Design and implementation of a triple-redundant dynamic positioning control system for deepwater drilling rigs

•Triple-redundant DP control architecture is proposed from a practical point of view.•The architecture together with a back-up system compliant to IMO Class 3 notation.•Hierarchical software is implemented with three layers.•Hardware-in-the-loop and model testing are carried out to verify the control scheme.

Triple-redundant control architecture of the main control station is proposed for dynamic positioning (DP) system from a practical point of view according to the International Maritime Organization's (IMO) DP Class 3 notation. To improve the single fault tolerance, both operator station systems and real-time control computer systems are designed with triple modular redundancy. Hierarchical software layers of the triple-redundant control architecture are implemented based on the different real-time response requirements of the layers. Input and output voting are incorporated to the positioning task to detect and isolate faults in the sensors and in the control system. Hard-in-the-loop (HIL) testing system together with model-scale tests are conducted to verify the proposed triple-redundant control architecture. The feasibility and fault-tolerant capability of the triple-redundant hardware and software architecture both in HIL and model tests are demonstrated.