System Analysis And Experimental Research Of Reactor Robot For Object Salvaging Underwater

Because of the high radiation,complex structure,and high causticity in nuclear power plant,operating personnel can be affected by radiation that greatly threaten their physical security and life safety.Using robots to operate can reduce the exposure dose and labor intensity of operating personnel,raise the level of overhaul,and increase efficiency of accident handling.Therefore,using robots instead of humans to operate in nuclear environment has become a broad consensus.The research,supported by subproject “Multifunction underwater crawling robot for nuclear” of “Reactor special robot technology and application” from the National High Technology Research and Development Program of China(No.2011AA040201),is aimed at developing an applicable nuclear robot with compound drive mechanism,underwater video system,and multifunction manipulator.The technologies include human-machine interaction,image processing and recognition system in radiation environment,radioactive anti-fouling and decontamination developing.The foreign matters to be hunted and salvaged can be small bolts and nuts in equipments of nuclear power plant,which makes it necessary to improve the efficiency and security of operations to guarantee the safety and smoothness of equipments in nuclear power stations.The main research contents of this thesis are as follows:1.Considering the limitation of the D-H rule when it is used to establish coordinate systems for robots,an improved D-H method is proposed as the extension of the traditional D-H rule.The details about how to construct the improved D-H method and how to use this method were stated comprehensively.2.The basic machine of the reactor robot for object salvaging underwater is made up with a four-DOF manipulator and a six-wheeled mobile platform.In this research,the manipulator is modeled by using improved D-H method,and then its forward kinematics formulation and inverse kinematics formulation are calculated,which lays the foundation of the Jacobi matrix and singularities of the manipulator.On the basis of kinematic analysis of the wheeled mobile platform,associated with the kinematic model of the manipulator,the reactor robot for object salvaging underwater is kinematically analyzed as a whole.3.The holonomic constraint system of the manipulator is dynamically analyzed by using Euler-Lagrange method,and the nonholonomic constraint system of the wheeled mobile platform is dynamically analyzed by using Newton-Euler method.On the basis of those,the whole dynamical equation of the reactor robot for object salvaging underwater is established by considering the effects of hydrodynamic force on the system and combining water resistance,added mass force,buoyancy with the dynamical model that has been established.4.The grabbing strategy of reactor robot for object salvaging underwater is investigated in both of Cartesian space coordinate and joint space coordinate,and the computational formulas of the robot are established.Then the grabbing strategy is verified through theoretical simulation and prototype test.5.An engineering prototype of the third generation of reactor robot which consists of the basic machine and remote control system including hardware and software is developed.The results of grabbing test show that the engineering prototype of reactor robot for object salvaging underwater meets the design indexes in the task book of this project,and has achieved the goal of grabbing foreign matters in nuclear reactor pool.