汽车桥壳压制成形液压系统控制研究

发布时间：2019-01-05 05:30

【摘要】：汽车桥壳胀压成形工艺是一种新兴技术,与传统的铸造和冲焊相比,具有制件质量轻、性能好等优点。该工艺将缩径后的管坯进行液压胀形得到预成形管坯,最后经过压制得到桥壳样件。压制液压主机本身具有大惯量和非线性的特点,而压机的运动会影响管坯的轴线位置,从而影响管坯两端的密封效果。本文围绕如何使管坯中心轴线始终维持在初始位置附近这一控制目标展开研究。首先,简单介绍了胀压成形汽车桥壳压制成形机的组成及工作过程,根据压制成形机工作要求,设计了主要的液压控制回路,并详细阐述了各个控制元件的动作顺序。根据提出的技术指标,进行了关键元器件的选型计算。其次,利用AMESim软件建立液压系统的插装方向阀、插装溢流阀和插装比例节流阀模型,进行动静态仿真分析,通过不断调试并与样本曲线作对比,验证了模型的合理性。针对液压系统控制精度的要求,提出了利用AMESim自带的NLPLQ算法优化PID控制器参数,不仅节省了常规整定法所耗费的时间,而且达到了良好的控制效果。最后,搭建了系统的联合仿真模型,通过给定一个阶跃信号,辨识出长、短行程缸的数学传递函数表达式。在此基础上,设计了针对纯滞后系统的大林控制器,并将原先系统的PID控制器换成大林控制器进行联合仿真,结果表明两缸位移误差几乎能达到相同的控制结果,这也间接地反映了辨识所得传递函数的可靠性。
[Abstract]:Compared with the traditional casting and impact welding, the bulging and pressing forming technology of automobile axle shell has the advantages of light quality and good performance. The pre-formed tube billet is obtained by hydraulic bulging and finally the bridge shell sample is obtained by pressing. The pressing hydraulic main engine itself has the characteristics of large inertia and nonlinearity, and the movement of the press will affect the position of the axis of the tube billet, thus affecting the sealing effect of the two ends of the tube blank. This paper focuses on how to keep the central axis of the billet near the initial position. First of all, the composition and working process of the bulging forming vehicle axle shell pressing machine are introduced briefly. According to the working requirements of the press forming machine, the main hydraulic control circuit is designed, and the action sequence of each control element is described in detail. According to the proposed technical specifications, the selection of key components is calculated. Secondly, the AMESim software is used to build the hydraulic system model of directional valve, plug relief valve and proportional throttle valve. The dynamic and static simulation analysis is carried out, and the rationality of the model is verified by continuous debugging and comparing with the sample curve. According to the requirement of control precision of hydraulic system, the NLPLQ algorithm of AMESim is used to optimize the parameters of PID controller, which not only saves the time consumed by conventional tuning method, but also achieves good control effect. Finally, the joint simulation model of the system is built, and the mathematical transfer function expressions of long and short stroke cylinder are identified by given a step signal. On this basis, a Dailin controller for the pure delay system is designed, and the PID controller of the original system is replaced by the Dalin controller for joint simulation. The results show that the displacement error of the two cylinders can almost reach the same control result. This also indirectly reflects the reliability of the identified transfer function.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U466

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