Research Of Trajectory Planning For Tokamak Flexible In-vessel Inspection Manipulator

The superconducting Tokamak is a device that can produce large-scale nuclear fusion reaction.Due to the bad environmental of vacuum,high temperature,and the strong radiation will be left,it's necessary to send the robot to inspect and maintain the in-vessel devices,Tokamak flexible in-vessel inspection manipulator is a ten-DOF manipulator that inspecting the bricks of the first wall in vessel.The end-effector of manipulator is a industrial camera for inspection,the camera images will feed back to operator to determine whether the brick is destroyed when the manipulator moving.The images quality of camera will influence the operator's judgment to the bricks,so the manipulator trajectory planning not only can make the robot complete the task as much as possible under the kinematics restriction,but also ensure the camera can get the clear images quality,which has the vital significance to operator's judgment for the in-vessel devices.According to the task requirement,this paper will thoroughly research the trajectory planning based on the Tokamak flexible in-vessel inspection manipulator.Firstly,this paper discusses the background and significance of the research on this topic,and comprehensively summarized the basic methods and research result of robot trajectory planning at home and abroad.Secondly,this paper introduces the manipulator kinematics model in detail for the special mechanical structure,and according to the actual task requirement,in order to ensure the images quality of camera,the manipulator trajectory planning is not only constrain with the velocity,acceleration and jerk of manipulator,but also limited by the camera observation distance difference rate in the robot operation space creatively.Based on the known operating space environment model and the end position and posture of manipulator,to calculate the observation distance of camera,then using different observation distance difference rate to improve the manipulator trajectory,thereby improving the images quality.Moreover,this paper uses curve-fitting to get the relation between the scanning velocity and observation distance,and according to limit the scanning velocity to optimize trajectory and improve the images quality father.This paper uses the conventional cubic spline interpolation function to get the manipulator trajectory,and solves the optimization model by the seqential quadratic programming to get the minimum trajectory execution time,then through a number of simulations and contrast experiments to testify the feasibility of methods and perform the planning trajectory using the actual manipulator to get the images to verify.According to the Laplace image sharpness evaluation method,which belong to gradient edge detection,to evaluate the images quality of different trajectory,which demonstrates the trajectory based on this topic is not only get the efficient work,but also improve the images quality of camera compared to traditional trajectory planning.