A RATIONAL APPROACH TO REMOTE HANDLING EQUIPMENT CONTROL SYSTEM DESIGN

摘要

The approach to the design of remote handling control systems for JET (Joint European Torus) has undergone a metamorphosis in recent years. The original concept of specifying functional requirements and tendering external companies without specifying the hardware and software that was permitted, resulted in a myriad of solutions which, although functionally correct, presented JET with a number of unforeseen problems: In-house engineers had to become familiar with a wide variety of hardware and software. Operators were presented with many different computer interfaces, which had a different look-and-feel, with the robots sometimes behaving in a contradictory manner (e.g. positive rotation being clockwise on one robotic transporter and anti-clockwise on another). Developments and fixes to the control systems usually needed long lead times and were sometimes impossible or prohibitively expensive. A large selection of hardware spares was needed to provide cover for all the systems. Support for obsolete hardware and software was increasingly difficult. The breakthrough came from the recognition that, although the remote handling equipment was specifically for and unique to JET, at a low level, the controls required were similar to industrial applications. Thus, widely available commercial products could be configured to handle the highly critical motion control, and implemented in a quite uniform control system framework. The high level control software, oriented about the objects and tasks involved, was developed in-house. At this level, the robotic systems have much in common, and a lot of the software modules could be shared or re-used.