A design strategy for obtaining reliable controllers for critical mechanical systems

The development of reliable controllers can be a complex task, mainly because there is no well-established systematic methodology developed specifically for this purpose, considering all range, from requirements analysis till code implementation in real controller and considering real-time implementation issues. This paper introduces a design strategy as a proposal for obtaining reliable controllers for critical mechanical systems, which is based on the integrated application of four analysis techniques usually used in dependable systems development: modeling, simulation, formal verification and conformance testing. The paper demonstrates, by means of a case study, that the adequate integrated implementation of such techniques results in a systematic concurrent approach for the development of reliable automatic control systems. The case study consists of a detailed application of the proposed approach in the synthesis of the automatic train control (ATC) system of an automated people mover (APM) operating in accordance within the concept of communication-based systems (CBTC - Communication-Based Train Control). This case study is used to illustrate the method, presenting and discussing the steps necessary to implement the proposed design strategy in the development of a typical piece of control software for critical mechanical systems.