【作者】 王静；

【导师】 方跃法；

【作者基本信息】 北京交通大学 ， 机械工程（专业学位）， 2018， 硕士

【摘要】 3D打印技术的飞速发展开启了工业“智造”的新时代,应用前景广泛,成为近几年先进制造业的研究热点。目前市场上大部分基于熔融沉积技术的3D打印机一次只能打印出一个产品,而且主要采用串联机构,以单向分层的打印模式成型产品。在实际应用中这类打印机存在打印精度低、稳定性差和效率低等缺点,当以单向分层打印的方式进行复杂斜面曲面的成型或二次修复加工时,易造成产品表面质量差、力学性能降低以及干涉等问题。在此背景下,本文的研究目标是设计一种基于熔融沉积技术的双输出多向3D打印并联机器人,使其可以实现多输出和多向分层打印,节约成本,提高3D打印的精度与效率。为设计一种能满足双输出和多向3D打印需求的并联机器人,本文首先基于李群理论提出一种综合含有铰接动平台的并联构型的新方法,这种方法可有效的增大并联机构的转动工作空间,在此基础上,设计了一类3T2R型的五自由度并联机构。从中选取一种3T2R型并联机构为主体,采用同支链共驱动的双输出方式,即一套驱动系统同时控制两个相同的输出机构,进一步设计得到双输出多向3D打印并联机器人。然后利用螺旋理论计算了 3D打印并联机构的自由度数目;基于封闭矢量法对机构进行了位置反解求解和速度分析;利用位置反解分析了机构的定姿态和定位置工作空间;基于速度分析得到的速度雅克比矩阵,分析了机构的正逆运动奇异以及灵巧性,计算了机构在工作空间内不同位置处的静刚度值。接着以定姿态工作空间和定位置工作空间为优化目标,基于各结构参数对优化目标的影响建立了优化约束条件,利用遗传算法优化计算得到了最优的结构设计尺寸。最后利用优化后的结构参数建立了机构的虚拟样机,在ADAMS软件中对其进行了自由度运动仿真与验证,基于双输出多向3D打印任务,对机构进行了平面打印和斜面打印的轨迹规划以及仿真分析。研究与分析的结果表明,本文设计的3D打印并联机器人具有较大的转动工作空间,能实现多向打印,一台机器一次能同时输出两个相同的打印轨迹,可实现双输出,而且机构在打印运动过程中平稳可靠。更多还原

【Abstract】 The rapid development of 3D printing technology has opened up a new era of"intelligent manufacturing" and has wide application prospects.It has become a research hotspot in the advanced manufacturing industry in recent years.At present,most of the 3D printers based on fused deposition technique can only print one product at a time,and mainly using series mechanism to form products in unidirectional layered printing mode.This type of printer has the disadvantages of low printing precision,poor stability and low efficiency in the practical application.It is easy to cause poor surface quality,mechanical properties,and interference problem when machining complex curved objects or repairing workpieces in unidirectional layered printing mode.Under this background,the research goal of this paper is to design a dual output multidirectional 3D printing parallel robot based on fused deposition technology,which can realize multi-output and multi-directional layered printing,save cost,and improve the precision and efficiency of 3D printing.To design a parallel robot that can meet the requirements of dual-output and multi-directional 3D printing,firstly,a new method of synthesizing parallel mechanism with articulated moving platform is proposed based on the Lie group theory,which can effectively enlarge the rotational workspace of the parallel mechanism.Using this method,a class of 3T2R type parallel mechanism with five degrees of freedom is designed,from which a 3T2R parallel mechanism was selected as the main body,and the dual output method used is the same limb shared driver,one set of drive system controls two identical output mechanisms,a dual output multidirectional 3D printing parallel robot is further designed.Then,the number of degrees of freedom of the 3D printing parallel mechanism is calculated by using the screw theory;the closed vector method is used to analyze the inverse kinematics and velocity matrix of the mechanism;the orientation workspace and attitude workspace of the mechanism were analyzed by using the inverse kinematics;the singularity and dexterity of the mechanism were analyzed and the static stiffness values of the mechanism at different positions in the workspace were calculated based on the velocity Jacobian matrix obtained by velocity analysis.Next,the orientation workspace and attitude workspace are determined as the optimization targets,and the optimal constraint conditions are established according to the influence of the structural parameters on the optimized target,the optimal structural design parameters is obtained based on genetic algorithm.Finally,the virtual prototype of the mechanism is established by using the optimized structural parameters,the freedom motion of the mechanism is simulated and verified in the ADAMS software,the path planning and simulation analysis of the planar printing and inclined plane printing are carried out based on the dual output and multidirectional 3D printing task.The results of the research and analysis show that the 3D printing parallel robot designed in this paper has large rotational workspace and can realize multidirectional printing.One machine can output two same printing tracks at the same time,indicating that the dual output can be realized,and the mecheanism is stable and reliable in the printing motion process.更多还原