During ITER maintenance shutdowns, the maintenance crews work for several months in 24/6 shifts, inspecting and replacing worn and broken components, all to bring the experimental ITER reactor back into an operational state as soon as possible. The level of contamination (with toxic materials) and activation (yielding high dose rates gamma radiation) of Tokamak components imply that many of these maintenance activities have to be done by Remote Handling (RH), using master / slave manipulators, cranes and automated transport containers. The more delicate and precise maintenance operations will be done by dexterous haptic telemanipulation systems.
In order to reduce the maintenance interval, maintenance activities will be performed in parallel at several locations, such as at various levels on the inside of the Tokamak, in the Neutral Beam Hot Cell, in the Cask Transportation System and in various work stations in the ITER Hot Cell Facility. All Remote Handling operations are coordinated and controlled from the High level Control Room. Up to 12 workstations with up to 4 operators each are foreseen. Each workstation is typically equipped with one or two master arms to directly control dexterous slave manipulators. In order to preserve flexibility in allocating master control stations to specific slave robots, middleware makes it possible to establish flexible real-time connections between different master and slave devices.
Figure 1 RH workstation with 4 operators in simulated ITER RH control room (left), dexterous slave robot and crane cooperating in the ITER Hot Cell facility (right).
The Remote Handling Study Center, located at FOM institute DIFFER, Nieuwegein, The Netherlands, has a work cell in an ITER relevant Remote Handling room setup which connects to a virtual hot cell back-end.
With ITS, the Interactive Task Simulator, remote maintenance studies are done. ITS simulates a mechanical slave arm and its environment in soft real-time. It uses the nVidia PhysX SDK to simulate the physical interactions. ITS is programmed to interface with master devices and a virtual reality system called VR4Max (soon Unity is also supported). The software allows users to interactively control the simulation using real master devices, including the force feedback from the simulated environment.
Master and slave are coupled through a so-called control loop. One of the master arms is the Haption Virtuose 6D. Its control takes place in the computer shipped with the device. This is to be shifted to be integrated in ITS. Important properties to take into account are
Work consists of