【摘要】 面向筒段类部组件的对接装配需求，提出一种转运小车大范围移动、六自由度并联机器人小范围调姿对接的机器人化装配系统，开展数字孪生装配研究。首先，以旋量为数学工具，进行并联机器人的全关节逆解与运动学标定，获取机器人任意位姿下各个构件的真实相对位姿关系，利用三维模型重建技术构建出与物理空间镜像映射的数字模型。随后，借助双目视觉动态摄影测量仪获取测量点坐标，通过点、线、面等几何特征拟合，建立转运小车、机器人以及筒段的坐标系，完成物理空间的初始特征测量与装配过程的实时反馈，在此基础上，设计数字空间与测量仪、转运小车、机器人控制器的通信，实现“从实到虚”和“以虚控实”。最后，利用数字孪生装配模型开展快速平稳无碰撞的装配轨迹规划，提出停泊点调姿-平移对接的装配工艺流程，并在停泊点处进行装配预测，据此提出对接过程中的实时调整算法。开展筒段特征测量实验，筒段平面、圆柱面、圆心与定位孔的测量精度均较高，满足装配需求；进行筒段位姿实时调整实验，结果表明所提出的算法提高了筒段对接的一次成功率；通过转运、调姿、对接的装配全流程实验，验证了所提出的数字孪生装配技术的有效性。更多还原

【Abstract】 Aimed at assembling of cylindrical components, a parallel robotic system including an AGV and a 6 degree-of-freedom(DOF) parallel robot is proposed, with which the digital twin assembling is studied. The AGV is responsible for transferring component and the 6-DOF parallel robot can adjust component pose for assembling. First of all, inverse kinematics of all joints for the 6-DOF parallel robot and its kinematic calibration is carried out by finite and instantaneous screw theory. For a given pose of the end-effector, the actual poses of links can be easily calculated. On this basis, a digital model reflecting physical assembling model is built by 3D model reconstruction. Through binocular vision measurement, coordinates of measuring points are obtained, and the point,line and surface of components are fitted by these coordinates. Relative poses among AGV, parallel robot and the components are calculated for real-time measurement. Further connecting measurement, AGV, parallel robot and its controller, the bi-directional communication between digital model and physical model is achieved. Trajectory is planned based on the digital twin model for a fast,stable and collision-free assembling. Also, assembling process is divided into pose-adjusting and pure translating. An assembly prediction algorithm is developed before pure translating. The translating trajectory is modified in real-time. Experiments are conducted to verify the presented system and algorithms. Results show that measuring accuracies of plane, cylinder, center point and holes are high, and the real-time adjustment ensures successful assembly. Finally, the transferring, pose-adjusting and docking of the components are tested. Feasibility of applying digital twin assembling is confirmed.更多还原