Research On Fully Automatic Assembly Of Segment Assembly Machine

Tunnel boring machine is a large-scale tunnel boring equipment integrating mechanical,electrical,hydraulic and optical technologies.With the construction boom of subway and underground space infrastructure in China and the rapid development of other rail engineering construction,the use of shield machines has gradually expanded,and the demand for large diameters and coal mine tunnels has also continued to increase.Segment assembly is a key technology in shield construction,and the segment assembly robot undertakes the heavy task of segment laying during the tunneling process.In this paper,the following research work is carried out on key scientific issues such as the mechanism design,segment automatic identification,segment assembly pose and accuracy,motion path and trajectory planning of the segment assembly robot:In terms of mechanism design,according to the analysis of the working principle of the segment assembling robot,based on the existing mixed segment assembling machine,a6-DOF robotic arm type segment assembling machine is designed.The fine-tuning mechanism is designed as a 3-degree-of-freedom series fine-tuning mechanism.The appropriate coordinate system is established according to the improved DH parameter method,and the kinematics model of the improved model of the segment assembly robot is established according to each parameter,and the positive and inverse kinematics solutions are solved.The change curve of the center position of the end of the grasping mechanism of the segment assembling robot in the segment assembling process is obtained.In the aspect of segment automatic identification technology,an automatic segment identification method based on machine vision is introduced.Through the analysis of the automatic segment identification results using the SIFT feature matching algorithm,it is concluded that the SIFT feature matching algorithm is affected by the assembly environment and is not suitable for An automatic identification method applied to segments.According to the construction environment of segment assembly,a method of automatic segment recognition based on machine vision is proposed,which preprocesses segment images,and uses OTSU threshold segmentation algorithm to perform binarization processing on the preprocessed segment images.Identify specific locations in the binarized image.Then cut the segment image with the segment position determined,cut out segment bolt image of appropriate size,perform grayscale processing and binarization on segment bolt image,and calculate the centroid of bolt in segment bolt image.,and obtain the world coordinates of the segment to be clamped according to the transformation of different coordinate systems.In terms of the pose and accuracy of the segment assembly,a segment location method based on the linear structured light binocular measurement system is proposed,and the segment location is solved by using the coordinate barycenter of the three-dimensional space point and the least squares method of the Rodriguez matrix.The pose transformation and rotation matrix are used to solve the actual pose of the segment assembly point.Random comparison of the pose calculation errors of multiple sets of detection points verifies that this method can accurately and quickly measure the segment assembly pose,and this method reduces or offsets the segment pose caused by the structural error and clamping error of the mechanism itself.error,and improve the accuracy of segment assembly.In terms of segment motion path and trajectory planning,the motion paths of segment assembling robot in three different stages of segment clamping,transporting and assembling are introduced.Comparing the three acceleration control algorithms of exponential acceleration and deceleration curve algorithm,T-shaped acceleration and deceleration curve algorithm and S-shaped acceleration and deceleration curve algorithm,the S-shaped acceleration and deceleration curve algorithm is selected.The S-shaped acceleration and deceleration algorithm based on NURBS curve is used to plan the trajectory of the segment assembling machine in the clamping stage and the assembling stage after measuring the segment assembling position,so as to generate a smooth and stable trajectory and reduce the joint wear of the segment assembling robot.