Research On Active Close-loop Cooling System For ITER Inspection Robot Arm Under Hazardous Environment

In International Thermonuclear Experiment Reactor(ITER), its controlled fusion nuclear reaction process will cause damage to its blank, which leads to our research topic-- automatic examination by in-vessel inspection robot arm. To tackle the 120 ℃ heated environment, we proposed this close-loop active water cooling comprehensive system solution as following.In this paper, ITER task requirement has been concluded as an in-vessel inspection robot arm with circumferential 360°reachable span and capability to execute D-shape high-resolution inspection at any section area. Then robot arm was design into four parts: binocular camera end-effector, rotary minor arm, retractable major arm and mobile base. Over this structure, cooling system was finalized as copper coil attached to arm case to absorb heat, and then carried away by water coolant out of the vacuum room.Close-loop water circulation employs a diaphragm pump as power source and a thermostatic tank as cold source to release the heat transferred out. In order to adapt our cooling system into robot arm compact layout, redesigned cooling control system improves its temperature sensor to avoid complex wiring. As for software interface, we take full consideration of hierarchy priority with regards to upper main control software by applying interface to a pop-up dialog box which displays itself only at emergency. The interface integrated function modules such as real-time data display, history data curve plotting, power management and alarm processing.Eventually inside an air-convention heated oven we carried out prolonged simulation experiment in three stages to test cooling system hardware structure and software architecture in terms of its effectiveness, efficiency and stability:- Stage One, experiment of binocular joint single cooling circuit toverify the rationality and feasibility of brass coil and water coolantcooling system.- Stage two begins after having finished manufacturing of minor armand end-effector, experiment has been conducted to test the wholecooling circuit connected in series, and to observe the coolingeffectiveness- Stage three,considering the heat generated by protecting electroniccomponents, we detected parts’ final temperatures using ourcooling system under hot environment by contrast with its normaloperating status.