液压助力转向器疲劳试验机液压系统建模与分析

Hydraulic system modeling and analysis of HPS fatigue testing machine

对液压助力转向器(HPS)疲劳试验机液压马达位置控制建立数学模型,进行模型分析,并根据伺服放大器、伺服阀及液压马达的相关参数确定系统开环传递函数,然后对其进行时频域分析。通过分析,系统虽然存在较大的稳态误差,还需要进行其他比例-积分-微分(PID)控制策略等加以校正以改善系统的控制性能,但是稳定时间较长,稳定性大大提高,达到试验台20 Hz的测控稳定性要求。

By building mathematical model and analyzing the position control of hydraulic motor in HPS fatigue testing machine, the open-loop transfer function is determined based on the parame- ters of the servo amplifier, servo valve and hydraulic motor. The frequency domain and time domain of the system were analyzed. Through analysis, it has been found that the stability of the system has greatly improved and will last for a long time, although there is a bit error, and other strategies such as PID control is needed to im- prove the control performance. Generally speaking, the stability can satisfy the 20 Hz testing requirement.