PLC在油毡卷毡机中的应用

介绍了用可编程序控制器(PLC)取代油毡卷毡机控制器实现定长控制,用PLC的高速脉冲输出(PWM)控制调速电机转速的方法．给出了PLC与现场信号的接线图和控制功能流程图,为系统的实现提供了技术支持．     

可编程控制器在南通狼山空中缆车中的应用

介绍了可编程控制器（ＰＬＣ）在南通狼山空中缆车中的应用及该系统的软、硬件结构。系统采用日本ＯＭＲＯＮ公司生产的Ｃ６０Ｐ－ＣＤＲ－Ａ主机、Ｃ６０Ｐ－ＥＤＲ－Ａ扩展机和少量的中间继电器来代替传统的继电－接触器控制系统,各接触器都有辅助触点反馈回ＰＬＣ,采用行程显示技术以实时显示吊厢的实际位置,出进站时的加减速均采用软硬件双重控制,用梯形图编制开／停车逻辑控制、速度给定处理、行程显示、各种紧停及报警处理程序。实践证明,该系统具有有效的故障自诊断能力,灵活的控制方式,检修、维护更简便,可靠性大大提高。     

PLC在B230龙门刨床电气控制中的应用

利用可编程序控制器对B 230龙门刨床电气控制系统进行电气改造的途径和方法。可为各机床使用厂家进行企业技术改造提供一定的技术支持．     

利用PLC设计农业温室控制系统

讨论了在温室控制中引入PLC技术构成分布式控制系统的方法,详细介绍了系统的特点、组成、软硬件设计、实时动态监控系统及通信问题。分布式的控制结构,使各子系统相对独立,管理与控制功能分开,易于实现群控化管理,提高了系统的可靠性,且易于扩展。系统成本低廉,性能稳定,通用性好,符合中国国情,具有广泛的应用前景。     

DDC与DCS集散型控制系统

讨论了DCS的特性,掌握DDC的输入和输出的连接,DDC控制的原理和方法。     

家禽孵化温度控制系统设计——基于Smith预估算法

为使禽蛋孵化箱控制系统的动态性能和稳态精度满足系统的要求,提出了Smith预估和PID结合的控制算法。采用DS18B20测量温度,LPC2103制作温度控制器;采用Matlab中Simulink控制系统仿真工具,分析了传统PID控制与Smith预估和PID结合的控制算法的区别,并对两种控制算法进行了比较,确定了控制参数。孵化箱的温度控制实验结果表明,该温度控制器满足系统控制要求。     

电液比例流量控制新原理理论及实现

针对现有电液比例流量控制技术的不足，首次提出一种新的控制原理，仅用一比例节流阀即可闭环精确控制流量，简化了阀的结构。该原理还可使阀具有压力流量复合控制、故障诊断和容错控制等智能功能，研究结果表明新原理阀的动静态性能亦非常优良。     

Technical Research for Detector of Grain Moisture Content Based on Error Compensation

According to the existing method including testing the frequency and establishing the relationship between moisture content and frequency, a corresponding instrument was designed. In order to further improve the accuracy and rapidity of the system, a new approach to describe the relationship between the measurement error and the temperature was proposed. The error band could be obtained and divided into several parts（based on the range of temperature） to indicate the error value that should compensate the grain moisture content for the changes in temperature. By calculating the error band at the maximum and the minimum operating temperatures, as well as by determining the error compensation value from the error band based on the measurement moisture content, the final effective result was derived.     

A novel control method for two-phase short current of lines

The tremendous power flow may be transfered when two-phase short line is shut down, which may result in unstable state of the system and large loss of electric power. A novel line fault current controller (LFCC) and control method for the fault current of the two-phase short are presented. LFCC, emdedded at the line terminal, is composed of a series-connection transformer, a shunt-connection transformer,2 controllable inductors and on-line taps and is equivalent to the series of the insertion voltage and the insertion inductor when it works. The insertion voltage at the sending terminal(receiving terminal) is controlled to lead (lag)the fault source voltage by 2π/3 by adjusting on-line taps states. Because the insertion voltage amplitude and the insertion inductance can be controlled independently, the fault current gets zero and the current through the fault line reaches the normal current by the appropriate control of the insertion voltage amplitudes and the insertion inductances. Therefore, the fault line keeps the operation and the current through the line during the two-phase short existing equals that in normal operation, which improves the supply reliability. In addition, the corresponding control strategy for two phase short current is proposed. The experiment results show that the proposed LFCC is able to control the fault current through the line to reach corresponding normal current. The proposed control method suited for the proposed LFCC for the two phase short current is verified with the simulation results.     

基于变增益单神经元PID的秸秆旋埋还田导航系统研制

水稻田土壤松软,收割机作业后会出现残留秸秆凸起、地表坑洼等现象,导致秸秆旋埋还田作业易出现重耕、漏耕和自动驾驶路径跟踪精度差等问题。该研究基于滑移估计模型推导了拖拉机路径跟踪的前轮转角控制率,并设计了一种变增益单神经元PID导航控制器。在自主设计的电控比例液压转向系统基础上开发了秸秆旋埋还田导航系统,采用双天线RTK-GNSS获取拖拉机的实时位置和航向角信息,由变增益单神经元PID控制器根据理论转角和航向角偏差变化输出实际执行转角,实现旋埋作业自主路径跟踪。田间试验表明,作业速度为1.15 m/s时,变增益单神经元PID控制器的自适应直线跟踪最大横向偏差不超过0.071 m,平均绝对偏差不超过0.031 m。与常规PID控制器相比,变增益单神经元PID控制器的最大横向偏差和平均绝对偏差控制精度分别提高了53.08%和51.72%;与单神经元PID控制器相比,最大横向偏差和平均绝对偏差控制精度分别提高了39.00%和28.21%。该研究设计的变增益单神经元PID控制器可以增强导航系统的适应性和鲁棒性,提高路径跟踪精度,适用于未来无人驾驶下的秸秆旋埋还田作业。