【摘要】 为减少不同被测液体凹型液面对毛细管粘度计液位检测和计时精度的影响,提出了一种以光电传感器为液位检测部件的毛细管粘度计自适应液位检测方法:首先以毛细管粘度计非计时刻度线区的液位检测信息为先验知识,采用罗曼诺夫斯基准则,自动搜索并确定非计时刻度线区向计时刻度线区过渡的特征点,并通过模糊判决自动调整液位检测电压的采样间隔;然后以此特征点为拟合起点,利用最小二乘法对毛细管粘度计计时刻度线区的液位检测数据进行线性拟合,获得计时起点或计时终点,实现粘度计自适应液位检测和自动计时。实验表明,采用这种自适应液位检测方法的毛细管粘度计操作简单、方便,获得的运动粘度标准差小于手动计时方式,运动粘度的重复性优于手动计时方式。更多还原

【Abstract】 In order to reduce the bad effects of concave liquid level of different liquids on liquid-level detection and timing of capillary-gravity viscometer,a new method for adaptive liquid level detection with photoelectric sensors is developed.Firstly,the start fitted point is automatically determined by Lomnaofski norm and some prior knowledge such as the data of the liquid level when it isn’t at the timing line,the sampling interval is automatically adjusted via fuzzy decision,then the start timing point and stop timing point are obtained by linear fitting of the liquid-level data when the liquid has fully flowed across the timing line with least squares method.All experimental results show that the standard deviation of kinematic viscosity obtained with capillary-gravity viscometer using this method is less than that using manual measurement method,the repeatability of kinematic viscosity is superior to that of manual measurement,and the capillary-gravity viscometer using this method is simple and convenient.更多还原