气浮无摩擦气缸及气浮特性仿真

为了满足气动系统中高精度伺服控制对低摩擦气缸的需求，提出一种利用静压气体轴承作为活塞的新型无摩擦气缸. 针对轴承耗气量及径向承载能力难以准确建模的问题，构建一种基于有限元数值求解方法的轴承气膜压力计算方法. 利用该方法，分析轴承的结构参数及时变的环境参数对轴承气浮特性的影响.结果表明,在节流孔末端引入均压腔能够显著增加了轴承的径向承载能力,消除气膜中节流孔附近的压力尖峰,使轴承稳定性增强；供气压力、径向载荷和偏心率等时变参数对气浮特性的综合影响增加了简化活塞泄漏模型的困难. 为了后续对气缸进行控制,根据气浮特性仿真结果,提出一种基于特定径向负载假设下的泄漏量模型简化方法.

Non-friction pneumatic cylinder and simulation of the flotation characteristics of the bearing

A new non-friction pneumatic cylinder with an aerostatic bearing as its piston was proposed to satisfy the demand of low-friction cylinder in high-precision pneumatic servo systems. The working characteristics of the bearing(WCOB), radial load carrying capacity(RLCC) and air consumption, are difficult to be modeled accurately. In view of this, the mathematical model of the pressure distribution of the air film was established, a numerical solution method of this model based on finite element method(FEM) was constructed, the influence of the bearing's structural parameters and time-varying parameters to the working characteristics of the bearing were studied. The simulation results show that introducing a recess chamber to the end of the orifice hole can increase the RLCC significantly and smooth the pressure distribution around the orifice in the air film, as a result of which the bearing will work more stable; the time-varying parameters, such as supplying pressure, radial load acting on the bearing and eccentricity of the piston, make a combined effect on the WCOB, which bring more difficulties to the model simplification. In view of this, a solution based on the assumption that the radial load acting on the piston lies between some particular working points was proposed in this paper to simplify the modeling of the leakage