Identifying Friction Model of Hydraulic Cylinder of Excavator Arm
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摘要: 挖掘臂的液压缸摩擦力使系统动态特性恶化,对其进行有效的摩擦补偿是提高控制性能的关键。为获得液压缸的精确摩擦模型,建立了铲斗关节动力学方程,方程中分别采用了库仑摩擦、库仑+黏性摩擦及Stribeck摩擦模型。针对系统中存在的有色噪声,采用了改进的递推最小二乘法辨识未知参数。将辨识的三种摩擦模型进行对比分析表明,Stribeck摩擦模型精度最高,能很好地预测液压缸驱动力。其中,Stribeck摩擦模型的辨识误差比库仑+黏性摩擦及库仑摩擦分别减少约8%与18%。Abstract: The friction force of the hydraulic cylinder of an excavator arm deteriorates its dynamic properties.Therefore, the effective friction compensation for the hydraulic cylinder is important for improving its control per-formance.In order to construct a precise friction model of the hydraulic cylinder, we build the dynamic function for the bucket joint and use in it the coulomb friction, the coulomb-viscous friction and the stribeck friction respective-ly.Due to the colored noise in the hydraulic cylinder, we use the improved recursive least squares method to esti-mate the unknown parameters.The comparison results on the three friction models show that the identified Stribeck model is the most accurate one and that it can effectively predict the actuation force of the hydraulic cylinder.The identification errors of the stribeck model are about 8% and 18% less than those of the coulomb-viscous model and the coulomb model.
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Key words:
- mathematical models /
- least squares approximations /
- functions /
- excavator arm /
- hydraulic cylinder
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