基于PLC的小型挖掘机电控系统研究

发布时间：2018-11-21 20:03

【摘要】：我国“十二五”规划的各项重点工程建设相继开工,将大量使用挖掘机械。小型挖掘机由于体积小、方便灵活的特点得到广泛应用。电控系统是挖掘机的重要组成部分,起到“中枢神经系统”的作用。所以研究挖掘机电控系统对节能减排、提高工作效率等方面具有重要意义。本文主要设计了小型挖掘机的电源电路、起动电路、充电电路、发动机控制电路和其它附属电路,重点研究了挖掘机油门电控系统。通过对油门伺服控制技术的相关分析和研究,建立了步进电机、传动机构、油门拉杆等整个油门控制系统的数学模型,推导了传递函数并进行了稳定性分析,经软件仿真发现系统稳定,但存在振荡和超调现象,需进行控制策略研究。设计了经典PID控制器,通过MATLAB环境建立了仿真模型,用试凑法对参数进行了调整,观察系统在阶跃信号输入下的响应曲线表明：系统的动态和稳态特性得到较好的改善,但还是不能满足系统在不同工况下稳定运行的要求,进而提出模糊控制策略的研究。设计了模糊PID控制器,用FIS编辑器建立了模糊控制规则表,列出各变量的隶属度表。通过MATLAB仿真实验,分析了系统在阶跃输入信号和方波输入信号下的响应曲线,结果表明：模糊PID控制器的效果要优于经典PID控制器,并能实现参数的在线调整,满足了设计要求。设计了PLC硬件控制电路、传感器电路和相关接口电路,编写了系统控制软件程序,并给出了程序流程框图及部分程序。搭建了油门控制实验系统,对系统程序在软件和实验环境下进行了运行、测试和优化,完成实验和设计任务。仿真和部分实验证明本文设计的电控系统性能可靠,运行稳定。可应用于小型挖掘机的电控系统。
[Abstract]:The construction of all key projects in the "Twelfth five-year Plan" will be carried out one after another and excavating machinery will be used in large quantities. Small excavators are widely used because of their small size and convenient and flexible features. Electronic control system is an important part of excavator and plays the role of central nervous system. So it is very important to study the electric control system of excavator to save energy and reduce emission and improve working efficiency. In this paper, the power circuit, starting circuit, charging circuit, engine control circuit and other auxiliary circuits of the small excavator are designed, and the electric control system of the throttle of the excavator is studied emphatically. Based on the analysis and research of throttle servo control technology, the mathematical model of the whole throttle control system, such as step motor, transmission mechanism and throttle rod, is established, and the transfer function is deduced and the stability is analyzed. The software simulation shows that the system is stable, but there is oscillation and overshoot, so it is necessary to study the control strategy. The classical PID controller is designed, the simulation model is established through MATLAB environment, and the parameters are adjusted by trial and error method. The response curve of the system under step signal input shows that the dynamic and steady-state characteristics of the system are improved. However, it still can not meet the requirements of stable operation of the system under different operating conditions, and then put forward the research of fuzzy control strategy. The fuzzy PID controller is designed, and the fuzzy control rule table is established by using the FIS editor, and the membership table of each variable is listed. The response curves of the system under step input signal and square wave input signal are analyzed by MATLAB simulation experiment. The results show that the fuzzy PID controller is better than the classical PID controller, and the parameters can be adjusted online. Meet the design requirements. The PLC hardware control circuit, sensor circuit and related interface circuit are designed. The system control software program is written, and the program flow chart and some programs are given. The throttle control experiment system is built, and the system program is run, tested and optimized in software and experimental environment, and the task of experiment and design is completed. Simulation and some experiments show that the electronic control system designed in this paper is reliable in performance and stable in operation. It can be used in the electric control system of small excavator.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU621

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