Research On Operation Planing And Force Control Of Blanket Maintanence Inside Fusion Vacuum Vessel

The blanket mounted on the vacuum vessel(VV) of the nuclear fusion device is composed of 400 modules. The maintenance operation of blanket module is highly restricted by the complex construction of vacuum vessel and has to be carried out remotely due to the high radiation level. The blanket module weighs 500 kg and the most critical issue of the remote handling task is to remove or replace the heavy module with high positioning accuracy of 1mm. Towards the project, a SelfAssemble Rail Based Vehicle Manipulator has been developed by a telescope manipulator which travel along the circular articulated rail to access the damaged blanket components. Rail segments are transferred from port cask of VV, and deployed by the rail deployment system to form a ring rail. The remote system is consist of vehicle manipulator, rail lifting mechanism, rail transfer cart, rail support equipment, rail connection tool, cable handling package and blanket transshipment part.This paper will describe the scheme of blanket maintenance system and the operation planning of the vehicle manipulator in detail based on the research and design activity of the project. The key technology during rail deployments and the connection method and procedures of rail connection will be presented. Using D-H method, the kinematics model of vehicle manipulator is established to solve the direct and inverse kinematic problem and trajectory planning is has also be performed after the kinematics characteristics analyses of the manipulator. In addition, we build the dynamic model of the manipulator by Lagrange’s equation for dynamic characteristics analyses which will be used for trajectory optimization through genetic algorithm. The minimum value of joint torque multiply velocity and operation time was select as the optimization objective to find a balance between operation time and maximum torque.Besides, to accomplish the aim of blanket maintenance, we propose a new hierarchical control strategy of rough and fine positioning technology based on combined sensors. Thus, the force sensing system of end-effector is designed. Impedance control of the manipulator is applied in the maintenance operation of blanket module to adjust the position and orientation of the end-effector for blanket grasp. The parameter of impedance control is discussed in detail in this paper to instruct how to choose a better parameter.Finally, the simulation prototype of the blanket maintenance system is developed based on the virtual robot experiment platform. The rail deployment and the manipulator operation planning are implement through simulation which demonstrated the feasibility of the scheme of blanket maintenance system and proposed reliable data to improve the system. Moreover, the control system is also designed to control the movements of the whole system and which was proved to be workable during experiment.