空间Bennett机构运动分析的几何投影法

基于画法几何投影坐标系统的方法研究了空间Bennett机构的运动分析,从几何角度出发,将空间连杆机构的空间问题转化成平面问题,使问题求解变得简单。给出了投影坐标系统建立原则,并建立Bennett运动分析模型,用Matlab绘制了输出构件的角位移、角速度、角加速度图。通过与用D-H坐标变换方法相比,该分析方法显得更简单和直观。最后以具体实例进行了分析,验证了该方法的有效性。     

三坐标测量机非刚性效应测量误差分布特征

本文采用坐标运动链系统分析法,研究三坐标测量机组成构件和运动副的各项基本误差与整机综合坐标测量误差间的关系,导出考虑构件和运动副非刚性效应的综合坐标测量误差数学表达式,并以移动桥式和固定桥式两种典型结构的三坐标测量机为例,进一步分析了非刚性效应坐标测量误差的空间分布特征,得出对三坐标测量机的综合非刚性效应坐标测量误差建模补偿有指导意义的新结论。     

增量式编码器的相位编码细分研究

在球坐标激光跟踪测量系统中采用球坐标法可将空间运动物体的三维坐标求出。增量式编码器的精度对于整个测量系统的精度而言，占主导作用。本论文对输出信号为正弦信号的增量式编码器提出一种细分方法一相位编码细分方法，从原理上进行了深入的分析，并设计了硬件电路。与其他方法相比，该方法具有细分数高且任意可调的特点。     

基于多维摄像系统的人体上肢动态测量

由三架或三架以上普通摄像机、运动学分析软件APAS以及标定框架等构成多维摄像系统。在建立上肢运动模型的基础上,对附着体表的人工标记点的运动进行跟踪测量,利用运动学分析软件APAS分析得到标记点的空间运动坐标,通过设计优化算法程序获得人体上肢的空间运动参数。     

修正的Craig-Bampton方法在多体系统动力学建模中的应用

针对空间实验室、柔性机械臂等柔性多体系统，借助结构动力学中的Craig-Bampton模态综合方法，对其进行修改并用于描述弹性变形，将模态综合方法和多体系统建模常用的混合坐标法相结合，以适合刚体运动与弹性运动的耦合，更好地反映了系统的动力学特性。结合ADAMS、ANSYS软件，可充分利用该方法对柔性多体系统进行计算机仿真分析，进而进行优化设计等。     

漂浮基空间机器人双臂协调操作逆运动学的完全笛卡尔坐标方法

运用完全笛卡尔坐标方法讨论了漂浮基双臂空间机器人系统的逆运动学问题。为此 ,以系统的完全笛卡尔坐标做为系统广义坐标 ,对双臂空间机器人捕捉目标物体时的运动学关系做了分析 ,并结合系统的动量和动量矩守恒关系 ,给出了自由漂浮状态下以笛卡尔坐标表示的双臂空间机器人闭合系统的运动 Jacobi关系。以此为基础 ,讨论了空间机器人双臂协调操作的分解运动速度控制方法。提出的方法不涉及三角函数运算 ,仅涉及简单的加、减、乘、除四则运算 ,计算效率较高 ,有助于缓解空间机器人系统机载计算机计算能力有限的矛盾。仿真运算证实了方法的有效性。     

柔性空间机械臂系统的双环积分滑模控制

讨论了载体位置不受控、姿态受控的情况下,漂浮基柔性空间机械臂关节运动及柔性振动主动抑制的控制问题。由系统动量守恒关系及假设模态法,利用拉格朗日方法建立了柔性空间机械臂的系统动力学方程,之后采用奇异摄动理论,将其分解为表示刚性运动的慢变子系统和柔性振动的快变子系统。以此为基础,针对慢变子系统———柔性空间机械臂的刚性运动,设计了系统参数未知情况下的双环积分滑模控制方案,以控制柔性空间机械臂的载体姿态及机械臂关节铰协调地完成各自在关节空间的期望运动;而对于快变子系统———柔性臂的振动,则设计了分级模糊控制方案来主动抑制柔性杆的振动。计算机数值仿真证实了该方法的可靠性和有效性。     

距离法运动目标激光跟踪测量系统的研究

运动目标空间位置坐标激光跟踪测量是计量测试领域的前沿课题。该测量系统集激光干涉测距、光电检测、精密机械、计算机及控制系统和现代数值计算于一体 ,对空间运动目标进行跟踪并实时测量其坐标和姿态。采用多个激光干涉仪进行冗余设计 ,仅通过测量距离的变化量而不需要测量角度量 ,就可以通过解最小二乘方程组计算出被测点的坐标。文中论述了纯距离法跟踪测量的数学模型、系统的光路设计以及基于 PID控制方法的跟踪控制系统 ,并完成了平面内运动物体的跟踪及测量可行性实验     

空间并联机构运动分析的有限元法

用有限元法的思想,对组成空间机构的梁和铰单元引人欧拉参数进行了描述,用传递函数的概念对机构各相关坐标及单元变形模态坐标的位置、速度和加速度进行了分析,在此基础上,编制了计算机程序ＣＡＡＭ,对三自由度－ＲＰＳ空间并联机机构的运动进行了分析,给出了平台中心点运动的数值模拟结果。     

基于空间网格的三维激光球杆仪系统误差标定

三维激光球杆仪是一种空间坐标测量设备,由二维转台和径向伸缩机构组成。伸缩机构的末端固定有一个由测量目标磁吸并带动设备运动的标准球。伸缩机构的位移由光栅尺测量,二维转台的旋转角度由圆光栅测量,测量系统测得的坐标经坐标转换后可以得出被测目标的坐标。分析了系统的主要误差来源,采用多体系统误差建模方法建立了误差模型。最后基于几何误差模型非线性优化对设备的单项误差进行标定。经过误差补偿后,设备在测量范围内测量空间点的位置误差可以达到0.06 mm以内。     

Constraint embedding in kinematics and dynamics of hybrid manipulator systems

An approach to kinematics and dynamics based on kinematic influence coefficient matrices is proposed for applications to the analysis and control of motion controlled multibody systems, e.g., hybrid robotic manipulator systems. The scheme is unique in a sense that all the kinematic constraints are completely embedded into the formulations at the kinematics level and equation of motion of the system is obtained in a closed form with respect to the minimal set of independent joint coordinates. Furthermore, all kinematic and dynamic formulations are expressed compactly in the same format by using two special algebraic operators. This isomorphic formalism allows systematic transformations of kinematic and dynamic informations between different sets of coordinates in a purely algebraic way.     

Kinematic Accuracy of Manipulators in Industrial Systems

A method is proposed for determining the kinematic error in relative manipulation systems when translation and rotation with respect to Cartesian coordinate axes are added. The method is based on differentiation of the coordinates of a specific point within one module in the mobile coordinate system of another module. The differentials of the variable coordinates are approximately replaced by finite increments. The kinematic errors are determined for systems with two or three degrees of freedom.     

Dynamic modelling of planar mechanisms using point coordinates

In the present study, the dynamic modelling of planar mechanisms that consist of a system of rigid bodies is carried out using point coordiantes. The system of rigid bodies is replaced by a dynamically equivalent constrained system of particles. Then for the resulting equivalent system of particles, the concepts of linear and angular momentums are used to generate the equations of motion without either introducing any rotational coordinates or distributing the external forces and force couples over the particles. For the open loop case, the equations of motion are generated recursively along the open chains. For the closed loop case, the system is transformed to open loops by cutting suitable kinematic joints with the addition of cut-joints kinematic constraints. An example of a multi-branch closed-loop system is chosen to demonstrate the generality and simplicity of the proposed method.     

新型三自由度并联机器人奇异位形研究

针对一种新构型的3-RRRT并联机器人奇异位形进行了研究,提出了一种建立运动学模型与研究奇异位形的方法,利用并联机器人支链中支杆的方向余弦和动平台绝对位置坐标为系统广义坐标的方法,推导了机构运动学模型和计算奇异位形的条件方程,在此基础上,提出运用浮点遗传算法和拟牛顿法相结合的混合遗传算法在MATLAB上编制奇异位形仿真程序,得到3-RRRT并机器人奇异位形分布情况,此结论对3-RRRT并联机构的运动控制及轨迹规划有重要意义.     

3D geometric constraint solving using the method of kinematic analysis

In this paper, an approach based on kinematic method for solving 3D geometric assembly constraints is presented. The relative generalized coordinates and generalized recursive formulations used in kinematic analysis are utilized to reduce the size of constraint equations. Based on the cut-constraint method, this approach can be used to solve all kinds of configurations. In the case of an open-loop constraint system, the geometric constraints can be satisfied by sequentially determining the values of relative generalized coordinates. With respect to a closed-loop constraint system, the proposed approach converts it to a spanning tree structure by cutting constraints and introducing cut-constraint equations. Furthermore, a topological analysis method is also developed to obtain the spanning tree with the minimal number of cut-constraint equations, and the analytical Jacobian matrix of cut-constraint equations is derived to enhance computational efficiency. In the end, the proposed approach is demonstrated and validated using two examples of closed-loop geometric constraint system.     

The simulation of elastic mechanisms using kinematic constraints and Lagrange multipliersLa simulation de mecanismes elastiques par emploi de contraintes cinematiques et multiplicateurs de lagrange

In the Lagrange multiplier method, the motion of each element is represented in terms of its own rigid-body and flexible body generalized coordinates. The elements are treated as uncoupled from each other except for the application of interaction forces (the Lagrange multipliers) which enforce constraint conditions between the elements. Rather than eliminating the multipliers and obtaining coupled system coordinates, the values of the Lagrange multipliers are solved in time as part of a numerical technique. The multipliers are applied in turn to the individual elements and the simulation proceeds to the next point in time using numerical integration.The method of solution is applied to an illustrative example, a slider-crank mechanism. Modeling considerations and appropriate kinematic constraints are discussed. The author hopes to present numerical results for this example at the conference.     

A recursive algorithm for generating the equations of motion of spatial mechanical systems with application to the five-point suspension

In this paper, a recursive formulation for generating the equations of motion of spatial mechanical systems is presented. The rigid bodies are replaced by a dynamically equivalent constrained system of particles which avoids introducing any rotational coordinates. For the open-chain system, the equations of motion are generated recursively along the serial chains using the concepts of linear and angular momenta. Closed-chain systems are transformed to open-chain systems by cutting suitable kinematic joints and introducing cut-joint constraints. The formulation is used to carry out the dynamic analysis of multi-link five-point suspension. The results of the simulation demonstrate the generality and simplicity of the proposed dynamic formulation.     

Die verwendung des matrizenkalküls in geometrie und kinematik von mechanismen mit gelenken höherer ordnungThe matrix kinematic analysis of mechanisms with a higher pair

In this paper a family of simple mechanisms having kinematic pairs of second class has been presented. For kinematic pairs of the second class (cam mechanisms) the radius and the coordinates of curvature have been described. The matrix method for calculation of the motion for cam mechanism with one kinematic pair of second class has been presented. An example application is also presented.     

机械系统动力刚化机理分析

采用计及变形约束的非线性运动学分析方法及传统分析方法建立简单柔性机械臂线性化的动力学方程。笔者认为：运动的柔性机械构件春变形运动的耦合产生动力刚化，传统分析方法失去了刚体运动与弹性振耦合的动力刚化项；如果在建立运动学方程时，计及运动学的非线性项，至少要计及振动坐标的二阶小量，将非线性保留到适当阶段，再线性化，熊猫是到一致化性化的动力学方程，这种方法适合于机械系统件的小变形问题，对动力刚化的研究实际     

机械运动方案知识库的对偶矢量表达及型综合

简要介绍了机械运动系统方案设计知识库的结构和螺旋理论及对偶矢量表达。提出了知识库基本元素的对偶矢量建模方法。通过输入运动旋量和输出运动旋量表达机构的运动行为要求和设计需求。在运动方案的型综合中，需要进行两项工作：一是将各备选机构坐标转换为机器的通用坐标；二是将各备选机构的轴线首末端空间方位按组合的先后顺序对齐。为此给出了基于对偶矢量表示的坐标变换和线性变换公式。最后列举了一个实例验证螺旋理论在概念设计中的可行性和意义。