Development of a new simulation model of plain bearing guideway in a fine positioning system based on the displacement to frictional load characteristics of reciprocating motion

在分析和综合精密滑动轴承导轨或滑轨伺服机构时，滑轨摩擦力的解析模型是建立系统仿真模型的关键。史崔贝克曲线曾被作为摩擦分析模型的基本理论。但由于Streibeck曲线是匀速单向运动条件下动摩擦力的稳态特性，基于Streibeck曲线的摩擦力模型并不总是能得到有用的结果，本文提出了一种新的非稳态滑动摩擦力模型。该模型是基于新的实验结果，即瞬态区和稳态区存在的往复滑动运动。对具有高定位精度和高刚度的力控液压定位系统进行了实验研究，得到了位移与摩擦载荷的关系曲线。瞬态区从运动方向反转后开始，范围从反转位置到几百纳米的位移量。该区域的摩擦力由反转前的运动历史和反转后的位移量决定。稳态区的摩擦力与Streibeck曲线上的力相同，根据位移-摩擦载荷特性推导出新的摩擦力模型。利用新的摩擦模型对磨床精定位系统进行了仿真。仿真结果表明，滑块的摩擦力和运动特性与实验结果吻合较好，研究结果对精细进给系统的综合以及摩擦学领域中对滑块摩擦的研究具有一定的参考价值。

In analysis and synthesis of a fine servomechanism with a plain bearing guideway or a slide way the analytical model of friction on a slide way is very critical to construct a productive simulation model of the system. The streibeck curve has been ever adopted as a basic theory for the analytical model of friction. However the model based on the Streibeck curve does not always produce useful results because the curve is steady state characteristics of kinetic friction under the conditions of constant velocity and unidirectional motion.This research presents a new model of friction in unsteady state slide motion. The model is based on new experimental results that both transient region and steady state region exist in reciprocating slide motion. The experiments were executed with the force operated hydraulic positioning system with both the high positioning resolution and high stiffness and the displacement to frictional load characteristics were derived. The transient region starts just after reversing of motional direction and is ranged from reversing position to several hundred nanometer of amount of displacement. The frictional force in the region is decided from both the history of motion until reversing and amount of displacement after reversing. The frictional force in the steady state region is same as the force on Streibeck curve.The new frictional model was derived from the displacement to frictional load characteristics. A fine positioning system of a grinding machine was simulated with the new frictional model. The behaviors of frictional force and motion of the slide derived from the simulation coincided with the experimental test results.The results of this research are useful for synthesis of fine feed system and also the research of friction of a slide way in the field of tribology.