TCP Coordinate 3d Online Calibration Of Manipulator Based On Laser And Vision Sensor Fusion

The precise planning of the working trajectory of industrial robots is the premise of ensuring industrial automation production.However,in the working process of industrial robots,the working trajectory may be out of alignment due to joint motor lost,friction,slight collision and other reasons.At present,industrial production usually relies on traditional manual detection,which requires periodic shutdown to detect and calibrate the robot’s working trajectory.However,with the collaborative use of industrial robots and the use in special environments(high temperature,high pressure,vacuum,etc.),traditional manual detection and calibration methods have been unable to meet industrial needs.This thesis proposes an online calibration method for industrial robot trajectory based on fusion of vision sensors and laser displacement sensors.In order to facilitate the detection and calibration of the robot’s working trajectory,the tool center point(TCP)is established on the robot tool,and the trajectory of the point is the visualization of the traj ectory of the robot.By detecting the change of TCP three-dimensional coordinates,the motion calibration is performed to realize the calibration of the working track of the robot.In this thesis,the three-degree-of-freedom robot moving in the X,Y and Z directions is taken as the research object,and the three-dimensional online calibration of the robot TCP coordinates is studied.In order to ensure the smooth progress of this research,this thesis designs a TCP coordinate three-dimensional online calibration system,carries out the selection of required hardware,and builds a system experiment platform.The main research contents of this thesis are as follows:1.A calibration method for coplanar image detection system is proposed.The method is based on the principle that the center of the image is basically undistorted.By obtaining the image of the checkerboard calibration plate,multiple sets of corner points in the central region are extracted,and the calibration coefficient is calculated,and the correspondence between the object surface and the image plane in the central region of the image is obtained.On the basis of this,the distortion of the imaging system is studied,and the image segmentation linear distortion correction method is proposed.2.The two-dimensional plane localization of TCP is studied The standard circle(feature circle)was chosen as TCP carrier,and the center coordinates of the feature circle were TCP two-dimensional plane coordinates.The image preprocessing and feature circle location of the collected image are studied by using the image processing technology.Through comparative experimental analysis,median filter,maximum entropy threshold segmentation,Roberts edge detection and improved Hough transform method which added radius limiting were adopted to achieve the precise 2d plane positioning of TCP.3.The Z-axis coordinate detection of TCP is performed by the laser displacement sensor.The relative distance from the sensor to the tool plane where the robot TCP is located is taken as the Z coordinate of the TCP.The change in the TCP coordinate in the Z-axis direction is judged by the change value of the relative distance.4.On the basis of the completion of the study of each part of the system,the data obtained by the visual and laser displacement sensors are analyzed and processed.According to the sensor fusion information,the TCP coordinate three-dimensional online calibration experiment was carried out to verify the effectiveness and practicability of the TCP calibration system.