运动副

• In this thesis , by means of the lagrange function , the finite element dynamic equations of the beam element are deduced . then all the element dynamic equations are assembled into the system dynamic equation through using the kineto - elastodynamics theory . the dissipation force derived from joint damping is applied as excitation force of the linkage system
  本文的主要内容如下：以平面弹性四连杆机构为研究对象，运用ked ( kineto - elastodynamics )方法推导出了连杆机构的系统动力学方程；在此基础上，将运动副阻尼等效为粘性阻尼，导出了包含运动副等效粘性阻尼系数的系统动力学方程。
• With different clearance value , displacement curves and velocity curves of generalized coordinates as well as slider displacement error curves in a motion period are obtained . these curves are discussed . results show that if manufacturing cost is kept invariableness , in order to improve precision of mould - cuting , fitting precision of joint connecting the crank and coupler has priority to be considered to increase
  采用四阶rong - kuta法求解连续接触模型的动力学方程，得到了一个运动周期内运动副间隙取不同值时，各广义坐标的位移、速度曲线和滑块位移误差曲线，并通过曲线分析，得出了要提高模切机主切机构精度，在相同加工成本条件下，应优先考虑提高曲柄与连杆铰接处的配合精度的结论。
• Considering joint clearances at both ends of the coupler , a continuous contact model is developed by modeling clearance as a massless rigid link . a set of strongly nonlinear equations is obtained by using angle displacement of clearances in kinematic pairs as generalized coordinates . four order rong - kutta method is adopted to solve the dynamical equations of continuous contact model
  考虑曲柄与连杆、连杆与滑块之间运动副间隙，将运动副间隙看成是一无质量的理想杆，利用连续接触模型进行建模，采用运动副间隙角作为广义坐标，得出一组强非线性方程组。
• The establishment of experimental platform and researches on controlled system will provide experimental grounds for the precise realization of any given motion by controlled five - bar mechanism . it also provides basis for adjustment of compensation movement , when further consideration in rod processing errors , elastic deformation and the intervals between kinematics pair
  此实验台的建立及控制系统的研究为受控五杆机构精确实现给定运动和轨迹提了供实验依据,也为下一步考虑杆件加工误差、弹性变形以及运动副之间的间隙时补偿运动的调整提供依据。
• Comparing the fitted expression with the established theory expression of the angular velocity , the equivalent viscous damping coefficient is gained . the closed form algorithm of the state space method is employed to solve the system dynamic equation with time - varying coefficients . the dynamic problem of a linkage mechanism with four joints is taken as example to show that the presented models and methods are correct and practicable
  引入求解线性微分方程的状态空间法，并对其求解时变系统运动微分方程的具体步骤进行了推导；在此基础上将实测获得的运动副等效粘性阻尼系数代入系统动力学方程，求解后获得了考虑运动副阻尼的平面弹性四连杆机构的仿真结果；结果表明运动副的阻尼在一定程度上对振动具有抑制作用。
• On this base , mechanism / pro module is been utilized in the paper , which links adams software with pro / e software . establish simulating model of large extensible satellite ' s antenna , include cad three - dimensional modeling and appending constraints along with movement - set by practice space link , at the same time make correlative enactment and explanation , which needed in the study of simulation
  在此基础上，研究中采用adams软件与pro e软件的接口模块? mechanism pro模块，在pro e软件环境下，建立了大型可展开卫星天线的仿真模型，工作内容包括cad三维实体建模以及根据卫星天线的实际空间连接情况添加约束和运动副，同时对仿真研究中所需要的参数作了相关的设定和说明。
• The analysis of precision about mould - cut main mechanism with clearances is advanced . on the basis of analysis of slider displacement error influenced by the crank length tolerance , the coupler length tolerance and clearances in revolute joints for mould - cut main mechanism , some reasonable suggestions about tolerance distribution of bars length and fitting precision of joints are put forward
  考虑运动副间隙对主切机构进行了精度分析，通过分析主切机构中各杆长误差和运动副间隙对滑块位移误差的影响，对商标模切机设计初期杆长误差分配和运动副间隙配合精度提出了合理的建议。
• Nevertheless , the widely existed overconstraints in the mechanisms will make the quality of the mechanisms very sensitive to the inevitable manufacturing , assembly errors ( especially , the errors resulted from the shape and position between kinematic pair elements and their axes ) . at the same time , because the internal and external uncertain factors such as non - plane characteristic of dynamic parameters of links ( such as mass distribution , inertia forces , etc . ) , bending and twist of links , and the changes of environment and operating condition are inevitable , they will form the disturbance to planar constraints and make them possess the characteristic of " uncertain "
  但是，平面连杆机构中广泛存在的过约束，造成机构对制造、安装误差特别是运动副元素的形位误差十分敏感；同时，由于不可避免的内部和外部不确定因素的影响，常常会造成机构运动的“障碍”及系统中某些构件的变形和运动副中的附加动载荷，引起机械的振动、冲击、噪声等而导致机械的效率和工作性能的降低。