【作者】 何剑钟；

【导师】 梅江平；

【作者基本信息】 天津大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 本文面向新型多杆汇交式网壳节点的加工需求,在国家863示范工程的资助下,对具有我国自主知识产权的新型5自由度可重构混联机械手EXE-M的关键技术进行了初步研究,内容涉及位置逆解、雅可比矩阵求解、尺度综合、逆动力学、伺服电机参数预估和轨迹规划,主要研究成果如下:1.位置逆解和雅可比矩阵求解:根据EXE-M混联机械手的结构组成,将其分解为3-SPR并联模块与2自由串联模块,提出一种利用Sylvester法求解以位置坐标为独立变量并具有显式解的逆解分析法。借助循环搜索法和纯轨迹理论得到串联模块的逆解模型。利用螺旋理论建立了并联模块的完整雅可比矩阵,就此构建了一般雅可比矩阵;2.尺度综合:为了克服机构正解的复杂性,提出一种利用CAD仿真模型求取3-SPR机构可达空间的简单方法。利用机构任务空间的特点及各尺度参数之间的关系,构造了一种可均衡条件数全域均值及其极差间矛盾的综合操作性能指标,进而将尺度综合归结为一类双参数的寻优问题,该方法避免了多参数非线性规划的复杂性,并通过算例验证了该方法的有效性和简单性;3.逆动力学和伺服电机参数预估:提出了一种借助支链动坐标系和动平台动坐标系联合求解各部件角速度、角加速度与动平台速度的解耦映射关系的方法,巧妙地得到了各驱动杆自旋角速度和角加速度。进而利用虚功率原理列出了精确的逆动力学模型。借助雅可比奇异值法预估了驱动伺服电机的参数,并通过典型轨迹验证理论模型的正确性和预估方法的有效性;4.轨迹规划:将机器人末端执行器的运动归为空间点矢的运动,提出适合任何混联机器人的时间同步运动轨迹规划算法及空间任意曲线运动的规划方法。应用三次样条函数进一步规划了从操作空间映射到关节空间的离散控制点,可防止驱动关节的运动波动,并通过节点的加工仿真验证了各方法的有效性。更多还原

【Abstract】 With the aid of the 863 Exemplary Project, to meet the demand for the manufacture of a novel Bars-Converging Joint used in the steel structure, the dissertation investigates into the design theory and method of the EXE-M robot—a novel 5-DOF hybrid reconfigurable robot possessing proprietary intellectual property rights. Research includes inverse position analysis, Jacobian matrix solution, dimensional synthesis, inverse dynamic analysis, servomotor parameters estimation and trajectory planning. The following work has been accomplished:1. Inverse position analysis and Jacobian matrix solution: According to the characteristics of the EXE-M robot, it is decomposed into 3-SPR parallel module and 2-DOF serial module. With three displacement variables, the former reveal inverse kinematic model has been developed by the Sylvester method, while the latter is proposed by the method of cyclic search and pure trajectory theory. The integrated Jacobian matrix of its parallel subsystem is simply formulated by the screw theory, and then the general Jacobian is constructed.2. Dimensional synthesis: To avoid the complexity of the forward solution, a simple solution to workspace of the 3-SPR parallel manipulator is constituted by using its CAD simulation mechanism. With the characteristics of the workspace of the mechanism and the relation between scale parameters, a integrated processability index is proposed which can balance the conflict between the scale average value and range. Then the dimensional synthesis of the parallel subsystem is considered as a two-parameters optimizing problem, which avoids the complexity of nonlinear programming including constraints, and the feasibility and simplicity of the method is verified experimentally.3. Inverse dynamic analysis and servomotor parameters estimation: Combining the branch-fixed secondary frame with the moving platform-fixed secondary frame, the decoupling mapping relation between the angular velocity and angular acceleration of branches and the velocity of the moving platform have been proposed, cleverly leading out the spin angular velocity and angular acceleration of three branches. Finally based on the inverse dynamic model, the speed rating, the power rating and torque of servomotor are estimated by the singular value of Jacobian matrix. The effectiveness of the approach has been verified using classic trajectory planning.4. Trajectory planning: The movement of the robot end-effector can be grouped into the spatial point-vector movement. A trajectory planning algorithms of time synchronization is proposed for any more-mobility hybrid mechanism, as well as the planning method for any space curvilinear motion. Using cubic splines function, the real-time trajectory programming in joint space mapped from the workspace is obtained further, which can guarantee the running stability of joints. At last, the effectiveness of the above-mentioned approaches has been verified by the simulation of joints machining.更多还原