一种改进型三平移并联机构的工作空间与运动灵活性分析

根据Delta机构的结构,设计提出了一种改进型三平移并联机构。在位置逆解的基础上,讨论了机构输入与输出速度关系的逆雅可比,并进一步对该并联机构作业空间的几何性质、机构的运动灵活性进行了分析,给出了几何参数变化对机构作业空间及运动灵活性的影响规律。分析表明,该机构具有几何形状规则的作业空间及较好的运动灵活性,是一种较为理想的实现三维移动的并联机构机型。     

纯转动型3-UPU并联机构工作空间分析

详细讨论了纯转动型3-UPU并联机构的工作空间。文中首先分析了3-UPU并联机构的纯转动运动的条件;然后用动平台的法向量、绕该向量转动的角度和连杆长度来直观地定义并联机构的工作空间,并分析了该定义该机构运动的几何和非几何约束条件,最后提出了纯转动3-UPU并联机构的工作空间搜寻算法,并利用M app le软件验证了该算法的有效性。本文研究的内容对3-UPU并联机构的可行性和优化设计有一定的作用。     

新型六自由度混联机床机构设计及位置逆解研究

提出了一种以新型三自由度并联机构3-PRP作为定位模块,串联上三自由并联机构3-RPS来共同实现六自由度运动的新型混联机床的机构设计方案。首先,运用螺旋理论中运动和约束的关系分析了该机床实现3T3R运动原理,计算出该机构的自由度,进行了输入选取;然后,利用解析矢量法及几何关系建立机构位置逆解方程;最后,应用MATLAB对逆解方程进行求解并利用ADAMS对求解结果进行仿真验证,验证了逆解模型的正确性及机构的可行性。     

微型3-PSP并联机构的工作空间及运动学分析

为满足在有限空间内实现对激光光束角度快速调节的需求,提出一种微型3-PSP空间并联机构,其中静平台的直径为Φ50 mm,机构整体高度范围为74 mm~80 mm;应用封闭环矢量法,建立并联机构运动学模型,得到机构运动学逆解;根据并联机构结构的几何特性求解运动学正解;在运动学逆解的基础上,结合驱动杆行程及机构结构参数,利用数值搜索法分析该机构的工作空间,并在Matlab中建立数学模型,绘制其可达工作空间点集;最后利用Solid Works及Adams协同仿真,对3-PSP并联机构进行正运动学仿真,证明机构能够实现三个自由度的运动,且运动平缓,无突变点。     

共形空间中的少自由度空间并联机构正解

针对3-RPS型空间少并联机构正解问题,利用3-RPS型并联机构在共形空间中的运动特性,对其运动学问题进行求解。首先,利用共形空间中的几何元素表达方式以及共形变换规律,求得并联机构动平台三个球铰在空间中的位置表达式,表达式中含有一未知数。接着,根据共形几何空间中的内积性质,以及并联机构运动规律,得到一方程组,该方程组为并联机构正解的符号辅助解。最后,结合已编写程序,将并联机构设计参数带入方程组,对符号辅助解进行求解,进而求得并联机构正解的数值解。计算结果表明,这种基于共形几何,将符号与解析结合的正解求解算法,由于不需要计算雅克比及其逆矩阵,也不需要进行数值解的反复迭代,计算速度优于传统算法,这使得该算法的实时性和准确性满足实时控制的需求。     

新型龙门式五轴联动混联机床机构设计及位置逆解研究

提出了一种以新型四自由度并联机构(3-RPR+R)UPS作为并联加工模块,辅以能实现并联加工模块滑动的直线导轨来共同实现五坐标联动加工的一种新型龙门式大摆角混联机床的机构设计方案。首先,运用螺旋理论中运动和约束的关系分析了该机床实现3T2R运动原理,计算出该机构的自由度,进行了输入选取;然后,利用解析矢量法及几何关系建立机构位置逆解方程;最后,应用MATLAB对逆解方程进行求解,并利用ADAMS对求解结果进行仿真验证,验证了逆解模型的正确性及机构的可行性。     

新型并联机构((2-RPR&RP)+R)&UPR构型及位置逆解分析

提出了一种新型1T2R大摆角并联机构。首先,运用螺旋理论中运动和约束的关系分析了该机构实现1T2R运动原理,计算出该机构的自由度,进行了输入选取;然后,利用解析矢量法及几何关系建立机构位置逆解方程;最后,应用MATLAB对逆解方程进行求解并利用ADAMS对求解结果进行仿真验证,验证了逆解模型的正确性及机构的可实现性。该并联机构可实现大的摆角,可作为并联模块应用于混联机床,实现大摆角五轴联动加工。     

3-SPS/UPR并联工作台运动学分析

提出一种以3-SPS/UPR并联机构为主体的工作台,用以辅助少自由度机床对工件进行曲面加工。建立3-SPS/UPR并联机构的运动螺旋矩阵,通过螺旋理论对其进行自由度分析,采用修正的Kutzbach-Grübler公式进行验证;通过机构中的几何关系,采用封闭矢量法求解该机构的位置逆解,并求出该机构的速度Jacobian矩阵;通过三维动态搜索法求解该机构的工作空间;通过Adams软件对该并联工作台进行了运动学仿真。该3-SPS/UPR并联机构能够进行两平移两转动的运动,可提高机床加工效率和加工质量,增大机床加工范围,提高机床的曲面加工的能力。     

3-RRS球面并联机构的位置解及工作空间研究

利用螺旋理论对3-RRS球面并联机构进行了运动分析。利用牛顿迭代法求解了3-RRS球面并联机构的运动学正解,应用闭环矢量法建立了3-RRS球面并联机构的位置逆解模型并推导出了相应的位置逆解算式,得到了3-RRS球面并联机构的8组逆解。实例分析验证了3-RRS球面并联机构位置解的正确性。利用数值搜索法求解了机构的可达工作空间,利用MATLAB编程绘制了机构在不同结构参数下的可达工作空间图,分析了工作空间的变化规律,为3-RRS球面并联机构的应用奠定了基础。     

3-RRR平面并联机器人工作空间边界求解和灵活性研究

提出了求解平面并联机器人工作空间边界的基于迭代搜索法的圆周式搜索算法,并分析了其灵活性指标。通过对3-RRR平面机器人工作空间的分析,根据迭代搜索法,在判别方程存在逆解的条件下,以圆周式搜索算法确定一系列的边界点,所得结果与运用几何方法得到的结果一致。利用末端执行器上点的速度来表示机构的运动,得出了受限制的、量纲一致的雅可比矩阵,从而衡量平面并联机器人的灵活性,并借助于Matlab绘图,直观地反映了新的雅可比条件数在工作空间内的分布情况。根据所得的雅可比矩阵,可以得到更准确的灵活性指标。     

五自由度3D打印并联机器人设计及分析

为实现多向3D打印,设计了一种新型五自由度3D打印并联机器人,该机器人具有两个转动自由度和三个平动自由度,其特点是采用铰接的动平台以获得大的工作空间。根据建立的运动学模型,计算了该机器人机构的运动学反解,分析了定姿态位置工作空间和定位置姿态工作空间,用螺旋理论方法建立了速度雅可比矩阵,在此基础上分析了五自由度3D打印并联机器人的奇异性、灵巧性,并进行了运动仿真分析。研究结果表明,所设计的五自由度3D打印并联机器人具有大的位置工作空间和姿态工作空间,该机器人在工作空间内存在奇异位置,通过添加冗余驱动后可以消除奇异位置,并且具有良好的灵巧性,适合多向3D打印。     

Dynamics analysis of novel parallel manipulator with one central rotational actuator and four translational actuators

A dynamics analysis of a novel parallel manipulator with one central rotational actuator and four translational actuators is conducted. A 3D model of the parallel manipulator is constructed and its characteristics and DoF are analyzed. The kinematics formulae are derived for solving the displacement, velocity and acceleration of the moving links. The dynamics formulae are derived for solving the inertial wrench of the moving links, the dynamic active forces along the active limbs, the dynamic active torque applied on a central active leg, and the dynamic constrained force exerted on the central active leg. A theoretical numerical example is given to solve the kinematics and dynamics solutions, and the theoretical solutions are verified by the simulation mechanism in Matlab. Finally, a reachable workspace of the novel parallel manipulator is constructed using CAD variation geometry.

     

DIMENSIONAL DESIGN THEORY AND METHODOLOGY OF 6-DOF SCISSOR PARALLEL MANIPULATOR

Parallel manipulators have many advantages over serial manipulators in terms of high load/weight ratio, velocity, stiffness and precision. A dimensional design theory and methodology of six degrees of freedom scissor parallel manipulator (SPM) is investigated. The SPM kinematics inverse equation is given. Based on the formulation of the local dexterity and the definition about the indexes of workspace incircle radius, the effects of the design parameters on the dexterity and workspace are discussed. Moreover the incircle radius change ratio about workspace are defined and used as the evaluated indicator to analyze the effects of the design parameters on the performances. A dimensional design theory that could satisfy the requirement of dexterity and workspace is proposed. The dimensional design theory and methodology can be of help in the design, trajectory planning and control of parallel manipulator.     

一种新型空间3自由度并联机构的正反解及工作空间分析

提出一种新型空间3自由度并联机器人机构,该机器人机构的动平台相对于定平台具有空间2个移动、1个转动自由度,建立了其运动学正反解的封闭形式,并对其工作空间进行了系统的分析和研究。该新型并联机器人机构在工业机器人、微动机器人、少自由度飞行模拟器和并联机床等领域具有广泛的应用。     

一种改进型三平移并联机构的运动学研究

根据Delta机构的结构,设计提出了一种改进型三平移并联机构。进行了机构的自由度、运动学和工作空间研究,建立了有关运动学模型。理论研究表明:该机构具有几何形状规则的作业空间,是一种较为理想的实现三维移动的并联机构机型。这为正确选择该机构的结构设计和运动学参数、实现机构的控制及工业应用奠定了基础。     

Design of a planar 3-DOF parallel micromanipulator

A planar three degree-of-freedom (DOF) parallel manipulator is proposed to be applied for alignment during assembly of microcomponents. It adopts a PRR (prismatic-revolute-revolute) mechanism to meet the requirements of high precision for assembly and robustness against disturbance. The mechanism was designed to have a large workspace and good dexterity because parallel mechanisms usually have a narrow range and singularity of motion compared to serial mechanisms. Inverse kinematics and a simple closed-loop algorithm of the parallel manipulator are presented to control it. Experimental tests have been carried out with high-resolution capacitance sensors to verify the performance of the mechanism. The results of experiments show that the manipulator has a large workspace of ±1.0 mm, ±1.0 mm, and ±10 mrad in the X-, Y-, and θ-directions, respectively. This is a large workspace when considering it adopts a parallel mechanism and has a small size, 100 × 100 × 100 mm³. It also has a good precision of 2 μm, 3 μm, and 0.2 mrad, in the X-, Y-, and θ-axes, respectively. These are high resolutions considering the manipulator adopts conventional joints. The manipulator is expected to have good dexterity.     

Kinematics and optimization of a 2-DOF parallel manipulator with a passive constraining leg and linear actuators

This paper presents a two degree-of-freedom (DOF) planar parallel manipulator with two linear actuators, whose degree of freedom is dependent on a passive constraining leg connecting the base and the platform. The kinematics of the presented manipulator is first studied: the inverse and forward kinematics problems are solved in the closed form, the practical workspace is described symbolically, the Jacobian matrix is derived, and several singular conditions are discussed. Then, in order to determine the geometric parameters and the operating range of the actuators, the optimization of the mechanism is performed considering its dexterity and stiffness.     

Workspace optimization and kinematic performance evaluation of 2-DOF parallel mechanisms

This paper presents the kinematics and workspace optimization of the two different 2-DOF (Degrees-of-Freedom) planar parallel mechanisms: one (called 2-RPR mechanism) with translational actuators and the other (called 2-RRR mechanism) with rotational ones. First of all, the inverse kinematics and Jacobian matrix for each mechanism are derived analytically. Then, the workspace including the output-space and the joint-space is systematically analyzed in order to determine the geometric parameters and the operating range of the actuators. Finally, the kinematic optimization of the mechanisms is performed in consideration of their dexterity and rigidity. It is expected that the optimization results can be effectively used as a basic material for the applications of the presented mechanisms to more industrial fields.     

六足步行机器人的并联机械腿设计

将并联机构用于六足步行机器人的腿部结构,以拓展六足步行机器人的应用领域.提出了一种基于(U+UPR)P+ UPS机构的并联机械腿,并对机械腿进行了结构参数设计.首先,对腿部机构进行了运动学分析,推导出了腿部机构的位置反解方程和速度传递方程;分析了腿部机构的工作空间并绘制了工作空间三维图,定义了工作空间性能评价指标,绘制了结构参数与工作空间性能指标的关系曲线.然后,对腿部机构进行了运动灵活性分析并绘制了雅克比矩阵条件数分布图,定义了运动灵活性评价指标,绘制了结构参数与运动灵活性指标的关系曲线.最后,基于工作空间性能指标和运动灵活性指标,采用蒙特卡罗法进行了结构参数分析,选取了一组性能较好的结构参数并考虑加工和装配工艺性,设计了一种新型3自由度并联机械腿的虚拟样机,为六足步行机器人的进一步研究奠定了基础.     

Kinematic analysis and optimal design of 3-PPR planar parallel manipulator

This paper proposes a 3-PPR planar parallel manipulator, which consists of three active prismatic joints, three passive prismatic joints, and three passive rotational joints. The analysis of the kinematics and the optimal design of the manipulator are also discussed. The proposed manipulator has the advantages of the closed type of direct kinematics and a void-free workspace with a convex type of borderline. For the kinematic analysis of the proposed manipulator, the direct kinematics, the inverse kinematics, and the inverse Jacobian of the manipulator are derived. After the rotational limits and the workspaces of the manipulator are investigated, the workspace of the manipulator is simulated. In addition, for the optimal design of the manipulator, the performance indices of the manipulator are investigated, and then an optimal design procedure is carried out using Min-Max theory. Finally, one example using the optimal design is presented.