Wide-speed-range maneuvering aggravates the nonlinearity in the dynamics of unmanned surface vehicles (USVs), making single-model-based controllers difficult to guarantee performance. This paper presents an efficient multi-model predictive path-following control strategy. The wide-speed-range nonlinear dynamics of the USV are modeled as a speed-scheduled piecewise affine system. Using time-scale separation, the speed-heading model is decoupled, with model errors and disturbances treated as lumped disturbances. We develop an improved adaptive heading guidance strategy to generate the desired heading, embedding speed into adaptive laws to boost USV dynamic adaptability across wide speed ranges. A combined feedforward-feedback heading controller is proposed, using a finite-time lumped-disturbance observer for feedforward compensation. The feedback employs an efficient MPC with offline gain design and online gain scheduling, partitioning the heading state space precisely via quadrilateral invariant sets, which yields lower conservatism than traditional ellipsoidal sets. Simulations show superior performance, with heading control efficiency improved by over 96%.
In this study, the dual-fuel combustion in ferry engine fueled by alternative fuels has been investigated. The numerical simulations of ferry powertrain were made by means of AVL Boost simulation model. The original diesel engine model was calibrated with the reference engine manufacturer data. Conventional dual-fuel combustion (methanol-diesel and hydrogen-diesel) was simulated using different energy substitution ratios of diesel fuel at several operating points typical for the assumed propeller curve. For the selected ferry route, the calculation of CO2 and NOx emissions was performed resulting with the maximum substitution ratios for both fuels. The application of green methanol resulted in CO2 and NOx emissions decrease by 78% and 93%, respectively. In the case of hydrogen-diesel, excessive NOx formation was observed at energy substitution ratios above 50%, while CO2 emission can be reduced by 44.5% compared to the conventional diesel engine.
