Robust Motion Control For The Lateral Dynamics Of The Fully Submerged Hydrofoil Vessel

As an advanced marine surface vessel,the fully submerged hydrofoil vessel(FSHV)offers superior maneuvering performance on rough sea conditions.When the vessel cruises at a high speed,the lift force of the hydrofoils generated by the high-speed fluid can elevate the ship hull from the sea,which highly attenuates the wave resistance of the ship.In contrast to the conventional marine vessels,the whole mass of the FSHV is supported by the hydrofoils.Thus the hull cannot provide restoring forces and moments,and the static stability cannot be guaranteed.For the advanced lateral motion control of the FSHV,the robust disturbance rejection performance is a necessary index for both guidance system design and attitude stabilization.In this dissertation,a robust control scheme is proposed for the lateral motion control of the FSHV.Based on the analysis of the nonlinear dynamics of the lateral dynamics of the FSHV,a series of control strategies are investigated for the global stability of guidance and control objective of the FSHV.Firstly,the author makes a brief exposition of the research progress,the existing problems and the overall idea of the thesis.In view of the lateral attitude control of the FSHV,the hydrofoil configuration of the FSHV is analyzed.The overall structure and equipment of the motion control system are given for the motion properties of the FSHV.Based on the overall design structure,aiming at the problem of course keeping and path following control,a control system architecture of the joint control of yaw/roll dynamics and path following control scheme of the FSHV are proposed,respectively.Hydrodynamic analysis of hydrofoil system and strut system under hydrodynamic conditions is carried out.The disturbed lateral motion of the FSHV under the perturbation of regular waves and stochastic waves is analyzed.Secondly,to guarantee the robustness and disturbance rejection performance of the joint control system for the lateral attitude of the FSHV,a novel output feedback control methodology is proposed for the yaw /roll stabilization of the FSHV based on a sampled-data iterative learning approach.An iterative learning observer is established for the state estimation as well as generalized disturbances.Then a sliding model controller with an iterative learning sliding manifold is presented for the stabilization of the lateral dynamics of the FSHV.The design of the iterative sliding surface introduces a memory effect for the controller,which includes both the current and past information of the system states and outperforms the standard sliding mode control.With the intervention of the iterative item,performance of the transient states can be improved for both state observer and controller,which achieves better estimate accuracy and disturbance rejection performance.The system conservation also decreases compared with conventional approaches.Then,in order to analyze the different time scale properties between the yaw dynamics and roll dynamics and present the effects of the yaw/roll interaction on the controller design,a two-time scale output feedback control strategy is investigated based on singular perturbation theory.Starting with the problem of system state observation,the passive state observer is designed based on the nonlinear passive theory,and the states of the system are reconstructed by the output of the system with measurement noise so as to obtain all the states required for the control of the yaw and roll dynamics.Based on the singular perturbation theory,the time-scale features of the yaw dynamics and the roll dynamics is proposed,and a composite feedback control strategy is designed for the stabilization of the lateral dynamicsof the FSHV by using the combination of the slow-time control and the fast-time control.And then,based on the research of the robust yaw/roll stabilization of the FSHV,the straight-line path following control for the FSHV is studied.The guidance algorithm of the kinematic subsystem and the attitude tracking control of the kinetic subsystem are designed through a cascade control design.Based on the investigation of the conventional line-of-sight guidance law and the kinematic characteristics of the FSHV,a dual-channel guidance strategy is specifically designed for the FSHV with the consideration of the coordinated turn dynamics.Then the desired heading angle and bank angle obtained by the guidance system are designed.The command filtering backstepping control law based on the extended state observer is designed to track the desired heading angle and the bank angle.Simulation results show the effectiveness of the proposed dual-channel guidance algorithm and the robustness of the lateral attitude control system under model uncertaities and complex disturbances from the environment.Finally,in order to further improve the maneuverability of the FSHV,a curved path following control structure is investigated with adaptive sideslip angle compensation.By evaluating the path planning method,the strategy of generating curved path based on cubic spline interpolation is designed.Based on the model characteristics of the FSHV,a coordinated turn aided adaptive LOS guidance algorithm is introduced to calculate the command course angle as well as the bank angle.A novel adaptive estimator is designed to compensate for the sideslip angle caused by the drift force of the ocean currents based on immersion and invariance theory.To track the command attitude generated from the guidance system,a robust integral feedback control is proposed for autopilot design,which guarantees robust attitude tracking with continuous control output in the presence of composite disturbances.Uniform asymptotic stability of the hierarchical system is achieved via Lyapunov stability theory and cascade system theory.Comparative simulation results validate the effectiveness and robustness of the proposed guidance and control methodology.