Timed fault-tolerant supervisory control
- International Robotics & Automation Journal
-
Aos Mulahuwaish,1
Amal Alsuwaidan,2
Ryan
J Leduc3
Abstract
In Mulahuwaish,1–4 we investigated the problem of fault tolerance in the framework of
untimed discrete-event systems (DES). This approach is different from the typical faulttolerant methodology as the approach does not rely on detecting faults and switching to a new
supervisor; it requires a supervisor to work correctly under normal and fault conditions. This
is a passive approach that relies upon inherent redundancy in the system being controlled.
In this paper we extend the work of Mulahuwaish1–4 to the timed DES (TDES) setting. We
introduce our setting, and then provide a set of timed fault tolerant definitions designed to
capture different types of fault scenarios and to ensure that our system remains controllable
in each scenario. As the nonblocking property is the same for timed and untimed DES,
the untimed fault-tolerant nonblocking properties and algorithms from Mulahuwaish1–4 can
also be used in the timed setting without any changes. We then present algorithms to verify
these properties followed by complexity analyses and correctness proofs of the algorithms.
An example is then provided to illustrate our approach.
Keywords
discrete-event systems, supervisory control, fault-tolerant
