PLC控制的热封机温度控制系统开发与研究

为了能够精确控制飞机隔音棉热封机大直线段长度压合时的封口质量。该系统提出使用快速响应的热电偶采集温度信号,进行实时监测与反馈控制,同时使用脉冲式数字直流电源,将误差信号送入PID控制器进行运算,再通过S7-200 PLC控制加热电源的输出电压,从而改变镍铬丝的加热温度。试验结果表明,该方法能够消除系统的各种外界干扰因素,稳定控制加热温度和加热时间,有效的提高了响应速度和控制精度。该系统确保了隔音棉的封口加工质量,具有较好的实用价值。     

七自由度仿生机器人系统冗余问题研究

人体下肢的七自由度模型包括髋关节,膝关节和踝关节,但实际中下肢的运动只需要6个自由度即可,由于冗余引起的运动学干涉却没有现成的数学方法可以解决,同时又期望可穿戴机器人即外骨骼与人的交互能够同步,因而从运动学角度解决系统冗余问题。为了用数学方法描述冗余,定义一个旋转角度:由下肢大腿和小腿组成的平面绕髋关节和踝关节之间的虚拟轴的旋转角度。通过Matlab软件得到机器人的运动空间并与正常人体的运动空间进行比对,从而验证其可行性。     

飞机隔音棉包覆层热封参数优化研究

目的研究飞机隔音棉制造过程中包覆层的最佳热封参数。方法分析不同的热封工艺参数(热封温度、热封压力、热封时间)对隔音棉包覆层热封强度的影响,建立主要热封参数与热封强度的数学模型。在此基础上,利用LabVIEW对材料进行热封强度仿真计算和热封参数优化设计,并对数学模型得出的最佳热封工艺参数进行实验验证。结果模型的理论计算值与实验结果基本一致,验证了模型的正确性。结论实现了隔音棉材料热封参数的优化,为某飞机制造公司在隔音棉热封中热封参数的设定提供了参考。     

Interface microstructure and properties of submerged arc brazing tin-based babbit

The submerged arc brazing method was used to connect the tin-based babbit alloy with the steel matrix.The microstructure of the submerged arc brazed Babbitt interface layer on the surface of Q235 B steel was analyzed by OM,SEM and EDS and the hardness properties of the joint interface layer were tested by MH-5 microhardness tester.the result of research shows that a layer of canine-shaped intermetallic compound with uneven thickness is formed at the interface,and the thickness is 10-20 μm.The interface layer includes two kinds of compound layers,namely the Fe Sn layer near the side of the steel substrate and FeSn layer near the side of the babbit.During the interfacial reaction process,Fe atoms in the steel matrix dissolve into the liquid babbit alloy and form a certain concentration gradient at the interface.The farther from the interface,the lower the Fe atom concentration.The growth of Gibbs free energy of Fe Sn is lower when the temperature is above 780.15 K,and the temperature during the welding process is much higher than 780.15 K,moreover the precipitation temperature of Fe Sn is higher.Therefore,in the subsequent cooling process,Fe Sn is first precipitated from the interface near the side of steel matrix and then FeSn is precipitated from the interface near the side of babbit alloy.Microhardness test showed that the intermetallic compound at the interface layer significantly improved the hardness properties.