LIU Jia-min, GU Li-chen, SUN Yu
（School of Mechatronic Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China）
Abstract：The instantaneous speed of a hydraulic system contains a wealth of operational information, and its accurate extraction is the basis for condition monitoring and fault diagnosis. In order to solve the problem of high hardware requirement for instantaneous speed measurement based on data acquisition card, a new method of high precision measurement is proposed. In this method, the time-displacement information of each tooth is obtained from the pulsed square wave signal of the gear disk collected by magnetoelectric sensors. The time-displacement curve is interpolated by the cubic spline interpolation method, and then the instantaneous speed is calculated by the five-point digital differential formula. The experimental results show that the method improves the speed measurement resolution and reduces the quantization error. The high precision instantaneous speed signal can also be acquired by hardware devices with less teeth and low sampling frequency. The related research results provide a theoretical basis and a method for improving the accuracy of instantaneous speed measurement.
Key words：instantaneous speed measurement; variable speed hydraulic system; cubic spline interpolation; five-point digital differentiation
CLD number：TP271+.31 Document code：A
Article ID：1674-8042（2019）04-0307-08 doi：10.3969/j.issn.1674-8042.2019.04.001
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液压系统高精度瞬时转速测量新方法
刘佳敏， 谷立臣， 孙 昱
（西安建筑科技大学 机电工程学院， 陕西 西安 710055）
摘 要： 液压系统的瞬时转速蕴含着设备丰富的运行信息， 其精确提取是进行状态监测和故障诊断的基础。 针对现有基于数据采集卡进行瞬时转速测量时对硬件要求太高的问题， 提出了一种高精度测量新方法。 本方法从磁电式传感器采集到的测速齿盘脉冲方波信号， 获取每个齿的时间位移信息， 利用3次样条插值方法对时间-位移曲线进行插值， 进而采用五点数字微分公式来计算瞬时转速。 实验结果表明， 本方法提高了测速分辨率， 降低了量化误差， 采用少齿数低采样频率的硬件设备也可获得高精度的瞬时转速信号。 相关研究成果为提高瞬时转速测量精度提供了理论基础与方法支持。
关键词： 瞬时转速测量； 变转速液压系统； 三次样条插值； 五点数字微分
引用格式： LIU Jia-min, GU Li-chen, SUN Yu. A new method for high precsion instantaneous speed measurement of hydraulic system. Journal of Measurement Science and Instrumentation, 2019, 10（4）： 307-314. ［doi：10.3969／j.issn.1674-8042.2019.04.001］
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