复杂行星齿轮系运动学分析及效率计算

针对现有的行星齿轮系运动学分析和效率估算方法存在计算复杂的问题，提出了一种图形解析法。该方法在齿轮传动结构的基础上对复杂行星齿轮系进行基本单元划分，推导出基本运动单元的普遍角速度和转矩方程以及效率表达式，基于角速度和转矩方程系数的特点，建立角速度和转矩方程的系数矩阵与解析图形数据的对应关系。应用该方法可方便、快速地求解复杂行星齿轮系的运动学参量及效率。     

永磁行星齿轮传动的参数设计与实验研究

为了提高磁齿轮传递转矩,将行星传动设计理念应用于磁齿轮传动机构设计中,对2K-H型永磁行星齿轮传动系统进行了研究,采用等效电流模型法推导了该传动系统的转矩表达式,通过分析设计参数对转矩的影响规律,确定系统设计参数,研制试验样机,设计实验,测试系统传动比、极限转矩及传动效率,测试结果表明,永磁行星齿轮传动样机能够正常运转,传动平稳且传动效率较高,说明转矩表达式的理论推导正确,传动系统的参数选择及结构设计合理。     

封闭行星齿轮传动系统的可靠性研究

通过对封闭行星齿轮传动系统进行运动学及力学分析，结合可靠性设计和Savage等提出的单级行星齿轮传动的可靠度模型，建立了以输入构件转速和转矩为变量的构件负载与寿命关系表达式；基于系统可靠度的乘积定律，建立了典型的封闭行星齿轮传动系统的可靠度模型；结合实例，研究了负载、有效齿宽、功率分配系数等因素对系统及其零件可靠性的影响。研究表明：系统的可靠度随着功率分配系数、负载的增大而减小，随着有效齿宽的减小而减小；合理地配置齿数可使传动系统获得较大的可靠度。     

封闭行星齿轮内部功率流与系统参数的关系研究

将封闭行星齿轮传动系统划分为功率分流输入和功率分流输出两种类型,通过对封闭行星齿轮传动系统的运动学分析,研究了功率分配系数与系统内部功率流的关系,确定了无功率循环的必要条件,建立了功率分配系数与单元传动比的关系表达式,为封闭行星齿轮传动系统的优化设计提供指导.     

多源驱动/传动系统机电耦合建模及同步特性研究

多源驱动/传动系统广泛应用于新能源、航空航天、海洋工程等领域重大装备中,其齿轮传动装置通常由多个电动机共同驱动。针对多源驱动/传动系统在工作过程中存在的多驱动源速度与转矩不同步问题,结合其复杂耦合非线性的结构特点,提出一种以轴系单元法为基础,包含驱动电动机、齿轮传动装置和负载特性的多源驱动/传动系统机电耦合动力学模型。研究了不同载荷变化率以及电动机故障条件下对系统同步特性(速度同步、转矩同步)的影响规律。研究结果表明,载荷变化率对多源驱动/传动系统速度同步特性影响较小;但在载荷突变瞬间对系统转矩同步特性影响较大。电动机发生故障时,非故障电动机间的速度和转矩同步特性基本保持不变。该研究结果将为多源驱动/传动系统同步控制策略的制定提供理论基础。     

误差对3K型行星齿轮系静力学不均载特性研究

建立了3 K型双联齿行星齿轮传动系统静力学模型,运用当量啮合误差原理,计算了载荷不均匀系数,获得不同齿轮偏心误差、安装误差与载荷不均匀系数间的关系曲线,进而分析了不同误差对传动系统均载特性的影响。结果表明:3 K型双联齿行星齿轮传动系统中,不同齿轮的偏心误差、安装误差单独作用时对传动系统不均载特性的影响呈不同周期性变化;齿轮的偏心误差、安装误差越大对传动系统不均载性影响越大;单个行星轮齿厚误差单独作用对传动系统的影响最大。     

基于有限元法的行星传动不均载系数计算

建立了2K-H行星齿轮传动系统的有限元分析模型,并在模型中引入行星轮位置误差。运用有限元接触分析理论,通过有限元分析软件ANSYS计算分析了在一定载荷和不同行星轮位置误差下的行星轮齿的接触应力,进而得出2K-H行星齿轮传动系统的载荷不均系数。为行星传动系统的不均载系数计算提供了一种新的方法,并为进一步研究行星传动系统的均载规律提供参考。     

基于LMS Virtual.Lab Motion的行星齿轮动力学建模及仿真

为获取准确的3K型行星齿轮传动系统轮对啮合力和齿轮传递转矩。基于3K型行星齿轮传动系统拓扑结构分析,建立平移-扭转耦合动力学模型;分析各构件间相对位移关系,确定动力学数学模型。以某3K型行星齿轮传动系统为研究对象在LMS Virtual.Lab Motion平台上进行实例仿真分析;验证平移-扭转耦合动力学模型和仿真方法的合理性;仿真结果为进一步研究系统的疲劳、振动、噪声提供动态输入。     

考虑多轴柔性的人字行星齿轮传动系统动态特性研究

基于有限单元法,建立了一种全自由度人字行星齿轮传动系统动力学模型。模型将时变啮合刚度、综合啮合误差和啮合相位作为动态激励,分析了太阳轮轴柔性和行星轮轴柔性对人字行星齿轮传动系统中内外啮合动态啮合力和动态传递误差的影响。结果表明:轴的柔性变形对人字齿轮行星传动系统的动态特性具有显著影响,考虑轴柔性后,人字齿轮左右两侧斜齿的均载性能得到显著改善,且太阳轮轴柔性比行星轮轴柔性对均载性能的影响明显。     

变风载下2.5MW风力发电机行星齿轮传动系统动力学特性分析

根据2.5 MW风力发电机行星齿轮传动系统在随机风场中复杂变工况的工作特点,利用双参数威布尔分布模型描述随机风速的分布,获得由随机风速引起的时变风载。采用集中参数法建立风力发电机行星齿轮传动系统平移-扭转耦合动力学模型。综合考虑风力发电机行星齿轮传动系统的轴承支撑刚度、齿轮副时变啮合刚度等内部激励对传系统的影响,对变风载下2.5 MW行星齿轮传动系统的动力学特性进行仿真计算分析,求得在外部风载作用下各构件的位移响应与速度响应,为风力发电机行星齿轮传动系统的故障诊断和优化设计奠定了良好的理论基础。     

卡特R型履带车辆差速转向机构之运动与力矩分析

主要目的是针对卡特R型履带车辆差速转向机构的运动与力矩特性进行系统化的分析,以做为履带车辆差速转向机构的设计参考。首先,以图论为基础,定义运动图表示卡特R型履带车辆差速转向机构的运动构造;然后,根据基本回路理论,由运动图推导其系统运动方程式,并由所得的系统运动方程式分析差速转向机构的运动特性;接着,根据力平衡原理、能量守恒原理及基本回路理论,由运动图推导差速转向机构的系统作用力矩方程式,发展履带车辆差速转向机构的力矩分析方法;最后,讨论了履带车辆差速转向机构传动比与力矩关系。本文所得的结果可做为相关产业设计履带车辆差速转向机构之参考。     

基于图论的2K-H型周转轮系效率计算的研究

图论是研究运动链构造学有效的工具。以图论为基础，提出了一种2K—H型周转轮系构造的图表示法，可以有效地表示周转轮系的拓朴与运动构造。根据图表示法和基本回路理论，建立角速度和力矩方程，给出了效率的计算方法，较传统方法直观、简便。同时，提出了用邻接矩阵来表示周转轮系的图，将遗传算法中适应度概念与轮系结构联系起来，为周转轮系的分析和设计提供了理论依据。     

Steady state and transient characteristics of a rubber belt CVT with mechanical actuatiors

In this paper, thrust equations for a rubber belt CVT are derived by considering the geometry and mechanism of the mechanical actuators. In order to solve the thrust equations, an algorithm to calculate the speed ratio is suggested for the given driver speed and load torque based on the actuator characteristic equations and existing formula for the belt thrust forces. Experiments are performed to investigate the driver speed-load torque-speed ratio characteristics at a steady state. The speed and torque efficiencies are measured and used to modify the actuator equations. It is found that the modified equations well predict the steady state characteristics. In addition, the shift dynamic model for a rubber belt CVT is derived experimentally. Simulation results of the CVT shift dynamics are in good accordance with the experiments and it is noted that different coefficients are required to describe the CVT shift dynamics for the upshift and the downshift.     

3K型行星轮系的单元分析法

将3K型行星轮系分解为3个简单的K-H型轮系单元,然后对这些单元进行运动分析和受力分析,列出方程组并求解。这种方法不仅可以求出每个构件的角速度和所受的力矩,整个轮系的功率流向也随之确定,而且还得到一个通用的效率公式。根据功率流向,发现轮系中存在的循环功率流就是这类轮系效率较低、甚至发生自锁的原因。同时,举例证明通过减小循环功率与输出功率的比值可以适当提高这种轮系的啮合效率,从而为这类轮系的改进和设计提出了一种新方法。     

传动比为-1的摆线曲柄槽轮组合机构综合

当槽轮的槽数一定时,普通槽轮机构的运动系数是定值。用摆线生成机构作为槽轮机构的驱动曲柄,相当于一个变长度、变速度、沿着摆线运动的曲柄,从而改变槽轮机构的运动系数。文中提出了按照运动系数进行组合槽轮机构综合的方法,给出了运动系数的最大值和最小值的计算方法,以及中位具有瞬时停歇或者近似匀速的组合槽轮机构参数。     

Automatic separation method for generation of reconfigurable 6R robot dynamics equations

A reconfigurable 6R kinematic robotic model, named the Reconfigurable Puma–Fanuc (RPF) model, was developed by leveraging the similarities between different robotic systems in a unified approach. This model involves properties of all unified robots which allow the robot model to easily change from one configuration to another which produce this model to be reconfigurable. The objective of this study is to automatically generate dynamic equations for the RPF model. For the symbolic calculation of the RPF dynamic equations, the recursive Newton–Euler algorithm is employed using the symbolic algebra package MAPLE 10®. This dynamic model is named the Reconfigurable Puma–Fanuc Dynamic Model (RPFDM). The significance of the RPFDM is that it automatically generates each element of the inertia matrix A, Coriolis torque matrix B, centrifugal torque matrix C, and the gravity torque vector G using newly developed Automatic Separation Method (ASM). The RPFDM model is extended to the RPFDM+ model by coupling the dynamics of the actuator motors. As a numerical example, the dynamic equations for the PUMA 560 robot are obtained and compared to parameters presented in the literature.     

拉锻式摩擦塞焊的热力耦合解析模型和试验验证

为快速得到拉锻式摩擦塞焊的焊接工艺参数，对焊接过程进行预测，建立了摩擦塞焊过程的扭矩、轴向力、功率和能量等指标的力学模型和热力耦合解析模型。模型的输入量为焊接塞棒的几何参数、材料属性、焊接转速和进给速度，输出量为焊接过程的扭矩、轴向力、功率和能量等。在自主设计的拉锻式摩擦塞焊设备上进行了焊接试验。通过将试验数据的输入和输出指标与理论模型值进行对比分析，验证了理论解析模型的可行性。     

Mathematical model and experiment validation of fluid torque by shear stress under influence of fluid temperature in hydro-viscous clutch

The current design of hydro-viscous clutch（HVC） in tracked vehicle fan transmission mainly focuses on high-speed and high power. However, the fluid torque under the influence of fluid temperature can not be predicted accurately by conventional mathematical model or experimental research. In order to validate the fluid torque of HVC by taking the viscosity-temperature characteristic of fluid into account, the test rig is designed. The outlet oil temperature is measured and fitted with different rotation speed, oil film thickness, oil flow rate, and inlet oil temperature. Meanwhile, the film torque can be obtained. Based on Navier-Stokes equations and the continuity equation, the mathematical model of fluid torque is proposed in cylindrical coordinate. Iterative method is employed to solve the equations. The radial and tangential speed distribution, radial pressure distribution and theoretical flow rate are determined and analyzed. The models of equivalent radius and fluid torque of friction pairs are introduced. The experimental and theoretical results indicate that tangential speed distribution is mainly determined by the relative rotating speed between the friction plate and the separator disc. However, the radial speed distribution and pressure distribution are dominated by pressure difference at the lower rotating speed. The oil film fills the clearance and the film torque increases with increasing rotating speed. However, when the speed reaches a certain value, the centrifugal force will play an important role on the fluid distribution. The pressure is negative at the outer radius when inlet flow rate is less than theoretical flow, so the film starts to shrink which decreases the film torque sharply. The theoretical fluid torque has good agreement with the experimental data. This research proposes a new fluid torque mathematical model which may predict the film torque under the influence of temperature more accurately.     

Calculating Jacobian coefficients of primitive constraints with respect to Euler parameters

It is a fundamental problem to calculate Jacobian coefficients of constraint equations in assembly constraint solving because most approaches to solving an assembly constraint system will finally resort to a numerical iterative method that requires the first-order derivatives of the constraint equations. The most-used method of deriving the Jacobian coefficients is to use virtual rotation which is originally presented to derive the equations of motion of constrained mechanical systems. However, when Euler parameters are adopted as the state variables to represent the transformation matrix, using the virtual rotation will yield erroneous formulae of Jacobian coefficients. The reason is that Euler parameters are incompatible with virtual rotation. In this paper, correct formulae of Jacobian coefficients of geometric constraints with respect to Euler parameters are presented in both Cartesian coordinates and relative generalized coordinates. Experimental results show that our proposed formulae make Newton–Raphson iterative method converge faster and more stable.