化油器过渡孔加工定位控制算法及其硬件设计

发布时间：2018-07-29 13:12

【摘要】：化油器是传统发动机里非常关键的部件,它的过渡孔为发动机从怠速工况向小负荷工况转变时提供汽油,过渡孔的位置精度对车辆启动性能、加速性能及低速到高速的衔接影响非常大。传统上,过渡孔加工一般以节气门轴定位,但这种定位方式会导致装配后过渡孔位置误差达0.5mm以上。本文通过模拟化油器的工作原理,提出了一种新的定位算法,提高了过渡孔的定位精度,改善了化油器的工作性能,使化油器更好地满足排放标准。论文主要工作:设计了过渡孔加工机床的工作流程,根据控制要求选择了控制系统的硬件。根据机床工作情况对关键部件进行了校核。分配了输入、输出端口。设计了系统主电路。选择了三菱触摸屏,型号为GT1265-VNBA。利用触摸屏界面设计软件设计了使用界面,其中包括欢迎界面、主控界面、手动界面等,充分考虑了操作机床的各种情况。根据伯努利方程,推导出恒流量气体通过化油器腔时节气门附近负压值模型,当节气门附近负压值是-500mm Hg时,节气门在水平方向位移4.04mm,与设计的4mm相差不大。根据该流体模型,提出了结合该机床的定位方法和PID控制器的一种新的定位算法。利用Matlab软件仿真了控制算法,得到PID控制器的三个主要参数。论文最后设计了一个算法验证实验。该实验利用电脑读取PLC的输出数据,经过数据处理后再用电脑将数据输入PLC,并将实验数据以图像输出。该图像与仿真图像一致,并收敛在-500.18mm Hg,满足过渡孔工作性能,验证了算法的有效性,表明运用本文提出的算法,机床可以实现精确定位,加工出提供稳定负压值的过渡孔。
[Abstract]:Carburetor is a very important component in traditional engine. Its transition hole provides gasoline for the engine from idle condition to small load condition. Acceleration performance and low-speed-to-high speed connection are very important. Traditionally, the throttle shaft is usually used in the machining of the transition hole, but the position error of the transition hole after assembly is higher than 0.5mm. By simulating the working principle of carburetor, a new positioning algorithm is proposed in this paper, which improves the positioning accuracy of the transition hole, improves the working performance of the carburetor, and makes the carburetor better meet the discharge standard. The main work of this paper is as follows: the working flow of the machine tool is designed, and the hardware of the control system is selected according to the control requirements. The key parts are checked according to the working condition of the machine tool. The input and output ports are allocated. The main circuit of the system is designed. Mitsubishi touch screen model GT1265-VNBA has been selected. The interface is designed by using touch screen interface design software, including welcome interface, main control interface, manual interface and so on. According to Bernoulli equation, the model of negative pressure near throttle when constant flow gas passes through carburetor cavity is derived. When the negative pressure near throttle is -500mm Hg, the horizontal displacement of throttle is 4.04mm, which is not different from that of 4mm. According to the fluid model, a new positioning algorithm combining the positioning method of the machine tool and the PID controller is proposed. The control algorithm is simulated by Matlab software, and three main parameters of PID controller are obtained. Finally, an algorithm verification experiment is designed. In this experiment, the output data of PLC is read by computer, and the data is input into PLC by computer after data processing, and the experimental data is output by image. The image is consistent with the simulation image and converges to -500.18mm Hg. it satisfies the working performance of the transition hole and verifies the validity of the algorithm. It shows that the machine tool can accurately locate and process the transition hole which provides the stable negative pressure value by using the proposed algorithm.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK403

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