Disturbance Observer-Based Finite-Time Speed Control for Marine Diesel Engine With Input Constraints

In this article, a finite-time observer-based speed control strategy for the marine diesel engine is proposed with consideration of system parameter uncertainties, external disturbances and input constraints. Initially, a finite-time disturbance observer is designed, by which the synchronized uncertainties are accurately estimated in the sense of finite-time stability. Based on the observed information, a speed control strategy is proposed, and practical finite-time stability of the closed-loop system is demonstrated by rigorous theoretical analysis. Besides, for solving the input constraints inherent with the speed control system, an auxiliary variable is introduced to compensate the extra part of control output signals. Finally, numerical simulation and comparison are presented. The common operation situations of the marine diesel engines are taken into account, including starting, acceleration and deceleration between speed set points, sudden load changing, varied propulsion system parameters and different slope limits, etc. Comparing with the related existing method, the effectiveness and advantages of the proposed finite-time observer-based control law are illustrated.