末端铰接三平动并联机构设计与性能优化  

Design and Performance Optimization of 3-DOF Translational Parallel Mechanism with Hinged End Structure

作　　者：梁栋[1,2] 刘军[1] 畅博彦 金国光[1,2] LIANG Dong;LIU Jun;CHANG Boyan;JIN Guoguang(School of Mechanical Engineering,Tiangong University,Tianjin 300387,China;Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology,Tiangong University,Tianjin 300387,China)

机构地区：[1]天津工业大学机械工程学院,天津300387 [2]天津工业大学天津市现代机电装备技术重点实验室,天津300387

出　　处：《农业机械学报》2022年第10期446-458,共13页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(52175243、52005368);天津市教委科研计划项目(2019KJ012)

摘　　要：针对高性能3D打印需求,提出了一种结构简洁且高效的三平动(3T)并联机器人。首先,为得到期望的自由度构型,提出一种拓扑演化设计方法,即将一种三平一转自由度(3T1R)并联机构作为初始构型,根据螺旋理论解析该机构自由度及其性质,在此基础上,将动平台向其中心无限缩聚至一点,并使3条支链的末端连杆铰接于该点,进而对机构的末端铰接杆进行再设计,最终演化得到一种仅存在转动副且末端含铰接结构的三平动并联机构。其次,根据输入关节与末端铰接点之间的关系,采用几何投影法和闭环矢量法构建该并联机构的运动学方程,推导其位置正/逆解,并进一步得到速度雅可比矩阵,进而建立速度和加速度映射模型。随后,利用分层切片的搜索算法,预估机器人工作空间,并分析其奇异性。为综合评估机器人性能,对机构灵巧度、速度、承载力及刚度性能指标进行分析,进而提出一种多目标优化设计模型,并据此开展尺度综合,获得最优尺度参数。最后,借助多体动力学软件进行轨迹跟踪仿真校验。研究结果表明,该并联机器人结构简洁紧凑,性能优良,为其后续实体样机制造及实际应用奠定了理论基础。To meet the requirement of high-performance 3 D printing,a three-translational(3 T)parallel manipulator with simple structure and high efficiency was proposed.Firstly,in order to obtain the desired degree of freedom configuration,a topological evolution design method was proposed,that was,a parallel mechanism with 3-DOF translations and 1-DOF rotation(3 T1 R)was taken as the initial configuration.According to the screw theory,the degree of freedom and its properties of the mechanism were analyzed.On this basis,the moving platform was infinitely converged to a point,and the end connecting rods of the three branches were hinged at this point.Then the end hinged rod of the mechanism was redesigned.Thus,a three-translational parallel mechanism with only revolute pairs and end hinged structure was obtained.Secondly,based on the relationship between the input joint and the end articulated point,the kinematic equations of the parallel mechanism were constructed by using the geometric projection method and the closed-loop vector method,the position forward/reverse solutions were derived,and the velocity Jacobian matrix was further obtained,and then the velocity and acceleration models were formulated.Subsequently,the hierarchical slicing search algorithm was employed to predict the workspace of manipulator,and then the singularities were analyzed.To comprehensively evaluate the performance of manipulator,the dexterity,speed,load carrying capacity and stiffness performance indexes of the mechanism were analyzed,and then a multi-objective optimization design model was proposed,and the optimal dimension parameters were obtained through dimensional synthesis.Finally,trajectory tracking simulation verification was carried out by using multi-body dynamics software.The research results manifested that the parallel manipulator had a simple and compact structure and excellent performance,which laid a theoretical foundation for its subsequent prototype manufacturing and practical application in future.

关 键 词：三平动并联机构 运动学 奇异性 性能优化 

分 类 号：TH112[机械工程—机械设计及理论]