Modular Supervisory Control for the Coordination of a Manufacturing Cell with Observable Faults

Area of Science:

• Manufacturing Systems Engineering
• Control Theory
• Automata Theory

Background:

• Manufacturing cells are susceptible to faults originating from process devices.
• Ensuring operational functionality and safety in fault-prone systems is a significant challenge.
• Existing control schemes may not adequately address fault tolerance at various levels.

Purpose of the Study:

• To develop a modular supervisory control scheme for manufacturing cells with device faults.
• To formulate desired functionality and safety specifications using formal languages.
• To achieve fault tolerance for process coordination despite low-level device faults.

Main Methods:

• Modular modeling of subsystems using finite deterministic automata.
• Formulation of desired functionality and safety specifications as eleven languages.
• Expression of languages as regular expressions and realization in supervisor forms.
• Computation of the complexity of the developed supervisor scheme.

Main Results:

• A modular supervisory design scheme was successfully accomplished.
• The scheme provides satisfactory performance in the presence of faults.
• Safety requirements are guaranteed through the designed supervisor.
• The control scheme demonstrates tolerance to upper-level faults despite low-level device faults.

Conclusions:

• The proposed modular supervisory control scheme effectively manages faults in manufacturing cells.
• The use of finite deterministic automata and formal languages ensures both performance and safety.
• This approach offers a robust solution for fault-tolerant manufacturing systems.