共查询到20条相似文献,搜索用时 250 毫秒
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提出了一种以主动纠偏原理为基础的模锻压机平衡控制系统,通过解析法和拉氏变换法,对模锻压机系统的活动横梁、驱动缸以及驱动系统完成数学建模,同时分析了偏心载荷作用于活动横梁不同位置时系统的同步纠偏精度。在简化控制变量的基础上,利用MATLAB软件进行仿真。分析结果表明,活动横梁在最大压制速度、最大偏心载荷、偏心载荷作用点最远处时的主动纠偏调整时间最长,调整时间为2.00 s,主动同步纠偏精度为0.714 mm·m-1;相比于现有基于被动纠偏原理的同步平衡控制系统,主动同步系统的纠偏调整时间更短,纠偏精度更高。 相似文献
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转向单辊纠偏装置纠偏效果分析 总被引:6,自引:0,他引:6
转向单辊纠偏装置中的纠偏辊平行于入口带钢摆动 ,使纠偏辊轴线摆动平面与入口带钢带夹角为 0°,纠偏效果很好 ;在不允许设计成此种摆动型式时 ,让纠偏辊轴线摆动平面与入口带钢夹角小于 45°,避免出现反向螺旋作用 ,才能收到较好纠偏效果。此结论与实用结果一致 ,对改造旧有的或研制新的转向单辊纠偏装置有参考价值 相似文献
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《锻压技术》2015,(8)
根据铝板带热连轧过程中板带的跑偏运动特点,建立了热连轧铝板带跑偏过程数学模型,分别求得了以辊缝差、来料厚差等跑偏诱因为输入,以轧制力差、跑偏量为输出的跑偏传递函数。建立了多冲量串级纠偏控制系统,并运用预测函数控制作为纠偏系统的控制算法。将纠偏预测函数控制系统运用到热连轧最容易发生跑偏的F4机架中进行纠偏控制数值模拟,并将纠偏控制效果与传统PID控制纠偏效果模拟进行对比。数值模拟结果显示:运用预测函数控制的纠偏控制系统,调整时间为0.5 s,轧制力差超调量小于10 k N,跑偏量超调量小于1 mm;其鲁棒性明显比PID强,调整时间短,超调量小,能够满足高速轧制下的纠偏控制。对纠偏预测函数控制算法进行了实验验证。实验结果显示,纠偏系统在以现场数据为输入和扰动时,能够快速、稳定、准确地减小各机架的轧制力差,防止出现轧制过程中出现大幅的跑偏现象。 相似文献
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《Synthetic Metals》1998,95(2):119-124
Rectifying diodes of the heterojunction between porous silicon (PS) and water-soluble copolymer of polyaniline (PAOABSA) with the rectifying ratio of 5.0 × 104 at ±3 V bias were fabricated and the rectifying characteristics of the heterojunction diode, Al/PS-PAOABSA/Au cell, were measured as a function of the sulfonated degree and thickness of the PAOABSA copolymer films, as well as the oxidation of silicon exposed to air. It was found that decreasing the sulfonated degree and thickness of the PAOABSA copolymer films is favorable for enhancement of rectifying characteristics of the heterojunction diodes. Moreover, it was noted that the oxidation of silicon exposed to air is harmful for the rectifying effect of the heterojunction diodes. 相似文献
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通过对直弧形连铸机辊列连续弯矫曲线公式的推导,得到理想连续弯矫曲线的方法。用该方法得到的连续弯矫曲线,具有在端点处位置连续、切线斜率连续、曲率连续、曲率变化率连续,且在曲线内部曲率变化率最大值趋于最小的效果;克服了已有连铸机连续弯矫曲线在端点处曲率、曲率变化率不连续的缺陷。 相似文献
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Evaporated multilayer sandwich structure of Au/NiPc/Al was fabricated by thermal evaporation technique. The electrical conductivity of Au/NiPc/Al device has been measured both as prepared and after annealing at 623 K for 2 h. Under forward bias conditions, ohmic and SCLC conductions were identified at low and higher voltages respectively. After annealing, a strong rectifying effect was observed. The potential barrier height and the depletion region width for annealed sample were calculated as 0.96 eV and 70 nm, respectively. Hole and trap parameters for as prepared and after annealing devices, also, were evaluated. 相似文献
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《Synthetic Metals》1995,72(1):35-39
We have studied the influence of plasma and thermal treatments on the electrical properties of poly(para-phenylene vinylene) (PPV) thin films in metal-polymer-metal structures. Thermal heating of the samples modifies the diode characteristic by reducing the voltage threshold and by favouring the formation of the rectifying contact at the bottom side. Plasma treatments with oxygen or nitrogen drastically change the conductivity of the polymer with disappearance of the rectifying behaviour and increase the current by many orders of magnitude. Attempts to explain the modifications of the electrical property of the treated samples are given, using previous results from X-ray photoelectron spectroscopy (XPS) which highlight the role of the interfacial layer formed by chemical reaction between the polymer and metallic electrode. 相似文献
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研究了工件的变形形式,并依此提出三坐标测量数据的软件矫正法。阐述了具体实现中的关键技术。给出了一个应用实例。 相似文献
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根据氯化镁电解多级槽的特性及要求,以设计的科学性和节能性为出发点,通过深入探讨镁电解整流系统的方案选择和设计方法,推出了科学合理的节能型解决方案。 相似文献