Research On The Key Problems Of Remote And Rapid Changing Attachments Of Nuclear Demolition Robots

Decommissioning and disposal of existing nuclear facilities has been listed as one of the major national research fields,and it is urgent to strengthen the research on decommissioning equipment of nuclear facilities.Nuclear decommissioning robot is a special nuclear industrial robot driven by hydraulic and controlled by remote control.It can be equipped with different attachments according to the task requirements of decommissioning and dismantling of nuclear facilities.The nuclear demolition robot can replace operators to enter the radioactive environment for waste disposal and demolition.It is an important equipment in the field of nuclear facility decommissioning and nuclear safety.When the existing nuclear demolition robots are replacing the fittings,the robots should return to the safety area,and then finished attachment changing manually or remotely.This method of demolition attachment changing reduces the working efficiency.In view of the above problems,this paper studies the key problems of remote and rapid attachment changing of nuclear demolition robot,the specific research contents are as follows:(1)Research on the kinematic modeling of nuclear demolition robots.The 3D model of nuclear demolition robot is established,the modified D-H parameter method is adopted to analyze the connecting rod parameters of robot and the coordinate system is established.The forward kinematics and inverse kinematics of the robot are mainly analyzed and solved.(2)Research on the attitude measurement method of the attachment based on visual positioning technology.The principle of visual positioning tag is analyzed,the vertex of the black outer edge of the positioning tag is used to calculate the homography matrix,and the attitude of the positioning tag is calculated by the relationship between the homography matrix and the external parameter matrix of the camera.(3)A method of real-time error compensation for the attachment changing of large-size demolition robots was proposed.This method converts the absolute error that is difficult to eliminate in the attachment changing process into a relative error,which is easy to control through real-time compensation of the camera coordinate frame.The experiments were carried out to verify that this method could reduce the level of error in the attachment changing process.(4)The motion trajectory of changing a nuclear demolition robot attachment is studied.By calculating the optimal docking position of joint {4},the inverse kinematics of the demolition robot are used to solve the coordinates of each joint,and the position of the robot base frame is determined.The proposed method for changing an attachment by remote control with a trajectory planning method is investigated through experiments.Compared with the existing attachment changing method,this proposed method does not need to manipulate multiple joints at the same time to complete complex motion,which reduce the operational difficulty of the range alignment and angle alignment in the process of attachment changing.On the other hand,the optimal docking of the attachment change was achieved,which minimize the distance error of the trajectory between the quick-hitch equipment and attachment during angle alignment,and it also ensure that no collision occurred between these two parts.The experimental results show that,at the same operating level,the time consumption in the process of changing the demolition robot attachment could be reduced by 46% by using the trajectory planning method.(5)Research and develop the hardware of the visualization system of demolition robot attachment changing.The URDF model of the demolition robot is established.The forward kinematics of the demolition robot,the visual measurement method of the attitude of attachment,the error compensation method and the trajectory planning method are unified and integrated.The package of the visualization system of demolition robot attachment changing are developed and applied to the actual demolition robot.In this paper,the key problems of remote and rapid attachment changing of nuclear demolition robots are studied.The research results can realize the attachment changing of nuclear demolition robots in the radiation environment,which is beneficial to improve the operation efficiency and safety of the demolition robot in decommissioning of nuclear facilities and reduce the cost of decommissioning projects of nuclear facilities.