信号重构的变转速液压系统恒压控制性能研究

为消除干扰信号对于变转速液压系统恒压控制性能的影响,提高系统的控制精度,对压力反馈信号进行了预处理。利用多分辨率分析分解反馈信号、剥离干扰信号成份,重构信号。采用Lab VIEW与MATLAB软件混合编程的方法,设计了压力信号重构的变转速恒压测控系统。通过实验对比分析了在PID控制系统中添加信号重构器前后对控制性能的影响。实验表明:对压力反馈信号进行分解与重构,能够在保持系统响应速度的基础上,减小恒压系统的稳态误差,降低压力波动,提高控制精度。

滤波器对变转速液压系统恒压控制性能的影响研究

针对变转速液压系统恒压控制中存在的信号干扰影响控制性能的问题,文中提出了对压力反馈信号进行滤波处理的方法. 结合变转速液压实验平台,通过MATLAB与LabVIEW软件联合编程方法设计了变转速液压系统压力闭环控制系统,并通过实验对比分 析了压力反馈信号未加滤波器、加非零相位滤波器以及加零相位滤波器3种方式下的系统压力控制性能.实验结果表明：对压力反 馈信号进行滤波处理可以明显提高系统的压力控制性能,且相比于非零相位滤波器,零相位滤波器能够在不降低系统响应速度的 基础上,进一步降低压力波动,提髙系统压力控制精度,改善系统鲁棒性.

数字滤波器对改善变转速液压系统恒压控制性能的实验分析

针对变转速液压系统恒压控制中存在的信号干扰影响控制性能的问题,本文提出先对系统反馈的压力信号的时频域特性进行滤波处理,滤波后的信号再作为PID控制器的反馈输入的方法。结合变转速液压实验平台,通过MATLAB与LabVIEW软件联合编程方法设计了变转速液压系统压力闭环控制系统,并通过实验对比分析了压力反馈信号未加滤波器、加非零相位滤波器以及加零相位滤波器三种方式下的系统压力控制性能。实验结果表明：对压力反馈信号进行零相位滤波处理能够在不降低系统响应速度的基础上,进一步降低压力波动,提高系统压力控制精度,改善系统鲁棒性。

变转速液压系统流量反馈信号重构控制

为了降低高频干扰信号对变转速液压系统流量控制性能的影响,提出了流量反馈信号小波重构控制方法.利用多分辨率分析理论分解流量反馈信号,剥离干扰信号成分,重构流量反馈信号,提高系统流量的辨识精度.通过实验对比分析了流量反馈信号未加滤波器、数字滤波与反馈信号重构三种方式对系统流量控制性能的影响.实验结果表明:相比未加滤波器和加数字滤波器,流量反馈信号小波重构控制方法能够在不降低系统响应速度的基础上,降低流量波动,提高系统流量控制精度,改善鲁棒性.

泵控缸液压系统全局功率动态匹配图示化监测方法

为在线监测液压系统的运行状态及功率匹配信息,识别其在典型工况下的功率匹配关系,以变转速泵控缸液压系统为例,基于多源信息融合思想,提出了李萨如图和功率圆图的动态功率匹配图示化监测方法。基于LabVIEW开发了测控程序进行变工况下的功率软测量,验证并分析了系统的能效特性。结果表明:恒定转速下,系统总效率随负载增大先升高后降低;阶跃加载时,系统存在功率冲击;溢流工况下,系统总效率为0;恒定负载下,系统总效率随转速增大先升高后降低;电机转速与负载相匹配时,可提高系统总效率。李萨如图和功率圆图特征参量可反映系统的功率及运行工况,该方法能够对液压系统的动态变化进行实时监测,为液压系统的功率监测和匹配研究提供了新思路。

Instantaneous rotation speed measurement and error analysis for variable speed hydraulic system

In order to monitor the working state of piston motor and measure its instantaneous rotation speed accurately, the measuring principle and method of instantaneous rotation speed based on industrial personal computer and data acquisition card are introduced, and the major error source, influence mechanism and processing method of data quantization error are dis- cussed. By means of hybrid programming approach of LabVIEW and MATLAB, the instantaneous rotation speed measurement system for the piston motor in variable speed hydraulic system is designed. The simulation and experimental results show that the designed instantaneous speed measurement system is feasible. Furthermore, the sampling frequency has an important influ- ence on the instantaneous rotation speed measurement of piston motor and higher sampling frequency can lower quantization er- ror and improve measurement accuracy.

A new method for high precsion instantaneous speedmeasurement of hydraulic system

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.