31m大型立式挤压淬火炉温度智能控制系统

【作者】 王春归；

【导师】 贺建军；

【作者基本信息】 中南大学 ， 控制理论与控制工程， 2004， 硕士

【摘要】 高强度铝合金是生产航天、航空飞行器的蒙皮、大梁、机翼等受力构件的主要材料。在高强度铝合金的生产过程中淬火是其最重要的热处理工序之一。淬火炉温度控制的精度直接影响到锻件的质量，影响锻件后续工序的进行。 对于大型淬火炉这种大时间常数多输入、多输出、强耦合的非线性系统，很难建立控制对象的精确数学解析模型。事实证明，基于精确数学模型的双闭环PID控制系统和预测控制等算法都达不到要求的炉温控制精度，其超调量甚至高达3％以上，无法满足大型航空锻件热处理要求。 针对被控对象的特点，本文提出了采用工控机(或触摸屏)和PLC两级计算机控制系统方案，通过对淬火炉内温度场分布情况的分析和计算，建立了被控对象的数值分析模型，较准确地掌握炉内温度场分布情况，用以优化温度控制系统的参数。在此基础上引入模糊控制算法，并充分吸收专家经验，提出了一种基于温度场的智能模糊PID控制算法。通过精确计算电热元件的占空比，采用脉冲宽度调制(PWM)方法，经PLC调节各调功柜输出功率，从而实现对淬火炉温度的精确控制。 本系统已经投入工厂运行，实际运行结果表明：系统硬件设计合理，软件功能完善，操作、维护方便，运行可靠，控制精度高，完全满足低超调快速升温、精确保温、温度分布均匀的生产工艺要求，提高了铝材产品的性能和产量。更多还原

【Abstract】 High intension aluminium alloy is stress mechanism’s main material of spaceflight aerocraft’s coating, beam girder, wing. Quench is one of the most important heat treatment processes of high intension aluminium alloy’s production. So the quench stove’s temperature control precision is the direct reason of forge pieces’ quality, it will infect the forges’ subsequent handling.Aiming at the problem that the temperature of the large-size vertical quench stove, for its thermal inertia is great, its delayed time is long, the coupling influence is severe, and its exact mathematical model is difficult to be established. The fact shows that based on precise mathematics model’s double loop-locked PID control system and predicted control algorithms don’t meet the temperature control’s precision, its’ overshoot even over 3%, so it doesn’t satisfy large scale spaceflight forge pieces’ heat treatment.Aiming to controlled device’s feature, two-stage computer control system composes of industrial control computer (or touch screen) and PLC is showed in this paper, through analyzing and calculating the quench stove’s temperature field’s distribute condition, and establish the controlled device’s mathematic analysis’s model, rather precious grasp the stove’s temperature distribute condition, then use it to optimize temperature control system’s parameters. We import fuzzy control algorithm and sufficient absorb experts’ experiences, put forward one intelligent fuzzy PID control algorithm based on temperature field. Through precious calculate electrothermal’s on-off ratio, and adopt pulse width modify (PWM) method, adjust every power cabinet’s output power through PLC, and then realize the quench stove’s precious control.This system is already bringing into service, the applied results prove that the system’s hardware is reasonable, software’s function is perfect, convenient to upkeep and operate, the system is credibility, and achives the high precious, and low overshoot, fast heating-up, precious temperature-keeping and the stove’s temperature distribute is even requirement, and raise the output and quality of aluminium material.更多还原