Implementation of an OROCOS based Real-Time Equipment Controller for Remote Maintenance of Tokamaks

A tokamak is a torus shaped device used to confine high temperature plasmas with the help of powerful superimposed magnetic fields. With high temperature, vacuum and radiation levels, the environment inside the tokamak is hostile to human beings. All the repair and maintenance tasks are handled by specialized Remote Handling (RH) equipment consisting of robotic manipulators, special tooling and deployment systems which are controlled by skilled RH operators. These RH equipment are integrated using a supervisory control architecture in which the control system is distributed into operator level and machine level control systems. The OROCOS real-time toolkit, available open source, is used to implement the equipment controller that encompasses the machine-level control system software and hardware for operating multi-joint programmable RH equipment devices. It provides a standard interface and insulates the operator level control system from details of low-level hardware. The communication between operator and machine level systems is achieved at 100Hz through a standard middleware. This paper presents the detailed implementation of the equipment controller with the operator level & machine level interfaces and its successful implementation for controlling the articulated RH equipment having 25 Kg payload with a toroidal reach of ~2m and a 6 DOF industrial robot. The master control is achieved using a commercial haptic device. A novel concept of virtual move is also implemented for carrying out offline simulations. The performance tests show low latency and smooth control over the RH equipment.