基于负载前馈及模糊控制的步进梁速度控制

步进梁由固定梁与移动梁组成,是步进式钢坯加热炉的核心部件。移动梁作矩形运动将钢坯在炉内加热的过程中逐步向前运送。移动梁必须轻托轻放钢坯,以免因频繁撞击而损坏移动梁与固定梁。移动梁自重加上一百多根钢坯的总重量达到数百吨,因此,步进梁运钢系统惯性巨大。在移动梁托起钢坯时发生阶跃式负载突变,造成速度和位移的大幅度跌落,并伴随着强烈抖动。在分析研究步进梁运钢系统的工作原理及数学模型的基础上,设计实现了基于负载扰动前馈的运钢速度模糊自整定PID控制。针对工程上负载无法测量问题,设计了构造负载扰动的状态观测器。仿真实验表明,控制方法能够使得系统运动准确快速地跟踪给定速度曲线。

Walking Beam Speed Control Based on Load Feed-forward and Fuzzy Control

The walking beam, composed of the fixed beam and moving beam, is the key component of the stepwise billet heating furnace. In the billet heating process, the moving beam moves in a rectangular way to move billets forward step by step in the furnace. The moving beam has to hold billets up and down lightly so as not to damage the moving beam and fixed beam through frequency impact. As the moving beam and over 100 billets weigh hundreds of tons, the transport system of the walking beam has a huge inertia. When holding up the billets, the moving beam undergoes step-like load mutation, resulting in a big drop of velocity and displacement, accompanied by a strong shake. Based on the analysis of the working principle and the mathematical model of the walking beam transport system, we have designed and realized fuzzy self-tuning PID control over the transport speed based on load disturbance feed-forward. Considering that load cannot be measured in engineering, we have designed a state observer for load disturbance. Simulation results show that this control method can enable the system movement to track the given velocity curve rapidly and accurately.