泵阀联合电静液作动器建模与仿真

针对当前泵阀联合电静液作动器机构和控制算法复杂的问题,采用基于永磁同步电动机、定量泵、蓄能器和伺服阀的压力和舵角双闭环控制回路体系,同时把舵角偏差作为前馈信号引入压力控制回路,以提高压力控制回路响应速度。阐述了泵阀联合电静液作动器工作原理,对其各个模块进行了建模和仿真分析。仿真结果表明,其较现有控制方案简单,综合性能指标良好,在未来的机载液压系统中具有很好的应用前景。     

基于MCU的液压双缸同步驱动控制器设计

液压双缸同步驱动一般采用工控机或PLC作为控制器,尽管具有组成简易、自动控制方便等特点,但工控机或PLC一般价格较贵、占地面积大,且专用性不强。针对液压双缸同步驱动的特点,为了给其提供一种小型廉价的专用型控制器,设计了一种基于AVR单片机的液压双缸同步驱动控制器,并详细说明了其硬件和软件构成。在液压缸位移闭环控制的数据检测及传输方面,采用了高精度的磁致伸缩位移传感器及同步串行接口输出技术,提高了位移检测数据传输过程中的抗干扰性。最后,通过试验验证了所设计控制器的实用性。     

某风洞两缸同步液压开环控制系统分析与改进

对国内某风洞两缸同步液压开环控制系统存在的问题进行分析,通过对比几种液压同步方案的特点,最终采用同步马达再合理配置单向调速阀进行流量补偿构建开环同步回路的方案。对改进方案的原理进行了详细阐述,分析调试过程中注意事项。该改进方案最后取得了良好的应用效果,为有类似需求的系统提供了借鉴。     

双电液伺服马达同步控制系统的研究

本文提出了电液伺服双液压马达实现同步驱动的几种控制方案。应用反馈控制理论和最优控制理论,着重研究了两传递函数不同的液压马达,通过状态差值反馈来实现同步的方案。通过数字仿真,证明这种控制方法的有效性和合理性。     

同步液压伺服激振控制系统的研究

采用LabVIEW软件、AD/DA采集卡和伺服阀等对同步液压激振系统进行闭环控制、相位和幅值自动补偿。根据系统反馈的液压缸位移量的变化使PID控制器参数Kp、Ki和Kd自动修正。实践结果表明:采用该控制系统控制同步液压伺服激振系统,有效地解决了幅值衰减和通道不同步的问题。     

大型构件液压同步提升的神经网络自适应控制

本文研究了采用单神经元的神经网络自适应控制在大型构件液压同步提升系统中的应用,结果表明它具有比传统ＰＩＤ控制更好的稳定性。     

一种多缸液压同步系统的控制策略及其仿真研究

针对液压控制系统中广泛存在的同步控制问题,提出一种新的基于模糊PID增量式输出的主从方式控制策略,并通过在MATLAB下编写仿真程序对某型号机床的液压同步控制系统进行建模和仿真.结果表明:该控制策略的控制效果很好,对液压同步控制系统的设计和调试具有一定的指导意义.     

同步缸同步回路系统改进设计

主要介绍某同步液压回路系统的改进设计。在分析原液压系统不足的基础上,对原同步液压回路进行改进,降低了零件加工精度、密封等因素对系统精度的影响,使整个液压系统得到优化,系统的性能明显提高。     

液压同步控制回路简析及应用

简要分析了开环同步回路和闭环同步回路的常用类型以及液压同步控制回路在生产中的应用。     

液压同步控制回路简析及应用

本文简要分析了开环同步回路和闭环同步回路的常用类型以及液压同步控制回路在实际生产中的应用     

线性摩擦焊机施力系统压力响应动态仿真

为研究线性摩擦焊机电液伺服施力系统对滑台压力的闭环控制特性,根据输入输出各变量之间的关系推导出电液伺服施力系统相对于压力信号的闭环传递函数,再根据该数学模型建立起系统的仿真模型并实施仿真.为验证建模与仿真的可信度,对电液伺服施力系统进行了闭环控制下的压力频率特性试验,并重点分析了系统压力对压力闭环响应特性的影响.结果表明,数值仿真与试验结果基本吻合;电液伺服施力系统相对于闭环压力为二阶惯性加一阶微分环节,系统工作频宽较大,稳定性较好;提高系统压力可改善压力闭环动态响应特性.

Abstract：

In order to study the closed-loop control qualities of the electro-hydraulic servo load system of the linear friction welding machine on the slipway pressure, closed-loop transfer function of the pressure for the electro-hydraulic servo load system was established according to the relationship between input and output variables, a simulation model was established according to the transfer function and the simulation was carried out. In order to validate reliability of the simulation result, a frequency characteristics experiment of pressure was implemented under closed-loop control, and the system pressure's affect on the pressure's closed-loop response characteristics was specially analyzed. The results show as follows, the emulational and experimental results are anastomosing; the electro-hydraulic servo load system is a second-order inertial & first-order differential link for closed-loop pressure control, the system frequency width is large, and the system stability is high; pressure s closed-loop dynamic response characteristics can be improved by promoting the system pressure.     

用于T716A立式镗床数控化改造的四坐标闭环系统

针对T716A立式金刚镗床的数控化改造，设计了一种双CPU结构的四坐标控制系统，该系统完成三个坐标的闭环控制和一个坐标的开环控制，可以实现任意两坐标的联动。选用DS80C320单片机作为CPU，采用直线光栅检测线位移、圆光栅检测角位移，闭环的控制采用一种特殊形式的PID数字调节器。分析了系统的硬件结构，给出了闭环控制的软件流程。提出了电接触法和光栅零位法两种对刀方式。借助于这种系统，T716A拓宽了加工范围，实现了精确的位置控制与轨迹控制，工效明显提高。     

比例溢流阀在液压系统中模拟加载实验研究

为了在液压系统上实现模拟加载,设计了以比例溢流阀为加载元件的加载实验,实现了系统压力闭环PID控制。将压力传感器的测量值和设定压力值比较,用两者差值作为控制信号调整比例溢流阀阀口面积,从而实时校正、调整实际压力使之达到设定值。实验表明:压力加载闭环控制系统抗流量扰动能力强;对于流量阶跃、斜坡干扰信号,该闭环控制系统能够消除压力设定值与实际值之间的误差;对于流量正弦干扰信号,该闭环控制系统能使实际压力值在设定值上下小幅波动。     

数控机床中直接位置闭环控制系统的研究

针对间接位置闭环控制系统存在的问题,给出了一种基于伺服驱动器本身的直接位置闭环控制系统的设计与实现.实验结果表明,直接位置闭环控制系统克服了间接位置闭环系统的固有缺陷,能够补偿机械环节的各种误差,使得实际的工作台位移能够准确地反映指令位置,达到了预期目标.     

Sensing, modeling and control for laser-based additive manufacturing

Laser-Based Additive Manufacturing (LBAM) is a promising manufacturing technology that can be widely applied to part preparation, surface modification, and Solid Freeform Fabrication (SFF). A large number of parameters govern the LBAM process. These parameters are sensitive to the environmental variations, and they also influence each other. This paper introduces the research work in RCAM on improving the performance of the LBAM process. Metal powder delivery real-time sensing and control is studied to achieve a controllable powder delivery for fabrication of functionally graded material. A closed-loop control system based on infrared image sensing is built for control of the heat input and size of the molten pool in the LBAM process. The closed-loop control results show a great improvement in the geometrical accuracy of the built features. A three-dimensional finite element model is also established to explore the thermal behavior of the molten pool in the closed-loop controlled LBAM process.     

伺服系统的鲁棒优化控制设计方法

对伺服系统采用状态反馈控制方式,应用内模原理,引入伺服补偿器,通过合理配置闭环极点,确定状态反馈矩阵和观测器矩阵.与常规的PID控制相比较,仿真结果表明该系统具有较强的鲁棒性和控制品质,可获得比PID控制方法更好的控制效果,是一种有效的控制方法.     

基于ARM和CPLD的脉冲TIG焊接电源的研究

研制了基于双ARM和CPLD的多功能TIG焊接系统,采用脉冲电源+基值电源的组合方式,实现多功能的电流输出。脉冲电源采用双闭环的PI控制方法,实现脉冲电流输出;基值电源采用单闭环的控制方法,实现基值电流的恒定输出。详细阐述了双电源二次逆变的架构及工作原理,并分析PI控制算法和A/D采样滤波。通过实验,实测出针对不同脉冲频率和脉冲宽度下的电流响应,系统对过电流、过电压等信号进行特殊处理,提高了系统的可靠性和稳定性。     

Accuracy improvement of wire-EDM by real-time wire tension control

In this paper, a closed-loop wire tension control system for a wire-EDM machine is presented to improve the machining accuracy. Dynamic models of the wire feed control apparatus and wire tension control apparatus are derived to analyze and design the control system. PI controller and one-step-ahead adaptive controller are employed to investigate the dynamic performance of the closed-loop wire tension control system. In order to reduce the vibration of wire tension during wire feeding, dynamic absorbers are added to the idle rollers of wire transportation mechanism. Experimental results not only demonstrate that the developed control system with dynamic absorbers can obtain fast transient response and small steady-state error than an open-loop control system, they also indicate that the geometrical contour error of corner cutting is reduced with approximately 50% and the vertical straightness of a workpiece can be improved significantly.     

板类件多点闭环成形的模糊控制方法

在金属板类件的加工中,无模多点成形是一种CAD数据模型驱动的柔性加工方法;多点闭环成形更是将板类件的加工与实时测量紧密结合到一起。本文在基本体群形状和工件形状的离散傅立叶变换描述的基础上,定义了不同类型的曲面误差;提出了多点闭环成形的模糊控制方法;实验证明,该方法能够控制板材快速收敛到所设计的目标形状,为实现板类件的数字化制造提供了一种新思路。     

Infrared sensing of full penetration state in gas tungsten arc welding

The objective of this study is to present an applicable top-side infrared sensing technique for the prospective closed-loop control of weld penetration in gas tungsten arc welding (GTAW). A model is developed to calculate the full penetration state, which is specified by the back-side bead width, from the sensed infrared images. To ensure the model validity in the prospective closed-loop control, the experiments, which generate the data for the model identification, are conducted under the experimental conditions that will be encountered during practical closed-loop control of the welding process. The heat transfer condition and electrode tip angle may vary during welding or from case to case. Also, the control variables which are used to adjust the weld process in order to reach the required weld penetration will also change. In many cases, the current can be employed as an on-line adjustable control variable because of the implementation ease, when the welding speed and arc length are maintained at the preset values. Thus, different currents, workpiece sizes, and electrode tip angles are arranged in the experiments to emulate the possible current adjustments, case to case heat transfer variations, and electrode wear. The infrared characteristics of the effects of these parameters are extracted to regress the full penetration state. Finally, the back-side weld width (the full penetration state) is calculated using the resultant model from the sensed infrared data.