分析了系统温度对机抖激光陀螺捷联惯性导航系统的影响因素,介绍了降低和补偿捷联系统温度误差的4种方法。通过重复性温度实验,利用逐步回归法分析了激光陀螺零偏与温度的关系;通过多项式拟合,分别得到了加速度计的零偏、标度因子和IF...分析了系统温度对机抖激光陀螺捷联惯性导航系统的影响因素,介绍了降低和补偿捷联系统温度误差的4种方法。通过重复性温度实验,利用逐步回归法分析了激光陀螺零偏与温度的关系;通过多项式拟合,分别得到了加速度计的零偏、标度因子和IF转换电路的温度补偿模型,并在捷联系统中得到应用。对其中的两种方法进行了实验研究和导航测试,并对两种方法的补偿效果进行了对比。结果表明:通过温度实验得到惯性器件的温度补偿模型对其温度误差进行实时补偿是捷联系统最理想的补偿方法。补偿后系统定位测试1 h的圆概率误差(CEP)优于0.3 n mile/h,达到国内先进水平。展开更多
A method to reach the globular weld structure of A356 aluminum alloy using stirring the localized semisolid zone during butt-joining is developed.Since the heat conductivity of this alloy is very high, the accurate co...A method to reach the globular weld structure of A356 aluminum alloy using stirring the localized semisolid zone during butt-joining is developed.Since the heat conductivity of this alloy is very high, the accurate controlling of temperature during joining must be considered.A gas heating system was used to heat up the nitrogen gas up to the required temperature.A dried and free oxygen gas was prepared when a stream of nitrogen gas could pass closely around a hot element.Hot and pure nitrogen gas flow through a precise ceramic nozzle was used to create a localized semisolid pool.At this stage a fine stirrer was introduced into the weld seam in order to mix the two sides into a single uniform joint.Substrates were moved in direction of joint line by a small trolley to avoid the deviation of nozzle from the joint line and its distance and angle from the substrate.A fixture system was used to hold two substrates together on the trolley.A narrow hot plate was located on the trolley to heat up the joint line due to high heat conductivity of aluminum.Effect of gas temperature was investigated on the microstructure and mechanical properties of weld seam.Results showed that increase in temperature promoted the final welding properties, and also at liquid fractions less than 50% joining was not fully practical.The best mechanical properties were achieved with liquid fraction of about 70%.展开更多
文摘分析了系统温度对机抖激光陀螺捷联惯性导航系统的影响因素,介绍了降低和补偿捷联系统温度误差的4种方法。通过重复性温度实验,利用逐步回归法分析了激光陀螺零偏与温度的关系;通过多项式拟合,分别得到了加速度计的零偏、标度因子和IF转换电路的温度补偿模型,并在捷联系统中得到应用。对其中的两种方法进行了实验研究和导航测试,并对两种方法的补偿效果进行了对比。结果表明:通过温度实验得到惯性器件的温度补偿模型对其温度误差进行实时补偿是捷联系统最理想的补偿方法。补偿后系统定位测试1 h的圆概率误差(CEP)优于0.3 n mile/h,达到国内先进水平。
文摘A method to reach the globular weld structure of A356 aluminum alloy using stirring the localized semisolid zone during butt-joining is developed.Since the heat conductivity of this alloy is very high, the accurate controlling of temperature during joining must be considered.A gas heating system was used to heat up the nitrogen gas up to the required temperature.A dried and free oxygen gas was prepared when a stream of nitrogen gas could pass closely around a hot element.Hot and pure nitrogen gas flow through a precise ceramic nozzle was used to create a localized semisolid pool.At this stage a fine stirrer was introduced into the weld seam in order to mix the two sides into a single uniform joint.Substrates were moved in direction of joint line by a small trolley to avoid the deviation of nozzle from the joint line and its distance and angle from the substrate.A fixture system was used to hold two substrates together on the trolley.A narrow hot plate was located on the trolley to heat up the joint line due to high heat conductivity of aluminum.Effect of gas temperature was investigated on the microstructure and mechanical properties of weld seam.Results showed that increase in temperature promoted the final welding properties, and also at liquid fractions less than 50% joining was not fully practical.The best mechanical properties were achieved with liquid fraction of about 70%.
