排序方式: 共有41条查询结果,搜索用时 15 毫秒
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基于质量的注塑保压过程建模方法研究:最优保压压力曲线设定 总被引:7,自引:0,他引:7
质量控制是注塑过程控制研究的重要内容,而保压过程是决定最终制品质量的一个重要阶段。在大量实验结果的基础上探讨了最优保压压力曲线的设定。实验结果表明,递减型线性保压压力曲线有利于减小模腔压力差和制品粗糙度,而递增型保压曲线则可能加大制品粗糙度。另外,阶跃型保压曲线与线性保压曲线相比,没有任何质量优势,还可能造成熔体倒流。 相似文献
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间歇过程不仅具有强非线性,同时还会受到诸如执行器等故障影响,研究非线性间歇过程在具有故障的情况下依然稳定运行至关重要。针对执行器增益故障及系统所具有的强非线性,提出一种新的基于间歇过程的T-S模糊模型的复合迭代学习容错控制方法。首先根据间歇过程的非线性模型,利用扇区非线性方法建立其T-S模糊故障模型,再利用间歇过程的二维特性与重复特性,在2D系统理论框架内,设计2D复合ILC容错控制器,进而构建此T-S模糊模型的等价二维Rosser模型,接着利用Lyapunov方法给出系统稳定充分条件并求解控制器增益。针对强非线性的连续搅拌釜进行仿真,结果表明所提出方法具有可行性与有效性。 相似文献
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针对具有输入时滞的多阶段间歇过程,考虑执行器故障影响,提出了无穷时域优化混杂容错控制器设计方法。该方法首先将给定具有输入时滞的模型转化为新的无时滞的状态空间模型,接着再将此模型转换为包含状态变量误差和输出跟踪误差的扩展状态空间模型,并用切换系统模型表示,然后引入有限时域的二次目标函数,利用最优控制理论,设计出在无穷时域中容错控制器。为获得最小运行时间,针对不同阶段设计依赖于Lyapunov函数的驻留时间方法。创新之处在于,控制律设计简单,计算量小,且每一阶段时间求取不需要引用任何其他变量,简单易行。最后,以注塑成型过程为例,仿真结果证明所提出方法具有可行性和有效性。 相似文献
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针对注塑成型(PIM)关键工艺参数操作不佳易引起产品质量缺陷问题,提出一种基于梯度增强型Kriging(GEK)模型的注塑工艺参数多目标优化设计方法。针对空调外罩注塑成型过程,根据工艺参数和质量指标开展七因子三水平的正交实验设计,并采用Moldflow软件进行模流分析计算,通过信噪比分析和方差分析选取影响产品质量的主要参数;基于GEK模型理论建立质量指标预测模型,采用多目标差分进化(MODE)算法以质量缺陷和周期时间最小化为目标搜寻全局最优解;将最优设计参数带回Moldflow软件进行模拟验证。结果表明翘曲量、体积收缩率和周期时间分别降低0.88%、4.68%和14.81%,大幅度提升了产品质量和生产效率。 相似文献
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Among the processing conditions of injection molding, temperature of the melt entering the mold plays a significant role in determining the quality of molded parts. In our previous research, a neural network was developed to predict the melt temperature in the barrel during the plastication phase. In this paper, a neural network is proposed to predict the melt temperature at the nozzle exit during the injection phase. A typical two-layer neural network with back propagation learning rules is used to model the relationship between input and output in the injection phase. The preliminary results show that the network works well and may be used for on-line optimization and control of injection molding processes. 相似文献
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基于时段过渡分析的多时段间歇过程质量预测(英文) 总被引:2,自引:0,他引:2
Batch processes are usually involved with multiple phases in the time domain and many researches on process monitoring as well as quality prediction have been done using phase information. However, few of them consider phase transitions, though they exit widely in batch processes and have non-ignorable impacts on product qualities. In the present work, a phase-based partial least squares (PLS) method utilizing transition information is proposed to give both online and offline quality predictions. First, batch processes are divided into several phases using regression parameters other than prior process knowledge. Then both steady phases and transitions which have great influences on qualities are identified as critical-to-quality phases using statistical methods. Finally, based on the analysis of different characteristics of transitions and steady phases, an integrated algorithm is developed for quality prediction. The application to an injection molding process shows the effectiveness of the proposed algorithm in comparison with the traditional MPLS method and the phase-based PLS method. 相似文献
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MADDOCK注塑螺杆性能研究 总被引:5,自引:1,他引:5
随着注塑技术的不断发展,注塑螺杆的性能越来越引起人们的重视。通过可视化实验和在线数据测控系统,研究了Maddock注塑螺杆的熔融、温度均匀性、塑化能力等性能,并和三段式通用螺杆进行比较。结果表明Maddock注塑螺杆的性能比普通三段式螺杆有较大的提高。 相似文献