单侧索驱轮系传动误差建模及同步性预测研究

发布时间：2018-07-20 13:11

【摘要】：单侧索驱轮系是一种以钢索单侧连接通过前轮牵引后轮进行运动传递的装置。钢索与绳轮间的连接方式决定了单侧索驱轮系在进行较大力矩传递时不易产生打滑现象,从而可进行较高运动精度的传递。然而,单侧索驱轮系传动过程中的回转误差不为零,不可避免地会在轮系间产生传动误差,从而影响其传动精度。对接机构锁系是由串联单侧索驱轮系组成的闭环传动装置。锁系运动同步性是航天器对接成功的关键技术之一,其主要靠串联单侧索驱轮系的装配质量来保证。由于在这方面缺少深入的理论研究,致使在对接机构锁系装配中,面临着装配效率低及质量难以保证的技术瓶颈。为此,本文针对串联单侧索驱轮系,从传动误差建模及同步性预测两方面展开研究。钢索形变是影响串联单侧索驱轮系运动同步性的主要因素之一,其主要靠调节钢索预紧力来控制。为预测预紧力作用下的钢索形变,根据串联单侧索驱轮系预紧力施加方式,建立了描述其形变的轮系传动误差预测模型。通过对传动误差主要影响因素及参数敏感度对传动误差控制影响的分析,为进一步开展串联单侧索驱轮系运动同步性的研究奠定基础。建立了单侧索驱轮系工况下的钢索蠕变修正模型。钢索蠕变是索驱轮系精密传动研究中不可回避的一个重要间题。对于运动同步性要求较高的串联单侧索驱轮系,单侧索驱轮系钢索蠕变的累计效应会明显影响传动的精度,严重时甚至导致传动功能的失效。为预测预紧力作用下钢索蠕变,考虑单侧索驱轮系工况条件的影响,基于Norton-Bailey蠕变本构模型建立了钢索蠕变修正模型,并分析了绳轮转角、预紧力和摩擦系数三因素的影响。根据单侧索驱轮系驱动顺序,建立了描述其钢索运动形变的传动误差预测模型,并分析了绳轮包角上钢索滑移和非滑移弧段对建模精度的影响。通过传动误差实验数据的变化规律对上述两弧段对应的包角值进行了界定,进而修正了传动误差预测模型。在此基础上,建立了串联单侧索驱轮系运动同步性预测模型,分析了运动同步性影响因素,并对运动过程中钢索张力变化规律及运动同步性误差补偿进行了研究。开展了串联单侧索驱轮系同步性预测研究。装配中影响串联单侧索驱轮系同步性的因素极其复杂,致使难以建立精确描述钢索张力与形变(传动误差)间关系的数学模型。为此,根据钢索刚性传动条件及装配时预紧力施加方式,提出了对称分配数据法,将单侧索驱轮系传动误差转换成对应的转角值对称分配到串联单侧索驱轮系上增加数据样本,开发了串联单侧索驱轮系同步性预测系统。利用该系统指导锁系现场装配,可提高其装配效率。
[Abstract]:One-side cable-drive gear train is a device which is connected by one side of steel cable through front wheel traction and rear wheel. The connection between the cable and the rope wheel determines that the slip phenomenon is not easy to occur in the transmission of large torque of the one-side cable drive gear train, so that the transmission with higher motion precision can be carried out. However, the rotation error is not zero in the transmission process of one-side cable drive gear train, which will inevitably lead to transmission error between gear trains, thus affecting the transmission accuracy. The locking system of docking mechanism is a closed-loop transmission device composed of series single-side cable-drive gear train. The synchronization of locking motion is one of the key technologies for the successful docking of spacecraft, which is mainly guaranteed by the assembly quality of series single side cable drive gear trains. Due to the lack of deep theoretical research in this field, the locking assembly of docking mechanism is faced with the technical bottleneck of low assembly efficiency and difficult quality assurance. Therefore, in this paper, the transmission error modeling and synchronization prediction are studied for series single side cable drive gear trains. The deformation of steel cable is one of the main factors that influence the synchronism of series single side cable drive gear train, which is mainly controlled by adjusting the pretightening force of steel cable. In order to predict the deformation of steel cable under the action of pretightening force, a prediction model of transmission error of gear train is established according to the mode of pretightening force applied in series single side cable drive gear train. Through the analysis of the main influencing factors of transmission error and the influence of parameter sensitivity on the control of transmission error, this paper lays a foundation for further research on the kinematic synchronicity of single-side cable drive gear trains in series. The creep modification model of steel cable under the condition of single side cable drive gear train is established. The creep of steel cable is an important problem in the research of precise transmission of cable drive gear train. For the series single side cable drive gear train which requires high kinematic synchronicity, the accumulative effect of the cable creep of the single side cable drive gear train will obviously affect the transmission accuracy, and even lead to the failure of the transmission function. In order to predict the creep of steel cable under pretightening force, considering the influence of working conditions of one-side cable drive gear train, a modified model of cable creep is established based on Norton-Bailey creep constitutive model, and the effects of three factors, such as rotation angle of rope wheel, pretightening force and friction coefficient, are analyzed. According to the driving sequence of one-side cable drive gear train, a transmission error prediction model is established to describe the deformation of cable movement, and the influence of cable slip and non-slip arc on the modeling accuracy is analyzed. The envelope angle value corresponding to the above two arcs is defined by the changing law of the experimental data of transmission error, and the prediction model of transmission error is modified. On this basis, the prediction model of kinematic synchronicity of series single-side cable flooding gear train is established, and the influencing factors of motion synchronism are analyzed, and the variation law of cable tension and the compensation of synchronous error during the process of motion are studied. Research on synchronism prediction of series single side cable flooding gear train is carried out. The factors that affect the synchronicity of series single side cable drive gear trains in series are very complicated, which makes it difficult to establish a mathematical model to accurately describe the relationship between cable tension and deformation (transmission error). For this reason, according to the rigid transmission condition of steel cable and the way of pretightening force applied in assembly, a symmetrical distribution data method is put forward, in which the transmission error of single side cable drive gear train is converted into the corresponding rotation angle value symmetry distribution to add data sample to the series single side cable drive gear train. A series single side cable drive gear train synchronization prediction system is developed. The system can be used to guide lock-system assembly in situ, and its assembly efficiency can be improved.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TH132

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