零位死区的谐波线性化及其对系统性能的影响

Harmonic Linearization of Null Dead-zone and Its Influence to System Performance

理论建模时比例方向阀零位死区常被忽略,而工程应用中常采用零位补偿法,这两种处理方法都忽略了零位死区本身的非线性特性及其对系统性能的影响。为此,提出了谐波线性化方法线性化零位死区,给出了线性化基波分量,推导了零位死区的描述函数,建立了考虑零位死区特性的系统数学模型,仿真分析了零位死区对自振幅值和自振频率、峰值时间及控制精度等系统性能的影响。仿真和试验结果表明,零位死区对自振频率和动态精度影响较大,对自振幅值、峰值时间和稳态精度的影响相对较小,同时也验证了该方法的有效性和考虑零位死区系统建模的正确性。

The null dead-zone of proportional directional valve was often ignored in modeling process,and the null compensation method was usually applied in valve engineering application.Actually this two methods neglected nonlinear characteristics of null dead-zone itself and its influence to system performance.To resolve the problem,the null dead-zone was linearized in this paper by applying harmonic linearization method,so the element of fundamental wave was established,the description function was obtained that could show characteristics of null dead-zone,and the mathematical model of proportional directional valve system was established on the basis of considering null dead zone.The influences of null dead-zone to some system performances were simulated and analyzed,including vibration amplitude and frequency,the peak time and control accuracy etc.The simulation and experimental results show that the null dead-zone has greater effect on vibration frequency and dynamic accuracy,less effect on vibration amplitude,the peak time and static accuracy;the modeling method considering null dead zone in this paper is effective and feasible.