Robotic splicing of steel arches is a challenging task that is necessary to realize the grasping and docking of steel arches in a limited space.Steel arches often have a mass of more than 200 kg and length of more than 4 m.Owing to the large volume and mass of steel arches and the high requirements for accurately positioning the splicing,it is dif-ficult for a general manipulator to meet the stiffness requirements.To enhance the structural stiffness of the steel arch splicing manipulator,a single-degree-of-freedom(DOF)closed-loop mechanism was added to the grasping structure of the manipulator.Based on the basic principle of structural synthesis,a solution model of the single-DOF closed-loop mechanism was developed,and alternative kinematic pairs of the mechanism with different input constraints and output requirements were derived.Based on this model,a design method for a single-DOF closed-loop grasping mechanism and a posture adjustment mechanism for a steel arch was devised.Combined with the same dimensional subspace equivalence principle of the graphical-type synthesis method,12 types of steel arch splicing manipulator were constructed.By analyzing the motion/force transmission and structural complexity of the steel arch splicing manipulators,the best scheme was selected.A prototype of the steel arch splicing manipulator was manufactured.Adams software was used to obtain clearly the output trajectory of the end of the manipulator.The relative spatial positions of the upper and lower jaws under different working stages were analyzed,demonstrating that the manipu-lator satisfied the grasping requirements.Through a steel arch splicing experiment,the grasping effect,docking accu-racy,and splicing efficiency of the manipulator met the design requirements.The steel arch splicing manipulator can replace the manual completion of the steel arch splicing operation,significantly improving the operation efficiency.

Yuanfu He;Yimin Xia;Zhen Xu;Jie Yao;Bo Ning;Xuemeng Xiao

College of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;State Key Laboratory of High Performance Complex Manufacturing,Central South University,Changsha 410083,China;China Railway Construction Heavy Industry Co.Ltd.,Changsha 410100,China;China Railway Siyuan Survey and Design Group Co.Ltd.,Wuhan 430063,China;National-Local Joint Engineering Research Center of Underwater Tunnelling Technology,Wuhan 430063,China.

中国机械工程学报

[1]Yuanfu He;Yimin Xia;Zhen Xu;Jie Yao;Bo Ning;Xuemeng Xiao-.A Φ 6-m Tunnel Boring Machine Steel Arch Splicing Manipulator)[J].中国机械工程学报,2022(02):121-134

jaws

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