Abstract：For the dimensional parameter optimization of 3-UPS&S parallel mechanism, an optimal geometric configuration of the shipborne stable platform is obtained to improve its kinematics performance by niche genetic algorithm with the workspace size and global force transmission rate as design indices. Specifically, a combination of numerical and analytical methods is used to determine the validity of constraint conditions such as branch chain length, joint rotation angle, singularity, etc., and to solve the workspace of the parallel stable platform. The minimum singular value of the inverse of force Jacobian matrix is used to define the local force transmission index, and the average value of the local force transmission rate in the workspace is used as the global force transmission index. Taking the weighted sum of the workspace size and the global force transmission rate as the optimization objective, the niche adaptive genetic algorithm is used to complete the optimization solution and obtain the optimal dimensional parameters. The performance comparative analysis with the initial configuration shows that the optimized configuration achieves a 35% improvement in force transmission performance and has better comprehensive kinematics performance. A test prototype is manufactured and related experiments are carried out to verify the effectiveness of the proposed optimization method for dimensional parameters. Finally, the law of the effect of different weight coefficients on the optimization results in the process of multi-objective optimization is discussed, and it is found that better comprehensive performance can be achieved by balanced weights.
 刘晓,赵铁石,边辉,等.耦合型3 自由度并联稳定平台机构动力学分析[J].机械工程学报, 2013, 49(1):45-52. Liu X, Zhao T S, Bian H, et al. Dynamics analysis of a 3-DOF coupling parallel mechanism for stabilized platform[J]. Journal of Mechanical Engineering, 2013, 49(1):45-52.  黄真,赵永生,赵铁石.高等空间机构学[M].北京:高等教育出版社, 2006. Huang Z, Zhao Y S, Zhao T S. Advanced spatial mechanism[M]. Beijing:Higher Education Press, 2006.  Gosselin C M, Jean M. Determination of the workspace of planar parallel manipulators with joint limits[J]. Robotics and Autonomous Systems, 1996, 17(3):129-138.  Aboulissane B, El Haiek D, El Bakkali L, et al. On the workspace optimization of parallel robots based on CAD approach[J]. Procedia Manufacturing, 2019, 32:1085-1092.  Castelli G, Ottaviano E, Ceccarelli M. A fairly general algorithm to evaluate workspace characteristics of serial and parallel manipulators[J]. Mechanics Based Design of Structures and Machines, 2008, 36(1):14-33.  Peidró A, Reinoso Ó, Gil A, et al. An improved Monte Carlo method based on Gaussian growth to calculate the workspace of robots[J]. Engineering Applications of Artificial Intelligence, 2017, 64:197-207.  Bohigas O, Manubens M, Ros L. A complete method for workspace boundary determination on general structure manipulators[J]. IEEE Transactions on Robotics, 2012, 28(5):993-1006.  Rouhani E, Nategh M J. Workspace, dexterity and dimensional optimization of microhexapod[J]. Assembly Automation, 2015, 35(4):341-347.  张新.一种3-UPS/S球面并联机构的运动参数优化研究[D].秦皇岛:燕山大学, 2013. Zhang X. Optimization of motion parameters of a 3-UPS/S spherical parallel mechanism[D]. Qinhuangdao:Yanshan University, 2013.  Chen X, Chen C, Liu X J. Evaluation of force/torque transmission quality for parallel manipulators[J]. Journal of Mechanisms and Robotics, 2015, 7(4). DOI:10.1115/1.4029188.  Liu X J, Wu C, Wang J S. A new approach for singularity analysis and closeness measurement to singularities of parallel manipulators[J]. Journal of Mechanisms and Robotics, 2012, 4(4). DOI:10.1115/1.4007004.  Wu G L, Zou P. Comparison of 3-DOF asymmetrical spherical parallel manipulators with respect to motion/force transmission and stiffness[J]. Mechanism and Machine Theory, 2016, 105:369-387.  Liu H T, Huang T, Kecskeméthy A, et al. A generalized approach for computing the transmission index of parallel mechanisms[J]. Mechanism and Machine Theory, 2014, 74:245-256.  刘海涛,熊坤,贾昕胤.等. 3自由度冗余驱动下肢康复并联机构的运动学优化设计[J].天津大学学报(自然科学与工程技术版), 2018, 51(4):357-366. Liu H T, Xiong K, Jia X Y, et al. Kinematic optimization of a redundantly actuated 3-DOF parallel mechanism for lower-limb rehabilitation[J]. Journal of Tianjin University (Natural Science and Engineering Technology Edition), 2018, 51(4):357-366.  叶伟,谢镇涛,李秦川.一种可用于微创手术的并联机构运动学分析与性能优化[J].机械工程学报, 2020, 56(19):103-112. Ye W, Xie Z T, Li Q C. Kinematics analysis and performance optimization of a parallel manipulator for minimally invasive surgery[J]. Journal of Mechanical Engineering, 2020, 56(19):103-112.  陈为林,冯梓泓,卢清华,等.多模式刚柔结合欠驱动抓取机构的设计、分析与实验测试[J].机器人, 2022, 44(2):139-152. Chen W L, Feng Z H, Lu Q H, et al. Design, analysis and experimental test of a multi-mode rigid-flexible underactuated grasping mechanism[J]. Robot, 2022, 44(2):139-152.  肖宇光,高峰.基于多约束条件下的机器人尺寸综合优化[J].机械设计, 2021, 38(4):1-8. Xiao Y G, Gao F. Dimension optimization of robots based on multi-constraints[J]. Machine Design, 2021, 38(4):1-8.  温海营,戴敏,张慧,等.含被动高副的冗余驱动并联机器人优化设计[J].机器人, 2021, 43(6):694-705. Wen H Y, Dai M, Zhang H, et al. Optimal design of a redundantly actuated parallel robot with passive higher kinematic pair[J]. Robot, 2021, 43(6):694-705.  程元皓,王孙安,于德弘.仿生并联眼动机构多目标优化设计[J].机器人, 2017, 39(2):176-181. Cheng Y H, Wang S A, Yu D H. Multi-objective optimization design of a bionic parallel oculogyric mechanism[J]. Robot, 2017, 39(2):176-181.  Shen Y, Jia Q X, Chen G, et al. Study of rapid collision detection algorithm for manipulator[C]//IEEE 10th Conference on Industrial Electronics and Applications. Piscataway, USA:IEEE, 2015:934-938.  Li B K, Wang K, Han Y G, et al. Singularity property and singularity-free path planning of the Gough-Stewart parallel mechanism[J]. International Journal of Advanced Robotic Systems, 2017, 14(6). DOI:10.1177/1729881417734971.  杨建涛.并联折叠式舰载稳定平台机构分析与控制理论研究[D].秦皇岛:燕山大学, 2015. Yang J T. Mechanism analysis and control theory research on ship-based stabilizing platform with foldable parallel mechanism[D]. Qinhuangdao:Yanshan University, 2015.  郭菲.电液驱动3-UPS/S并联稳定平台机构优化及动力学模型研究[D].秦皇岛:燕山大学, 2016. Guo F. Research on dynamic model and optimization of electrohydraulic 3-UPS/S parallel stabilized platform[D]. Qinhuangdao:Yanshan University, 2016.  Zhang H Z, Liu F, Zhou Y Y, et al. A hybrid method integrating an elite genetic algorithm with tabu search for the quadratic assignment problem[J]. Information Sciences, 2020, 539:347-374.