Research On Motion Control And Vision Positioning Of Four Axis Manipulator Based On ROS

In the past thirty years,robot technology has been developed rapidly and widely used in all fields of society.Especially in some special circumstances of poor man-made operation,the robot has played a tremendous role.In the field of nuclear power,some tools and foreign objects will inevitably fall into special areas during daily maintenance and regular overhaul of nuclear power plants.In this case,the robotic arm is required to complete the salvage work of these foreign matter.Traditionally,manual remote control is adopted but the whole operation process takes a long time,and has a low efficiency and accuracy,which makes it lack intelligence.With the development of artificial intelligence and machine vision,it is essential to upgrade the foreign-body salvage robots in a special environment.Therefore,research on the accuracy and intelligent control of mechanical arm is a very necessary and important thing.For a physical manipulator,it is not easy to realize its intelligent control.To solve this problem,this paper considers the method of virtual simulation,and proposes to make a study of manipulatorsimulation and visual positioningin the same simulation platform.The advantage of this method is that the data on the same platform can be exchanged more efficiently and quickly,without considering the compatibility between different platforms,which is the important foundation for intelligent control.Considering the factors such as applicability and so on,finally,we choose the popular ROS(Robot Operation System)platform on the choice of simulation platform,and carry out the following research work.Studying the kinematics of a four-axis robot developed by our laboratory,and analyzing and simplifying the four-axis robot.Using the D-H method to model the simplified model,and establishing the coordinate system and characterizing the robot arm with the D-H parameter.Finally,deriving it's positive kinematics and inverse kinematics solutions and verifying it.To build a simulation platform in ROS,the model in Solidworks is transformed into URDF(Unified robot description format)file.Making the file process and display via Rviz visualization tools and finishing kinematic analysis and configuration file construction of the processed file.To this step the model file is converted into a package that can be called and make a path planning.Next,the virtual simulation experiment of four axis manipulator is carried out in ROS,and the research of path planning and control is carried out.In the ROS platform,we explore the orientation of the manipulator.We choose Microsoft's Kinect sensor in vision location,and propose a method of target location in ROS using Kinect.Establishing the connection between Kinect and ROS,and exploring the calibration of Kinect in ROS platform.Then adopting some methods to calibrate the Kinect internal and external parameters and getting the positioning information of the target object.