【作者】 李响；

【导师】 赵阳；

【作者基本信息】 哈尔滨工业大学 ， 航空宇航科学与技术， 2018， 博士

【摘要】 围绕我国航天技术的国家重大需求,空间站大型机械臂、卫星天线等航天机构的应用日益广泛,且执行空间任务的复杂度越来越高,对这类机构的精度、稳定性、可靠性等要求也越来越高。传动关节作为其核心部件,主要完成机械连接、动力传递等工作,对空间机械臂的位置精度、卫星天线的指向精度等具有直接影响。本文针对行星轮系传动系统中存在的多间隙现象,刚柔耦合现象,建立多种动力学模型并进行数值仿真,主要研究工作如下:聚焦于课题研究的意义及相关背景,分析了相关研究的发展状况和优缺点,提出了本文的研究方向及重点。此外,航天机构的动力学研究有助于提高航天机构的设计及分析水平,延缓航天机构的磨损,延长其使用寿命,同时对其他大型机构的研制具有指导借鉴意义。针对行星轮系传动系统中多使用斜齿轮作为传动元件的应用现状,建立斜齿轮传动的弯-扭-轴耦合6自由度动力学模型。考虑斜齿轮传动中的齿侧间隙,时变啮合刚度和啮合阻尼等因素,推导齿轮啮合刚度及间隙函数方程。为分析轮齿修缘对齿轮啮合传动的影响,建立轮齿修缘模型,并用不同曲线分析修缘曲线方程,代入原斜齿轮传动动力学模型,得到系统综合考虑轮齿修缘的5自由度动力学方程。数值仿真结果表明外部激励,齿侧间隙等因素对齿轮传动的振动影响较大,合理的轮齿修缘曲线能够有效减小系统振幅。在此基础上,分析含有多组斜齿轮副传动的行星轮系关节,建立考虑多间隙因素的行星齿轮传动系统动力学模型及柔性臂杆动力学模型,利用拉格朗日乘子法建立含行星轮系关节及柔性臂杆的系统动力学方程。数值仿真中,通过对多间隙模型及刚柔耦合模型的对比,发现柔性臂杆与关节内部多间隙的耦合作用致使传动系统振动剧烈,但也加快了碰撞的衰减,因此,刚柔耦合动力学模型更符合实际工作情况。在刚柔耦合动力学的基础上,改变转速、间隙等参数大小,分析不同因素对系统动力学特性影响。结果表明较高转速时运动偏差波动次数衰减较快但启动时刻的冲击与碰撞程度较大,同时得到了维持系统最佳工作状态时各间隙大小的合理取值。此外,以2K-H行星齿轮传动系统为研究对象,建立平移-扭转耦合模型,将星载天线视为包含卫星本体、行星轮系关节,机械臂杆,天线反射面的多体系统,建立星载天线多体模型。重点分析双行星轮系关节情况下齿轮侧隙、啮合误差、摩擦力、耦合误差、空间温度等非线性因素对天线指向精度的影响。数值仿真结果表明,合适的齿侧间隙能够避免齿轮啮合过程中的卡齿现象,也能保持较高的传动精度,选用泊松比较大的齿轮材料能够减弱齿轮啮合误差造成的影响,在低速、匀速、低摩擦的情况下更易于保持天线的平稳。但由于双行星轮系关节的耦合作用,更容易引起天线指向精度偏差的波动。更多还原

【Abstract】 With the important national demand of China’s space technology,the application of the aerospace institutions such as space station large-scale robotic arm and satellite antenna is becoming more and more extensive,and the complexity of performing space tasks as well as the accuracy requirement of the stability and reliability of such institutions is increasing.As the core part of them,the transmission joint mainly completes the mechanical connection,power transmission and other works,and has a direct impact on the position accuracy of the space robotic arm and the satellite antenna pointing accuracy.In this paper,in response to the multi-gap phenomenon and rigid-flexible coupling phenomenon in the planetary gear train system,a variety of dynamic models are established and numerical simulation is performed.The main research work is as follows:Firstly,the significance and related backgrounds of the research are expounded,the development status,advantages and disadvantages of the related research are analyzed,and the research direction and key points of this paper are put forward.The study of the dynamics of the aerospace mechanism will help to improve the design and analysis level of the aerospace institutions,delay the wear of the aerospace institutions,prolong the service life,and provide reference for the development of other large-scale institutions.Secondly,as the helical gear is widely used as transmission part in the planetary gear train system,a six-degree-of-freedom bending-torsion-axis coupling dynamic model is established for the helical gear.Considering the tooth side clearance,time varying meshing stiffness and meshing damping in the helical gear transmission,the gear meshing stiffness and the gap function equation are deduced.In order to analyze the influence of the tooth profile modification on the gear meshing transmission,the tooth profile modification model is established,and the modification curve equation is analyzed by different curves.The results are substituted into the dynamic model of the original helical gear transmission,and a five-degree-of-freedom dynamic equation systematically considering tooth profile modification is obtained.The numerical simulation results show that the external stimulation,the tooth side gap and other factors have great influence on the vibration of the gear transmission,and the reasonable tooth profile curve can effectively reduce the system amplitude.Thirdly,a planetary gear train joint with multiple sets of helical gears is analyzed,and the dynamic models of the planetary gear transmission system and the flexible arm considering multi-gap factors are established.The Lagrangian multiplier method is used to establish the systematical dynamic equations involving the planetary gear train joint and the flexible arm.In the numerical simulation,through the comparison of the multi-gap model and the rigid-flexible coupling model,it is found that the coupling of the flexible arm and the multi-gap inside the joint causes the vibration of the transmission system to be violent,but also accelerates the attenuation of the collision.The rigid-flexible coupling dynamic model conforms more to the actual working condition.On the basis of the rigid-flexible coupling dynamics,the size of parameters such as the rotational speed,the inertia load and the gap are changed to analyze the influence of different factors on the dynamic characteristics of the system.The results show that at higher speeds the number of the motion deviation fluctuations decreases rapidly but the degree of impact and collision at the start-up is high.Also,the reasonable value of the gap size to maintain the optimal working condition of the system is obtained.Finally,the 2K-H planetary gear transmission system used as the research object,the translation-torsion coupling model is established.The satellite antenna is regarded as a multi-body system including satellite body,planetary gear train joint,mechanical arm and antenna reflection surface.The satellite antenna multi-body model is built up.The influence of nonlinear factors such as gear backlash,meshing error,friction force,coupling error and heat effect on the pointing accuracy of the antenna is analyzed emphatically in the case of a double planetary gear joint.The numerical simulation results show that the suitable tooth side clearance can avoid the latches phenomenon during gear meshing and maintain high transmission precision.The choice of gear material of larger Poisson ratio can reduce the influence of gear meshing error and make it easier to keep the antenna steady in the case of low speed,uniform speed and low friction.And due to the coupling effect of the double planetary gear joint,it is more likely to cause the fluctuation of the antenna pointing accuracy deviation.更多还原