摘要
针对摩擦力给气动比例系统带来的稳态误差和低速爬行问题,从实用角度来探索解决非线性摩擦力补偿的方法。基于粘弹性理论及Stribeck模型建立气动比例系统的摩擦数学模型。将该摩擦模型引入阀控缸系统的动态模型中,建立完整的系统运动模型。将高频低幅颤振信号叠加于系统中,对系统的摩擦机理变化以及稳定性的影响进行分析。理论分析表明,叠加合适的颤振信号后,系统的部分静摩擦力转化为动摩擦力,最大静摩擦力减小,响应速度提高,从而将系统的粘滑运动转换为一种平稳运动。试验发现,当颤振信号频率为系统固有频率的3.3倍,系统的定位精度由原来的0.516mm提高到0.284mm,滞后时间由原来的0.17s缩短为0.02s。证明对气动比例系统提出的摩擦颤振补偿理论是正确的。
In order to overcome steady-state error and low-speed creeping problems caused by friction in pneumatic proportional systems, nonlinear friction force compensation method is adopted. A Friction model of the pneumatic proportional system is constructed on the basis of viscoelastic theory and Stribeek model. Incorporating the friction model in dynamical model of valve-controlled cylinder system constructs a complete system motion model. The high-frequency low-amplitude chatter signal is introduced into the system to analyze its influence on the system friction mechanism and stability. The results show that a part of static friction is turned into dynamic friction, the maximum static friction is reduced and the response speed is raised. Consequently, the stick-slip motion is transformed into a steady one by adding proper chatter signal. The experimental results show that the positioning precision is improved from 0.516 mm to 0.284 ram, and the hysteresis time is shorten from 0.17 s to 0.02 s when the chatter frequency is 3.3times of the natural one. The results prove that the friction chatter-compensation theory proposed for the pneumatic proportional system is correct.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2010年第5期68-73,共6页
Journal of Mechanical Engineering
基金
国家高技术研究发展计划资助项目(863计划
2008AA04Z130)
