping capacity of the secondary plant to augment the convergence rate of the adaptive feedforward controller. Experimental results indicate that the hybrid controller effectively reduces the vibration of active trim panels and therefore also reduces the sound transmission of the panel.     

Advanced process control of metal sputter deposition using a time series analysis

Using a time series model, we constructed a disturbance model for the aluminum sputter deposition process, and derived an autoregressive integrated moving average and recursive least-squares (ARIMA-RLS) controller based on this new disturbance model. Experimental results revealed that the ARI(3,1) model appropriately characterized the dynamic behavior of the disturbance for this process. The ARIMA-RLS controller, which includes information on process noise, is able to automatically regulate the model coefficients as the target is replaced or degrades. In this paper, the d-EWMA controller, the age-based d-EWMA controller, and the ARIMA-RLS controller were applied to aluminum sputter deposition processes in order to predict deposition rates and compare their performances. Application of the ARIMA-RLS controller is proven herein to significantly improve the estimation accuracy of the aluminum sputter deposition process, regardless of whether or not deposition rates are measured for each run.     

Robust iterative learning contouring controller with disturbance observer for machine tool feed drives

In feed drive systems, particularly machine tools, a contour error is more significant than the individual axial tracking errors from the view point of enhancing precision in manufacturing and production systems. The contour error must be within the permissible tolerance of given products. In machining complex or sharp-corner products, large contour errors occur mainly owing to discontinuous trajectories and the existence of nonlinear uncertainties. Therefore, it is indispensable to design robust controllers that can enhance the tracking ability of feed drive systems. In this study, an iterative learning contouring controller consisting of a classical Proportional-Derivative (PD) controller and disturbance observer is proposed. The proposed controller was evaluated experimentally by using a typical sharp-corner trajectory, and its performance was compared with that of conventional controllers. The results revealed that the maximum contour error can be reduced by about 37% on average.     

Two-dimensional pheromone propagation controller applied to run-to-run control for semiconductor manufacturing

This paper presents a new perspective on process control, called the two-dimensional pheromone propagation controller (2D-PPC), which considers the spatial information about disturbances of the process within a wafer to generate new predicted intercepts of the models for the subsequent use in time–effect controller (the exponentially weighted moving average, EWMA, in this study). The 2D-PPC assumes that the disturbances have their own behavior and affect others nearby in a wafer at a run; thus, it involves the “space-effect” among disturbances of the process at measurement positions within a wafer. The framework of the space–time controller (STC), which interlaces the time–effect controller and the space–effect 2D-PPC is constructed, and the stability analysis and intrinsic characteristics of the STC are discussed. Simulations are conducted using two-dimensional anthropogenic disturbances generated from fabrication data. The results show that the STC has better performance as compared to the conventional time–effect controllers. From implementation view point, since STC does not change the original code of time–effect controller, it can be easily implemented in the current process control loop by only adding an additional space-effect controller.     

融合输入整形和滑模的锻造机器人振动抑制

为抑制锻压机冲击对锻造机器人造成的残余振动,提出了融合输入整形和滑模的振动抑制策略.首先在开环控制中设计了零振动微分输入整形器;然后在闭环控制中设计了带滤波的滑模控制器;进一步通过对基本克隆算法进行云变异和反向选择,设计了融合云模型和反向学习的克隆算法并实现了滑模参数优化;最后基于MATLAB/Simulink平台完成...     

柴油机冷EGR温度控制器的研究

为了降低柴油机NOx的排放量,设计了一种冷EGR温度控制器。该控制器可通过控制直流电动水泵的转速来调节冷却水的循环量,确保不同工况下的最佳EGR冷却温度。通过传感器信号获得EGR的冷却温度,如果EGR的冷却温度不在最佳冷却温度范围内,控制器通过PID控制改变脉宽调制信号PWM的占空比来调整水泵电机的平均电压以改变水泵的转速进而调节冷却水的循环量,从而实现冷EGR温度的自动控制。在CA498型柴油机上对该温度控制器进行了试验,结果表明,与未冷却的EGR系统相比,该冷EGR温度控制器可以有效地降低NOx的排放量。     

Controller design for high-frequency cutting using a piezo-driven microstage

Controller design consists of a feedforward and a feedback controller to support a microstage with flexure hinge structure driven by piezoelectric ceramic actuator for high-frequency nanoscale cutting is developed in this article. The feedforward controller is designed based on a hysteresis dynamic model in order to reduce the nonlinear hysteresis effect of piezoelectric actuator. The position feedback controller is designed based upon an exponentially weighted moving average (EWMA) method embedded in an internal model control (IMC) structure constructing a run-to-run IMC (RtR-IMC) control scheme in order to deal with system bias or modeling inaccuracy. Also, disturbance due to temperature rise will influence actuator's performance, hence an additional compensator is included in the IMC structure. Surfaces dimple micro-machining utilizes piezoelectric-driven microstage for high-speed cutting is selected as an example to investigate system performance. The developed control algorithm is implemented on a DSP-based system to provide 1 kHz operating speed. In experiment, the proposed feedforward and feedback controller is verified to be able to overcome those negative factors efficiently and preserve good positioning accuracy.     

Finite time stability and controller design for nonlinear impulsive sampled-data systems with applications

This paper investigates the finite time stability (FTS) for nonlinear impulsive sampled-data systems. By constructing an appropriated Lyapunov function and employing average impulsive interval (AII) method, some FTS criteria for the nonlinear impulsive sampled-data systems are derived in terms of linear matrix inequalities (LMIs), which can be easily verified via the LMI toolbox. The hybrid controller including sampled-data controller and impulsive controller is designed via the established LMIs. Moreover, the impulse effect considered in this paper including stabilizing impulse and destabilizing impulse. Our developed results are less conservative than the recent work in the literature. Finally, two numerical examples are provided to show the applications of the proposed criteria.