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一种协作机器人设计方法与实验研究
Alternative TitleThe Design Method and Experiments of a Collaborative Robot
胡明伟
Department工艺装备与智能机器人研究室
Thesis Advisor王洪光
Keyword协作机器人 设计方法 模态分析 刚度建模 结构优化
Pages154页
Degree Discipline机械电子工程
Degree Name博士
2020-05-26
Degree Grantor中国科学院沈阳自动化研究所
Place of Conferral沈阳
Abstract协作机器人能够将自身的高精度、高忍耐性与人类的灵活适应能力相结合,具有人机融合、安全易用、灵敏精准及灵活通用的特征,不仅适应工业领域中小批量、多品种、用户定制的柔性制造需求,在应对老龄化的社会服务、康复医疗等领域也有潜在的应用前景。协作机器人具有高负载自重比、轻质、灵活易用、安全性高等特点,但上述特点也对机器人的设计和性能的提高造成了一定困难。冗余自由度及偏置的存在提高了机器人的灵巧性,但对机器人的结构设计和运动控制带来了困难。轻质、高负载自重比的设计理念使机器人引入了大量的柔性因素,使机器人的刚度、机械带宽难以提升,从而影响了其定位精度及动态性能。高安全性的特点要求机器人采用小负载、低速的设计方法,从而牺牲了机器人的工作性能。针对在轻质、高负载自重比约束下,协作机器人刚度、精度以及动态性能难以提高的问题,在考虑安全机制的基础上,对协作机器人本体设计方法进行研究,通过机构、结构设计及优化等方法获得具有优良运动和动态性能的机器人本体。主要研究内容如下:(1)协作机器人设计方法研究,探讨通过正向设计、优化综合等方法确定协作机器人各项性能指标的设计方法,主要研究内容包括工作性能与安全性能耦合均衡的协作机器人安全设计方法,通过该方法来确定在满足安全性能约束下,使机器人工作性能最优化的刚度、速度、有效质量等性能指标;基于“肩肘-腕”分离的七自由度机器人构型优化综合方法,通过该方法能够获得工作空间和灵巧性最优的七自由度机器人构型和尺度参数;位姿重复性约束下的机械臂主动设计方法研究,在给定位姿重复性要求的前提下,寻找各关节随机运动精度的最优分配方案,该优化方法能够使协作机器人设计更加合理,对降低机器人制造成本有重要意义。(2)协作机器人实时模态分析,基于有限元子结构法,提出了一种有限元法与解析法相结合的机器人实时模态分析方法,该方法能够实时、高效、高精度地获得机器人在任意位姿下的固有频率及振型。通过有限元法和振动试验验证了该方法的正确性和建模精度。通过机器人自运动空间、关节空间及笛卡尔空间下的模态分析验证了该方法的实时性和高效性,为后续的协作机器人结构与性能优化提供支撑。(3)协作机器人刚度建模与辨识,提出了一种有限元—虚拟关节法相结合的协作机器人刚度建模、辨识和修正方法,该方法既拥有虚拟关节法的计算效率,又具有较高的有限元建模精度。基于虚拟关节法,建立了考虑自重的机器人弹性变形模型,为机器人实时在线弹性误差补偿和刚度性能优化提供理论基础。通过静态柔顺性试验验证了所提方法的正确性。最后,探讨连杆、关节等因素对协作机器人刚度性能和定位精度的影响。(4)协作机器人结构与性能优化,探讨轻量化约束下,进一步提高协作机器人工作性能的优化设计方法。基于正交设计和有限元子结构法,提出了一种以机器人刚度、固有频率以及质量等多种性能指标为优化目标,以机器人结构参数、元器件为优化变量的协作机器人全域多目标优化设计方法。通过多目标全域优化设计能够有效提高机器人的静、动态性能。(5)SHIR5协作机器人研制及实验研究,介绍了SHIR5协作机器人的系统组成,并基于该机器人开展了相应的安全评估仿真。基于激光跟踪仪、六维力传感器以及振动试验系统等设备搭建实验平台,对SHIR5协作机器人进行了位姿重复性、静态柔顺性以及固有频率等性能测试和运动学标定实验。简要介绍了SHIR5协作机器人在3C装配、航空等行业的应用。
Other AbstractCollaborative robots(Cobots) can effectively combine the high endurance and precision performance of robots with the flexible adaptability of human, which have features of human-robot-collaboration, high safety, ease of use, high precision-dexterity, and versatility, etc. It not only adapts to flexible manufacturing mode of small and medium-sized batches, wide varieties, and customization in industry, but also has potential application prospects in dealing with aging social services, rehabilitation medicine and other fields. Although cobots have the characteristics of high load/weight ratio, light-weight, dexterity and easy to use, high safety, etc., the above characteristics also cause certain difficulties in the design and improving performances of the robot. The existence of redundant degrees of freedom(Dof) and link offset improves the dexterity performance of the robot, but it brings difficulties to the robot structure design and kinematic solution. Due to the design concept of light-weight and high load/weight ratio, a lot of elastic factors are introduced to cobots which is bring difficulties to improve stiffness performance and mechanical bandwidth of robots and further affects the positioning accuracy and dynamic performance of robots. The high safety feature requires the robot to adopt the design method of small-load and low-speed, which sacrifices the working performance of robots. In the view of the problem that the stiffness, accuracy and dynamic performances of cobots are difficult to improve under the constraints of light-weight and high load/weight ratio, the design method of cobots is researched with considering the safety performance of robots. The cobot with excellent kinematic and dynamic performances is obtained through mechanism design and optimization, structure design and optimization, etc. methods. The research process and detailed descriptions are as follows: (1) Research on the design method of collaborative robots. This section studies the design method of determining the performance indexes of cobots through the top-down design, the optimization synthesis and other methods. The main research contents include: the safety design method of cobots with the tradeoffs between the working performance and the safety performance, by this way, the performance indexes, such as the stiffness, the end-tip speed and the effective mass of robots, etc., are determined to optimize the working performance with the constraint of the safety performance; A 7 Dofs robot configuration optimization synthesis method based on “Shoulder elbow-Wrist” separation, by this method, the optimal configuration and dimensional parameters of the robot with optimal workspace and dexterity can be obtained; Research on the top-down design method of manipulator under the pose repeatability constraint, with the requirement of pose repeatability of robots, searching the optimal arrangement scheme of random motion accuracy of joints for enhancing the rationality of robot design and reducing the development cost of robots. (2) Real-time modal analysis of collaborative robots. Based on the finite element substructure method, a real-time modal analysis method of cobots combining the finite element method(FEM) and analytical method is proposed in this paper, the natural frequencies and mode shapes of robots in any pose can be obtained in real time with high efficiency and high precision by using this method. The modeling accuracy and effectiveness of this method are verified by finite element method and vibration experiment. The real-time and high efficiency of this method are verified by the real-time modal analysis of the robot in the self-motion space, the joint space and the Cartesian space. This method provides a theory basis for the structure and performance optimization of cobots. (3) Stiffness modeling and identification of collaborative robots. A stiffness modeling, identification and updating method, which is combined the virtual joint method(VJM) with FEM-based technique, is proposed in this paper. This method not only preserves the computational efficiency of the VJM, but also has high modeling accuracy of the FEM simultaneously. Based on the VJM, the elastic deformation model of robots considering self-weight is established, which provides a theoretical basis for the real-time online elastic error compensation and stiffness performance optimization of the robot. Static compliance tests are performed for verifying the validity of the proposed method. Finally, the influences of links, joints and other factors on the stiffness performance and positioning accuracy of cobots are discussed. (4) Structural and performance optimization of collaborative robots. For further improving the working performance of cobots under the lightweight constraints, a novel optimization design method is studied. Based on orthogonal design experiment(ODE) and finite element substructure method(FESM), a multi-objective optimum design method of cobots is proposed with the structural dimensions and parameterized joint components as the optimization variables, the natural frequency, the Cartesian stiffness and the mass of the robot as optimization objectives. The stiffness and dynamic performances of the robot are effectively improved by the multi-objective global optimum design. (5) Development and experiments of SHIR5 collaborative robot. The system composition of SHIR5 cobot is introduced and its safety evaluation simulation is carried out. Based on the laser tracker, force sensor, vibration test system and other equipment, several experimental platforms are built for pose repeatability, static compliance, and natural frequency tests of SHIR5 cobot. And kinematic calibration experiments are performed at the same time. The applications of SHIR5 cobot in 3C assembly, aviation and other industries are introduced briefly.
Language中文
Contribution Rank1
Document Type学位论文
Identifierhttp://ir.sia.cn/handle/173321/27161
Collection工艺装备与智能机器人研究室
Affiliation中国科学院沈阳自动化研究所
Recommended Citation
GB/T 7714
胡明伟. 一种协作机器人设计方法与实验研究[D]. 沈阳. 中国科学院沈阳自动化研究所,2020.
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