Stability checking of a real digital control system with a neuro-fuzzy PD-controller

Technical regulations in many countries require stability proof for control systems. Neuro-fuzzy (nf-) controllers realize strongly nonlinear input/output mappings. Therefore they make the stability checking very difficult what hampers their implementation in the practice. The paper presents a systematic method for stability proof basing on hyperstability theory of Popov applied for a digital control system of the underwater vehicle. Owing to considerable reduction of the analytical part of the proof the method is relatively easy, understandable and practical. It allows strict stability proof of fuzzy MIMO-control systems.