考虑磨损后含间隙指向机构运动特性

为了提高空间指向机构磨损寿命的预测精度，克服传统静态磨损寿命预测的缺陷，计及间隙、摩擦磨损耦合因素，以实现机构关节动态磨损的精确预测，并对综合考虑间隙、摩擦磨损等因素的空间二维指向机构动力学问题和磨损问题进行了研究。采用牛顿 欧拉法，将间隙变量嵌入动力学模型，构建含间隙二维指向机构的动力学模型。基于Archards磨损模型，找到运动副接触面不同位置处的磨损深度，重构运动副表面形貌，并对磨损前后含间隙指向机构的动态特性进行分析，得到了关节处接触碰撞力和切向摩擦力的变化规律；采用动态拟合变量法和离散处理法分别对含间隙运动副内部间隙与接触力间、运行时间与相对滑移速度间的对应关系进行拟合，并建立了动态磨损数学模型；进一步预测了二维指向机构在跟踪模式、调姿模式下的运行时间分别为1259192h、76444h。研究工作为二维指向机构的本体设计、制造与应用奠定基础。

Motion characteristics of pointing mechanism with clearance in consideration of wear

For the accurate prediction of the joint dynamicwear, the coupling factors of clearance, friction and abrasion were considered.The dynamic problems and abrasion problems of the two dimensional space pointing mechanism werestudied, which considered the factors of clearance, friction and abrasion. Usingthe Newton Euler’s law, the dynamic model of the two dimensional space pointing mechanism withclearance was constructed by embedding the clearance variables. Based on the Archardswear model, by finding the wear depth at different positions of the moving contactsurface and reconstructing the surface morphology of the kinematic pair, the dynamiccharacteristics of the pointing mechanism with clearance were analyzed in the processof wear, and the change laws of the contact collision force and the tangent frictionforce at the joints were obtained; the dynamic fitting variables method and thediscrete processing method were used to fit the correspondences between the clearanceand contact force, and the running time and the relative slip velocity of the kinematicpair with clearance, and the dynamic wearmathematical model was established; furthermore, the predicted service lives ofthe two dimensional pointing mechanism are 12591.92 hours and 764.44 hours underthe tracking mode and the attitude adjustment mode. The work in this thesis providedthe theoretical base for the ontology design, manufacture and application of thetwo dimensional pointing mechanism.